1
vote
3answers
115 views

What fraction of sites are expected to be polymorphic?

Question Consider a very long (eventually infinite) DNA sequence of neutral sites. Consider a panmictic population of constant size $N$ with a per site mutation rate of $\mu$ where all individuals ...
4
votes
2answers
21k views

What are the functions and differences between axons and dendrites?

My textbook doesn't do a very good job of pointing out what the differences between the two are. It basically mentions axons only in the same breath as the synapse (that synapses are the endings/tips ...
5
votes
1answer
369 views

What flowering green plant is this?

I got this green plant as a gift many years ago, but I have never seen it flower before. It has a strong, pleasant scent and cool flowers so I'd really would like to know what it is.
0
votes
0answers
53 views

Are there any non-harmful viruses that can alter a specific mutation?

Are there any non-harmful viruses that in going into a cell and using the cells 'machinery' and genetics to 'copy' itself actually changes some of the cells genome , maybe altering some mutations? ...
9
votes
3answers
10k views

What is the distinction between chemokines, cytokines, interferons and interleukins?

They all seem to describe molecules of similar function and many people seem to use them interchangeably. Also please include any other similar molecules if I've forgotten any in the list above.
10
votes
1answer
1k views

How do female hormones cause blood to clot?

On most female-hormone supplements you get a warning that is something like this: The use of a combination hormonal contraceptives (CHC), like NuvaRing, is associated with increased risks of ...
4
votes
1answer
77 views

What is the fluid clearance rate inside the retina?

I'm attempting to model the chemical concentration between several compartments of the eye, including the retina. Does anyone have any idea what the rate of fluid removal is in the retina, or could ...
2
votes
0answers
118 views

Do domesticated animals necessarily live longer than wild animals? counterexample wanted!

Generally domesticated animals do not need to worry about their food and other predators. They have a lower probability to get sick. However, it seems there is no sharp difference between wild pigs ...
5
votes
1answer
81 views

Is transplantation of neurons between species possible?

Can brain tissue from one species be implanted into the brain of another species? Because the brain is tolerant to the introduction of antigens (it is said to be immuno-privileged), I was wondering ...
5
votes
1answer
240 views

How to calculate the percentage of heterozygous cells based on a gene map

I've encountered the following question and am quite stumped by it. A female with genotype AABBCC has been hybridized with a male that has the genotype aabbcc. The first generation (F1) has been ...
2
votes
2answers
131 views

Osmotic Pressure and Enzyme Activity

Is it true that in an enzyme-catalyzed reaction, the rate of reaction does not vary with varying osmotic pressure? Instead of just a true or false answer, why does it, or why does it not vary with ...
1
vote
1answer
57 views

Correct enzyme nomenclature

I notice many wikipedia articles, courses, pathway sites use a different abbreviation for the same enzyme. Eg: Wikipedia lists the abbreviation of phosphoglycerate mutase as PGM, whilst wikipaths ...
7
votes
1answer
82 views

How does chromosome fusion get fixed in the population?

It's well known that one of human chromosomes is the result of fusion between two chromosomes in a primate ancestor. If we put anthropocentrism aside, it becomes clear that fusion events happened a ...
0
votes
0answers
86 views

Saline solution for animals

A popular "well-known fact" is that all creatures on Earth consist mostly of water (i.e. H2O). Indeed, a liquid called "normal saline solution" is just a solution of 0.9% sodium chloride in distilled ...
4
votes
1answer
88 views

How does botulinum toxin enter the blood stream from the digestive tract?

To my understanding, large polypeptides such as botulinum toxin cannot pass the intestinal lining intact. How, then, can it enter the bloodstream and cause botulism poisoning?
3
votes
1answer
99 views

Do bees make honey from fallen fruit?

I know bees make honey from nectar, and I know they drink the juice of fallen fruit, but do they actually make honey from fruit, or do they only eat from it for themselves?
10
votes
3answers
548 views

Why are the organs for reproduction and urinary excretion combined?

