0
votes
0answers
46 views

Why aren't D-amino acids used in proteins? [duplicate]

Possible Duplicate: Why are amino acids in biology homochiral? Why are only L-amino acids used in protein construction, and not D-amino acids?
7
votes
2answers
4k views

At what age do babies begin to synthesize their own antibodies?

When babies are first born, they receive their antibodies from their mother (I assume because they do not yet have the capacity to synthesize their own). So my question is, at what age do babies ...
2
votes
1answer
100 views

Photosynthesis - Light Intensity

Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis?
6
votes
1answer
94 views

Cooking with sawdust

In a book about post-war Japan (Embracing Defeat, Dower) the author mentions a process for making sawdust at least partially edible, so it could be used in recipes in a 1:4 ratio with flour for ...
2
votes
1answer
100 views

What is the cannabinoid autoreceptor?

"Is there a cannabinoid autoreceptor? And if so what is the cannabinoid autoreceptor?" (i.e. is the cannabinoid autoreceptor CB1, CB2 or is it one of the G protein coupled receptors, GPR18, GPR55 or ...
4
votes
2answers
237 views

Effects of exercise on the brain

I am well aware of the phenomenon of neurogenesis induced by exercise, as well as the dopamine release that results from exercise. I am really interested in neuropsychology and the effects of exercise ...
-2
votes
2answers
216 views

Why human body cannot defend against HIV? [closed]

Some says that HIV destroy IRF3, and some says HIV overruns T-cells.
5
votes
3answers
190 views

What is the inbreeding coefficient for the female offspring of a sib-mating in a haplodiploid system?

The inbreeding coefficient of a sibling mating for a diploid organism is 0.25 (each allele has a 25% of being identical by descent in the offspring). In haplodiploid organisms, males result from ...
3
votes
3answers
5k views

What type of cell do you start with in Meiosis?

Okay, I was learning about mitosis and meiosis in school and had a question. I know in Mitosis you first start off with a Diploid (2N) cell and then end up with two ...
4
votes
3answers
100 views

Can a tumor produce something not currently found in our own bodies?

While speaking with my co-workers, the topic of tumors growing things came up. The examples were (and backed by images) of tumors growing a tooth, hair, and sometimes even more complex objects such ...
3
votes
1answer
72 views

What is the extent of the effect of Tris on E. coli?

I was a fool and dissolved my antibiotic (Kanamycin) into Tris Buffer rather than H2O. The Kanamycin still seems to be active but a fellow labmate mentioned that Tris messes around with the membrane ...
2
votes
0answers
37 views

Endocannabinoid Transporters - which ones are Likely to Exist and what is the Evidence for their Respective Existence?

Endocananbinoid = Endogenous Cannabinoid or CB1 and CB2 ligands. I'm asking which endocannabinoid transporters exist and could the one answering show all the evidence for the existence of the ...
3
votes
4answers
547 views

What evolutionary reason is there for having the urinary duct and reproductive organs so close together?

As the old joke goes, "God must have been a civil engineer. Who else would put a waste facility straight through a recreational area?" But maybe it wasn't God. Is there any evolutionary reason (or ...
4
votes
1answer
100 views

How is respiration an unbalanced equation

The equation for respiration is C6H12O6+6O2→6CO2+6H2O+36ATP. The chemical formula for ATP is C10H16N5O13P3. How is this possible, since it violates the law of conservation of mass because it is ...
1
vote
1answer
42 views

Does difference in expected life duration between men and women have biological nature?

It is known that men in most countries live less than women. I wonder whether it is due to different life conditions or because male and female organisms differ? For example, I heard that ...
7
votes
2answers
467 views

Do hormone drugs affect whether a person feels sexual attraction to males or females?

I know that ingesting testosterone and other hormonal drugs may stimulate libido and increase sexual desire. But I wonder, if a man ingests female hormones such as estrogen, will he experience sexual ...
7
votes
3answers
271 views

How can you test what color different people perceive?

If I would show someone a yellow object and ask them, "is this object yellow?" That person would say "yes". But I could never know if my perception of the color yellow is the same as that other ...
3
votes
3answers
2k 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. ...
4
votes
1answer
29 views

position of cell penetrating peptide

I'd like to add a cell penetrating peptide to my custom peptide (30aa). Can I just add it to the end of the peptide sequence or does it have to be positioned on an outward facing external chain?
12
votes
2answers
3k views

Why do people have antibodies against other blood types?

The ABO blood type divides each blood type according to whether they have the "A" and "B" antigen(s) (AB has both, O has none). People also have antibodies against the antigens they don't have (AB has ...
3
votes
1answer
323 views

What causes Acne?

What exactly is going on biologically at the molecular level with acne and causes breakouts? Hormonally, there is a lot going on but I'm curious about what is going on chemically.
2
votes
1answer
31 views

What signals histone methyl transferases to function?

I wanted to find out if anyone knows what stimulates histone methyltransferases to function? I know that it is a process still trying to be understood, but I can't find anything that seems to direct ...
1
vote
1answer
288 views

Breathing water vapour

Normal air consist of oxygen, CO2 and nitrogen, with traces of water etc. Now imagine displacing all gasses except oxygen with water vapour. By water vapour I don't mean hot steam or fog. Just ...
4
votes
1answer
268 views

Why do we squint?

Recently, I was having an eye exam and admitted to squinting my eyes to sharpen blurred edges. Later, while waiting for the dilation to set in, my brother (a would-be pharmacist fresh off an anatomy ...
3
votes
1answer
75 views

Regeneration capabilities in humans?

To what extent can humans, (mammals in general), theoretically regenerate, and is their a way to speed up and/or exceed this original extent.
4
votes
1answer
71 views

Is it possible to purify antigens from a vaccine and to separate them from the adjuvant?

