7
votes
2answers
255 views

How many human proteins are very well characterized?

Following up on How many human proteins have a solved 3D structure?,is there a list of very well characterized human proteins / protein complexes? My criteria for "very well characterized" ...
9
votes
2answers
2k views

How is eye color in humans inherited?

In high school we studied the inheritance of eye color, as it was explained to us in the most simple way: blue eye color is a recessive, monogenic, autosomal trait. Now I know that it is a bit more ...
5
votes
2answers
236 views

When does oxidation destroy prions?

It seems like a no-brainer than oxidation, playing the, er, role it does in the universe, would destroy prions just like it destroys everything else. But when does it do that? I assume this has been ...
11
votes
1answer
292 views

How do members of cryptic species know who to mate with?

According to Wikipedia: In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each ...
9
votes
1answer
173 views

Do taller people have larger somatosensory cortices than short people?

Do taller people have larger somatosensory cortices than short people? What about larger motor cortices? And if so, could this imply that they have less space devoted to other functions, like ...
0
votes
1answer
8k views

How reversible is decerebrate posturing caused by brain stem damage?

This is a follow-up question to How likely would Abraham Lincoln be to survive his wounds today? You don't have to see a CT scan or autopsy to know if the brainstem is injured (directly or ...
22
votes
4answers
9k views

Is there any advantage to one blood type over another?

All humans can be grouped into ABO and Rh+/- blood groups (at a minimum). Is there any advantage at all to one group or the other? This article hints that there are some pathogens that display a ...
5
votes
1answer
1k views

Transcription and translation of prokaryotic operons

I'm taking a molecular genetics course, and we're currently discussing prokaryotic operons. The lacZ operon came up frequently for me as an undergraduate as an example for teaching regulatory control ...
11
votes
1answer
513 views

Did researchers evolve multicellular yeast or did they just turn on multicellularity?

In this new paper "Experimental evolution of multicellularity" found via Ars Technica the researchers describe having developed multicellularity and apoptosis within 60 days from a unicellular yeast ...
12
votes
2answers
514 views

Are there neurons that can sense light shining in your ears?

I know someone who bought earphones that shine light in you ears. According to what he was told, there are neurons that sense light and then make you feel wide awake when activated, which seemed like ...
6
votes
1answer
190 views

What is the origin of “melting” in molecular genetics?

I'm reading some papers about prokaryotic transcription mechanisms, and I've come across a term I haven't heard before: DNA melting or promoter melting. After reading a bit, it's pretty clear that ...
21
votes
2answers
8k views

If a human takes antibiotics are all bacteria in the body killed?

From my basic understanding, antibiotics kill living things, bacteria for example. Do the antibiotics consumed by a human-being distinguish between what they kill? Or do they just kill every bacteria ...
12
votes
2answers
363 views

Are there any plants that fix their own nitrogen?

I know that most nitrogen is fixed through industrial processes and bacterial symbiotic relationships. However, are there any plants that can fix their own atmospheric nitrogen?
10
votes
2answers
214 views

Overlapping genetic information in eukaryotes

In my research, I look at a lot of gene predictions / annotations. Frequently, I see loci where multiple gene models overlap. I haven't taken a systematic approach to analyzing these cases, but I do ...
13
votes
2answers
3k views

How will rising carbon dioxide levels in the troposphere affect photosynthetic producers?

Much discussion has been had about the affects of climate change on plantlife, but how will rising carbon dioxide concentrations affect the photosynthetic process itself? Since CO2 is a reagent in ...
9
votes
1answer
91 views

Which patterns do I have to avoid when modifying the 3'-UTR?

I want to change a pre-miRNA sequence (in my case the pre-miRNA is encoding in a 3'UTR of a gene) and then put it in a lentivirus to see if it is still processed. After modification (permutation of ...
13
votes
1answer
195 views

What is the prehistory of amino acids in cells?

As a followup to Why 20 amino acids instead of 64? and What is the smallest number of amino acids required for life?, I am trying to understand the prehistory of amino acids in cells. All living ...
6
votes
1answer
134 views

Could someone recommend a book for surveying species?

I'm trying to get/renew basic knowledge of species. Could someone recommend a book for surveying "important"/"representational" species? I am looking for a book with good illustrations and that covers ...
8
votes
1answer
1k views

How can a monocot get so massive?

Some monocots (such as palms) are impressively thick and massive, yet botanists maintain that they don't have secondary growth. Why do botanists say this? How can it get so big without secondary ...
8
votes
3answers
210 views

Can elements of one's environment act directly as hormones?

Can pollution and things in an organism's environment serve as hormones?
6
votes
1answer
253 views

First discovery of long-term depression?

LTP was first described by Tim Bliss and Terje Lømo in their paper Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the ...
4
votes
1answer
309 views

What is the largest perennial herbaceous plant?

What is the largest perennial herbaceous plant? My guess would be some kind of banana or bamboo.
-3
votes
1answer
414 views

Which plants live for more than one year and less than two years? [closed]

What kinds of plants live for more than one year and less than two years? Are there any categorical or taxonomical names for such plants?
44
votes
4answers
5k views

Why 22 amino acids instead of 64?

This question got me thinking about amino acids and the ambiguity in the genetic code. With 4 nucleotides in RNA and 3 per codon, there are 64 codons. However, these 64 codons only code for 22 ...
14
votes
1answer
930 views

What is the smallest number of amino acids required for life?

Is there any hypothesis on the minimum number of amino acids required for life?
12
votes
2answers
190 views

Can a color-deficient person be made to visualize the missing colors?

Hope this is within the scope of this site. Color-deficient persons lack the cells in their retina needed for differentiating some (or all) colors. However, the part of the brain that actually ...
10
votes
1answer
558 views

Why doesn't a substance like loperamide promote analgesia?

