All Questions
11
votes
1answer
142 views
What histological stain can I use for beta-keratin?
I'm trying to find a histochemical stain for beta-keratin, the type found in Reptilia which is organized in beta-sheets. It's different than alpha-keratin which is found in mammalian skin, hair, ...
11
votes
1answer
126 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 ...
11
votes
2answers
806 views
Why do cockroaches flip over when they die?
This question has always mystified me since young. For beetles, I can reason that they flip over because they have a higher centre of gravity causing them to be in unstable equilibrium when they tuck ...
11
votes
1answer
72 views
Does a theory exist for the formation of thylakoid structure?
I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to ...
11
votes
1answer
188 views
What are the limitations to current nucleotide sequencing technologies?
Using the Illumina platform, it is cheap and (relatively) easy to sequence huge amounts of DNA or RNA. There are various other platforms out there (Roche/454, SOLiD, PacBio, Ion Torrent) each with ...
11
votes
1answer
187 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 ...
11
votes
1answer
104 views
Has the human 7-day week had any impact on the evolution of species?
Most (if not all) industrialized countries follow a 7-day work week now, such that we are bound to follow a certain weekly trend in matters such as pollution generation, where to go (e.g. stay in town ...
11
votes
1answer
383 views
Given ATP synthase's structure, how can 3.33 protons ultimately synthesize one and only one ATP?
I am familiar with the structure and function of ATP synthase, but one small detail doesn't seem to make sense. It also happens to be a detail that seems very hard to express.
Depending on the ...
11
votes
1answer
127 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 ...
11
votes
1answer
218 views
How much energy does human body fat contain?
I have been reading the Wikipedia article about food energy, but as I'm not a biologist, I don't really understand it properly, so I came here to ask you guys.
My question is: If a human body needs X ...
11
votes
1answer
147 views
Why do some trees have a life span, while some don't?
I have heard that there is no limit on the growth of trees, but then why do some trees, such as boxelders and poplars, tend to live shorter than redwoods, for example? Some advertisements for improved ...
11
votes
1answer
111 views
How would one calculate the availability of nucleotides to an enzyme?
How would one calculate the availability of nucleotides to an enzyme like a polymerase ?
I imagine an answer in units like nucleotides per second per enzyme, but I'm also imagining an answer that is ...
11
votes
1answer
279 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
0answers
102 views
How straightforward is in vitro compartmentalization?
in vitro compartmentalization (IVC) is one of those technologies that everyone knows about, talks about, but never actual does due to the rather technical difficulties in setting the system up. I was ...
11
votes
3answers
254 views
How did the huge dinosaurs cope with gravity and loads on bones, etc.?
It's very costly to be a huge animal. Your mass grows in cube when you scale up, but you still only have two/four legs to support the same weight. This increases the pressure that your body needs to ...
10
votes
3answers
284 views
What is the most heat-tolerant organism?
What is the most heat-tolerant (or heat loving - hyperthermophile) organism so far identified? What adaptations does this organism have in order to endure such high temperatures?
10
votes
5answers
1k views
How did the first self replicating organism come into existence?
When people try to explain evolution, they tell me that evolution is a cumulative result of mutations & natural section of the more superior individuals of a particular species. I think I'm fairly ...
10
votes
2answers
6k views
What is a coupled reaction and why do cells couple reactions?
I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
10
votes
2answers
156 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 ...
10
votes
2answers
269 views
Could hydrogen replace oxygen in cellular respiration?
I was wondering what oxygen actually does in the body. I have seen a few answers to other questions that involve the electron chain and I am really not sure what that is. So I was wondering what ...
10
votes
3answers
189 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 ...
10
votes
4answers
192 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.
10
votes
2answers
141 views
Why is the microbial ecosystem of the gut so susceptible to disruption by pathogens?
From all accounts, it seems as if the Escherichia, Enterobacter, etc. that live and thrive in the human gut are pretty well entrenched. I know that these microbial populations are often analyzed as ...
10
votes
2answers
402 views
Why are restriction enzymes not frozen?
We all know restriction enzymes are proteins, but we never freeze them. They are instead provided in high glycerol containing solutions by companies and stored at -20C. Is there a reason why this is ...
