1
vote
0answers
23 views

Identity By Descent vs Identity By State

Background The concepts of Identity By Descent (IBD) vs Identity By State (IBS) are central in population genetics, yet I fail to fully wrap my head around the definitions. You can find examples ...
-1
votes
1answer
49 views

How can two individuals of the same species have different chromosome numbers? [closed]

It is known that male drones develop by arrhenotoky, and have haploid chromosome constitution, whereas the queen bee and workers are diploid. Thus we can see two different types of ploidy occurring ...
0
votes
1answer
46 views

Evolution to store limited Fat

Why are our bodies not evolved to store only limited amounts of fat, which won't kill us with all diseases associated with obesity? Wouldn't obese people die faster and clean the gene pool for people ...
1
vote
1answer
30 views

Hardy-Weinberg equilibrium generalized to add inbreeding (non-random mating)

Background Quoting from Gillespie's book The level of inbreeding is measured by the inbreeding coefficient, $F_I$, which is the probability that two alleles in an individual are identity by ...
2
votes
2answers
28k views

Teens concerned about impregnation through clothes

Dry Humping, is: dry humping is the process of two people repeatedly moving up and down and back and forth on top of each other fully clothed( or missing various pieces, but the penis must not ...
6
votes
4answers
150 views

Do all cells produce the same proteins?

If DNA is more or less the same in all cells, and DNA is used to produce proteins from aminoacids, then do all cells produce the same proteins or are they specialised/controlled by something?
12
votes
3answers
282 views

Is there any evolutionary advantage of selection of L-amino acid over D-amino acid?

After listening to a scientific talk, I had this question that why in the natural selection process, are the L-amino acids selected over the D- form. However, we still we produce D-amino acids; ...
3
votes
2answers
56 views

Light and Dark Reaction of photosynthesis?

I'm having a hard time understanding light and dark reactions because all the sites I've gone through provide different equations. Some say photolysis is H20 = H+ + O2 while some present it as H20 = ...
1
vote
4answers
81 views

Significance of upper-case, lower-case and Ns in UCSC DNA files

I have downloaded human chromosome's data from UCSC FTP. Some part is in small alphabets and some is in large alphabets. Does it show the coding and non-coding region? Here is an example from the ...
1
vote
1answer
28 views

meaning of arrows in a 3D biomolecule representation

I would like to know what those arrows and also thin wires between them in this cd4 biomolecule's 3d representation mean. Thanks in advance.
0
votes
1answer
24 views

Genes that exist in old Affymetrix platform but not in the newer one

I am using two gene expression datasets from an Affy U95Av2 platform and an Affy U133 Plus 2.0 platform. When I map the Affy probe names to HUGO gene names, there are thousands of genes which exist in ...
1
vote
1answer
10 views

Methods for varying insert size in E. coli clones

I'm writing my master's thesis proposal, and I need to improve the solution-behavior of some truncated protein domains which have previously shown poor solubility when expressed in E. coli. To ...
1
vote
2answers
54 views

What animal produces male gametes by mitosis?

The following question came up in my biology examination but I could not answer it: "What animal produces male gametes by mitosis?" I know that some plants produce their gametes by mitosis in ...
-3
votes
1answer
40 views

What are anagenesis and cladogenesis?

Are they two types of speciation? I have read wikipedia but can't figure out if they are really two types of speciation
3
votes
2answers
495 views

Key points of Wagner's theory of innovation

What are the key points of Andreas Wagner's "theory of innovation" from his book The Origins of Evolutionary Innovations? Specifically: What is new in his theory? What problems in evolutionary ...
2
votes
0answers
45 views

Population size and genetic drift - What are the evidences?

Wright-Fisher model From the Wright-Fisher model of genetic drift, the random sampling of allele from one generation to the next is taken from a binomial distribution with parameters $2N$ and $p$, ...
8
votes
3answers
125 views

Do any amphibians start their lives on land?

Most amphibians - at least, all the ones I know of - start their lives in the water (at least, after they hatch). They then spend time maturing before venturing onto land, where they can breed. The ...
2
votes
1answer
43 views

What contribute to the variation of protein sequence across different species and how do they influence?

