4
votes
2answers
143 views

Why sleep? No, actually, why wake?

I was just reading the sleep threads, and I wondered, why is the body so constructed so that sleep is necessary? (Is it just a design error?) But then, how do things come to be awake at all? How did ...
1
vote
0answers
20 views

Segregation Analysis for predicting age-specific cancer risk

I am relatively new to the world of genetics research and have been tasked with presenting to my lab the potential value of a paper that uses Complex Segregation Analysis for a risk analysis. The hope ...
2
votes
1answer
23 views

Transcription rate expressed in microarray per hour

This article gives measurement of transcription rate and the unit they're using is microarray per hour. For example, at 27°C the average expression of their genes is 236.1 microarray per hour (page ...
1
vote
0answers
23 views

Difference between thylakoids and lamellae in a chloroplast?

I'm slightly confused as to the difference between thylakoids and lamellae. My understanding was that thylakoids are 'discs' that are stacked into grana and there is a membrane between the grana ...
2
votes
2answers
199 views

Why does a blood test show ethanol when no alcohol was consumed?

Why would ethanol show up in a blood test if a person had not been drinking alcohol in many years. What are other reasons for showing ethanol?
0
votes
0answers
22 views

Is there sugar secreted into blood even after complete digestions in healthy humans? What about dogs?

Suppose we're feeding a high GI food to a person and that the digestion lasts five hours. Does the body secrete sugar into the blood afterwards? What about in diabetic dogs and humans? Update: I am ...
1
vote
2answers
829 views

NaCl role in CTAB - DNA complex in DNA extraction

I have a question about the role of NaCl in the DNA extraction process. So for NaCl concentrations under 0.5M, CTAB and DNA molecules can create complexes. In those concentrations, proteins and other ...
34
votes
2answers
6k views

Do ants or other insects sleep, and if so why?

I was thinking yesterday about insects (as there was a spider in the house, and I couldn't help but think of anything else, even though they aren't insects), and I started to wonder if ants sleep? ...
3
votes
2answers
33 views

where to find the relative frequency distribution of synonymous codons

Most amino acids can be encoded by more than one codon. For example, Serine can be encoded by any one of ...
0
votes
1answer
12 views

what is the function of satellite in a chromosome?

What is the specific function of a satellite in a chromosome ? How are sat-chromosomes different from others ? On molecular basis, what are the functional advantages of it ?
8
votes
2answers
1k views

What would happen if one eats silica gel?

What happens if one actually does go about eating the beads in those "do-not-eat" packets?
0
votes
0answers
17 views

DNA extraction from oil-containing seeds

Which protocol of DNA extraction from plant oil-containing seeds take fast and good result in purity that can use in RT-PCR(Real Time polymerase chain reaction)?
47
votes
11answers
10k views

Can humans survive without consuming life? [closed]

Some people say that it's awful that humans eat animals. They feel that it's barbaric, because you're killing life and then on top of that, you're eating it, and that you should eat vegetation ...
2
votes
1answer
46 views

Is this a grackle with an unusually long decurved bill (Phoenix AZ, USA)

Can someone help me identify this bird (sorry only had the iphone)? It looks like a grackle, but the bill is much longer than any I have seen. The bill looks like a Le Conte's thrasher, but it was all ...
11
votes
3answers
149 views

Why can white hairs get dark again?

I have learned (probably in high school?) that hairs turning white is caused by the part of the folicle which produces the pigment dying and being replaced by an air bubble. This sounds very ...
3
votes
1answer
39 views

Trisomy 21 XXY & X-inactivation

I read that X-inactivation doesn't tend to happen in males, but then when someone is XXY, they are a male because of the Y. However these individuals tend to live. So does that mean that ...
6
votes
1answer
810 views

Chest muscle and female breast size

Do female chest size have anything to do with muscle? I know many female athlete and their average breast size is much bigger than normal female that does not tend to play sports. Do this have any ...
39
votes
1answer
4k views

Do bacteria die of old age?

I know that the cells of mammals at least stop dividing when they are old, and then die a programmed cell death. Then other cells have to replace them. But in a bacterial colony, each cell ...
4
votes
1answer
31 views

Can a single axon propagate multiple simultaneous action potentials?

I have not been able to locate any research that indicates whether a single axon of a neuron or nerve cell can conduct multiple simultaneous (i.e. spatially separate) action potentials. I am aware ...
4
votes
2answers
354 views

Rate of cell division in humans

On average, how many cells divide each day in a human being? How long does a cell wait before dividing itself ? I have tried to look on the internet but surprisingly the answer is difficult to ...
3
votes
2answers
89 views

Ni-NTA purification, problem with the chaperone protein

I'm trying to purify the protein by Ni-NTA affinity chromatography. It seems that my protein (size about 54 kDa) is co-purified with chaperone protein (probably GroEL - as the band is around 57kDa). ...
1
vote
2answers
55 views

Is the mutation rate in organisms in general consistent over the genome?

Coming from computer science with an interest in genetic programming (a process emulating evolution) I'm curious about whether the rate of mutation is homogeneous across the whole genome, or if some ...
12
votes
3answers
407 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 ...
3
votes
1answer
37 views

Does human eye lens have a magnification of its own?