I need to separate the antigens from several vaccines in order to use them for coating microplates to run an indirect ELISA. I at least need to remove the adjuvant from the vaccines. Is this possible ...
6
votes
2answers
5k views

Can positive and negative blood type of a couple lead to miscarriage?

I want to know can $+ve$ and $-ve$ blood group of a couple could be a cause of miscarriage in pregnancy?
1
vote
1answer
410 views

What is the difference between average and monoisotopic mass calculations of peptides?

I often have to calculate the mass of peptide sequences using calculators such as here. I have the option of calculating the average and monoisotopic mass, but what is the difference?
5
votes
1answer
485 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 ...
4
votes
1answer
209 views

Why are eggs “egg” shaped?

Is there a reason as to why chickens lay "egg" shaped eggs, as opposed to spherically shaped eggs (or a random shape)? <--- Main Question For extra points (actually just to add more words in ...
2
votes
1answer
3k views

Why are bacteria and archaea in different domains?

As I understand it, the main difference between the Bacteria and the Eucaryota domains are that eukaryotes have a nucleus and bacteria don't. I understand that bacteria and archaebacteria have enough ...
1
vote
0answers
22 views

Does regulate always mean suppress when it comes to heteroreceptors?

Do heteroreceptors always suppress the release of the neurotransmitter they regulate upon their (the heteroreceptor's) activation?
4
votes
1answer
59 views

Parsimony (cladistics)

I don't understand how to sum the changes in a phylogenetic tree. Here for example: http://www.med.nyu.edu/rcr/rcr/course/phylo-cladistic.html How do you end up with 8 for the first and 9 for the ...
4
votes
2answers
53 views

Cell cycle selection

Is it possible to select from colonies only cells which are at a certain stage in the cell cycle? E.g. if I was trying to analyse expression of a number of genes during different stages of the cell ...
7
votes
1answer
5k views

What is the composition of human feces?

Are there any studies or general information on the composition of human feces? I'd specifically like to know the percentage of carbohydrates and amino acids relative to the amount that was ingested ...
1
vote
0answers
47 views

Black mold on years old soaked paper [closed]

Recently I bought a box of really old trading card game and unfortunately it has been soaked some time ago in the past. Some of the packages were fully damaged and the cards where covered with black ...
3
votes
0answers
51 views

What percentage of human capillaries are located in the skin?

As in the subject line, what percentage of capillaries in a human (expressed in terms of total length, I suppose) are located in the skin, as opposed to internal organs? Google scholar has not turned ...
6
votes
3answers
937 views

Why does human facial and head hair continue to grow?

Many people can grow extremely long head hair and facial hair. Are there evolutionary theories as to why this is the case? It seems like having long hair could be a disadvantage, and extremely long ...
5
votes
1answer
58 views

Is the eyes' movement discrete?

When tired and it was dark, I noticed that if I focused on a dim light source and moved my eyes fairly rapidly sideways, the resulting images that lingered for a short while were not smoothly blurred ...
1
vote
1answer
70 views

Hearing system as in visual system: exists well also - in protecting the inner mechanical parts of both sensing systems - a similarity?

I prefer answers, not just discussing. In the mechanical part of the human eye the control system to protect for overload of the diaphragm in the iris with a strong coupling to the light intensity ...
6
votes
3answers
9k views

Do animal cells have vacuoles?

I overheard a rather heated argument about whether or not animal cells have vacuoles. One person said that they do, but they're much smaller than vacuoles in plant cells. The other person said they ...
6
votes
1answer
120 views

Can jellyfish improve Black Sea environment?

According to this study, cited by many popular science magazines, jellyfish and other, smaller animals can contribute to the vertical ocean stir as much as currents do. Black Sea chemistry and ...
1
vote
0answers
8 views

Difference between Diffuse Optical Tomography and Optical Tomography

What are there the differences between these two modalities? Diffuse Optical Tomography (DOT) Optical Tomography (OT) Are there forms of OT that are not DOT?
3
votes
2answers
48 views

Are there inherent problems in simulating marine environments, as compared to terrestrial systems?

We cultivate a number of terrestrial organisms in greenhouses and stables where they live in completely artificial environments. This seems to extend far less to marine organisms, such as fish. ...
5
votes
1answer
4k views

How long will norovirus live?

I hope this is the right place to ask. I subscribe to several Stack Exchange threads, and regard them as the best internet forum for genuine and credible answers. I spent last evening talking to ...
2
votes
1answer
61 views

Do siblings have a bias toward believing they look different from each other?

Anecdotally, I have observed (myself included) that siblings tend to think that they look less similar to each other than an unrelated observer would say. Is there any experimental data to back this ...
4
votes
1answer
74 views

Are there known minimal marine ecosystems that are stable?

A more entertaining phrasing of the question would be "what would a marine ecologist put into a perfect aquarium?" I was reading about Prochlorococcus, among other photoautotrophs, and found that ...
2
votes
2answers
550 views

Is it possible that the recipient of a heart transplant would display some of the donor's personality traits, as if the heart has memories?

I've read somewhere that after a person has a heart transplant, it is possible that his/her attitude, action or behavior would change slightly or significantly, as though he/she possesses some aspects ...
3
votes
1answer
64 views

Atomic force microscopy: depth penetration?

What depth penetration can one typically get with atomic force microscopes? (i.e. how far into the tissue can one image?). I have found numbers on acquisition times (minutes) and spatial resolutions ...
3
votes
3answers
129 views

Super-resolution imaging in vivo

Are there any microscopy modalities or techniques for in vivo imaging at higher resolutions than the diffraction limit? I was looking at this list: Super resolution microscopy, but they don't talk ...

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