What contribute to the variation of protein sequence across different species (e.g. phenotype, environment, evolutionary pressure) and how do those factors contribute to the variation? I have tried ...
4
votes
4answers
689 views

What kind of tree could this be?

This may be a strange question, but does anyone know what kind of tree this could be? I know, it's just a comic, but these trees, at “walking distance” within that comic are easily identifiable as ...
0
votes
1answer
23 views

Find the concentration of free receptors in a solution of 90% free ligand and 10% receptor-ligand complex, knowing only the value of kD

I could use some guidance on how to utilise the equation for the disassociation constant kD to find the concentration of free receptors [R] in a solution containing 90% free ligand [L], and 10% bound ...
0
votes
1answer
24 views

Why does meiotic recombination disrupt the independent assortment of genes on the same chromosome?

There are many sources that say that genes that are "linked" by being on the same chromosome assort with each other -- that when an allele is passed on that the gamete containing said allele will also ...
1
vote
1answer
128 views

sodium chloride and amylase activity

So, I did an experiment on the effect of sodium chloride on amylase. and I found out the higher the concentration, the slower the activity. Therefore, is it valid to make the assumption that when we ...
0
votes
2answers
54 views

Which strand of a gene specifies a protein? [closed]

A gene is a segment of DNA (I hope double stranded) and each strand when transcribed form a mRNA and after being translated a protein. As from each gene there are two proteins that are being formed. ...
3
votes
2answers
82 views

Does sweat contain DNA information?

I was reading this article : Perspiration The first question which came to my mind after reading the composition of sweat was whether it contains any information about the DNA or not? I haven't had ...
6
votes
0answers
58 views

Can a Turner syndrome patient develop male characteristics artificially?

From an answer to the question Can stem cells from male convert to cells of female-only organs, and vice versa? Y chromosome is the sex determining chromosome with SRY gene that determines testes ...
9
votes
4answers
10k views

Why does the oxygen produced in the photosynthesis come from water and not CO$_2$?

In the photosynthesis equation $$6*CO_2+6*H_2O+sunlight\rightarrow C_6H_{12}O_6+6*O_2$$ the only place where we have 6 molecules of $O_2$ is in the $6*CO_2$. Then it reacts with $H_2O$ to form ...
3
votes
1answer
211 views

Where do the H+ ions come from in light reactions?

In the light-dependent reactions of photosynthesis, H+ ions pass to the thylakoid space. Where do these protons come from?
0
votes
0answers
13 views

Compare wood density at different moisture content and conversion

Say I have a measurement of wood density g/$cm^3$ measure at a certain moisture content, say 12%, and I want to know the equivalent wood density at 15% moisture content. Is there a specific rule to ...
5
votes
1answer
37 views

Are there differing organelle to cytoplasm ratio in animal cells?

Could anyone provide me with examples of cells with high organelle to cytoplasm ratios (heavily packed), and examples of cells with low organelle to cytoplasm ratios (sparsely packed)?
0
votes
1answer
22 views

Distance to source populations and/or environmental gradients?

How do you disentangle the effects of distance to source populations and environmental gradients when the environmental gradient occurs in the same direction as the source population? For example, ...
7
votes
1answer
92 views

What species of fox is this?

I found this picture of a fox in a news article about arctic foxes in Sweden (source), but I'm not sure whether it is actually an arctic fox. On the one hand, it has white fur, which is the correct ...
5
votes
5answers
134 views

How can I search for and find specific biology topics in scientific journals?

I looked on google to find "scientific paper on biological explanation of homosexuality" but nothing comes up that appears reliable or from a journal. Then I looked up "scientific journals" and I ...
-2
votes
0answers
25 views

How sympathetic system lead to an increase in GFR?

ADH is a vasopressin. It affects the kidney by its constrictive effect on blood vessels. This causes an increase in blood pressure. The sympathetic nervous system follows the same process to decrease ...
2
votes
2answers
186 views

Coalescence time: Is it different for haploids and diploids in population genetics?

