3
votes
0answers
36 views

How is nutrient uptake in humans measured? [closed]

There are many claims made about nutrient absorption, eg "Juicing helps you absorb all the nutrients from the vegetables". I'm curious to know how nutrient uptake is measured. Eg is it a pure ...
3
votes
1answer
85 views

What is meant by single molecule sequencing?

When sequencing papers refer to single molecule sequencing, what is their definition of a "molecule". Are they saying base by base? The entire DNA chain in a chromosome can also be though of as a ...
2
votes
2answers
166 views

How were the first primers made

I keep reading about how primers are useful in pcr -- they allow you to select a specific dna region. Similarly, in NGS or Sanger sequencing they give you a starting point. The primers I see are about ...
3
votes
1answer
71 views

How does regurgitated food go to the 3rd stomach chamber instead of going to the 1st?

Ruminants are known for their regurgitation of food; the food goes through the 1st and 2nd stomach chambers, then returns to the oral cavity in cuds. The cuds then come back into the stomach, but this ...
4
votes
1answer
27 views

When does exposure to an allergen increase / decrease allergy?

In immunotherapy a person is regularly exposed to an allergen to decrease the allergy. Yet apparently "repeated intranasal challenges ... induces robust allergic airway inflammation, " [0] So when ...
0
votes
4answers
467 views

Strictly from a biological perspective, what is the functional expectation of a human being [closed]

Just like the title says: Strictly from a biological perspective, what is the functional expectation of a human being. No religious or philosophy-based answers will be accepted, we are talking ...
0
votes
1answer
72 views

What is accumulation and release centre of neurohormones?

What is accumulation and release centre of neurohormones? Is it hypothalamus?
4
votes
1answer
587 views

Identical twins' biological sexes

Can identical twins have different genders (as in biological sex)? I thought they should have absolutely the same genes. If they can, what caused it? I'd assume it MAY be because of errors in ...
2
votes
1answer
127 views

What kind of small insect is this?

Found in central florida in the bath tub. Its about the size of a pencil marking, very small. What is it?
2
votes
2answers
94 views

Is there a name for this principle in biological contexts?

This is mostly a question about usage. There is a probability-related idea that has been used in at least two biological contexts. The idea is that if something happened, it was probably likely to ...
6
votes
2answers
186 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
5
votes
0answers
40 views

Effect of Aging on SA node's sympathetic fibers

I am trying to understand the effect of aging on the sympathetic fibers of SA node. I know that aging shifts the vagal curve to left in frequency due to aging. However, I am interested if aging has ...
4
votes
3answers
313 views

What does “kcal/mol” mean when speaking of enzyme catalysis?

After thinking about it, I'm confused by what the reaction barrier of an enzyme actually means. Imagine a reactor containing enzyme and substrate. If the enzyme in the reactor has a reaction barrier ...
1
vote
1answer
26 views

Detecting a Fasting State in the Body via Lasers

I was just wondering wether it would be possible to detect if the body is in a "fasting" state, via lasers attached to the body. If it is possible, what sort of laser would be needed?
1
vote
2answers
49 views

How do exon tandem exon duplications occur in the genome?

By this I mean in cases where tandem exons are introduced by replication slippage how would a DNA polymerase by chance duplicate an entire exon cleanly (i.e. from exact start to exact end) when it ...
1
vote
1answer
141 views

Heterozygosity and overdominance

Consider $m$ loci with heterozygote advantage (overdominance) such that the fitness of the two homozygotes is $1-\frac{s}{2}$ and the fitness of the heterozygotes is $1+\frac{s}{2}$, where $s>0$. ...
5
votes
2answers
275 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
1
vote
1answer
46 views

How are new chromosomes replicated into the next generation via sexual reproduction?

If an individual has a new chromosome, which is very unlikely to happen, he will not have any luck in finding a sexual partner with this same trait. How will the offspring inherit this trait. And ...
7
votes
1answer
341 views

List of np-hard problems in biology/bioinformatics

I'm not sure if this is the right place for this but... I am looking for a list of computationally "hard" problems such that if a problem from this list could be solved effectively, it would be ...
2
votes
1answer
100 views

Could someone Identify this Insect Hive on my Balcony Grill

A smallish insect hive has been forming on the grill of my balcony in the last month or two, and I wanted to know should I be worried or can I just let it be. Its 13th floor in Singapore, if the ...
1
vote
1answer
402 views

In an open circulatory system, how is blood moved?

In the mollusks section, the powerpoint mentioned that gastropods and bivalves have an open circulatory system. According to the note, this means that the blood does not travel in vessels. How, then, ...
4
votes
2answers
421 views

How can CI repressor both activate and repress $P_{RM}$ promoter found in $\lambda$ phage?

I'm reading a paper where the authors constructed a toggle switch that uses bidirectional $P_R/P_{RM}$ promoter found in the $\lambda$ phage. There are 3 binding sites - $O_{R1}$, $O_{R2}$, $O_{R3}$ - ...
-1
votes
1answer
134 views

Punnett square and hybrid cross [closed]

A plant breeder crossed two plants, one with red flowers, and the other with white flowers. Red is dominant. Calculate the phenotype and genotype ratios of the F2 generation of this cross. Is this a ...
1
vote
1answer
103 views

Percentage of understood human DNA [closed]

I want to know what's the approximate percentage of understood human DNA, as in, which part does what. I'm not asking for details, just the amount. Thank you.
0
votes
1answer
63 views

Effect of nerve pills and relationship to Shingles

Do nerve pills actually suppress the nervous system and how would that effect the Shingles virus which is known to activate under large amounts of stress?
2
votes
1answer
58 views

Speed of effective lymphatic drainage?

