12
votes
2answers
335 views

Is there any reason for the variation in mitochondrial DNA size?

As my textbook An Introduction to Genetic Analysis points out, yeast mitochondrial DNA has approximately 78 kb of genetic data, while the human mitochondrial DNA contains 17 kb. Is there any evolution ...
12
votes
2answers
133 views

Why do some fruits have a much wider range of acceptable sizes than others?

Some fruits such as pumpkins can grow to be 100 lbs. Under different conditions, the same variety of pumpkin can produce a 15 lb. fruit. Both plants are healthy, and look the same except for their ...
12
votes
3answers
274 views

What is Curved DNA?

CbpA is DNA binding protein found in E. coli and binds non-specifically to curved DNA (Cosgriff et al., 2010), when the bacterium is in a static phase of growth. The use of "curved DNA" confuses me. ...
12
votes
1answer
171 views

How does herpes (HSV) infection suppress HIV?

HIV compromises the human body to defend against infection. Yet people who are infected with herpes are at less risk of developing AIDS. How does this work?
12
votes
1answer
183 views

Can plants get cancer?

I can't think of any reason why plants wouldn't be able to get cancer, but I've never heard of a plant growing a tumor. I've also never seen a plant with a noticeable abnormal growth. Can plants get ...
12
votes
2answers
706 views

Impact of Alan Turing's approach to morphogenesis

Shortly before his untimely passing, the computing pioneer Alan Turing published his most cited paper The Chemical Basis of Morphogenesis (1952). The central question for Turing was: how does a ...
12
votes
1answer
198 views

Why do people dying of immune deficiency diseases appear sick?

Please forgive the obviously silly appearance of this question, and/or of the tenor which may come across as flippant or dismissive of real world suffering. My intention is none of the above. As a ...
12
votes
1answer
5k views

What is the significance and method behind Ramachandran plots?

My PI showed a Ramachandran plot in class today with minimal explanation, but I'm interested in finding out more. I understand that the Ramachandran plot shows the relation between the omega phi and ...
12
votes
1answer
500 views

Sequencing the genomes of polyploid organisms

I've done some transcriptomics work in the past with a polyploid organism, and this presented some unique challenges in the data processing and analysis. Since then, I have been brainstorming about ...
12
votes
1answer
3k views

How does Golgi's neural histological stain work?

What is known about the targets of Golgi staining of neurons? Are larger neurons more likely to be stained? Are specific cell types more susceptible than others? The current wikipedia article says ...
12
votes
3answers
136 views

How are long time periods measured in biological systems?

Biological systems are pretty good at measuring fairly long times, for example, menstrual cycles (month), or puberty (years). Counting days or years seems to be implausible, and chemical concentration ...
12
votes
5answers
4k views

Origin, or source, of rhesus negative in human blood

This is my first post here, so please be gentle. I recently learned that I have Rh- blood (I'm A-), and was idly looking into blood types on Wikipedia. I was surprised to find that relatively few ...
12
votes
1answer
1k views

What causes REM atonia to be lost in sleepwalking?

I understand that in normal REM sleep the voluntary muscles are in effect paralysed in order to prevent an individual acting out their dreams. This paper indicates that there are likley to be ...
12
votes
1answer
213 views

Can DNA act as a translation substrate?

I get conflicting answers. One would think if it was true, it would be rather seminal and widely known. There are papers from Khorana[1], Holland[2], and Bretscher[3] (late 60s) that suggest that it ...
12
votes
1answer
401 views

How fast will cells lyse under hypotonic conditions?

Routinely, lysis of cells with hypotonic solutions is carried out along with some physical (douncing) or enzymatic (lysozyme) method to break open the cells. If one were not to do any of these and ...
12
votes
1answer
317 views

Is it correct that the body only responds to the most painful stimulus?

I'm rather ashamed to say that this question is partly based on an episode of House. I have previously heard that, if there are multiple simultaneous painful stimuli, the mind will only feel the ...
12
votes
1answer
165 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
12
votes
1answer
154 views

Have any mutations or genetic loci been associated with exceptional longevity in humans?

Individuals that avoid age-related diseases into later life are known as 'exceptional survivors', and have increased longevity compared to their 'controls' (those that were born at a similar time, yet ...
12
votes
1answer
295 views

How are epigenetic marks transmitted during cell division?

As far as I know, this is one of the biggest questions in the epigenetic field: how are the epigenetic marks like histone modifications propagated through cell division? A lot is already known about ...
12
votes
1answer
336 views

Looking for a cancer drug target database to guide sequencing of patient tumor DNA

I have a question I would like to pose to the community. I have recently received access to a bench-top ion torrent DNA sequencer. Our idea is to use this machine to sequence the DNA from patient’s ...
11
votes
4answers
892 views

Are there any examples of sudden leaps in evolution?

As far as I understand, various abilities like flying, sight, hearing etc. were caused by slow evolution, where those with a greater ability to to these things had better chance of survival. (If this ...
11
votes
3answers
459 views

Is Behe's experiment (evolving the bacterial flagellum) plausible in the lab?

[Warning: this question is motivated by a prominent proponent of "intelligent design": Prof. Michael Behe. I'm not interested in debating creationism.] According to Wikipedia[1]: In Darwin’s ...
11
votes
4answers
3k views

Do cows produce milk excessively?

Do cows produce more milk than it is required for their calves? It seems like cows are able to provide milk all the time (all year around). Is it so? Or do they, like other mammals, produce milk only ...
11
votes
4answers
203 views

What was the reason for some plant and animals to become giant in course of evolution?

