0
votes
0answers
19 views

Homology ratio comparison between different species

I found the following homology ratio: protein coding genes of the organism with an homolog in mouse / all protein coding genes in the organism I have done this for all protein coding genes between ...
4
votes
2answers
2k views

Why does yawning impair hearing?

When I yawn I can't hear anything happening around me. I also feel some kind of muscles inside my head contract and hear a faint hum, but it is not loud enough to explain not hearing other sounds. I ...
18
votes
2answers
373 views

How is menstruation not suicide in the wild?

Watch any wilderness special for more than a few minutes, and you'll notice a familiar pattern: when a predator catches the scent of blood on the wind, the hunt is on. Wounded animals make the best ...
3
votes
1answer
34 views

What color was the most recent common ancestor of all swans?

Was the most recent common ancestor of all swans black, or white, or some other color? How do we know, and how certain can we be?
1
vote
1answer
56 views

Amino acid compatibility

The (human) genetic code encodes 20 amino acids. They form a protein using peptide bonds. Each amino acid has a carboxyl group (COOH) and an amino group (NH2) that can potentially form a peptide bond. ...
2
votes
1answer
16 views

Is it possible to accurately measure micronutrient levels with the blood volume from a Dermal / Capillary puncture?

I have not been able to find much information beyond what tests are normally done with Capillary puncture sampling, as opposed to what tests are possible. Could we test for a single micronutrient, or ...
1
vote
0answers
16 views
2
votes
2answers
166 views

Using an analytical balance (0.0000 precision) to measure µg (micrograms)?

If i needed to prepare 200µg/ml of proteinase K, and the proteinase K was in a solid powder form, would I have to weight out 200 µg using an analytical balance, and if so, is it possible with a ...
0
votes
0answers
14 views

Steps in making mass/volume concentrations? [duplicate]

[TLDR When making mass/volume concentrations, is the general workflow to make a stock and dilute from it to yield the proper diluted concentrations? Could anyone detail their methodology on the ...
4
votes
1answer
55 views

How pain can stimulate the vagus nerve

I'm trying to find out why a prompt, severe, short pain is causing a stimulation of the vagus nerve. What could the physiological explanation be? Is that because the pain is triggering the ...
1
vote
0answers
24 views

Why can't some organisms match miRNA perfectly to the target mRNA like in plants? [on hold]

What causes other organisms to be impaired in making perfect matches like plants do and is there a way to increase matching?
1
vote
1answer
37 views

MHC restricted peptide

What is an MHC restricted peptide? "MHC-restricted antigen recognition, or MHC restriction, refers to the fact that a given T cell will recognize a peptide antigen only when it is bound to a host ...
8
votes
1answer
120 views

Why don't birds in flocks fly into each other?

I've seen videos of hundreds of birds flying in the same general direction but creating incredible patterns in the sky seemingly instantaneously! How do they all know in what direction to turn at the ...
2
votes
1answer
56 views

Can silverfish climb and produce silk?

I am equally disgusted and fascinated by the "Silverfish" (Lepisma saccharina) that we regularly find in our UK home. I tried searching for information on the internet but they seem poorly understood. ...
15
votes
9answers
5k views

Why didn't the polar bear change its color from white to black during evolution to absorb heat?

Polar bears are white in color and white color is not a good absorbant of heat. Why then didn't they evolve a black color to absorb more heat?
5
votes
2answers
46 views

What percentage of a cell's volume is occupied by protein?

I was looking at one of David Goodsell's illustrations of a cell: And it seems to suggest a very crowded picture of the intracellular environment. Just how crowded are cytoplasms? What percentage ...
13
votes
2answers
1k views

How do birds deal with their eyes drying out at high speeds?

My eyes tear up when cycling at 15 mph, which is nothing compared to bird airspeeds. Do birds continuously produce lots of tears and blink a lot, or do the eyes self-moisturize from the inside ...
3
votes
2answers
221 views

Can someone who cannot talk still whistle?

Can someone who has a damaged larynx, which does not allow them to talk, still create a tune when they whistle? I know that the larynx is what allows a person to manipulate their pitch and volume, ...
2
votes
1answer
30 views

Is the Klein's bottle a good analogy to the relation between T-tubule and sarcolemma? [on hold]

I am not quite seeing how the T-tubule and sarcolemma is connected. It says that the T-tubule is an "invagination" of the sarcolemma, which is sarcolemma folded from the inside to form a T-tubule Can ...
6
votes
1answer
45 views

Why can good music raise goosebumps?

Listening to really good music right now, I was wondering why it raises goosebumps. Is there any physiological reason for this reaction to specific wavelengths or something? EDIT: Due sometimes ...
1
vote
0answers
34 views

Primer Designing [on hold]

I have a basic idea about the requirements in primer designing. Basically my knowledge is limited to theoretical knowledge and have no experience in actual primer designing. And also I have a basic ...
0
votes
2answers
20 views

Risk of autosomal dominant disorder [on hold]

What can you conclude about the risk (with each pregnancy) that a couple could have a child affected with an autosomal dominant disorder if... One parent is affected (heterozygous) and the other ...
7
votes
2answers
8k views

Why are 3 nucleotides used as codons for amino-acid mapping in DNA?

DNA is made of 4 unique nucleotides. When coding for a protein, a sequence of 3 nucleotides is used to code for each amino acid. Why are codons 3 nucleotides in length? A related question can be ...
1
vote
1answer
47 views

How detachment/separation works in biology?

It might be a strange question, but I'm interested in the mechanics of separation/detachment during asexual reproduction, for example when an organism reproduces by budding (I don't mean cellular ...
19
votes
4answers
2k views

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

When a human being exhales CO₂, 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 ...
2
votes
0answers
37 views

Examples of Vestigial Genes

I consider the existence of a broken GULO gene in humans to be the clearest evidence for human evolution - just what else is it doing there otherwise? Are there any other examples of vestigial genes ...
0
votes
1answer
40 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
6
votes
2answers
105 views

Is there a biological neuron that spikes in response to hyperpolarizing currents?

