9
votes
3answers
3k views

How is the fluoride in toothpaste absorbed?

How is the fluoride in toothpaste absorbed by our body? Does the tooth absorb the molecule directly, or is it absorbed by the mouth? The answers to this question suggest that some materials can be ...
2
votes
1answer
74 views

Science experiments at home with Minimal Cost

What is a good recipe for making agar at home for a minimal cost? Are there materials that could be found in the kitchen cabinet?
5
votes
2answers
1k views

The probability of indirect human fertilization?

What is the probability of conception in situations when sperm isn't directly ejaculated into the woman's vagina, like: The man's or the woman's hands come into contact with sperm, for example when ...
3
votes
0answers
115 views

Electrodes in the brain and 'repetitive orgasms' [closed]

The advent of chlorpromazine in 1955 put an end to one of the more bizarre chapters in American psychiatry.$^1$ Dr. Robert Heath implanted wires or delivered injections of acetylcholine (a ...
4
votes
1answer
201 views

Local storage of NCBI database in MongoDB [closed]

My short term goal in a project is to build a local database of the NCBI dbSNP database. The data and schema are available on the FTP site(). I was going to implement the database using MySQL, but I ...
7
votes
1answer
195 views

What is the best file format to store gel images?

I store many gel images which are included in my Latex notebooks. The geldoc software normally produces TIFF files, however, Latex only accepts PNG or JPEG. If I am going to store only a single copy ...
3
votes
1answer
297 views

What does 'H' in BamHI stand for?

It's not explained on the wikipedia page. So if, apparently, 'H' is not relevant, why is it part of the name? And if it is relevant, why is it not explained?
2
votes
2answers
92 views

Databases for metabolic pathways of human disease

Which databases contain the metabolic pathway of human diseases? I have searched Metacyc and KEGG but didn't find the appropriate metabolic pathway.
2
votes
2answers
90 views

Is the tomato a very very close relative of the pepper?

I ask because if you look at a tomato, the way it grows on a vine, its color, the texture, and make up of its skin and internal structure it seems very much like a pepper. The only thing I can think ...
0
votes
2answers
112 views

alpha tubulin molecular weight problem

Is there any academic reference that shows α-tubulin is around 50-55 kDa? The only thing I found is some data sheets from companies. I need the real reference.
4
votes
4answers
10k views

Why are mosquitoes repelled by smoke?

A well known way to have a rest of mosquitoes during camping is to stand in the fire's smoke. Moreover, I learned recently that shepherds in certain regions of Africa use the same tactic for cattle. ...
2
votes
2answers
133 views

What are the naming conventions for mutations of proteins?

I have been reading about Maltose Binding Proteins. Mutant forms of the molecule seem to be named MalE_ where the _ represents a number, for example MalE36 or MalE50. Please can someone explain the ...
0
votes
1answer
39 views

Can TGF beta family induce all somatic stem cells?

I think this is not possible. Conclusion about this preview article TGF-$\beta$ family signaling in stem cells: While TGF-$\beta$ family signaling regulates stemness of normal and cancer stem ...
0
votes
2answers
148 views

Can jellyfish swim backwards?

Jellyfish use jet propulsion to move forward, according to http://earthsky.org/earth/how-do-jellyfish-swim. Otherwise, they drift with the ocean currents. Does this mean that, without the presence of ...
2
votes
1answer
57 views

Why some neurons are tetraploid

Why are some neurons tetraploid, and how does this result from it's ancestor cell ?
1
vote
2answers
446 views

How many recombination events are there per generation in humans?

I'm looking for a reference that tells me how many recombenation events occur in humans from one generation to the next. Assuming that the human genome is a 3.3 GigaBases long DNA sequence, how many ...
0
votes
1answer
51 views

Does melatonin change the appearance of humans?

Melatonin (not to be confused with melanin) was sold as a wonder drug during the 90s. I remember images of mice, which supposedly got a more beautiful fur. I would like to know whether the effect is ...
4
votes
1answer
8k views

Is there a difference between NADH and NADH2?