Loperamide is frequently used to slow gastrointestinal motility. It is available over the counter (in the US, I don't know about elsewhere) without any regulations whatsoever, yet it's derived from ...
4
votes
0answers
95 views

Could an organism theoretically produce a metamaterial-like structure? [closed]

I'm curious to know if this is physically feasible because during my reading up on synthetic biology and just general research i realise that life is capable of producing some exquisitely complex ...
11
votes
1answer
782 views

Does bioluminescence occur in humans too?

I read that Japanese researchers have developed very sensitive camera that recorded bioluminescence in humans; is it possible and if so what is the mechanism behind it?
33
votes
5answers
1k views

Human perception of time depending on age

From what I can tell and what thus far all people with whom I discussed this subject confirmed is that time appears to "accelerate" as we age. Digging a little, most explanations I found basically ...
6
votes
2answers
726 views

Reverse transcription PCR optimization

What is the ideal amount of RNA to use for the RT? and how much cDNA to use then for the PCR? I did RT with a solution of RNA of 0.36 ug/ul. Then for my PCR I used 1 ul of the cDNA obtained and used ...
9
votes
1answer
24k views

Absorption ratios 260/280 and 260/230 for RNA

I extracted RNA from different cell lines, an I want to perform reverse transcription and then PCR. To get good results, in which range should the absorption ratios 260/280 nm and 260/230 nm be? And ...
1
vote
1answer
539 views

Why do plants have pith and how is it useful to them?

Many plants have pith, from walnut trees to corn to ragweed, but I can't think of anything it does them. What is pith and how is it useful to them?
13
votes
2answers
469 views

Intrinsically disordered proteins as potential drug targets

Intrinsically disordered proteins (IDPs) are a class of proteins that do not adopt a stable secondary or tertiary structure under physiological conditions in vitro, but still have biological ...
7
votes
1answer
2k views

The effect of the start codon GTG on translation in E. coli

Translation in E. coli is initiated at the start ATG codon, which encodes for the amino acid Methionine (Met). In some cases, the start codon can be GTG, which within the open reading frame (ORF) ...
5
votes
1answer
99 views

What are the different ways an exon gets spliced?

Exons are produced by more than one mechanism, e.g. splicing out introns after transcription, if I remember correctly. Please list all mechanisms.
27
votes
4answers
534 views

Why are amino acids in biology homochiral?

Why are nearly all amino acids in organisms left-handed (exception is glycine which has no isomer) when abiotic samples typical have an even mix of left- and right-handed molecules?
20
votes
1answer
488 views

How, on a physical level, does ATP confer energy?

When ATP is used as the energy currency to make, say, reaction X + Y → Z happen, is what happens on a physical level down at the molecular scale that during the reaction ATP + H2O → ADP + Pi ...
6
votes
2answers
453 views

Why would stablising selection ever happen?

If the aim of evolution is to allow an organism to better compete against rivals, why would stabilizing selection ever happen? If you're not selecting the most highly adapted competitors at either end ...
10
votes
1answer
122 views

What portions of the brain have drastic changes in activation when we “sense” someone is there?

I was watching an old Arnold Schwarzenegger movie ("Commando") where he plays an elite soldier (surprise). An enemy tries to sneak up on him, and Arnold says that he smelled the other guy ...
6
votes
1answer
197 views

In C. elegans, why does knock-down of cco-1 in some tissues increase lifespan, and knock-down of cco-1 in other tissues decrease lifespan?

Full question: In C. elegans, why does knock-down of cco-1 via RNA interference in specific tissues like body wall muscle decreases life span, whereas knock-down in the nervous system and intestine ...
8
votes
1answer
198 views

Is the squid giant axon the fastest conducting unmyelinated axon known?

The conduction velocity of the squid giant axon can reach 30 m/s. Is there any known example of an even faster conducting unmyelinated axons?
14
votes
1answer
1k views

Why do some mammals not have testes in a scrotum?

Coming from an evolutionary approach, Is the only purpose of a scrotum to regulate the temperature of the testes? Knowing all mammals are warm blooded, shouldn't all mammals have testes in a ...
8
votes
2answers
286 views

How does a veggie-less diet affect the human body?

I have some question, which I'm sure would fit better in the fitness section but proper answers should probably come from someone that knows biology. My question is rather simple. How can a person ...
12
votes
10answers
864 views

A good book for history of biology/biotechnology for lay people

I have many friends who are interested in Biology and want to know more about the subject in general (like a history of biology, from Darwin's theory, to DNA structure discovery, to the human genome ...
12
votes
2answers
2k views

How does a brain distinguish stimuli?

If all the brain ever "sees" is action potentials, how do we know that one set of action potentials denotes a flash of light, another one signifies a loud sound, etc ?
9
votes
1answer
507 views

How does laser surgery correct accommodation problems?

When someone undergoes laser surgery to improve eyesight, how does it correct accommodation problems? Why does it not help presbyopia?
25
votes
4answers
52k views

What's the maximum and minimum temperature a human can survive?

This is a question that has been in my mind since I was a kid. I'm not a doctor, nor even a biology student, just a curious person. What is the minimum and maximum temperature a human body can stand ...
8
votes
3answers
471 views

What triggers meiosis in gonadal cells?

What specific biochemical processes are involved in inducing meiosis rather than mitosis? Why are gonadal cells the only cells in the human body which do undergo meiosis?
7
votes
3answers
2k views

What are the function(s) of Alu elements in the cell?

My 2008 biology book (1) states that some 10% of the human genome consists of relatively short (~300 nucleotides long) Alu elements which do not code for proteins but many of which are transcribed ...

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