As some background I've been building Electrophysiological models of neurons, and in the process stumbled upon a model, that in all respects is biologically plausible, but has a bizarre property I ...
2
votes
0answers
25 views

Contact Inhibition of Cell Division: Signaling Pathway

The following article refers to contact inhibition of cell division in epithelial cells, specifically MDCK cells: Collective and single cell behavior in epithelial contact inhibition. In their review ...
7
votes
4answers
846 views

Is there any way a human could whistle and be unable to speak?

Is there any situation anatomically, where a human could understand the speech of others perfectly, without any capabilities of speech themselves, but would retain the ability to whistle with a tune? ...
5
votes
2answers
72 views

Do changes in an organism's cell modify the genetic information it uses for reproduction?

What I'm actually interested about is whether a modification in one cell during the life of an asexually reproducing organism affects its genetic information? Which cell's genetic information is used ...
0
votes
0answers
38 views

How much of the biological research can be still run without high-cost high-precision instruments? [on hold]

To me it seems like much of the biological research today requires an array of expensive devices before it can be run. How much of the current research could be still done with a basic compound/stereo ...
3
votes
0answers
41 views

How does an organism know when to stop growing, whether it is already on the outermost layer? [on hold]

When a multicellular organism is under its development how does the current outermost layer of cells "know" that they should not divide furthermore, as their bodyplan coded into DNA is already ...
13
votes
2answers
2k views

Is it known how the first viruses formed?

The oldest known virus is known to have infected prehistoric insects 300 million years ago. A virus is basically a parasitic strand if DNA or RNA encapsulated in a protein coat. It enters cells by ...
1
vote
1answer
141 views

What is the blood ejection speed outward from human body vein? [closed]

At what height blood can eject from human vein ? I see, sometime there is direct blood transfer from one person to patient. So sometime blood bottle is kept at certain height and blood is transfered ...
2
votes
0answers
32 views

How to get only perfect matches with blastn?

I have installed Blast locally and I've configured the nucleotide database to use. I want to search some sequences (from a .fastafile) in this genome. So I used blastn: ...
3
votes
1answer
29 views

How to determine genotype?

In humans, the ability or inability to roll the tongue is a single gene trait. The allele for tongue rolling (R) is dominant to the allele for not being able to roll the tongue (r). Whether ...
5
votes
1answer
48 views

Genes-of-interest analysis between organisms

I am interested in identifying the differential expression between several genes-of-interest of different organisms. I am trying to assess the benefits of RNA sequencing over microarrays. Both ...
6
votes
1answer
10k views

Can dish soap really be used to kill ticks and fleas?

An answer at Pets suggested using dawn dish soap to kill fleas. I did a little looking around, and found several references supporting the idea. Most of what I found was in 'selfhelp' and 'save a ...
0
votes
0answers
39 views

Punnett Square X-linked [on hold]

Color blindness is an X-linked recessive disorder. Maria has the genotype X^B X^b What is her phenotype? I put NOT COLOR BLIND Maria's husband Carlos has the genotype X^B Y I put that his ...
11
votes
6answers
3k views

What is the use of eye banks, if eyeball transplants do not exist at present?

Corneas are donated and transplanted, but not the eyeball. I don't understand. What is the purpose of donating a cornea without an eyeball to a blind person?
6
votes
3answers
2k views

Why do we squint when tasting very sour things?

Sometimes while tasting a very sour thing (like tamarind, lemon etc.) our eyes squint immediately and involuntarily for a second, but a little later becomes normal again. Why, and how, does this ...
7
votes
1answer
777 views

Where is the aneurysm in this picture?

I'm a curious person, I've never had any medical training, but I wish to know some more about aneurysms. Aneurysms are basically weakened spots in the elastic artery wall. This can eventually result ...
-3
votes
1answer
29 views

Blood Type/Punnett Square [on hold]

Male: Blood type O (Genotype written as: i^o i^o since O allele is recessive to the A and B alleles). Female: Blood type AB Draw a punnett square to show all of the possible offspring. I got Ai^o, ...
7
votes
2answers
38 views

Naming convention of miRNAs

I'm trying to understand naming convention of miRNAs. I've found the wikipedia article about it nomenclature Based on it, I try to figure out what is hsa-let-7a. As far as I understood, hsa refers to ...
1
vote
1answer
34 views

Serious question about a piece of meat

Does anyone know some scientific rigorous way to look at a slice of meat. I am not asking what kind of meat it is or which part of the animal it came from. I wonder what is the different lining on ...
1
vote
1answer
27 views

What factors, other than its homochirality, make our “brand” of biology unique? [on hold]

If humans were to discover organisms on another planet, it is supposed that (unless both we and they were seeded by the same source) we would have nothing to fear from alien pathogens, as they would ...
2
votes
1answer
19 views

Why are skin tactile receptors considered to be phasic receptors?

A phasic receptor by definition is one that quickly adapts to change. In terms of neuron firing, this means that it does not trigger another firing because the receptors are used to the stimulus. But ...
-2
votes
0answers
19 views

Punnet Square help [on hold]

Just wanting to make sure I am doing this correctly. Given: R dominant allele for able to roll tongue r not able to roll tongue T dominant allele for taster of PTC t not able to ...
21
votes
6answers
5k views

Why is cold water more refreshing than warm water?

Obviously, the temperature of water does not affect its chemical composition. At least not in the ranges we are likely to drink it in. Yet it is clearly far more pleasant and refreshing to drink cool ...

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