The World Will Not End Tomorrow

The world will not end tomorrow.

The Sun will rise on the morning of December 22 and find most of humanity still living. I can say that with a great deal of confidence, though my scientist’s brain tells me I should say the world “probably” won’t end tomorrow. After all, there’s a tiny chance, a minuscule probability…but it’s so small we don’t have to worry about it, just like we don’t have to worry about being struck down by a meteorite while walking down the street. It could happen, but it almost certainly won’t.

My confidence comes from science. I know it sounds hokey, but it’s true. There’s no scientific reason—absolutely none—to think the world will end tomorrow. Yes, the world will end one day, and Earth has experienced some serious cataclysms in the past that wiped out a significant amount of life, but none of those things are going to happen tomorrow. (I’ll come back to those points in a bit.) We’re very good at science, after centuries of work, and the kinds of violent events that could seriously threaten us won’t take us by surprise.

Why the World Won’t End

So where does this stuff come from? Whose idea was it that “the end of the world will be on December 21, 2012”? The culprit, according to those who buy into the idea, is that the end of the world was predicted by the Mayas in their mythology, and codified in their calendar. However, it’s pretty safe to say that the Mayas didn’t really predict the end of the world, even though I don’t know much about the great Mayan civilization that existed on the Yucatan peninsula in what is now Mexico from antiquity until the Spanish conquest.

See this calendar? It’s being touted as a Mayan
calendar in articles about the “end of the world”,
but it ain’t Mayan. It’s an Aztec calendar. Please
don’t mix up civilizations.

The Mayas were the only people in the Americas known to have developed a complete written language, which is part of how we know a lot about them despite their destruction by the hand of European invaders. In particular, we know about their calendar, and the divisions they used. We use what’s called a decimal system for numbers, based on the 10 fingers of our hands. That’s why we break things up into decades (ten years) and centuries (ten decades), as well as a millennium (ten centuries). The Mayas liked different divisions of time: their b’ak’tun is approximately 394 years, and they placed a certain significance on a cycle of 13 b’ak’tuns. (I suspect the Klingon language in Star Trek borrowed some of its vocabulary from ancient Mayan.)

In the “Long Count,” one version of the Mayan calendar known to us, the present world came to be on August 11, 3114 BC. That world will end at the close of the 13th b’ak’tun from that creation day, which happens to be December 21, 2012. However, there’s good reason to think that the Mayas didn’t believe this would be the end of all things: other calendars exist that refer to an even longer span of years, stretching thousands of years into the future!

Even more importantly, though: the Mayan cosmology (their view of the universe) was cyclic, as in many other religions. This world was not the first in this cosmology, and it won’t be the last. In such a view, the true universe is eternal, and the cycles of time are a kind of divine rebooting, which don’t really end anything. The end of the 13th b’ak’tun might be a transformative event in the Maya cosmology, but it’s not the end of the world.

Frankly, I’m not sure why we should care even if the Mayas did believe this was the end of the world. As I said previously, there’s no scientific reason to think the world will end tomorrow. But maybe you might think there’s a non-scientific reason—divine intervention to wipe out the Earth, perhaps. However, I’d venture to guess that most of us don’t adhere to the Mayan religion. Their gods are not the gods most people worship. The prophesied arrival on Earth of Bolon Yookte’ K’Uh, the Nine-Footed God is not something central to my belief system, and probably not yours either.

In fact, millennial thinking is far more a Christian thing than it is a Mayan thing—or frankly most other religions. When people talk about the supposed end of the world tomorrow, they use the Christian terminology: Armageddon (referring to Megiddo, a place in northern Israel, named in the Book of Revelation as the site of the last battle) or the apocalypse (literally the “uncovering”, when all that was hidden becomes revealed). These weren’t concepts in the Mayan religion, and nothing in the Christian religion says the world will end on December 21, 2012.

The World Will End…Eventually

Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
–Robert Frost

Science tells us the world won’t end tomorrow. It also tells us the Mayan cosmology is wrong: time doesn’t go in cycles forever. Earth began 4.5 billion years ago, and will end in about 5 billion years more—at least as a livable world, which is what counts for us. In between its beginning and end, it is defined by cycles: the length of rotation (days) and the time to travel around the Sun (years), with its associated seasons. Other cycles are pretty arbitrary: centuries and b’ak’tuns don’t have any particular significance in terms of astronomical events.

The end of the world as we know it will happen in about 5 billion years, when the Sun ceases fusing hydrogen into helium in its core. When that happens, the Sun will grow into a red giant star, swallowing up Mercury and Venus. Earth probably won’t be devoured, but with the Sun’s surface so much closer, things will become distinctly unpleasant. It’s unlikely the atmosphere or oceans could survive, meaning the end of most life. (Some microbes could probably continue to live underground. That kind of thing is a story for another day.) However, 5 billion years is a long time from now.
Could another cataclysm overtake us before that time? Yes. As you may know, about 65 million years ago, a large asteroid smashed into Earth, an event that at least helped end the reign of dinosaurs, and ushering the extinction of many other species.

Unfortunately, we can’t rule out the possibility that could happen again. There are enough asteroids and comets in our Solar System that could eventually cross orbital paths with Earth; if a large specimen collided with us, it would be devastating.

However, we’re talking about tomorrow. No asteroid will strike Earth on December 21: astronomers keep careful track of everything near our planet, and nothing we know of is on a collision course with Earth for the near future. Asteroids and comets are really the only things we have to worry about doing serious damage for life on Earth, but you can sleep easy tonight and tomorrow night: we’re safe.

If you could somehow see the planets during
daylight hours, here’s how they would
appear tomorrow at noon. There’s no
alignment. (You can see this for yourself
using the free planetarium program
Stellarium.)

Some people have talked about fairly far-fetched ideas: alignments of planets, or lining up Earth, the Sun, and the center of the galaxy. The planets of the Solar System aren’t aligned tomorrow—the image shows where several of them are in relation to the Sun at noon. Jupiter isn’t anywhere close to the planets you see. You’d need a pretty strong imagination to say they’re lined up in any way: while they do lie along a line, that’s the way they always are, since they all orbit the Sun more or less in the same plane. Alignment with the galactic center is even more simple to dismiss: about once a year, the Sun appears aligned with the galactic center in the sky. And nothing happens.

Another explanation I’ve seen involves a mysterious planet called “Nibiru” or “Planet X,” which either will collide with Earth or otherwise generate a baleful influence. Phil Plait, the Bad Astronomer, has a lot about the Nibiru nonsense, so I won’t repeat what he says. Suffice to say Nibiru doesn’t exist: there’s no evidence for it, and (surprise!) it’s not anything that came from Mayan mythology to begin with, so there’s no reason to associate it with a December 21 apocalypse.

A Positive Conclusion

Science, I think, is reassuring in the midst of panic. Why people like to scare themselves and others with misguided ideas of the world’s end, I am not qualified to say. I don’t know how many people are convinced the world will end tomorrow, compared with the number of people who are either wholly skeptical or those who might be a little worried. However, let me reassure you again: the world will not end tomorrow. We can take comfort in the knowledge that December 22 will come, 2012 will end, and a new year—a new cycle—will begin. Any remaking of the world is up to us, so rather than worrying about imaginary apocalypses, let’s commit to improving the lives of those who live on our magnificent planet.

Double Xpression: Debbie Berebichez, PhD Physicist

Deborah is the first Mexican woman to graduate with a physics PhD from Stanford University. She is a physicist, author, and media personality whose initiatives to popularize science have impacted thousands of people around the world. Her passion is to popularize science and motivate young minds to think analytically about the world. This has led her to pioneer learning initiatives in schools and universities in Mexico, Africa, the US and Israel. She is a frequent public speaker and has been recognized by numerous media outlets such as Oprah, CNN, WSJ, TED, DLD, WIRED, Martha Stewart, City of Ideas, Dr. Oz Show, Celebrity Scientist and others. She regularly appears as a science expert on different international TV networks; currently she is the TV host of National Geographic’s “Humanly Impossible” show. And she will appear on the Discovery Channel’s upcoming show ‘You’ve Been Warned.’  You can find Deborah on Twitter, or on her blog, Science With Debbie.  You can also find Deborah telling her story for The Story Collider.



DXS: First, can you give me a quick overview of what your scientific background is and your current connection to science?

