1
vote
1answer
320 views

Why sigmoid curves appear in quantitative analysis of many biological phenomena? [closed]

I know two examples: 1-The binding of hemoglobin to oxygen (binding of oxygen to one site of hemoglobin induces conformational changes which increase the affinity of the other sites for oxygen - the ...
4
votes
1answer
104 views

Do cell membranes have more phospholipids in one layer than in the other?

Assuming the cell membrane to have a spherical shape, geometry tells us that the area of the inner leaflet is smaller than the area of the outer due to the difference in radius between them. Does this ...
2
votes
1answer
22 views

Are the proteolytic enzymes in syconiums and nettles identical to those in rennet?

I would like to compare rennet capability under various conditions. The issue is, I don't want to use calf rennet, but I can't figure out if nettle and syconium, which also coagulate milk, contain ...
2
votes
4answers
5k views

Why are there both stop and start codons?

Based on my understanding from wikipedia, there is the (RNA) start codon AUG and the stop codons UAA, UGA, UAG. AUG can also encode Methionine, I'm assuming if it appears in the middle of a mRNA ...
-3
votes
1answer
531 views

Why do humans need a heart? [closed]

When I looked up the function of the heart, it says the heart pumps blood throughout the body. But the blood is already throughout the body, as it is recycled back to the heart. It is a chick-egg ...
0
votes
1answer
44 views

Two heterozygote mice for skin color are reproduced. Find the probability that in 3 children 2 will be dark and one white

Two heterozygote mice for skin color are reproduced. Black is dominant to white color. Find the probability that in 3 children 2 will be dark and one white. How did you do the ordering. Well I found ...
8
votes
1answer
602 views

Are bacteria necessary for an individual's life, or, how long could a person live without bacteria? [closed]

Bacteria are essential to life in that they are responsible for breakdown of organic substances, etc. but are bacteria necessary for an individual's life? In other words, how long would a human ...
5
votes
1answer
397 views

To which negatively charged components of the cell envelopes do the crystal violet complexes bind in gram staining?

The gram positive have negative components in the peptidoglycan layer in the form of teichoic acid phosphodiester bonds, and the gram negative have negative components in their outer membrane in the ...
1
vote
1answer
78 views

interpreting enhancer and promoter regions of a target gene

I am reading a paper which talks about promoter/enhancer regions of certain protein coding genes. These genes are for which evidence points to having strong MEF2 transcription factor binding sites. ...
2
votes
1answer
59 views

Detailed mechanism of the cause of diabetes mellitus type 1?

I have read in some texts that diabetes mellitus type 1 is caused by degeneration of beta cells due to our body's own immune reaction.Is it true? Can you explain further how are such types of immune ...
1
vote
0answers
26 views

how food moves in horizontal coils of small intestines [duplicate]

This is a very very basic question, and I am looking at it more from point of view of physics. The small intestine is a highly coiled structure, which means it has horizontal coils as well. I can ...
3
votes
1answer
73 views

Survival of streptococcus after my scarlet fever

I'm currently sick because of scarlet fever but I got treated with antibiotics. I know that after 1.5 day using antibiotics the streptococci I release at home are dangerous anymore. But my question ...
1
vote
0answers
10 views

Plants and animals ability to survive polypoidy conditions [duplicate]

In mammals the condition polyploidy produce something euphemistically termed "general developmental disruption" ,practically speaking this means system meltdown which happens very quickly. There is ...
3
votes
0answers
40 views

Protein-Bound Drugs in Kwashiorkor

Kwashiorkor is characterised by decreased serum protein (including serum albumin) due to poor dietary protein intake. What is the effect of this lowered serum protein on highly-protein-bound drugs? ...
5
votes
2answers
3k views

Are Asians more genetically homogenous than other races?

I've heard that Asians (I'm not entirely sure which subgroup was being referred to) tend to be more genetically homogenous than other races, with people of African lineage being on the other end of ...
4
votes
1answer
81 views

What (open) software there are for simulating behaviour of human (cortical) neurons?