We eat food for getting energy to our body parts, and we excrete the wastes through urine, feces, and perspiration. Why has nature combined the urinary tract with the genital system (urogenital ...
6
votes
2answers
55 views

Why do epithelial cells arrest in response to serum?

Primary epithelial cells, for example human mammary epithelium, fail to proliferate (arrest) in serum-containing medium. Therefore, a common growth medium for epithelium contains pituitary extract ...
1
vote
1answer
448 views

Generate full dimer from monomer with C2 symmetry?

I downloaded a PDB file of a dimer, but it only contains the monomer, and it says that the dimer can be obtained from C2 symmetry. For an example see here: http://www.rcsb.org/pdb/explore/explore.do?...
4
votes
2answers
827 views

Is it true that bees and wasps don't sting if struck by hand while they are in flight?

Is it true that wasps don't sting if struck by hand while flying? I know of one person who claims to have done this at least 20 times and has never been stung. And out of curiosity (not that I'd want ...
4
votes
2answers
408 views

Does learning increase the number of neurons in the brain?

I am attempting to understand neurogenesis related to learning. Does learning increase the number of neurons in the human brain? What would be some good scientific publications to read?
10
votes
1answer
96 views

Can a lizard shed a regrown tail again?

Some lizards are famous for their ability to voluntarily shed their tail to elude predators (Autotomy). After a while, the tail will be regenerated, though with slightly different qualities, as ...
2
votes
1answer
37 views

Why is there a compound highlighted in red in a KEGG Module search?

Considering the following module: http://www.kegg.jp/kegg-bin/show_module?M00115+C00003 why is the compound C00003 marked in red?
0
votes
1answer
33 views

Presence of reaction module in bacteria but not in Eukaryotas (human)

From the statistics page, I found that the Module-M00008 is present only in bacteria and not Eukaryotes. Why so? I noticed that all the compounds necessary or the reaction are present in human body ...
1
vote
1answer
135 views

shRNA knockdown not showing with Western

I've recently been performing shRNA transfections and was hoping to get some advice on why I'm not seeing any knockdown via western blot I transfected by MDAMB468 breast cancer cell lines with shRNA ...
1
vote
1answer
206 views

Can roots have cuticle, especially aerial roots?

In my school biology book, it is written that cuticle covers the epidermal cells in aerial parts of plants and root epidermis doesn't have cuticle. My question is that whether aerial roots, in plants ...
3
votes
2answers
87 views

Cell line immortalisation biosafety

Cell lines are often immortalised by artificial expression of proteins which specifically cause the knockout of important cancer suppression genes or the activation of proto-oncogenes. Cellular ...
6
votes
2answers
68 views

Can a woman possessing 1 mutated allele show attenuated color-vision deficiency?

Women possess two X chromosomes. However, during development, when the embryo has about 32 - 64 cells, one of these chromosomes is randomly inactivated (in each cell) by an lncRNA named Xist. As a ...
3
votes
1answer
67 views

Color vision across species

Is it true that color vision is sex-linked for all species with binary sexes? Is there an evolutionary significance to the fact that color vision is X-linked in humans? E.g., only female humans can be ...
1
vote
1answer
20 views

What information does the KEGG Module statistics page show?

While browsing through the home page of KEGG Module, I clicked the button named Module statistics. Can someone tell me what does these numbers signify? What are they the statistics of?
1
vote
2answers
98 views

Difference between modules in KEGG Module

The KEGG module M00115 includes a set of reactions while M00542 does not have any; it just shows the list of enzymes. Is the reaction set for M00542 still unknown?
2
votes
1answer
184 views

Does “squinting” make you concentrate better on a logic test?

We have all had those moments of intense concentration on some tough exam, perhaps a college test or whatever... Why is it that when we squint, it feels like we can focus and concentrate better on ...
2
votes
1answer
2k views

Is it possible to still grow taller after growth plates have been closed?

