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Bio 103, Week8, Macromolecules and Life

Paul Grobstein's picture

Glad you're here, to share explorations of life. If you're registered in Biology 103, remember to log in before posting here. Others are welcome to contribute without logging in. Such comments though will be checked to avoid spam postings and so be delayed in appearing.

In any case, remember that this isn't a place for polished writing or final words. Its a place for thoughts in progress: questions, ideas you had in class (or afterwords), things you've heard or read or seen that you think others might find interesting. Think of it as a public conversation, a place to put things from your own mind that others might find useful and to find things from others (in our class and elsewhere) that you might find useful. And a place we can always go back to to see what we were thinking before and how our conversations have affected that. Looking forward to seeing where we go, and hoping you are too.

You're free to write about anything that came into your mind this week. But if you need something to get you started, what do you think of the ways macromolecules help us account for the properties of living organisms? Are there things yet to be accounted for?
andrelle's picture

I knew a little bit about

I knew a little bit about DNA and mutations and so when we learned about it in class, it didn't have much of an impression on me.  But i do think that it is very interesting how one minor change can cause so much difference.  I really think that it is this randomness that makes life special.   And it is what makes every organism that is alive special.

Catrina Mueller's picture

I think it is quite

I think it is quite interesting how longer strings of hydrocarbons only tend to show up in organizims. I understand that the bigger the chain of atoms, the less probable that they will come together as such, but clearly they are uniting on a much higher rate in organizims' bodies. I wonder if there is something fueling these strains to come into existance or it is just coincidence.
LaKesha's picture


I have always found mutations interesting because you never know what's going to come of it. It's all random and it can have negative effects or positive effects. I remember doing a project on different disorders in high school and we had to find out what was the cause of the disorders and most of them were caused by a mutation of different chromosomes. It's crazy how something as small as a change in a chromosome can cause a person to have fatal disorders later on in life. I was also wondering how much of a role mutations played in evolution? DO mutations help species to evolve?
OrganizedKhaos's picture

Macromolecules and such

This weeks class was very interesting along with the lab. I liked how we approached the idea of DNA and randomness. We went in depth enough to understand the ideas and concepts but not too into it as to get boggled down with tons of detail. The idea of randomness and mutation also intrigued me. It left me with a lot of questions that I thought I knew. For example what does cause a mutation is it interior or exterior? Is it the surrounding atmosphere. I don't know but it intrigues me how random combinations can make so many different people.

The lab was also interesting because we got to use new instruments and develop our own hypothesis. While, doing this we learned better ways to run experiments through minor errors and variation among trials.

kcough's picture

It’s amazing to me that

It’s amazing to me that with the number of possibilities for genetic defects and disorders that so many people’s genes actually work. Given that it only takes one small change in one tiny base pair for a mutation to occur, and there are so many different reactions that have to happen perfectly, it’s incredible we work at all. I’m really liking learning about all of this. It just reinforces the idea that everything is so random—it seems like so much luck, and how in the world did it all work out? I especially enjoyed the lab on Thursday—but I wonder what it means that when you’re distracted your reaction time is slower. Does it mean you’re using more neurons for something else and so they’re divided and can’t decide what to do?

Samar Aryani's picture

Can an energy drink

Can an energy drink increase a person's response time? When we explored this question in lab on Wednesday we were able to see the effects of an energy drink in relation to a person's response time.  The end result was that it does make a person's reaction time faster.  This was very fascinating because only 10 minutes after consuming the drink the effects were evident! It was amazing to see that my response time improved a great deal and even though there was some variation in our data, the conclusion was still proven because there was no overlapping between the times before and after consumption.  It makes me wonder what else will improve a person's response time and in comparison to that, what will slow down a person's response time?



Rachel Tashjian's picture

Did you guys happen to

Did you guys happen to measure the response time a while after drinking the energy drink, as well? I've always wondered about the "crash" that supposedly occurs after drinking one of those.
Jen's picture

I may have said this before,

I may have said this before, but it amazes me how something that isn't even visible can have such a large impact on the thing which it is a part of. It also seems a little arbitrary; it's incredible how our personality traits, fitness and likelihood of disease can all be determined by how our molecules fit together.
ekoike's picture

I completely agree. Even

I completely agree. Even some of the most arbitrary aspects such as the primary sequence of protein can eventually cause a change in the shape of the cells and eventually sickle cell anemia.

It's so interesting how even the slightest changes in sequence or composition can give way to completely unintended consequences/diseases.

Shanika's picture


Shanika Bridges-King

Randomness is also an active word" played" within our Biology ourse. If many things are random then how can one make sense of things!Is randomness an important Notion in ''Biology"? As of now, I am convinced it is! Making sense of things through the term "Randomness'' makes "biology" more complex! However "biology" does challenge Science, so i guess it does make sense.


eharnett's picture

Like other people have

Like other people have posted above, it stills seems amazing to me that something such as one simple mistake in pairing up adenine to thymine, or cytosine to guanine, can have such awful effects: sickle cell amenia, for example, which we looked at in class.  I wonder how common these mistakes are in the body.  I remember learning in ap biology that there are certain mechanisms that could possible correct for these errors (dna polymerases?).  what makes some errors able to be corrected, but makes others unable to be corrected ?  Could these simple mistakes in matching up nucleotides be the reason for other diseases that we are still learning how to cure?