Is there any reliable open-source software for simulating the behaviour of human cortical neurons? I am looking for serious software, so let's assume I have access to a computer with more than 10,000 ...
4
votes
2answers
674 views

Are these cats calico?

Calico cats are cats that have 3 fur colors and are always female or males two X chromosomes. I've seen many cats that will have 2 fur colors (one of them is usually white) and another, third, color ...
5
votes
1answer
6k views

Why does high pH result in the denaturation of DNA?

In the Southern blot method, for example, a solution of NaOH is used to denature the DNA in the sample. I find this counterintuitive since I expected that $\text{Na}^+$ cations would neutralize the ...
2
votes
0answers
22 views

protein with highest affinity to lactose

I was wondering: What is the protein with the highest affinity to lactose ? Are there some databases with values for affinity ? Thanks in advance
1
vote
0answers
71 views

How do I use BEAST for divergence time estimation in this case?

I am interested in using BEAST to find the divergence time estimates of species separations within a genus of frogs. The genus separated from a outgroup taxon I have chosen around 80 million years ...
1
vote
0answers
157 views

What is the chemical makeup of mealworm frass?

We have been raising mealworms for some time and while mealworm frass has proven very useful as a plant fertilizer, I started wondering about other potential uses of this leftover waste. Can someone ...
1
vote
0answers
103 views

Common properties of herbs in creating anaphrodisiac effect?

Recently came across Wiki article about anaphrodisiac herbs and other products. An anaphrodisiac (also antaphrodisiac or antiaphrodisiac) is something that quells or blunts the libido. It is the ...
6
votes
1answer
1k views

Which will produce more oxygen? Less number of (larger) trees or more number of (smaller) plants?

In a given area A, we have two choices - (i) we can plant maximum number of trees (which are larger in size) possible in A, say m OR (ii) we can plant maximum number of plants (which are smaller in ...
4
votes
0answers
37 views

Procedure for doing western blot [closed]

I am writing a step by step guide for doing a western blot for a class. It is intended for any one with basic Biology lab skills. I am hoping people will review my draft and give feedback on how to ...
1
vote
1answer
71 views

What are pseudoknots?

I'm trying to get my head around what a pseudoknot is and how I can identify them given some RNA string. For example, suppose I have a string s = CGUUGUGUACACGAUAGUACAU. Suppose the two longest ...
4
votes
1answer
191 views

Why is the upper respiratory tract so vulnerable to infections?

Wikipedia has the following statement on its Upper respiratory tract infection page: In United States URIs are the most common infectious illness in the general population. What is it about ...
0
votes
1answer
641 views

What is the role pyruvate carboxylase in lipogenesis?

I just know that Acetyl-CoA is a positive allosteric modulator for pyruvate carboxylase, but I cannot find anything else.
2
votes
1answer
66 views

The human organism knows what we have to eat? [closed]

My mother has told that if your organism needs a vitamin, you want fruits include that vitamin. For example you have lack of C-vitamin you would like to eat lemon. Is there any explanation for it, or ...
11
votes
2answers
152 views

Are codons that map to the same amino acids interchangeable?

(disclaimer - I'm just getting interested in genetics so sorry if this is an obvious/silly question.) From wikipedia, in the section on the RNA codon table, I see a mapping between codons and amino ...
2
votes
0answers
37 views

Are there anyother method under research for curing rabies? [duplicate]

Why is rabies incurable after onset of symptoms? Although we administer HRIG (lyssa virus antibody) to the patient, why doesn't it work after onset of symptoms? And are there any other successful ...
0
votes
1answer
695 views

Alternative protocol for evaluating RNA integrity, using a bleach gel

I hate having to run MOPS PFA agarose gels with DEPC and everything just to verify my RNA integrity. I came across an alternative protocol that uses ordinary household bleach in the gel to inhibit ...
2
votes
0answers
43 views

why plants cannot use atmospheric nitrogen? [duplicate]

Earth's atmosphere constitutes 78% of Nitrogen, then why do plants need to absorb Nitrogen from the soil. Why couldn't it possible for them to absorb the atmospheric Nitrogen like they do in the case ...
1
vote
0answers
68 views

“Gold standard” for CNV detection methods?