I grew up in Mexico City in a fairly conservative community, and as a child, I was discouraged from doing and studying science.  My parents, family, and peers would all ask, “oh, why don’t you study a more feminine career?” Although I was pretty good in school, I wasn’t exactly a math wizard.  I used to say that I loved philosophy and physics – because philosophy was a deep discipline of asking questions about the world.  And physics studied the world itself.   
It was clear when I was born that my personality was was quite different to the one of my mom.  When I was growing up, my mom was scared because she didn’t know what to do with this little girl that was smart and always asking questions.  She is not a naturally curious person, so she kept trying to tame down my curiosity and kept telling me not to tell boys that I was interested in math and science because I would never find a husband.  According to her, the life goal for a girl was to find a husband, have kids, and that’s it.  Women didn’t have to have a career.  (Not that there is anything wrong with not having a career.)  My high school teachers and counselors were not so different and encouraged me to go into philosophy or literature, not into math or physics.  And my friends in school told me I literally had to be an out of the world genius to be able to study physics.      
Given the circumstances, I started studying philosophy in Mexico.  There were some classes with logic, and some with a little bit more math, and those were the ones I just devoured!  And, at the same time – secretly – I was reading the biographies of scientists.  For some bizarre reason, I was hugely attracted to their life stories.  I didn’t have any family members, or anyone else for that matter, that had pursued a career in science, so I didn’t have a mentor or a role model.  I felt an extreme kinship with Tycho Brahe, who in the late 1500’s was locked in a tower, doing all of these calculations for years, hated by everyone in the town.  Go figure! I felt some kinship with these scientists.   But I didn’t have the courage nor the means to switch majors.  I did confess that I wanted to study another area (physics), but in Mexico one cannot study two majors. So, I studied philosophy for two years.

In the middle of it, I felt way too curious about science and I decided to apply to schools in the US.  It was hard at the time because college in Mexico was a lot cheaper than in the states.  At the private school where I was attending, my tuition was about $5,000 per year.  If I were to come to the US, I would be looking at costs exceeding $35,000 per year. I couldn’t really ask my dad to help me with that price tag so I started to apply everywhere and anywhere that had scholarship opportunities.

I ended up getting a letter from Brandeis 

University saying that they would let me take this advanced placement test and write an essay, which, if I did well, would give me a full scholarship.  I received a full Wien Scholarship and was to continue studying philosophy in the US.  This was probably the nicest thing that has ever happened to me because it opened the path of opportunity.

Brandeis transformed me as a person – I saw females doing science!  But, the bravado moment that changed my life was a very general course called Astronomy 101.  The teaching assistant, Roopesh, was a very sweet man from India and he saw that my eyes would just light up when I was in that class – I was much more curious than the random student that was just taking it to fulfill some requirement.   
At the end of that year, Roopesh and I 

were walking around Harvard Square and stopped to sit under a tree.  I started to tell him, with tears in my eyes, that I just don’t want to die without trying.  What I meant by that is I don’t want to die without trying to do physics.  Everyone’s questioning of my decision made me question my actual ability.  Everyone telling me ‘no’ hampered my development.  I mean, I was good at math, but I definitely didn’t have the same background as all the kids coming in with advanced math and physics courses. 
 

I told Roopesh that I don’t even remember how to solve the equation (a+b)2 – even my algebra was rusty!  But, he believed in me and went back to his professor and told him my story.  This professor decided to meet with me and ends up telling me about someone who had done this sort of thing in the past.  His name was Ed Witten and he went on to become the father of string theory.  

He said “Witten had switched from history to physics, and I will let you try too.”  With that, he handed me a book on vector calculus called ‘Div, Grad and Curl’ and told me that If I could master it in three months by the end of the summer, they would let me switch my major to physics and also let me bypass the first two years of course work.  This would allow me to graduate by the time my scholarship ran out.        
I have never in my life experienced the level of scientific passion condensed into such a short amount of time and I am jealous of the person I was that summer.  I had so much perseverance and focus.  I don’t think I can ever reproduce that intensity again.  From the moment I woke up to the moment I went to sleep, and even in my dreams, I only thought about physics. Roopesh, who became my mentor for the summer, taught me.  

I always wanted to pay Roopesh for his tutoring, but he would never accept any money.  He told me that when he was growing up in the mountains of Darjeeling in India, there was this old man who would climb up to his home and teach him and his sisters English, the musical instrument Tabla, and math.  Roopesh’s father always wanted to pay the old man for his tutoring, but the man always declined.  The man said that the only way he could ever pay him back was if Roopesh did the same thing with someone else in the world.  And by mentoring me, Roopesh fulfilled his payment to the old man.  
Out of that, that became a seed for my physics journey and purpose.  It is now my life’s mission to do the same for other people in the world – especially women – who feel attracted to science but feel trapped.  They for some reason, whether it is social, financial, etc., just can’t find the way toward science.  That is the motivation that dictates my actions.
I was able to pull it off and graduated Brandeis Summa Cum Laude with highest honors in physics and philosophy. I went back to Mexico afterwards to figure out what to do next and to spend some time with my family. At the same time, I did a master’s degree in physics at the largest university in Mexico UNAM.  My curiosity for physics didn’t diminish and in 1998, I randomly applied to two physics PhD programs in the US.  I applied very, very late, but, fortunately, I won a merit-based full scholarship from the Mexican government who provided me with funding, which made it easier for me.    


Because I loved biophysics, I did a search on who was doing this line of research.  I came across Steven Chu, who is currently the secretary of energy.  At the time I was applying, he was at Stanford and was one of the first to manipulate a single strand of DNA with his ‘optical tweezers.’  To me, his story was fascinating!  Without really knowing who he was other than what I found on the web, I wrote him an email asking him if I could work in his lab.  Had I known who he was – that he had just won the Nobel prize in 1997 – I would have been too intimidated.  


I was admitted to Stanford and was invited to work with Dr. Chu, but after two years I decided to switch labs.  As expected, it was a very challenging environment and having only studied two years of physics at Brandeis, I wasn’t as prepared as most of the other students.  I struggled for the first two years.  Everyone worked so extremely hard at Stanford and there I was, struggling to be the best, but, in the beginning, I couldn’t even be average.

Fast forward four years.  I had worked my butt off and ended up becoming the first Mexican woman to graduate with a PhD in physics from Stanford.  It was the best day of my life – I kept thinking that I was so blessed to have my parents live to see this!  It was so moving, I was crying so much and I couldn’t believe what had happened.  My friends had flown in from all over the world to be with me.  It was amazing. 

When people hear what I do, they – especially teenage girls – feel intimidated.  But, when they hear the whole story, their tune changes.  I tell them that I know what it is like to not understand something.  I was not the kind of person where comprehension of my science came naturally.  But I did it.  And if I can do it, anyone can do it!  My story can be inspirational to someone who comes from a background completely lacking in science because they, like me, can reach their goal. 
DXS: What ways do you express yourself creatively that may not have a single thing to do with science?

I was always a very curious girl growing up. I had a lot of interests, one of which being theatre.  I wanted to be an actress when I was young, but my father didn’t let me pursue that as a career, which was probably a good idea.  But, during high school, I went to an after school drama program.  I wrote my own plays – three of them – and performed one of them.  I was in heaven when I was on stage. 

In NY, I have tried to do a little bit of that.  Of course, I’ve never done any big roles, but I will be an extra in a film, or if there is a small production being made in Spanish, I will play a part.  It doesn’t matter how big the role is – I just love doing something creative and getting into a character. 

DXS: What types of productions and/or films have you done?

I don’t think I would come up in the credits as an extra, but I did a movie with Simon Pegg, Kirsten Dunst and Megan Fox in the movie “How to lose Friends and Alienate People.” It was a very, very fun film!  In theatre, Jean Genet, who is a French playwright, has a play called The Maids, and I was the madame.   

DXS: Do you find that your scientific background informs your creativity, even though what you do may not specifically be scientific?

Debbie talking to the TEDYouth audience about waves.

I have a concept that I call “physics glasses.”  And what I mean by that is, for me, physics is not a subject that you just teach in a complex way in a classroom.  Rather, physics is something that is related to everyday life.  From the moment you wake up, you can just put on your physics glasses.  It is a mode of thinking – it is a way where although reality can be very rich and diverse, physics goes very deep and it abstracts commonalities, general principles that apply to many things.  To give you an example, I asked the kids in the audience of my TEDYouth talk, “what do the sun, the ocean, and a symphony orchestra have in common?”  When just looking at them on the surface, there isn’t much in common.  I mean, they are all beautiful things but they are not obviously related.  But, to a physicist, they are all waves.   You have sound waves, light waves, and water waves and you can interchange many of the concepts in physics to explain all three.



Where most of us see the world with our eyes through light waves, other might see the world differently.  Take, for example, my friend Juan, who is blind.  He “sees” the world with sound waves – he senses sound as it bounces off the objects around him.  Through this, he can bike, play basketball, and do a load of activities using sound as a guide.  This is one of my favorite analogies because, really, physics “infects” the way I see the world. 

Deborah the Physicist model

To give you a more specific example in the creativity realm, when I got to NY, I felt really un-feminine.  When I was studying physics, I felt that if I was even slightly feminine, I wouldn’t be respected.  It didn’t help that some of the other women in the physics program at Stanford were more of a “guys girl,” always wearing a baseball cap and t-shirts.  Now, since I am Latin, I first showed up wearing a skirt to class, but I quickly learned to dress down.  Looking feminine would assure that no one would talk to me in class.



So, when I got to NY, I had an explosion.  I wanted to know what it was like to express myself as a woman and my friend suggested that I do some modeling.  So I did.  It was a brief, lasting about a year.  But during that time, my friend, who was a designer from Mexico, asked me to work with her and I wrote and did some videos about the physics of fashion, which also included the physics of high heels video.  