I've been reading a lot about the oxidative dissimilation etc, and often I see different sources use NADH and NADH2 in the same reactions. One source uses NADH and another uses NADH2 in the exact same ...
3
votes
1answer
102 views

How is olfactory acuity rated/measured?

Acuity of one's sight is rated on the 20/20 scale. An online search appeared to indicate there is no comparable 'standard' to rate olfactory acuity. How is acuity of the olfactory system rated?
10
votes
4answers
11k views

Do we get 1/4 of our genes from each grandparent?

I know that we get half of our genes from each parent, but does it necessarily mean we get 1/4 of our genes from each grandparent? Or is it possible that we might get say 30% from one grandparent, 20% ...
3
votes
1answer
60 views

Non-fatal / low-harm measurement of Drosophila traits

I am trying to generate some candidate traits to measure in a fitness assay of wildtype outbred (lab population) flies. The key trait I will measure is lifespan. I am looking for some additional ...
2
votes
1answer
59 views

What is the focus distance of a 3D screen?

I've thought long and hard about wheter this is the appropriate section for this question, because I guess it's kind of an interdisciplinary subject. My understanding of stereopsis (please, correct ...
3
votes
2answers
157 views

How does guanidium denature DNA?

Guanidium salts like (G-isothiocyanate) disrupt the hydrophobic interactions inside a protein or nucleic acid and denature it. What happens when hydrophobic interactions in DNA are broken? (I don't ...
3
votes
2answers
243 views

What happen's to a virus's capsid after it injects its genetic material into the host cell?

After a virus (one of the varieties which infects the cell via injection and not endocytosis) injects its genetic material into the host cell, what happens to its protein coat? I would guess that it ...
2
votes
2answers
370 views

Single stranded DNA in gel electrophoresis

From http://www.nfstc.org/pdi/Subject05/pdi_s05_m01_01.htm : ... The separation medium contains a denaturant in order that the electrophoresis is conducted on single-stranded DNA fragments. ...
7
votes
1answer
281 views

Can HIV be transmitted via breastfeeding?

If a pregnant women is HIV positive and she is treated with medicines to deliver a normal child,can she transfer the HIV virus back to her normal HIV free child by colostrum?
1
vote
0answers
60 views

Solunar theory of animal activity

Solunar theory, which states that animal activity in wild (fishes, deer) depends on position of sun and moon in sky. Based on the solunar calender, hunters seek for optimal time for hunting fishes. ...
7
votes
3answers
1k views

Why don't all ants have wings?

Since the new queens-to-be have wings, it means that ants either evolved from insects that can fly, or insects that can fly evolved from ants, or that we have a case of parallel evolution (which is ...
2
votes
1answer
68 views

Why is duck fat less saturated than cow fat?

Why does the composition of fat in animals vary? Is there an evolutionary advantage to producing fat that is less or more saturated?
0
votes
1answer
63 views

Why are some chemical dangerous to aquatic environment only?

Recently I was changing the thermal grease on my PC. I have noticed on the back of box, that the grease is not dangerous when ingested or when touched. But there was specifically stated, that is ...
2
votes
1answer
304 views

Anaerobic respiration choice in E. coli

Under anaerobic conditions E. coli has two options to generate ATP: fermentation (substrate-level phosphorylation), and respiration (proton gradient, chemisomotic phosphorylation). Which is favored? ...
1
vote
1answer
74 views

Anatomy suffixes?

Here are some suffixes I want to know their meaning: -ium: trapezium (carpal bone) -ius: trapezius (column muscle) -ous: Talous and calcanous (tarsal bone) -alis: Acromialis, Ulnaris (shoulder ...
8
votes
1answer
825 views

How do Benzodiazepines induce Rewarding (Euphoric) effects?