I have always wondered if the lens in our eyes have any sort of magnification by default. And if yes, if we're actually seeing everything around us bigger/smaller than what they actually are! Has any ...
3
votes
1answer
29 views

SEREX serological analysis of cDNA expression library

What is Serological Analysis of cDNA expression library? I went through this article:http://cancerimmunity.org/serex/introduction/ but could not really make out. Can someone please explain this to me ...
19
votes
3answers
20k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
2
votes
1answer
25 views

Effect of 260/230 values on PCR

To what extent does the 260/230 value affect the efficiency of PCR reactions ? Do the constituents leading to a low 260/230 value (EDTA, guanidine salts and oligosaccharides) inhibit PCR ? I have been ...
0
votes
3answers
78 views

Conscious evolution

Does intelligence play a vital role in the evolution of an organism? In other words does an expansion of learning capacity increase the odds of evolution for the particular biological entity?
1
vote
2answers
41 views

What kind of spider is this? And is it dangerous? (photo)

I found this spider hanging from a web off the side of my house (in Buffalo, NY). It's probably 3-4in total length. Any thoughts on what kind of spider this is? And if it's dangerous?
0
votes
0answers
11 views

Stress-responding enhancer?

I wonder if anyone knows a well characterized human enhancer which has been shown increased activity (in e.g. reporter assays) under stressed conditions, such as DNA damage, hypoxia, ...
1
vote
0answers
34 views

Why are carnivorans more efficient predators than birds or reptiles?

The Wikipedia page on island gigantism says, "Birds and reptiles generally make less efficient large predators than advanced carnivorans. What does it mean for a predator to be "efficient" and why are ...
0
votes
0answers
16 views

Difference in structure of B-cell epitope and T-cell epitope

What is the difference in the structure of B-cell epitope and T cell epitope? Also please enlighten me with the fact of discontinuity or conformation of the b or t cell. Went through a number or ...
2
votes
0answers
28 views

Why Hasn't my Cactus Grown Deadly Spines?

I recently purchased a small cactus plant from my local store for about $5. I've been giving the cactus lots of sunlight and a good watering every week. I've noticed that since I bought it, the ...
1
vote
1answer
65 views

What is the difference between second and third generation sequencing

I am writing the section about history of DNA sequencing in the introduction chapter and after reading quite a few research papers, I am still confused about them. Here I compile some questions to ...
1
vote
0answers
17 views

Enzyme Assay - pectinase

During assaying an enzyme at high temperature, the substrate (Pectin) is degraded by the high temperature rather than by enzyme, so, how can I minimize degradation of the substrate by the temperature? ...
1
vote
0answers
20 views

Gymnosperm Spores and Seeds

In gymnosperms, what is the difference between spores and seeds? My textbook does not explain it clearly. Are seeds released during reproduction or are the spores released during reproduction? In the ...
4
votes
1answer
42 views

Why do I see so many handicapped dorbeetles?

Living in southern Germany, I often visit nearby forests and pastures. From early spring to autumn, I frequently see lots of dorbeetles on my wanderings. An estimated amount of 50% of those bugs seem ...
3
votes
2answers
134 views

Definition of “Effective population size”

Could you explain to me, what is the meaning of "Effective population size ($N_e$)"? I would appreciate an example as well.
3
votes
1answer
23 views

What is meant by drug tolerance?

What is meant by drug tolerance? This question is in my biology textbook for IGCSE and I have no idea what drug tolerance is. It would be very helpful if someone could clarify. Thank you.
1
vote
1answer
26 views

DNA Fingerprint

I recently came across an article indicating that the half life of DNA in the most ideal situations is 521 years (http://www.nature.com/news/dna-has-a-521-year-half-life-1.11555). However, since ...
0
votes
0answers
26 views

Why aren't whales more wary of boats?

Whales of many species were hunted to near extinction in human memory, and in whale memory too. I'd imagine that some whales took no notice of boats, and others tended to avoid them, so that hunting ...
5
votes
1answer
132 views

Importance of knowing GC Content of an organism

I was looking at the GC content percentages of few organisms. I also know calculating the GC content percentage. But, what I want to know is, what information would we get., let us suppose if human ...
0
votes
1answer
21 views

Chromatids in metaphase?

Please see the following picture: In my book, the author claims that these chromosomes are in metaphase (a metaphase stopped by cholchicin). I don't understand why they don't have two ...
6
votes
1answer
68 views

What does “Mutational Variance” mean?

Background The concept of mutational variance can be found in many articles including this one for example. The mutational variance of a trait number $i$ can be found in the M-matrix in position ...
1
vote
1answer
22 views

Complementarity Determining Regions (CDR)

Complementarity determining regions (CDRs) are part of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively, where these molecules ...
2
votes
1answer
108 views

Why do we absorb vitamins better from whole foods than from pills?

We can't rely on pills to provide us our nutrients because we don't absorb the nutrients from the pills as effectively. Presumably this is because pills are lacking components that are required for ...
5
votes
2answers
825 views

Do octopuses have better eyes than humans?

I've read that unlike humans, octopuses have eyes "designed" the "right way", i.e. with the nerve fibers behind the retina, thus getting rid of the blind spot we humans have as well as theoretically ...
1
vote
2answers
54 views

Is there a medical condition in which you can't cut your hair?

Just curious, does there exist a medical condition in which a patient is advised not to or simply cannot cut their (head) hair?
1
vote
2answers
93 views

Is greed an evolved trait?

Thanks for looking. I am not a biologist, but I am fascinated by evolution. I was watching the news this morning and, as so often is the case, there was a news story about a corrupt politician who ...
2
votes
2answers
35 views

What does it mean to perform in vitro experiments with mutant bacteria?

I came across the following sentence while reading the paper: Nanchen, Annik, et al. "Cyclic AMP-dependent catabolite repression is the dominant control mechanism of metabolic fluxes under glucose ...

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