Some people could consider fashion to be superficial, but not me.  I love fashion and color.  But, other scientists generally looked down upon you for liking this sort of thing.   This fueled my desire to prove to everyone that there actually is science everywhere, including fashion, and that they shouldn’t be snobs about it.  There is complex science in how different materials work, how they interact with the environment and you can prove to the women, like my mother and friends back home who think that science has nothing to do with their everyday lives, that it has EVERYTHING to do with it.   So I talked about a Newtonian theory for color – how to pick the right color for you based on how much light the color would reflect on that day, etc.  

DXS: Like a more sophisticated version of colors based on your “season?”

DB: Exactly! 

I also did pieces on the materials, including some of the newest engineering accomplishments with fabric.  For example, I hooked up with a woman and helped her to design a fashionable and very scientific coat.  It ended up costing $11,000, but it was made up of nano fibers and it had a patch in it that could detect the temperature and the probability of rain.  Based on this probability, it could change permeability of the fabric.  It was a very light coat that was comfortable in nice weather, but when it would rain, it would become impermeable to water once it detected a high probability of rain, transforming into a raincoat.

DXS: That’s incredible!  I wish it wasn’t $11,000!

DB:  Yeah, that’s usually the problems with these technologies.  They are often so novel, but one day I’m sure we can figure out how to make things like this scalable.

Science is very much what guides my thinking when I am being creative and I wish I had more time to do creative things while being influenced by a scientific mindset.

DXS: It is so cool that physics has such an incredible overlap with everyday living.  Like, when we take a shower, I want to know “how is the water getting pumped from the ground or through pipes and make its way out of the showerhead?”  But, as a biochemist, I often find it hard to relate everyday things to biochemistry, but I would like to!

DB: Its funny that you say that.  When I try to teach girls that the worst thing they can do is memorize.  Critical thinking is so important and they shouldn’t take anything at face value, and they should even question teachers and authoritative figures in their lives.  Always ask: what goes into making this?  Why is this here?  Why is it this way and not another?  Constantly ask questions.  That s the gift that physics will give you. 

DXS: Have you encountered situations in which your expression of yourself outside the bounds of science has led to people viewing you differently–either more positively or more negatively?

Without saying I am a scientist, I can tell you that people have come up to me and told me that before they even hear me speak, they think I am dumb.  They are usually surprised that I am smart!  I think it is because I am bubbly and friendly and that often makes an impression as being unintelligent.  For them it seems that if a woman is intelligent, she is very cold and distant and serious.  


I’ve met a lot of physicists, and yes, some of them do tend to be that way, often as a reaction to how others treat them.  Or, people would say to me that, because I am Latin, my cultural identity comes across as being warm and the last thing they’d expect me to be into was something as cold as physics.  So yeah, I have definitely been judged so many times!  


It even happens in my current job on Wall Street, especially with my male peers.  When there are off site client meetings, I’m often accompanied by my male sales colleague.  Sales people are generally required to know less about the complexities behind our risk models compared to someone on a more research-oriented role, like me and he will bring me along to these sales meetings in case the potential client has more sophisticated questions that go beyond what he can comfortably answer.  Many times upon meeting the clients for the first time they think that I am the sales person, there to be the smiling face to sell them something, and that he is the risk modeler.  They always direct their mathematical questions to him. 
It came to a point where I became so annoyed that I decided to stop caring.  Now, my sales colleague goes out for drinks with the clients and I know that I am going to be invisible. So I don’t go anymore. I know that I am always going to struggle to get the full intellectual respect in that industry – it will always be a challenge.

DXS: Have you found that your non-science expression of creativity/activity/etc. has in any way informed your understanding of science or how you may talk about it or present it to others?

Yes, absolutely.  For example in Mexico, unlike the US, you absolutely have to do an honors thesis project as an undergrad in science.  Because I had already studied philosophy for four years, I wanted to do a thesis project in philosophy.  But I also wanted to do one in physics.  I recall that back in 1997, when you presented a dissertation in front of the physics community, if you had any power point, forget it.  You would be immediately be called dumb or not a good physicist.  Because, who takes the time to do something fancy!  If you had any color in your presentation, forget it!  


So, literally, the smartest students in physics were people who didn’t really communicate that well, or didn’t really speak English that well, or just didn’t really make an effort.  Their slides were on those overhead projector things with those rolls of plastic sheets, and most of their talks were so confusing and couldn’t be interpreted!  But they were respected!  It was just assumed that if the formula looked complex, they were probably right. 
So what I did was completely different.  I infused my talk with my spiciness and color.  I did an artwork of liquid crystals, which was my research at Brandeis.  Liquid crystals are little cigar-shaped molecules that actually make up the screen of your laptop.  If you pass an electric field through them, they all orient themselves and that is how we can use them for displays in our laptops and TVs. 

I colored these cigar-shaped molecules with purples and reds and greens, and I tried to explain it at the most basic level. This is because of one my philosophy professors in Mexico, who told me that if you cannot explain what you do to your grandmother or 6 year old niece, you don’t understand what you are doing – I loved it!  


And I said to myself that I shouldn’t care what they think.  I pretty much expected to not gain a lot of respect from the physics department, but it had the opposite effect!  I actually had one of the professors from that department come up to me and tell me that he had never really understood what a liquid crystal looked like or what it really was!  He said that “finally I understand [liquid crystals] because of your drawing.  Thank you!”  It was incredible!  


To see the effect on people and from then on, I bounced up in down, I made jokes, I put in creativity.  It doesn’t always have a great effect on very serious audiences, but the younger generation is definitely appreciative.  When it keeps going well, you gain confidence.  And, for me, I even started wearing high heels to the next talk.  When someone commented about my attire, I would counter, hey I have a PhD!

DXS: How comfortable are you expressing your femininity and in what ways? How does this expression influence people’s perception of you in, say, a scientifically oriented context?

This question is deep and a little bit of a struggle at the moment.  This is because I still have that fear – when I arrived in NY, I did that short stint in modeling and I expressed myself and I would dress very creatively – just like my other girlfriends who were not scientists.  But I did feel a little bit of a backlash.  By that I mean that I would post a photo of myself on Facebook or something like that.  They were pretty pictures, not at all seductive or provocative, and my high school mates, usually male, would write me saying: “I always knew you as a serious person and you have achieved so many things – I am just telling you for your own good that this can really damage your image.”  That made me reply with “so you’re telling me that being smart is actually kind of a bummer?”  That actually means that I have to dress very differently from what other women wear for the rest of my life? 

I remember feeling very upset about all of that.  I think that not being taken seriously is still a little bit of a fear of and I think my website has damaged my serious image a little bit.  As a scientist, I was very secluded from the outside world.  I didn’t have a lot of friends when I moved here, but I did know an amazing and powerful woman who happened to be the CEO of Blip TV.  She was insisting that I do videos!  So she invited me to her place and showed me how to do video.  Being the quick woman that she was, she asked me to make up a name for myself on the spot.  When I didn’t answer, she instantly coined “The Science Babe” for me.  I was like, sure, what a cool idea! 

It was kind of a cute name, but because English is not my first language, I don’t always understand some of the cultural connotations associated with some English words.  A few months later, I started to get a few emails from mothers who were upset that I was using my looks.  They would say things like “Are you saying that women have to be in the kitchen or wear short skirts  to be scientists?”  I would answer that no, that was not it at all.  I would further explain that I was trying to change the definition of “babe.”  If you are smart, if you are empowered, you will be a babe no matter how you look.  I am trying to shift what people think of when they think “scientist.”

I don’t feel quite successful with The Science Babe.  It seems like there are quite a few people, especially some from the older generation, who say that they’d love to introduce me to fancy science organizations but are worried that the name “the science babe” will make it difficult.  Also, I had the BBC wanted to talk to me about doing a TV show in NY, and then they said but there’s so much bad stuff out there about you!  And I was like, what do you mean?  They answered “All these things with the “science babe” brand…”

It doesn’t happen all the time, but some people are really critical about the science babe theme, citing that its way too feminine.  Other female scientists that haven’t gone that route have perhaps discounted my seriousness about science.  They assume that what I am doing is not really that important because I do focus on the science everyday life, which is simpler, and it is too much color and too much vivaciousness for our field.  I feel like my femininity has decreased over the last few years because I’ve been too nervous about not being taken seriously.  It s almost like the balance tipped the other way. I feel like perhaps I’ve feminized things to a fault and now I want to appear more serious.  So, I am changing my website to “Science With Debbie” because I really felt the backlash.

It is a struggle to find the balance between being able to express my femininity and presenting myself in a way that people will take me seriously.  In a way, I wish I had a little more courage to not care that much about what people have to say about the science babe but, unfortunately, agents have told me that if I don’t go to the “dumbed down version of femininity” I would get better speaking engagements.  Being feminine has literally affected my career, and it’s because of other people’s perceptions.  I’m never going to be bland, but I will try to change things so I am more serious

DXS: Do you think that the combination of your non-science creativity and scientific-related activity shifts people’s perspectives or ideas about what a scientist or science communicator is? If you’re aware of such an influence, in what way, if any, do you use it to (for example) reach a different corner of your audience or present science in a different sort of way?