Is there a generally accepted "gold standard" for testing the performance of CNV detection methods? I'm interested both in learning about existing datasets that may serve as gold standards for CNV ...
2
votes
2answers
4k views

Why is it that heterozygous loci appear as two separate bands during gel electrophoresis while homozygous loci appear as one band?

Is it because heterozygotes have a greater base pair length? (And if they do, why is that?) Or is it because recessive alleles are moving slower than the dominant alleles in the gel?
1
vote
2answers
352 views

How does the size of insert affects the rate of Homologous Recombination in yeast?

When performing genetic knockouts in yeast using homologous recombination to replace a target gene sequence via a vector DNA, does the region between the flanking regions in the vector have to be the ...
2
votes
1answer
408 views

What is the difference between gene and CDS annotations?

I have a bunch of sequence files fetched from the EBI ENA and I'm trying to find the end of the 5' UTR for specific genes. The UTR itself doesn't seem to be annotated in most sequence files I have. ...
1
vote
1answer
213 views

How does ANF increase GFR?

ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
1
vote
4answers
721 views

How does HIV mutate into other strains while keeping their virulent phenotype?

How does a virus like HIV mutate into so many strains, and yet all of them are harmful to our immune system? What gives this virus the ability to mutate so efficiently?
6
votes
1answer
343 views

How much total RNA can be extracted from Drosophila brain

I am wondering how much total RNA could be extracted from a single D. melanogaster brain. I could not find this information from the literature. The closest hit was this paper, that claims that ...
4
votes
1answer
37k views

Why are (some) cats attracted by bleach?

(Sorry if this question is only partly biological) I have noticed that several cats (including the one that keeps sleeping in my house), are fond of the odor of bleach (eau de Javel) and chlorine. ...
16
votes
1answer
32k views

Fish “coming back to life” after being frozen

I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says: For everyone ...
5
votes
1answer
2k views

How does food intake affect medicine? Why pill instructions recommends taking them before (after) meal?

Even simple vitamins seem to have this in the instruction. Why is is so? Is there some simple model of how do pills interact with food? Does it depend on the food type? (What about drinks?) Should ...
2
votes
0answers
39 views

Link between macro lncRNA and DNA looping

I was wondering if anybody knows some publication about macro lncRNA (very long unspliced RNAs) or more generally a transcribed RNA that may lead to cis-DNA looping of genomic regions overlapped by ...
13
votes
1answer
26k views

How to store vegetables in the refrigerator: In plastic bags or not?

My wife and I are having a debate similar to this one: I claim that it's better to take the fresh veggies out of the bags and put them in the crisper with humidity control because: That's what the ...
2
votes
0answers
149 views

Parasites with both plant and animal hosts?

Are there animals (or plants) that are parasitic on both animals and plants? Especially such that they rely on their plant host being eaten by their animal host?
1
vote
0answers
73 views

What are the white spots?

What are these white spots? It's like Braille writing or something. How is the appearance encoded in the plant? (which I think is a Pine, though I am not sure).
2
votes
1answer
43 views

About modern dating techniques

In a comment to this question, it was said that Radiocarbon dating won't work. For a start the tree needs to be dead, which since you're not using the rings I'm assuming it isn't. Also the atomic ...
3
votes
3answers
314 views

How is it possible for the absolute fitness to be more than 1?

The wikipedia definition of Absolute fitness is "the ratio between the number of individuals with that genotype after selection to those before selection. It is calculated for a single generation and ...
1
vote
1answer
218 views

Examples of how the presence or absence 2'-hydroxyl groups influence physicochemical properties of DNA and RNA

I know, for instance, that RNA is much more succetible to alkaline hydrolysis than DNA and this difference is determined by the presence of 2'-hydroxyl group in ribose. I have also heard that "DNA is ...
0
votes
0answers
97 views

With humans, is being transgender innate, or caused by social factors?

In humans, is being transgender something that is innate, or is it caused (or made more likely) by social factors such as their political beliefs, their religious views or their social environment?

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