Lymphatic drainage occurs from many portions of the body: To venous angle: head axillary lymph nodes hands abdomen legs (I think legs' drainage goes through abdomen) The speed of the lymph ...
2
votes
1answer
80 views

Do any nonhuman species have effective ebola immunity?

I've read that ebola is an effective killer in humans because it has the ability to interrupt dendritic cells from manufacturing proteins that cause the immune system to destroy the dendritic cells ...
0
votes
1answer
27 views

How is bacterial plasma membrane made?

Eukaryotes have ER which manufactures plasma membrane of cells. How is prokaryotic plasma membrane made ? What is the pathway and which enzymes are involved ?
3
votes
2answers
388 views

Why does methylation not occur in viral DNA?

Why does methylation not occur in viral DNA? Can viral DNA undergo the process of methylation? If not then why does this process does not occur in viruses?
3
votes
0answers
81 views

What is the main challenge in creating a chemical male contraceptive?

More than 50 years after hormonal contraception for women was invented, a contraceptive pill for males is still not available. With the obvious major biological differences in mind, why does it appear ...
2
votes
1answer
181 views

List of heritability estimates in humans?

Many people on this site ask questions that directly or indirectly have to do with heritability in human. Do you know a list of estimates of heritability of various traits in humans? Or could you try ...
1
vote
1answer
41 views

Why doesn't the avocado turn brown when it is kept with its seed?

Why doesn't the avocado turn brown when its kept with its seed? What does the seed release that slows down the oxidation process?
3
votes
3answers
107 views

Book recommendations for evolutionary models

I was recently working on getting a statistical model of a DNA sequence. To do this I found that understanding evolution quantitatively seems to be quite important. I would really appreciate any book ...
4
votes
2answers
116 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
2
votes
1answer
74 views

Average face shape

I am doing face detection application where every face detected is inside a rectangle. The rectangle always contains some background behind the face and now I need to extract as much of the face as ...
2
votes
1answer
148 views

Development of vitreous humor

I have tried reading about development of vitreous humor but it is all very confusing. When does it first developed ? Does it renew itself ? Please provide reliable sources..
2
votes
2answers
574 views

TCGA gene expression data are missing matched normal

I'm trying to use the TCGA data portal to get gene expression data for cancer tissues, but I'm not sure what "Tumor matched normal" means. It is unclear to me if the values are already compared to a ...
1
vote
1answer
37 views

Coalescent Theory - Probability for $k$ alleles that of one coalescence event occured $t+1$ generations ago

From this textbook Under the wright-Fisher model of genetic drift and under the assumption that all alleles are neutral, the probability that $k$ alleles had $k$ distinct parent alleles the previous ...
2
votes
1answer
27 views

Roles of creatine and bilirubin in foetus circulation

I think they are not inputs from maternal placenta. I think they are the results of foetus metabolism. However, I do not understand it how and where exactly. What are the roles of creatine and ...
2
votes
1answer
59 views

Most human-like teratoma ever recorded?

I'm curious to learn about the most human teratoma ever recorded. By most human I mean the teratoma which most resembles the form of a human being. I suppose there are several criteria which would ...
2
votes
1answer
89 views

Where does the fate map of a human embryo end?

I'm confused about the fate map of a human embryo. Is it just a particular part of the embryo development or does it include everything, from the conception (germinal stage) to the day the baby is ...
4
votes
3answers
315 views

Does the genetic material the sperm carries affect it's physical properties

Basically, what I'm asking is, is the actual sperm cell built from the blueprint in the DNA of the man or is it itself also a consequence of the DNA it carries? I'd like to know a few more things ...
1
vote
1answer
28 views

Is there a Lyme disease vaccine?

Each Spring, our local health unit begins its campaign of Lyme disease and tick-bite awareness. I was wondering if there has ever been a vaccine available, and if so, what antigen does it target?
9
votes
1answer
256 views

If all B cells are present at birth, why should the primary response to an infection take longer than the secondary response?

When learning about the immune response, my teacher mentioned that all the bodies B cells are present at birth, and there is one to counter every disease. But if this is the case, why should the ...
5
votes
3answers
529 views

Does our eyeball increase in size as we grow?

Does the size of the eye increase as we develop from the stage the complete eye first forms to infancy and then to adulthood ?
6
votes
1answer
100 views

Book suggestion on computational molecular evolution

I'm currently reading Computational Molecular Evolution by Yang. Can you recommend alternative books? I am finding it to be lacking on conceptual discussion (it's more focussed on the mathematics and ...
2
votes
1answer
46 views

Number of autoregulation and FFL motifs in a network

Suppose we have a network with N* nodes (N* is the number of internal nodes). Every directed link in this network exists with probability p. What would be the number of: motifs that are ...
6
votes
1answer
78 views

Evolution of Chromosome Numbers

Some species have different numbers of chromosomes, as we all know. Throughout evolution, how was a species able to survive with an extra chromosome? How was this organism able to breed successfully ...
1
vote
2answers
123 views

Which was the last significant event in human evolution? What's next?

At 10.000 BC (12 ka), we became the last of the Homo species on Earth. In evolutionary terms this is a very little time range to something happen, but I'm wondering anyway, in this meantime which are ...
1
vote
1answer
120 views

Earwax versus Mucus

Something I have wondered for a while is why have two different primary defense mediums, ie earwax and mucus, that perform the same function? As far as I know, mucus and earwax are both part of the ...

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