The fact that I am approachable and pretty down to earth has allowed me to reach corners of society that more distant and fancy scientists would never even consider. For instance, I am going to a small university to give a talk.  Some of my friends ask why I even bother, especially considering that this insitution is not the most renowned university.  But, I feel the opposite – it is these corners that need the influence the most!  Similarly, when I go to Hispanic high schools, many of the mothers have never seen a scientist.  And there I am, a scientist from Mexico, speaking to them and their kids.  It is that powerful combination of being a smart and warm female that can be shocking, which is cool.

In line with this, there was an experiment where women were asked to draw a female scientist.  Most drew a plain, relatively unattractive woman.  Immediately when you break that mold, it has an incredible effect.  People say, “Hey! She kind of looks like me and she dresses like me.  Maybe I can do science too!”  Some girls are afraid that by being smart, boys won’t talk to them.  My femininity allows me to be a voice in a field that has tended to isolate themselves from the public, which is bad. Some of my colleagues have become a little snobbish.  The fact that I have serious credentials (PhD and 2 postdocs) shows that I had to work like crazy – looks and personality can only go so far.  It s hard work that gets you there! Serious science communication has a lot of math and problem solving in order to explain things accurately to the public. So I still feel like I am doing science!

   

   

DXS Op-Ed: How birth control can save the world


By DXS Biology Editor Jeanne Garbarino


Over the last few months, the concept of birth control has been under great scrutiny in the American eye.  Many politicians have been discussing it’s “moral” implications, and whether institutions or organizations should have the right to deny insurance coverage for hormonal contraception if it does not fall within the confines of their belief systems.  And while American women have narrowly escaped legislation that would impede their reproductive health and freedom, politicians, mostly men, feel it necessary to make misinformed or even completely false statements about birth control. 

For some strange reason, there is this erroneous idea that birth control is not a matter of health, but rather a means by which a woman can engage in careless and frequent sexual activity, with a man, and without the consequences of pregnancy.  It’s clear that the picture these politicians are trying to paint is that of debauchery and immorality, which, of course, is a departure from the puritanical integrity they embody.  But, rather than focus on this utter nonsense, I would prefer to highlight the significant impact birth control will have on the future of our civilization and our planet.

The human population has grown steadily since the beginning of our species.  However, the rate of growth began to skyrocket after the industrial revolution, and our population has actually doubled over the last 50 years, reaching 7 the billion mark in March of this year.  This is an astounding statistic since it took until 1804 – around 50,000 years – to reach our first billion. 

World Population: 1800 – 2100 (Wikimedia Commons)

What makes these numbers really scary is the concept of carrying capacity, which is an ecological term used to describe the maximum number of individual members of a species that a certain habitat can support.  In this case, the species is human and that certain habitat is planet earth. 

Here’s the thing: the availability of our resources will not match the rate of population growth.  Given our current technologies, there is only so much food we can grow, only so much water we can drink, only so much space we can inhabit, only so much waste we can safely rid, only so much energy we can harness.  There will be a point that the human population will hit its carrying capacity on earth, and when it does, the chances of widespread famine will be great, and the delineation between the developing world and the developed world will be no longer.  

Given this very serious issue, Britain’s Royal Society has recently convened to discuss the future of the human population and on April 26th, 2012, and published their findings in the People and the Planet Report [PDF].  For me, key findingnumber three struck a cord:

Reproductive health and voluntary family planning programmes urgently require political leadership and financial commitment, both nationally and internationally. This is needed to continue the downward trajectory of fertility rates, especially in countries where the unmet need for contraception is high. (emphasis theirs)

Political leadership and financial commitment – Did you see that, American politicians??  For those of you who are unnecessarily waging war on women’s reproductive rights, its time to get your giant heads out of your collective asses and realize the implications of legislation that would go against ensuring both the continued success of our species and the health of our planet.  It is time to stop spending money on these regressive and oppressive campaigns guised under the false pretense of “religious freedom” and start making a financial commitment to the women (and by association, men) who live in our nation.

To drive this point even further, here is another excerpt from the People and the Planet Report (my favorite bit, found in Box 2.5 on page 33):

Women bear the main physical burden of reproduction: pregnancy, breastfeeding and childcare. They also bear the main responsibility for contraception as most methods are designed for their use. Men, it may be argued, reap the benefits of children without incurring an equal share of the cost. It follows that women may be more favourable to the idea of small families and family planning than their partners but unable to express their inclinations in male-dominated systems. Such views received international endorsement in the Program of Action resulting from the UN conference on population in 1994. Paragraph 4.1 states that “improving the status of women is essential for the long-term success of population programs”.

We currently live in a nation where 99% of women who are of reproductive age have used some form of birth control at least once.  And when it comes to hormonal contraception, over 80% of sexually active women aged 15-44 have relied on “the pill” as a means to prevent unwanted pregnancies.  This has contributed to an average of two births per American woman, which is considered to be the replacement rate for a population.  Compare this number to countries where birth control and reproductive education is scarce – countries like Niger (7.52 births per woman) or Afghanistan (5.64 births per woman) – and one can see the impact of family planning through contraception.  Furthermore, it has been well documented that women in developed worlds who are provided with the means to control their fertility are more empowered and their families are healthier.   

While our situation in the US is significantly better compared to underdeveloped nations where rape and the cultural devaluing of women is commonplace, we still have a responsibility to uphold – a responsibility that would undoubtedly increase the quality of life for women (and men), as well as contribute to the overall health of the human population.  Why would we want to go backwards and remove the ability of a woman to decide when, if ever, she would like to reproduce? 

Having access to birth control empowers women and allows them to make greater contributions to society.  And because contraception is primarily the responsibility of a woman, our society needs to ensure that birth control, reproductive education, and family planning resources are readily available to EVERYONE.

The United Nations predicts that the ten-billionth person will be born around 2050.  Will we continue to fight this ridiculous fight against women’s rights or will we redirect our collective energy to developing technologies that will help our species and planet better cope with the increasing demands associated with a steadily rising population?  Let’s stop allowing stupidity to prevail and let’s start doing the right thing: making sure that birth control is readily available to any woman who wishes to use it.  Because, now more than ever, it is clear that birth control will save the world.   


Note: In my readings for this article, I came across a wonderful resource for anyone interested in learning more about human fertility and population growth.  Through the wonders of the internet, Academic Earth is offering a free (!) online course called Global Population Growth, given by Yale University professor Robert Wyman. 


These views are the opinion of the author and do not necessarily either reflect or disagree with those of the DXS editorial team.

Biology Explainer: The big 4 building blocks of life–carbohydrates, fats, proteins, and nucleic acids

The short version
  • The four basic categories of molecules for building life are carbohydrates, lipids, proteins, and nucleic acids.
  • Carbohydrates serve many purposes, from energy to structure to chemical communication, as monomers or polymers.
  • Lipids, which are hydrophobic, also have different purposes, including energy storage, structure, and signaling.
  • Proteins, made of amino acids in up to four structural levels, are involved in just about every process of life.                                                                                                      
  • The nucleic acids DNA and RNA consist of four nucleotide building blocks, and each has different purposes.
The longer version
Life is so diverse and unwieldy, it may surprise you to learn that we can break it down into four basic categories of molecules. Possibly even more implausible is the fact that two of these categories of large molecules themselves break down into a surprisingly small number of building blocks. The proteins that make up all of the living things on this planet and ensure their appropriate structure and smooth function consist of only 20 different kinds of building blocks. Nucleic acids, specifically DNA, are even more basic: only four different kinds of molecules provide the materials to build the countless different genetic codes that translate into all the different walking, swimming, crawling, oozing, and/or photosynthesizing organisms that populate the third rock from the Sun.

                                                  

Big Molecules with Small Building Blocks

The functional groups, assembled into building blocks on backbones of carbon atoms, can be bonded together to yield large molecules that we classify into four basic categories. These molecules, in many different permutations, are the basis for the diversity that we see among living things. They can consist of thousands of atoms, but only a handful of different kinds of atoms form them. It’s like building apartment buildings using a small selection of different materials: bricks, mortar, iron, glass, and wood. Arranged in different ways, these few materials can yield a huge variety of structures.

We encountered functional groups and the SPHONC in Chapter 3. These components form the four categories of molecules of life. These Big Four biological molecules are carbohydrates, lipids, proteins, and nucleic acids. They can have many roles, from giving an organism structure to being involved in one of the millions of processes of living. Let’s meet each category individually and discover the basic roles of each in the structure and function of life.
Carbohydrates

You have met carbohydrates before, whether you know it or not. We refer to them casually as “sugars,” molecules made of carbon, hydrogen, and oxygen. A sugar molecule has a carbon backbone, usually five or six carbons in the ones we’ll discuss here, but it can be as few as three. Sugar molecules can link together in pairs or in chains or branching “trees,” either for structure or energy storage.

When you look on a nutrition label, you’ll see reference to “sugars.” That term includes carbohydrates that provide energy, which we get from breaking the chemical bonds in a sugar called glucose. The “sugars” on a nutrition label also include those that give structure to a plant, which we call fiber. Both are important nutrients for people.