In addition, when do we know we stop growing taller? Or we keep growing taller? To the first question: Recently, I went to a doctor to have a check up, he said that my growth plates are closed and ...
5
votes
1answer
315 views

Why did Opabinia have 5 eyes?

I recently read about a fossil called Opabinia. What intrigues me is that it had five eyes. I was under the impression that most features, such as eyes, ears and legs are always even-numbered, i.e., 2,...
3
votes
1answer
51 views

Why is the administration of exogenous Anti-D not harmful to the foetus?

Haemolytic disease of the newborn can result from Rhesus incompatibility in utero. In this disease a Rh-ve mother becomes exposed to the antigens of a Rh+ve foetus by fetomaternal haemorrhage causing ...
3
votes
0answers
40 views

How do paper wasp larvae not fall from their nest?

There is now a paper wasp nest hanging from the eaves of my bedroom. Not very big, I supposed about a hundred chambers and about 7 to 10 adults in total. I observe it every now and then. It just ...
0
votes
1answer
102 views

Why is Benzylpenicillin better in Bacterial Meningitis than Amoxicillin?

Both are beta lactams. However, benzylpenicillin, which is also called penicillin G i.e. narrow group antibiotic. I have now in both the following as a mechanism of action Binds to PBP in ...
2
votes
1answer
41 views

Who compared developmental biology to crystallography?

I need to find out the name of a nineteenth century biologist who compared developmental biology to crystallography. His idea was that crystals are formed from 'cells' (defined molecular units) that ...
-2
votes
2answers
429 views

Why does a gene have two alleles? [closed]

Why does a gene have two alleles? When there is a gene for producing the color pigment for a flower, why are there there two alleles, producing either same color or different color (homozygous and ...
2
votes
1answer
53 views

Can we change the direction of a neurological signal? [closed]

My question is can we change the direction of a neurological signal? When a neurological signal is generated it goes to the brain. Along the way it passes synapses. Can we make it change it's pathway ...
2
votes
1answer
56 views

Are these termites?

These are outside a window in Phoenix, Arizona. I looked on the internet for pictures and these guys looked very similar to winged termites.
0
votes
1answer
60 views

What are 'factors' in biology? [closed]

My question is what does the word 'factor' mean in words like transcription-factor or nerve growth-factor? What is similar between these different compounds such that they deserve the word 'factor' in ...
2
votes
2answers
87 views

How do t-lymphocytes become mature if thymus has lost its function?

The development of t-lymphocytes are done by thymus and we also know that the thymus degenerates before puberty and we also know the maximum lifespan of WBC's is 15 days. So, how do t-lymphocytes ...
0
votes
1answer
99 views

Would a human survive eating only living ants?

After reading an admittedly foolish question about 1 googol ants vs. 1000 humans, I had a question. Could a human survive solely on eating ants (common ants, not the stinging kind, or leafcutters etc.)...
1
vote
0answers
29 views

Why can't diamine oxidase be supplemented?

I've read that diamine oxidase cannot be supplemented from an academic article but it had no explanation as for why. I am curious as to why this? Article reference: http://onlinelibrary.wiley.com/doi/...
1
vote
0answers
40 views

Can I explain the kinetics of a ligand looking at the ligand-protein co-structure?

Can I explain the kinetics of a ligand binding to a target protein (association and dissociation rates) by looking at the protein-ligand co-structure? Editing my question after a few comments: I ...
3
votes
1answer
119 views

Sex biased gene expression in the X chromosome

It has been shown that the X chromosome is frequently enriched for female biased genes, and has a deficit of male biased genes. For example in this paper, and this one. However, I'm struggling to ...
31
votes
5answers
2k views

Why did life not evolve to use radio?

We use electromagnetic communication everywhere these days. Cell phones, wifi, old-school radio transmissions, television, deep space communication, etc. I'm curious about some of the possible ...
12
votes
3answers
2k views

Databases for gene regulatory network graphs?

What databases are available for gene regulatory network graphs starting from a given gene? For example, starting from p53 gene, where can I find a gene regulatory network image that can be exported ...

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