The dinosaurs, mammoths, giant plants etc are known to be bigger than modern animals. I wonder why they had been lived and why they are not living now? I really don't know much but is it something ...
11
votes
2answers
189 views

Under what conditions do dendritic spines form?

I'm looking for resources or any information about the formation of dendritic spines and synaptogenesis, especially in relation to how new connections are formed on a daily basis. Does the ...
11
votes
3answers
874 views

What implications has the missing 2'-OH on the capability of DNA to form 3D structures?

The chemical difference between RNA and DNA is the missing 2'-hydroxyl group in the nucleotides that build DNA. The major effect of that change that I know of is the higher stability of DNA compared ...
11
votes
1answer
172 views

Are there any pre-Holocene venomous animals?

The novel (and subsequently movie) Jurassic Park featured a dinosaur called Dilophosaurus, that was purported to be venomous and had an ability similar to that of the extant spitting cobra. ...
11
votes
3answers
285 views

Number of beneficial mutations cataloged?

I can see from Wikipedia that there are possibly thousands of harmful mutations that have been cataloged and linked to disease. There are also unnumbered neutral mutations. But, does anyone know how ...
11
votes
3answers
2k views

Why do red blood cells contain haemoglobin and not myoglobin?

So I am reading about muscles and I come across myoglobin. It has a much higher affinity for oxygen than haemoglobin. So why have animals evolved to have haemoglobin in red blood cells, rather than ...
11
votes
3answers
955 views

Where does the 'C' in exhaled CO2 mostly come from?

When a human being exhales $CO_2$, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
11
votes
4answers
524 views

Has there ever been an attempt to create nutritionally tailored food for adult human consumption?

For all domestic animals, and for all animals kept in laboratory, complete and precise composition of perfect food is figured out (cat food, dog food, cattle, rats, laboratory monkeys and apes) -- ...
11
votes
4answers
236 views

What can you tell about a person, having only their whole genome as information?

Well, the question is in the title, no explanation need.
11
votes
2answers
23k views

NADH vs. NADPH: Where is each one used and why that instead of the other?

I know NADH is used in cellular respiration and NADPH is used in photosynthesis. What difference does the phosphate group make that the same one isn't or can't be used for both? Is there a greater ...
11
votes
2answers
373 views

When did vision evolve for the first time?

Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a ...
11
votes
3answers
324 views

How did the human brain evolve?

A common question posed is, "how did the eye evolve?", because the eye is so complex. However, this has been answered rather clearly and there are several examples around the world of animals in ...
11
votes
1answer
1k views

Why does looking at bright light trigger sneezing in some people?

Why does looking at bright light trigger sneezing in some people? Are there any recent studies that have found a cause for this Photic sneeze reflex? The Wikipedia article only references studies ...
11
votes
3answers
953 views

What happens to dextrorotatory amino acids in humans?

As indicated by this question, most of the amino acids in the human body have the L-chirality. As enzymes also have handedness, what happens to the D-amino acids that end up within the human body? Are ...
11
votes
1answer
2k views

How does a plant grow before photosynthesis is possible?

During photosynthesis, a plant translates CO2, water and light into O2. I assume the carbon C is further used for the growing process. I wonder how the plant grows before the time where photosynthesis ...
11
votes
2answers
439 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 ...
11
votes
2answers
388 views

What are limiting factors for intron length?

For predicting genes from a sequenced genome, you need to set a maximum intron length. How long can introns get in animals? Is there some limit?
11
votes
1answer
971 views

Why does oxygen bind to hemoglobin in an specific angle?

There is an specific angle of the bond between oxygen and hemoglobin in lungs, which I don't know, but what interests me more is the question, why is it specific?
11
votes
1answer
721 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?
11
votes
1answer
429 views

How to reduce edge effects in cell-based high-throughput experiments?

In high-throughput experiments where cells are cultured, treated, stained, and imaged in 384-well microplates, I frequently see significant edge effects. For instance, the following plot shows cell ...
11
votes
4answers
144 views

Is there any other function of DNA?

We all know that DNA acts as a genetic molecule. Does DNA have any other function in the cell other than being a genetic material and carrier of information?
11
votes
1answer
217 views

Evolution of long necks in giraffes

In this question, the OP uses giraffe necks as a supportive example of evolution. Is the mechanism described in this post accurate? At some point, I thought I remember hearing that giraffes did not ...
11
votes
2answers
230 views

Why is there a difference in the rotation of the tail fin in fish compared to marine mammals?

I've been thinking about this one, but I can't seem to find what causes this difference. All fishes that I've seen have their tail fin positioned vertical: But all the marine mammals I know have ...
11
votes
2answers
1k views

How do insects breathe?

Do ants even breathe? If they don't, how do they stay alive? On what resources do they depend upon to stay alive? How are they different form mammals?
11
votes
2answers
77 views

determining genome-wide exogenous binding of pathogens to host genome?

I've read this paper where they specifically modify a region in the rice genome to ablate the binding site of a pathogen, Xanthomonas oryzae, and disrupt the hijacking of a gene network in the rice ...
11
votes
2answers
282 views

Why do pandas have a high probability of giving birth to twins?

According to the BBC documentary "Wild About Pandas", about half of panda birth result in twins. Why do they have such a high probability compared to other mammals? What factor(s) control that ...
11
votes
2answers
5k views

Does an annealing temp higher than primer's Tm contribute to primer dimer?

I am attempting to reproduce results from a number of journal articles all referring to the same SNP. In doing this I'm using the same primer set outlined in the articles. When I attempted a run the ...

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