Sugars serve many purposes. They give crunch to the cell walls of a plant or the exoskeleton of a beetle and chemical energy to the marathon runner. When attached to other molecules, like proteins or fats, they aid in communication between cells. But before we get any further into their uses, let’s talk structure.

The sugars we encounter most in basic biology have their five or six carbons linked together in a ring. There’s no need to dive deep into organic chemistry, but there are a couple of essential things to know to interpret the standard representations of these molecules.

Check out the sugars depicted in the figure. The top-left molecule, glucose, has six carbons, which have been numbered. The sugar to its right is the same glucose, with all but one “C” removed. The other five carbons are still there but are inferred using the conventions of organic chemistry: Anywhere there is a corner, there’s a carbon unless otherwise indicated. It might be a good exercise for you to add in a “C” over each corner so that you gain a good understanding of this convention. You should end up adding in five carbon symbols; the sixth is already given because that is conventionally included when it occurs outside of the ring.

On the left is a glucose with all of its carbons indicated. They’re also numbered, which is important to understand now for information that comes later. On the right is the same molecule, glucose, without the carbons indicated (except for the sixth one). Wherever there is a corner, there is a carbon, unless otherwise indicated (as with the oxygen). On the bottom left is ribose, the sugar found in RNA. The sugar on the bottom right is deoxyribose. Note that at carbon 2 (*), the ribose and deoxyribose differ by a single oxygen.

The lower left sugar in the figure is a ribose. In this depiction, the carbons, except the one outside of the ring, have not been drawn in, and they are not numbered. This is the standard way sugars are presented in texts. Can you tell how many carbons there are in this sugar? Count the corners and don’t forget the one that’s already indicated!

If you said “five,” you are right. Ribose is a pentose (pent = five) and happens to be the sugar present in ribonucleic acid, or RNA. Think to yourself what the sugar might be in deoxyribonucleic acid, or DNA. If you thought, deoxyribose, you’d be right.

The fourth sugar given in the figure is a deoxyribose. In organic chemistry, it’s not enough to know that corners indicate carbons. Each carbon also has a specific number, which becomes important in discussions of nucleic acids. Luckily, we get to keep our carbon counting pretty simple in basic biology. To count carbons, you start with the carbon to the right of the non-carbon corner of the molecule. The deoxyribose or ribose always looks to me like a little cupcake with a cherry on top. The “cherry” is an oxygen. To the right of that oxygen, we start counting carbons, so that corner to the right of the “cherry” is the first carbon. Now, keep counting. Here’s a little test: What is hanging down from carbon 2 of the deoxyribose?

If you said a hydrogen (H), you are right! Now, compare the deoxyribose to the ribose. Do you see the difference in what hangs off of the carbon 2 of each sugar? You’ll see that the carbon 2 of ribose has an –OH, rather than an H. The reason the deoxyribose is called that is because the O on the second carbon of the ribose has been removed, leaving a “deoxyed” ribose. This tiny distinction between the sugars used in DNA and RNA is significant enough in biology that we use it to distinguish the two nucleic acids.

In fact, these subtle differences in sugars mean big differences for many biological molecules. Below, you’ll find a couple of ways that apparently small changes in a sugar molecule can mean big changes in what it does. These little changes make the difference between a delicious sugar cookie and the crunchy exoskeleton of a dung beetle.

Sugar and Fuel

A marathon runner keeps fuel on hand in the form of “carbs,” or sugars. These fuels provide the marathoner’s straining body with the energy it needs to keep the muscles pumping. When we take in sugar like this, it often comes in the form of glucose molecules attached together in a polymer called starch. We are especially equipped to start breaking off individual glucose molecules the minute we start chewing on a starch.

Double X Extra: A monomer is a building block (mono = one) and a polymer is a chain of monomers. With a few dozen monomers or building blocks, we get millions of different polymers. That may sound nutty until you think of the infinity of values that can be built using only the numbers 0 through 9 as building blocks or the intricate programming that is done using only a binary code of zeros and ones in different combinations.

Our bodies then can rapidly take the single molecules, or monomers, into cells and crack open the chemical bonds to transform the energy for use. The bonds of a sugar are packed with chemical energy that we capture to build a different kind of energy-containing molecule that our muscles access easily. Most species rely on this process of capturing energy from sugars and transforming it for specific purposes.

Polysaccharides: Fuel and Form

Plants use the Sun’s energy to make their own glucose, and starch is actually a plant’s way of storing up that sugar. Potatoes, for example, are quite good at packing away tons of glucose molecules and are known to dieticians as a “starchy” vegetable. The glucose molecules in starch are packed fairly closely together. A string of sugar molecules bonded together through dehydration synthesis, as they are in starch, is a polymer called a polysaccharide (poly = many; saccharide = sugar). When the monomers of the polysaccharide are released, as when our bodies break them up, the reaction that releases them is called hydrolysis.

Double X Extra: The specific reaction that hooks one monomer to another in a covalent bond is called dehydration synthesis because in making the bond–synthesizing the larger molecule–a molecule of water is removed (dehydration). The reverse is hydrolysis (hydro = water; lysis = breaking), which breaks the covalent bond by the addition of a molecule of water.

Although plants make their own glucose and animals acquire it by eating the plants, animals can also package away the glucose they eat for later use. Animals, including humans, store glucose in a polysaccharide called glycogen, which is more branched than starch. In us, we build this energy reserve primarily in the liver and access it when our glucose levels drop.

Whether starch or glycogen, the glucose molecules that are stored are bonded together so that all of the molecules are oriented the same way. If you view the sixth carbon of the glucose to be a “carbon flag,” you’ll see in the figure that all of the glucose molecules in starch are oriented with their carbon flags on the upper left.

The orientation of monomers of glucose in polysaccharides can make a big difference in the use of the polymer. The glucoses in the molecule on the top are all oriented “up” and form starch. The glucoses in the molecule on the bottom alternate orientation to form cellulose, which is quite different in its function from starch.

Storing up sugars for fuel and using them as fuel isn’t the end of the uses of sugar. In fact, sugars serve as structural molecules in a huge variety of organisms, including fungi, bacteria, plants, and insects.

The primary structural role of a sugar is as a component of the cell wall, giving the organism support against gravity. In plants, the familiar old glucose molecule serves as one building block of the plant cell wall, but with a catch: The molecules are oriented in an alternating up-down fashion. The resulting structural sugar is called cellulose.

That simple difference in orientation means the difference between a polysaccharide as fuel for us and a polysaccharide as structure. Insects take it step further with the polysaccharide that makes up their exoskeleton, or outer shell. Once again, the building block is glucose, arranged as it is in cellulose, in an alternating conformation. But in insects, each glucose has a little extra added on, a chemical group called an N-acetyl group. This addition of a single functional group alters the use of cellulose and turns it into a structural molecule that gives bugs that special crunchy sound when you accidentally…ahem…step on them.

These variations on the simple theme of a basic carbon-ring-as-building-block occur again and again in biological systems. In addition to serving roles in structure and as fuel, sugars also play a role in function. The attachment of subtly different sugar molecules to a protein or a lipid is one way cells communicate chemically with one another in refined, regulated interactions. It’s as though the cells talk with each other using a specialized, sugar-based vocabulary. Typically, cells display these sugary messages to the outside world, making them available to other cells that can recognize the molecular language.

Lipids: The Fatty Trifecta

Starch makes for good, accessible fuel, something that we immediately attack chemically and break up for quick energy. But fats are energy that we are supposed to bank away for a good long time and break out in times of deprivation. Like sugars, fats serve several purposes, including as a dense source of energy and as a universal structural component of cell membranes everywhere.

Fats: the Good, the Bad, the Neutral

Turn again to a nutrition label, and you’ll see a few references to fats, also known as lipids. (Fats are slightly less confusing that sugars in that they have only two names.) The label may break down fats into categories, including trans fats, saturated fats, unsaturated fats, and cholesterol. You may have learned that trans fats are “bad” and that there is good cholesterol and bad cholesterol, but what does it all mean?

Let’s start with what we mean when we say saturated fat. The question is, saturated with what? There is a specific kind of dietary fat call the triglyceride. As its name implies, it has a structural motif in which something is repeated three times. That something is a chain of carbons and hydrogens, hanging off in triplicate from a head made of glycerol, as the figure shows.  Those three carbon-hydrogen chains, or fatty acids, are the “tri” in a triglyceride. Chains like this can be many carbons long.

Double X Extra: We call a fatty acid a fatty acid because it’s got a carboxylic acid attached to a fatty tail. A triglyceride consists of three of these fatty acids attached to a molecule called glycerol. Our dietary fat primarily consists of these triglycerides.

Triglycerides come in several forms. You may recall that carbon can form several different kinds of bonds, including single bonds, as with hydrogen, and double bonds, as with itself. A chain of carbon and hydrogens can have every single available carbon bond taken by a hydrogen in single covalent bond. This scenario of hydrogen saturation yields a saturated fat. The fat is saturated to its fullest with every covalent bond taken by hydrogens single bonded to the carbons.