I'm trying to model Cyanobacteria cells divergence in 2 populations with mutation rate $-\mu$ and I need to verify my model with a valid theory. I don't have much biology background and all the ...
4
votes
2answers
72 views

Why don't antibodies generally bind to food and drugs?

Are these excluded thru central tolerance? What if you ingested something with a unique molecular structure that you hadn't ingested before?
0
votes
0answers
16 views

General PCR is presenting with mysterious bands?

I have a small question. I recently performed a PCR reaction on FFPE DNA yielding a 125 BP fragment. However, a strange thing occured when I analyzed the results on our Fragment Analyzer. I got a ...
2
votes
1answer
65 views

Under what circumstances does Batesian mimicry evolve?

Batesian mimicry is a form of biological resemblance in which a noxious, or dangerous, organism (the model), equipped with a warning system such as conspicuous colouration, is mimicked by a harmless ...
3
votes
3answers
5k views

If the top epidermal layer is burned away, what is it replaced with?

If the squamous (top) layer of epidermis, or skin, is burned or damaged in another way, will it then be replaced by the next layer of below? Also, from where does the basal membrane originate? Does ...
5
votes
2answers
84 views

Which of the following lacks DNA?

a) An Enucleated ovum b) Mature RBC c) A mature spermatozoan d) Hair root According to me, there can be 2 answers, a and b because an ovum whose nucleus has been removed lacks DNA. And also, ...
1
vote
1answer
34 views

In flowering plants food is transported in which form? [on hold]

In flowering plants food is transported in which form? I searched on google and found that it is sucrose. Why not glucose/fructose/starch?
1
vote
0answers
20 views

Barcode exchange between neighbouring cells

I am currently interested in equipping animal cells in a tissue with individual barcodes. These barcodes should get amplified in the cells (not to a cell degrading extent, of course), and also ...
1
vote
1answer
40 views

Why aren't we immune to the “cold” [duplicate]

As far as I know, people suffer from the cold since ever. Why didn't and don't we evolve to resist it?
1
vote
0answers
15 views

I see various exposure limits for carbon monoxide, but what about one breath?

I see exposure limits for carbon monoxide like 50 ppm over 8 hours. This would correspond to a total inspired volume of carbon monoxide on the order of a few hundred milliliters. This exposure is ...
3
votes
1answer
92 views

How many protons are pumped out per pair of electrons from NADH in oxidative phosphorylation?

I have searched the web and found that 10 protons are suppose to get pumped out during the electron cycle, but i'm a bit confused. I'm trying to count, for every complex(1/3/4), the number of protons ...
3
votes
1answer
109 views

How do lipid-soluble substances diffuse through the cell membrane?

It’s said that water-soluble substances can diffuse through cell membrane with less ease than lipid-soluble substances because the former encounters impedance in the hydrophobic region of the ...
4
votes
1answer
263 views

Why is DNA double stranded and RNA single stranded? [closed]

Why is DNA present as a double helix structure and RNA as a single helix? What causes the difference between them? Why they are not the same? what is the role of these differences?
3
votes
1answer
71 views

How does beta branching stop alpha helices from forming?

I am told that beta branching interferes with alpha helix formation. Problem is that I don't see how beta branching has anything to do with alpha-helix formation. Beta-branches are on the outside of ...
10
votes
3answers
1k views

Are there species that occupy several roles in the food hierarchy?

Are there species that occupy several roles in the food hierarchy? By role, I am referring to producer, primary consumer, secondary consumer, tertiary consumer, quaternary consumer and so on. ...
4
votes
1answer
81 views

Synthesis of Fatty Acids Longer than 16 Carbons

I understand that the human body when performing Fatty Acid Synthesis can synthesize only until C16 (palmitate). However the ER has desaturases and elongases. I know that desaturases are used to add ...
0
votes
0answers
8 views

What is the optimum pH of Isospora suis?

What pH range does the Isospora suis parasite thrive most? If you can give me any information, please give me a paper about this as well.

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