10
votes
3answers
433 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 ...
10
votes
1answer
146 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. ...
10
votes
3answers
256 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 ...
10
votes
1answer
332 views
Do large animals often evolve into smaller animals?
There are several examples where the largest animals were killed off preferentially due to a major ecological shift:
The KT extinction event
The Holocene extinction, as well as the major megafauna ...
10
votes
1answer
161 views
Could a fetus properly develop in micro/zero-gravity?
I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses?
And if things would go wrong, what sort of things would they be, and what would be ...
10
votes
2answers
187 views
What is the highest competency possible for E coli?
I am looking to find a highly competent E coli strain. I am making a library of a ~6.6kb plasmid and I am not getting high enough efficiency. Does anyone have a suggestion of a strain/protocol with ...
10
votes
3answers
98 views
How do baby animals that primarily subsist on cellulose get their initial gut flora?
In the case of mammals like giraffes and koalas, is that bacteria common on the plants they eat so when a baby starts to try to stick something besides its mother's milk in its mouth, it can't digest ...
10
votes
1answer
182 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 ...
10
votes
2answers
137 views
Can DNA produce ribozyme-like structures?
RNA is known to act as an enzyme via its ability to fold itself in specific ways.
Is DNA capable of such structures? Or is it some biochemical reason stopping the folding?
Have they been observed in ...
10
votes
1answer
201 views
Does electricity cause damage on a cellular level?
As I understand it the mechanism of death when a mammal is electrocuted is that the current disrupts the SAN/AVN in the heart causing it to fibrilate or arrest. That's on a macro scale, however. ...
10
votes
2answers
2k views
How do I clean phenol contaminated RNA without losing any of the sample?
I recently extracted RNA from developing plant leaves for the first time, as part of a very long and intensive experiment. The samples were extremely precious because of the amount of effort that went ...
10
votes
2answers
259 views
Could an “overactive” brain increase the chances of Alzheimer's Disease?
From Raichle ME. 2010. Two views of brain function. Trends in cognitive sciences 14: 180–90:
Alzheimer’s disease (AD) is the most common cause of progressive
cognitive decline and dementia in ...
10
votes
2answers
150 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 ...
10
votes
1answer
165 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 ...
10
votes
2answers
192 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 ...
10
votes
2answers
299 views
Antibacterial hand soaps (and related products); what are they good for?
From Wikipedia:
Household use of antibacterials in soaps and other products, although not clearly contributing to resistance, is also discouraged (as not being effective at infection control).
...
10
votes
1answer
255 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 ...
10
votes
2answers
124 views
How deep in the soil can a seed be placed and still develop into a plant/tree?
The selected answer to How does a plant grow before photosynthesis is possible? indicates that a sprout grows beneath the soil using the food stored within the seed.
Does this limited ready food ...
10
votes
2answers
470 views
Why do only only two sexes exist for animals?
Why, from the natural selection point of view, do only two sexes exist for animals?
10
votes
1answer
980 views
Fish “coming back to life” after being frozen
I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says:
For everyone ...
10
votes
3answers
382 views
Why do restriction enzymes tend to have an even number of bases in their recognition site?
When reading my textbook I noticed that in all examples but one from eight the recognition site was an even number of bases.
I wondered if this was just a co-incidence, so I took the data from this ...
10
votes
1answer
2k views
Why does scar tissue change color?
I was wondering why, when you are cold, scar tissue turns bluish or purple while original skin stays the same color.
The only thing I can think of, is that maybe scar tissue gets less circulation ...
10
votes
2answers
3k 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 ...
10
votes
2answers
1k views
Why is a lack of oxygen fatal to cells?
In animals temporary anaerobic respiration leads to the breakdown of the pyruvate formed by glycolysis into lactate. The buildup of lactate in the bloodstream is accompanied by a large number of ...
10
votes
2answers
157 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
220 views
How would I explain different properties of the same protein in different species?
I recently finished an experiment where I analyzed the rate of ATP hydrolysis of Heat shock protein 104 in three species of fungi. They have shown to all have different rates of ATPase activity. How ...