Saturated fats have predictable characteristics. They lie flat easily and stick to each other, meaning that at room temperature, they form a dense solid. You will realize this if you find a little bit of fat on you to pinch. Does it feel pretty solid? That’s because animal fat is saturated fat. The fat on a steak is also solid at room temperature, and in fact, it takes a pretty high heat to loosen it up enough to become liquid. Animals are not the only organisms that produce saturated fat–avocados and coconuts also are known for their saturated fat content.

The top graphic above depicts a triglyceride with the glycerol, acid, and three hydrocarbon tails. The tails of this saturated fat, with every possible hydrogen space occupied, lie comparatively flat on one another, and this kind of fat is solid at room temperature. The fat on the bottom, however, is unsaturated, with bends or kinks wherever two carbons have double bonded, booting a couple of hydrogens and making this fat unsaturated, or lacking some hydrogens. Because of the space between the bumps, this fat is probably not solid at room temperature, but liquid.

You can probably now guess what an unsaturated fat is–one that has one or more hydrogens missing. Instead of single bonding with hydrogens at every available space, two or more carbons in an unsaturated fat chain will form a double bond with carbon, leaving no space for a hydrogen. Because some carbons in the chain share two pairs of electrons, they physically draw closer to one another than they do in a single bond. This tighter bonding result in a “kink” in the fatty acid chain.

In a fat with these kinks, the three fatty acids don’t lie as densely packed with each other as they do in a saturated fat. The kinks leave spaces between them. Thus, unsaturated fats are less dense than saturated fats and often will be liquid at room temperature. A good example of a liquid unsaturated fat at room temperature is canola oil.

A few decades ago, food scientists discovered that unsaturated fats could be resaturated or hydrogenated to behave more like saturated fats and have a longer shelf life. The process of hydrogenation–adding in hydrogens–yields trans fat. This kind of processed fat is now frowned upon and is being removed from many foods because of its associations with adverse health effects. If you check a food label and it lists among the ingredients “partially hydrogenated” oils, that can mean that the food contains trans fat.

Double X Extra: A triglyceride can have up to three different fatty acids attached to it. Canola oil, for example, consists primarily of oleic acid, linoleic acid, and linolenic acid, all of which are unsaturated fatty acids with 18 carbons in their chains.

Why do we take in fat anyway? Fat is a necessary nutrient for everything from our nervous systems to our circulatory health. It also, under appropriate conditions, is an excellent way to store up densely packaged energy for the times when stores are running low. We really can’t live very well without it.

Phospholipids: An Abundant Fat

You may have heard that oil and water don’t mix, and indeed, it is something you can observe for yourself. Drop a pat of butter–pure saturated fat–into a bowl of water and watch it just sit there. Even if you try mixing it with a spoon, it will just sit there. Now, drop a spoon of salt into the water and stir it a bit. The salt seems to vanish. You’ve just illustrated the difference between a water-fearing (hydrophobic) and a water-loving (hydrophilic) substance.

Generally speaking, compounds that have an unequal sharing of electrons (like ions or anything with a covalent bond between oxygen and hydrogen or nitrogen and hydrogen) will be hydrophilic. The reason is that a charge or an unequal electron sharing gives the molecule polarity that allows it to interact with water through hydrogen bonds. A fat, however, consists largely of hydrogen and carbon in those long chains. Carbon and hydrogen have roughly equivalent electronegativities, and their electron-sharing relationship is relatively nonpolar. Fat, lacking in polarity, doesn’t interact with water. As the butter demonstrated, it just sits there.

There is one exception to that little maxim about fat and water, and that exception is the phospholipid. This lipid has a special structure that makes it just right for the job it does: forming the membranes of cells. A phospholipid consists of a polar phosphate head–P and O don’t share equally–and a couple of nonpolar hydrocarbon tails, as the figure shows. If you look at the figure, you’ll see that one of the two tails has a little kick in it, thanks to a double bond between the two carbons there.

Phospholipids form a double layer and are the major structural components of cell membranes. Their bend, or kick, in one of the hydrocarbon tails helps ensure fluidity of the cell membrane. The molecules are bipolar, with hydrophilic heads for interacting with the internal and external watery environments of the cell and hydrophobic tails that help cell membranes behave as general security guards.

The kick and the bipolar (hydrophobic and hydrophilic) nature of the phospholipid make it the perfect molecule for building a cell membrane. A cell needs a watery outside to survive. It also needs a watery inside to survive. Thus, it must face the inside and outside worlds with something that interacts well with water. But it also must protect itself against unwanted intruders, providing a barrier that keeps unwanted things out and keeps necessary molecules in.

Phospholipids achieve it all. They assemble into a double layer around a cell but orient to allow interaction with the watery external and internal environments. On the layer facing the inside of the cell, the phospholipids orient their polar, hydrophilic heads to the watery inner environment and their tails away from it. On the layer to the outside of the cell, they do the same.
As the figure shows, the result is a double layer of phospholipids with each layer facing a polar, hydrophilic head to the watery environments. The tails of each layer face one another. They form a hydrophobic, fatty moat around a cell that serves as a general gatekeeper, much in the way that your skin does for you. Charged particles cannot simply slip across this fatty moat because they can’t interact with it. And to keep the fat fluid, one tail of each phospholipid has that little kick, giving the cell membrane a fluid, liquidy flow and keeping it from being solid and unforgiving at temperatures in which cells thrive.

Steroids: Here to Pump You Up?

Our final molecule in the lipid fatty trifecta is cholesterol. As you may have heard, there are a few different kinds of cholesterol, some of which we consider to be “good” and some of which is “bad.” The good cholesterol, high-density lipoprotein, or HDL, in part helps us out because it removes the bad cholesterol, low-density lipoprotein or LDL, from our blood. The presence of LDL is associated with inflammation of the lining of the blood vessels, which can lead to a variety of health problems.

But cholesterol has some other reasons for existing. One of its roles is in the maintenance of cell membrane fluidity. Cholesterol is inserted throughout the lipid bilayer and serves as a block to the fatty tails that might otherwise stick together and become a bit too solid.

Cholesterol’s other starring role as a lipid is as the starting molecule for a class of hormones we called steroids or steroid hormones. With a few snips here and additions there, cholesterol can be changed into the steroid hormones progesterone, testosterone, or estrogen. These molecules look quite similar, but they play very different roles in organisms. Testosterone, for example, generally masculinizes vertebrates (animals with backbones), while progesterone and estrogen play a role in regulating the ovulatory cycle.

Double X Extra: A hormone is a blood-borne signaling molecule. It can be lipid based, like testosterone, or short protein, like insulin.

Proteins

As you progress through learning biology, one thing will become more and more clear: Most cells function primarily as protein factories. It may surprise you to learn that proteins, which we often talk about in terms of food intake, are the fundamental molecule of many of life’s processes. Enzymes, for example, form a single broad category of proteins, but there are millions of them, each one governing a small step in the molecular pathways that are required for living.

Levels of Structure

Amino acids are the building blocks of proteins. A few amino acids strung together is called a peptide, while many many peptides linked together form a polypeptide. When many amino acids strung together interact with each other to form a properly folded molecule, we call that molecule a protein.

For a string of amino acids to ultimately fold up into an active protein, they must first be assembled in the correct order. The code for their assembly lies in the DNA, but once that code has been read and the amino acid chain built, we call that simple, unfolded chain the primary structure of the protein.

This chain can consist of hundreds of amino acids that interact all along the sequence. Some amino acids are hydrophobic and some are hydrophilic. In this context, like interacts best with like, so the hydrophobic amino acids will interact with one another, and the hydrophilic amino acids will interact together. As these contacts occur along the string of molecules, different conformations will arise in different parts of the chain. We call these different conformations along the amino acid chain the protein’s secondary structure.

Once those interactions have occurred, the protein can fold into its final, or tertiary structure and be ready to serve as an active participant in cellular processes. To achieve the tertiary structure, the amino acid chain’s secondary interactions must usually be ongoing, and the pH, temperature, and salt balance must be just right to facilitate the folding. This tertiary folding takes place through interactions of the secondary structures along the different parts of the amino acid chain.

The final product is a properly folded protein. If we could see it with the naked eye, it might look a lot like a wadded up string of pearls, but that “wadded up” look is misleading. Protein folding is a carefully regulated process that is determined at its core by the amino acids in the chain: their hydrophobicity and hydrophilicity and how they interact together.

In many instances, however, a complete protein consists of more than one amino acid chain, and the complete protein has two or more interacting strings of amino acids. A good example is hemoglobin in red blood cells. Its job is to grab oxygen and deliver it to the body’s tissues. A complete hemoglobin protein consists of four separate amino acid chains all properly folded into their tertiary structures and interacting as a single unit. In cases like this involving two or more interacting amino acid chains, we say that the final protein has a quaternary structure. Some proteins can consist of as many as a dozen interacting chains, behaving as a single protein unit.

A Plethora of Purposes

What does a protein do? Let us count the ways. Really, that’s almost impossible because proteins do just about everything. Some of them tag things. Some of them destroy things. Some of them protect. Some mark cells as “self.” Some serve as structural materials, while others are highways or motors. They aid in communication, they operate as signaling molecules, they transfer molecules and cut them up, they interact with each other in complex, interrelated pathways to build things up and break things down. They regulate genes and package DNA, and they regulate and package each other.