Rachel Tashjian's picture

I was thinking about the

I was thinking about the same thing: I didn't realize just how small a change has to occur for such a serious issue to be created. This is really interesting to me, not only because, as Elizabeth said, it would be interesting to know how common these issues are, and if they can be corrected. It's also interesting because (and I know someone brought this up in class on Friday, but I don't remember who) having sickle cell anemia can make you immune to another disease (which I believe is malaria). Isn't it interesting that something so random (an accident, really) is turned into something that can, potentially, have a somewhat positive effect on someone's life? These are the kinds of questions I find so fascinating about biology.
Ruth Goodlaxson's picture

I was thinking a lot about

I was thinking a lot about how something as small as a nucleic acid can have such a vast impact on who we are. It really hit home to me how unlikely the existence of life itself is, let alone the existence of each of us as individuals. We have these tiny nucleotides in us, that link together and form a specific three dimensional shape and all of this was, apparently, randomness ordered by a set of rules. It's kind of maddening that things at such a small scale can effect the human scale so vastly. I mean, it seems strange that people can get debilitating diseases because their guanine, adenine, cytosine and uracil are all bopping around in their cells linking to their dna to replicate it, and then they happen to bump into the dna in such a way that makes their red blood cells sickle shaped, for instance. It just seems a little hollow to me.
MarieSager's picture

In class this week we talked

In class this week we talked about mutations in DNA. These mutations mean that life is constantly changing and even more, always has the potential to change. I was thinking about this in relation to life, and more specifically in relation to evolution. Maybe mutations are the foundation of evolution and adaptation, in that they occur randomly and create situations and changes that are conducive for life to adapt. Just something to think about...
kgould's picture

DNA replication and all that jazz

I took AP Biology in high school last year and we went into this topic, that of DNA, deeply. Or, at least, we tried to. I'm not sure how much of it I actually absorbed. (We were forced to memorize all of the proteins, ick).

In any case, this time around, once again, the subject seems much more approachable. The fact that we didn't go down into the tiniest details about DNA (DNA polymerase, ligase, blah blah blah) makes it much easier to understand. 

Just one question: is the chance of mutation affected by external sources? (Smoking, drinking, pollution, disease...?) Can something that you put in your body (or are exposed to) affect how your DNA is replicated?


ekoike's picture

I was completely thinking

I was completely thinking the same exact thing while we were discussing this topic on Friday. From our discussion it sort of seemed as if mutation mainly occurs out of a random occurance but maybe that's just half of the story.

So does the mutation occur as a direct result of random occurance or do external factors influence them --> DNA is affected in the way it is replicated?

ekim's picture

on macromolecules.

this may be a silly question, but...
if macromolecules are organic chemicals that are naturally made and found in living things, then...why do we need to consume more of it (i.e. carbs, protein, lipids/fat) in the food we eat?
do we need to consume more macromolecules in order to produce more within our body? but from looking at the virtual protein synthesis experiment, it seemed like our bodies functioned automatically (in terms of producing protein or whatnot) and randomly.

and speaking of random, if the zipping and unzipping of DNA replication (and passing it on to one's offspring) is random, then what accounts for "better" genes in one sibling than the another sibling? is it pure statistics or luck? b/c if it was really random, then the trend of one sibling having "better" genes would not be as prominent, no?

Kee Hyun Kim's picture

yes, i think there are still thinks to be accounted for

Like Luisiana mentioned, I was surprised and also impressed how big of a difference a change in something as miniscule as nitrogen base can make to its parent cell and organism.

This led me to ponder upon the question of what causes such change to take place? If everything works out as they are supposed to in the DNA/RNA replication process.. (such as g going with g, a going with a) this kind of alternation should not happen.

So what causes such things to happen? is it that Thymine can at special circumstances be attracted to Glycine? or is it that it is a Thymine on the outside but has the chracterisitcs of a Glycine...

With chemistery being involved, things are getting a bit more complicated than before but i think this would be a interesting topic worthy of future discussion



Sharhea's picture

Lab this week

I really enjoyed the lab this week, but I wish we had more time to explore the differences between one's response time to a hit anywhere in there body. I think most of the groups saw so many different correlations and I wish we could have explored those external factors. We didn't have enough data to come to a real conclusion but I do want to explore the idea that, we are more sensitive in one spot than another. How do we determine that sensitivity to test it in a labatory setting?
LuisanaT's picture

Small changes make big differences

An alteration in something as minusucle as a nitrogen base undergoes a snowball effect and causes everything that is based on this subunit's specfic sequence to be drastically different.

But if theres a slight change in, for example part of DNA replication process, where nitrogen base T reacts and "attaches" with G, a nitrogen base that is not its complement, would the first nitrogen base still be Thymine? The only way for it to fit Glycine's specific active site is if the mutation in Thymine causes it to appear more like Cytosine. Maybe it is the Gylcine that has a mutation, allowing it to interact with Thymine's shape. Does this mean that there can be a nitrogen base that is a combination of characteristics of other nitrogen bases, allowing it to be Thymine but still interact with Glycine? Or is the mutated nitrogen base automatically renamed based on the new nitrogen base it now reacts with?