Benzodiazepines are a class of drugs that serve as positive allosteric modulators of the GABAA receptor by binding to their own "site" on the aforementioned receptor. By doing this they produce ...
48
votes
1answer
13k views

Why do Humans not produce Vitamin C like other mammals?

Why do most mammals produce their own Vitamin C? Why do Humans not?
2
votes
1answer
46 views

Allergic rhinitis vaccine

Note : Any answer to this question will not be (and should not be) taken as medical advice. One of my friends has allergic rhinitis and has been prescribed an oral vaccine. He is allergic to 3 ...
4
votes
1answer
149 views

Epistasis Involving Multiple Loci

The following problem is from Schaum's Outlines on Genetics, 5th edition, by Elrod and Stansfield. I'm having some trouble solving it. It is found under a section entitled "Interactions with Three ...
9
votes
3answers
11k views

What's the worst that can happen from eating too many spicy peppers? Can you die?

Some peppers, such as the habanero or Carolina reaper are extremely spicy, and when eaten in larger amounts than one is accustomed to, can cause some discomfort. I've also heard anecdotes claiming ...
2
votes
1answer
71 views

On which part of the DNA will the new DNA nucleotide connect? [closed]

My question is: Where will the new DNA nucleotide connect on the (part of the) DNA shown on the picture? Will it connect to the phosphate group? What does the 5' --> 3' mean? Thank you in ...
3
votes
1answer
718 views

Death by exsanguination not painful?

Several places on the internet seem to purport that animal sacrifice is painless because exsanguination causes no pain. That sounds unscientific to me and an attempt to appease culture than than using ...
1
vote
0answers
104 views

Why does low temperature make RuBP, GP and TP concentrations fall in Calvin cycle?

In my A level revision guide and places on the internet it states that at low temperatures levels of RuBP, GP and TP all fall. However I don't quite understand how this is the case, because as far as ...
3
votes
1answer
83 views

Can frequent ultrasound diagnostics be harmful?

Are there any short or long term effects apparent in tissues if a zone (or the whole) of human body is scanned with ultrasonic waves often?
1
vote
1answer
67 views

Can someone provide resources on human electromagnetic frequencies?

Pardon all of my questions below. I'm basically looking to find online resources regarding my inquiry. If you can answer any of them off the bat, that would be awesome!! It seems that humans and ...
1
vote
2answers
307 views

How are proteins formed?

Somewhere, I have read that we need to consume proteins to make amino acids to make new proteins. What does it suggest? How do we make proteins from proteins?
2
votes
0answers
47 views

$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ ...
5
votes
1answer
223 views

What happens to fecal matter if it's continually re-eaten?

After class today, the topic of eating one's one fecal matter came up. There was a sharp divide as to how people thought the defecations would change. I realize this is a bit of an odd question but ...
1
vote
1answer
42 views

How does a blunt force stimulate histamine to develop early stages of inflammation?

I know that viruses and sharp forces can stimulate mast cells by cut or by a virus infecting them and then release histamine. How can blunt force do this and cause inflammation? It doesn't have the ...
1
vote
3answers
190 views

Are hens and roosters the same species?

I know that one is a female chicken and the other is male chicken. Are the chickens laying eggs considered the same species as those that we use for poultry meat? Or, are they different sub-species, ...
1
vote
1answer
85 views

Why are hens so different from other birds? [closed]

Hens lay many eggs during their lifetime (at least, I don't know of one which can lay more eggs) and they can't fly. Compared to other domestic animals it seems to me they are the least capable of ...
3
votes
1answer
961 views

What is the biological function of nose hair?

What is the biological function of nose hair? In general, can we consider underarm hair and pubic hair to be vestigial structures?
3
votes
2answers
129 views

Highly spherical Radiolaria; does this image accurately depict the organism?

If I understand correctly, Cenosphaera spp. is a type of Radiolaria, which is a type of zooplankton. The following is an image of Cenosphaera spp. is from the supplementary material (Figure S2) of ...

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