As described above, proteins are the final folded arrangement of a string of amino acids. One way we obtain these building blocks for the millions of proteins our bodies make is through our diet. You may hear about foods that are high in protein or people eating high-protein diets to build muscle. When we take in those proteins, we can break them apart and use the amino acids that make them up to build proteins of our own.

Nucleic Acids

How does a cell know which proteins to make? It has a code for building them, one that is especially guarded in a cellular vault in our cells called the nucleus. This code is deoxyribonucleic acid, or DNA. The cell makes a copy of this code and send it out to specialized structures that read it and build proteins based on what they read. As with any code, a typo–a mutation–can result in a message that doesn’t make as much sense. When the code gets changed, sometimes, the protein that the cell builds using that code will be changed, too.

Biohazard!The names associated with nucleic acids can be confusing because they all start with nucle-. It may seem obvious or easy now, but a brain freeze on a test could mix you up. You need to fix in your mind that the shorter term (10 letters, four syllables), nucleotide, refers to the smaller molecule, the three-part building block. The longer term (12 characters, including the space, and five syllables), nucleic acid, which is inherent in the names DNA and RNA, designates the big, long molecule.

DNA vs. RNA: A Matter of Structure

DNA and its nucleic acid cousin, ribonucleic acid, or RNA, are both made of the same kinds of building blocks. These building blocks are called nucleotides. Each nucleotide consists of three parts: a sugar (ribose for RNA and deoxyribose for DNA), a phosphate, and a nitrogenous base. In DNA, every nucleotide has identical sugars and phosphates, and in RNA, the sugar and phosphate are also the same for every nucleotide.

So what’s different? The nitrogenous bases. DNA has a set of four to use as its coding alphabet. These are the purines, adenine and guanine, and the pyrimidines, thymine and cytosine. The nucleotides are abbreviated by their initial letters as A, G, T, and C. From variations in the arrangement and number of these four molecules, all of the diversity of life arises. Just four different types of the nucleotide building blocks, and we have you, bacteria, wombats, and blue whales.

RNA is also basic at its core, consisting of only four different nucleotides. In fact, it uses three of the same nitrogenous bases as DNA–A, G, and C–but it substitutes a base called uracil (U) where DNA uses thymine. Uracil is a pyrimidine.

DNA vs. RNA: Function Wars

An interesting thing about the nitrogenous bases of the nucleotides is that they pair with each other, using hydrogen bonds, in a predictable way. An adenine will almost always bond with a thymine in DNA or a uracil in RNA, and cytosine and guanine will almost always bond with each other. This pairing capacity allows the cell to use a sequence of DNA and build either a new DNA sequence, using the old one as a template, or build an RNA sequence to make a copy of the DNA.

These two different uses of A-T/U and C-G base pairing serve two different purposes. DNA is copied into DNA usually when a cell is preparing to divide and needs two complete sets of DNA for the new cells. DNA is copied into RNA when the cell needs to send the code out of the vault so proteins can be built. The DNA stays safely where it belongs.

RNA is really a nucleic acid jack-of-all-trades. It not only serves as the copy of the DNA but also is the main component of the two types of cellular workers that read that copy and build proteins from it. At one point in this process, the three types of RNA come together in protein assembly to make sure the job is done right.


 By Emily Willingham, DXS managing editor 
This material originally appeared in similar form in Emily Willingham’s Complete Idiot’s Guide to College Biology

Double Xpression: Meghan Groome

Meghan Groome, PhD, Director of K12 Education and Science & the City, New York Academy of Sciences
[Ed. note: Double X Science has started a new series: Double Xpression: Profiles of Women into Science. The focus of these profiles is how women in science express themselves in ways that aren’t necessarily scientific, how their ways of expression inform their scientific activities and vice-versa, and the reactions they encounter.]
Today’s profile is an interview with Meghan Groome, PhD, New York Academy of SciencesDirector of K12 Education and Science & The City, who answered our questions via email with DXS Biology Editor Jeanne Garbarino.

DXS: First, can you give me a quick overview of what your scientific background is and your current connection to science?

MG: I was a bio major since age two. Growing up (and still today) I had a deep love of all things gross, icky, creepy, and crawly and a deep dislike of anything math related. My parents didn’t really know what to do with me, so a theme to my scientific background is that although I was a straight-A student in my bio classes, no one had any idea that I should be doing enrichment programs or making an effort to learn math. I figured that by being a great bio major, I would become a great scientist. So I was an excellent consumer of scientific knowledge but only realized late in life that I needed to be a producer to actually become a scientist.

Being a straight-A student doesn’t actually get you a job when you graduate from a small liberal arts college with a degree in biology and theater, and out of desperation, I took a job teaching. While I wasn’t a good scientist, I turned out to be an excellent teacher and loved the creativity, energy, and never-ending questions that go along with being a science teacher. If you teach from the perspective that science is an endless quest for knowledge, you’ll never get bored taking kids on that journey.

While my background is in biology, my graduate degree is in science education, and I study gender dynamics and student questioning the middle-school classrooms. I currently work for the New York Academy of Sciences as the Director of K12 Education and public programs and spend most of my day convincing scientists that education outreach is not only part of their jobs but a lot of fun.

DXS: What ways do you express yourself creatively that may not have a single thing to do with science?

MG: I’m also a photographer and spend a lot of time wandering around neighborhoods in Brooklyn with a special love of decaying buildings and empty lots. I love how nature conquers things that we humans consider to be permanent – like how we have to constantly beat back the invading hordes of plants and animals even in one of the most man-made environments in the world.

I was also a theater major, so (I) have a strong background in costume design and stage directing. I hate acting but love dance. If I had any talent I would have become a musical theater star but unfortunately enthusiasm and determination can only get you so far.

DXS: Do you find that your scientific background informs your creativity, even though what you do may not specifically be scientific?

MG: I find great joy in seeing how nature conquers human engineering. When I learned about Lynn Margulis’ Gaia hypothesis, I began seeing it everywhere and I think I love photography because I’m documenting the Earth fighting back.

Most of my creative energy comes from working with kids and listening to the wonderful way in which they think about the natural world. Adults can be so rigid in their thinking and are often afraid to say ideas that are out of the mainstream thinking. The older a kid gets, the more we expect them to conform to the adult way of thinking. Middle-school kids are old enough to express their wacky ideas, and young enough to not recognize that their ideas are considered “wrong.”

DXS: Have you encountered situations in which your expression of yourself outside the bounds of science has led to people viewing you differently–either more positively or more negatively?

MG: People tell me all the time “You’re not what we expected” and I’m not really sure how to respond.

In the science education world, my research is informed by my experiences teaching in a very poor district and from a social justice perspective. It’s a rather controversial theoretical framework because it says, “I have an agenda to use my research to bring about equity in an unequal world.” From a research perspective, it means you need to be explicit in your point of view and your biases and have much greater validity and reliability to show that your research is solid. My work is very passion driven so I’ve had to learn when it’s appropriate to pull out my soap box and go full-out social justice to them.

This is changing, but for a long time I kept my personality under wraps in a professional setting. It’s only now — with 10 years professional experience, great organizations on my resume, and a PhD — that I can be clever, confront those I disagree with, and even smile. Anyone who’s ever had a beer with me knows that I’m a goofball and will do just about anything to make someone laugh. I’m a science person, a theater person, a teacher, researcher, policy maker, consultant, and have seen a lot of exquisitely bad and good stuff in my life and so I am frequently the voice of an outsider even though I look and sound like a total insider. That can really freak people out especially if they’ve only read my bio or seen me in my most professional mode.
DXS: Have you found that your non-science expression of creativity/activity/etc. has in any way informed your understanding of science or how you may talk about it or present it to others?

MG: I approach teaching science from a fairly theatrical perspective. In my class we dance, sing, laugh, talk about the real world. I’ve never used the textbook, and I’m very insistent that everything be in the first person when writing or speaking about science. I much prefer teaching regular classes — not honors or AP — and can’t stand kids who remind me of myself in high school.

I approach scientists in the same way and try to make them comfortable admitting that their more than a brain on a stick. I’ve found one of the biggest fears of young scientists is that their PI will find out that they’re interested in something more than life in the lab so I always try to work within the existing power structure and make sure the PIs and Deans indicate to them that working with the (New York) Academy (of Sciences) is okay.

DXS: How comfortable are you expressing your femininity and in what ways? How does this expression influence people’s perception of you in, say, a scientifically oriented context?

MG: This question confounds the heck out of me. I am still such a tomboy and have always chosen to present myself as a somewhat genderless individual. I’ve always considered myself “smart not pretty” because I can control how smart I am but not how pretty. A few years ago, my sisters pulled me aside and told me I needed to stop dressing like such a slob. They started buying me pretty, fashionable clothes and insisting that I wear skirts above the knee and get a real hair cut.

Since I started working at the Academy, I have a very public facing role and have grown to accept that I should look nice. This goes along with slowly feeling comfortable letting my personality out in professional settings but I still consider myself a tomboy and consider my outward appearance to be a costume designed to do a job.

So I guess the answer is, femininity, what femininity?

DXS: Do you think that the combination of your non-science creativity and scientific-related activity shifts people’s perspectives or ideas about what a scientist or science communicator is? If you’re aware of such an influence, in what way, if any, do you use it to (for example) reach a different corner of your audience or present science in a different sort of way?

MG: I think very few people are brains on a stick but that being a scientist often requires us to pretend we have no life outside the lab. I’ve now worked with hundreds of young scientists who spend time working with kids and I’m so pleased to see how quickly they shift from lab geek to real person when talking with a 4th grader. I want scientists to be evangelicals for science, and I want that to include the fact that scientists are real, fallible, wacky, wonderful people too.

DXS: If you had something you could say to the younger you about the role of expression and creativity in your chosen career path, what would you say?

MG: I was always encouraged to be an individual and be myself. I credit my parents with allowing me to pursue my passion and not try to box me in to one identity. It’s never been easy to forge my own path, and I dedicate a lot of myself to my work.

My advice to my younger self would be to slow down a bit, know that you don’t have to get 100% on everything, and know that the problems of the world don’t have to be solved right now.

And perhaps to learn how to be a bit more like a girl. It’s incredibly powerful to see yourself as smart and pretty.


———————————————————————
Meghan Groome is the Director of K12 Education and Science & the City at the New York Academy of Sciences, an organization with the mission to advance scientific research and knowledge, support scientific literacy, and promote the resolution of society’s global challenges through science-based solutions. After graduating from Colorado College in Biology and Theatre, she desperately needed a job and took one as a substitute teacher at a middle school in Ridgewood, NJ. She discovered that she had a knack for making science interesting and enjoyable, mostly through bringing in gross things, lighting things on fire (but always in a safe manner), and having a large library of the world’s best science writing and science fiction. After teaching in both Ridgewood and Paterson, NJ, she completed her PhD at Teachers College (TC) Columbia University with a focus on student question-asking in the classroom. While at TC, she was a founding member of an international education consulting firm and worked on projects from Kenya to Jordan with a focus on designing new schools and school systems in the developing world. 

After graduating, Dr. Groome became a Senior Policy Analyst at the National Governors Association on Governor Janet Napolitano’s Innovation America Initiative. Prior to her work at the Academy, Dr. Groome worked at the American Museum of Natural History and authored the policy roadmap for the Empire State STEM Education Network and taught urban biodiversity in the Education Department. At the Academy, she is responsible for the Afterschool STEM Mentoring program, which places graduate students and postdocs in the City’s afterschool programs, and the Science Teacher program, where she designs field trips and content talks to the City’s STEM teachers. Connect with her on Twitter, and read her NYAS blog!

Why a UN ban on thimerosal in vaccines would be a big mistake

By Tara Haelle, Health Editor

[This post appeared previously at Red Wine and Apple Sauce.]

Several articles published in Pediatrics today discuss an issue that could affect the protection of children everywhere from vaccine-preventable diseases. The posts center on a controversy that keeps coming up related to vaccines – the  use of thimerosal in them.

All three Pediatrics articles deal with the same thing: an international treaty drafted by the  United Nation Environmental Program’s  Global Mercury Partnership to reduce mercury pollution and environmental mercury exposure across the world. Great! This is an important and valuable initiative – except for one part. As part of the treaty, the UN wants to ban the use of thimerosal, a mercury-containing preservative, used in vaccines. Not so good. The short version for why? This proposed ban threatens millions of children’s lives across the world, including children in the U.S. and in other developed countries. I’ll get to the long version in a moment.

First, the  World Health Organization and American Academy of Pediatricians (AAP) have already pushed for the thimerosal ban provision to be removed from the UN treaty. But today’s three AAP articles drive the point home. One of these provides some  historical context for why thimerosal was removed from childhood vaccines in the U.S. (as  recommended by the AAP and the U.S. Public Health Services in 1999) and in other high-income countries. The other two emphasize just how important it is – and how ethically essential it is –that the ban not be included in the UN treaty.

Here’s the back story:
A  1997 US FDA review of the mercury content in products revealed that the amount of thimerosal in childhood vaccines could, possibly theoretically, build up to exceed the EPA’s guidelines (but not the FDA’s guidelines or those of the Agency for Toxic Substances Disease Registry) on safe exposure limits for  inorganic mercury, called  methylmercury.

Methylmercury is the neurotoxin you hear about when you’re warned not to eat too much fish ( especially while pregnant). Back in 1999, scientists knew a lot about methylmercury, but they didn’t know much about  ethylmercury, the type in thimerosal. As Dr. Louis Cooper and Dr. Samuel Katz, both involved with the 1999 recommendations,  put it, “the absence of clear data for ethylmercury did not allow any assumption to be made about its safety.”

Meanwhile, debates were raging in Congress about concerns over vaccines and autism, fueled by the now-retracted and  thoroughly debunked (pdf) study by Andrew Wakefield  linking the MMR vaccine to autism. Parents were scared and confused. Media coverage was exacerbating the impression that public health officials weren’t being forthright about vaccine risks.

So, poof! All thimerosal was pulled from childhood vaccines except the multi-dose flu vaccine, since kids getting that would only get amounts below the EPA guidelines for methylmercury (even though, again, thimerosal is ETHYLmercury).

Now fast forward to today. We know a LOT more about ethylmercury: namely, that it’s not as bad as methylmercury and  sails through our bodies a lot more quickly. In fact, methylmercury’s half-life is about  seven times that of ethylmercury, which does not build up in the body like methylmercury does.
“There is no credible scientific evidence that the use of thimerosal in vaccines presents any risk to human health,” writes Dr. Katherine King in one of  today’s Pediatrics articles. Dozens of studies and a massive review at the Institute of Medicine back this up.

Thimerosal in vaccines is not a problem. But what is a problem is thimerosal’s PR image. Again, from one of  today’s AAP articles: “Given the complexity of the science involved in making guidelines, the polarity between vaccine advocates and those believing their children have been harmed, the media’s attraction to controversy, and, in retrospect, inadequate follow-up education about the issues to clinicians and the general public, it is not surprising that the steps taken left misunderstanding and anxiety in the United States and concerns in the global public health community.”

Basically, they’re saying, yea, we kinda screwed up with conveying that thimerosal really IS safe after all. We wanted to be over-cautious before, and we were, and that was good, but now we’ve sorta dropped the ball on following through in letting you know that YOU HAVE NOTHING TO WORRY ABOUT with the ethylmercury in thimerosal. As Dr. Walter Orenstein  today’s AAP articles, “Had the evidence that is available now been available in 1999, the policy reducing thimerosal use would likely have not been implemented. Furthermore, in 2008 the World Health Organization endorsed the use of thimerosal in vaccines.”

But apparently, the WHO’s endorsement can’t overcome thimerosal’s PR image problem in the eyes of the UN. And so the UN is short-sightedly and dangerously trying to ban thimerosal in vaccines.

Well, that just means getting rid of it in flu vaccines (many of which don’t even have thimerosal since they’re single-dose), so what’s the big deal anyway? The big deal is that not all countries got rid of thimerosal in their childhood vaccines. Many high-income countries like the U.S. did – because they could afford to be overly cautious.

But more than 120 middle- and low-income countries – including the developing countries where vaccine-preventable diseases have the highest rates of infection and death –  have continued using thimerosal-containing vaccines because the preservative allows them to make cheaper vaccines that withstand less rigorous storage without compromising safety.

Getting rid of thimerosal would mean overhauling vaccine production and storage in those countries, which the WHO estimates would cost more than  $300 million for vaccines supplied by UNICEF or the Pan American Health Organization alone. As Dr. King argues, “it is banning thimerosal that would cause an injustice to those living in low- and middle-income countries and relying on these vaccines for effective protection against many harmful infectious diseases.”

Why does this matter to people in the U.S. or in other higher income countries? Because we live in a global world. Vaccines with thimerosal are currently used to immunize about  84 million children across the world every year, saving an estimated 1.4 million lives from vaccine-preventable diseases.That also includes lives saved in developed countries, where a future outbreak could potentially be imported from other countries in which a vaccination program may have ceased following a thimerosal ban.

More simply put: If the UN forces the removal of thimerosal from vaccines, then 84 million children risk not getting vaccinated (and/or vaccinated on time) due to delays in vaccine production or due to a shortage of vaccines because of increasing costs. This, in turn, could (and likely would) mean an increase in vaccine-preventable infections, which will, in turn, kill more children worldwide and risk disease carriage to other countries.

Over and beyond the increases in vaccine-preventable infections and deaths throughout the world, a thimerosal ban in vaccines could also still pose problems for developed countries. In an emergency, as Dr. Orenstein and colleagues argue, not being able to manufacture vaccines with thimerosal could endanger lives during an epidemic if it slows down vaccine production. This proposed UN ban – and the necessity of its removal – matters.

Dr. Cooper and Dr. Katz – again, both pediatricians who were closely involved in the original 1999 decision to pull thimerosal out of vaccines – sum it up best: “The World Health Organization recommendation to delete the ban on thimerosal must be heeded or it will cause tremendous damage to current programs to protect all children from death and disability caused by vaccine-preventable diseases.”