5
votes
2answers
300 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 ...
2
votes
1answer
48 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 ...
8
votes
1answer
389 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
119 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
467 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
578 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 - $O_{R1}$, $O_{R2}$, $O_{R3}$ - ...
-2
votes
1answer
148 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
118 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.
-1
votes
1answer
82 views

Effect of nerve pills and relationship to Shingles [closed]

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
73 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
82 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
443 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
84 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
216 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
45 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?
4
votes
3answers
124 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
118 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
80 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
207 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
725 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
40 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
29 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
69 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
98 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
410 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
33 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
267 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 ...
6
votes
3answers
751 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
105 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
48 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
82 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
129 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
210 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 ...
2
votes
1answer
253 views

For emphysema, which of the respiratory volumes is effected. I have a couple of educated answers

It could be the tidal volume because it effects how a person inhales and exhales normally. It could be the residual volume and functional residual volume, because it increases its amount. Because it ...
6
votes
1answer
207 views

What exactly makes bananas go brown?

I know that often oxidation processes are mentioned when referring to the color change from yellow to brown in bananas (specifically: those that you get everywhere in supermarkets, with no seeds). ...
3
votes
1answer
362 views

What is the beneficial function of IgE antibody?

Dont tell me the "function" of IgE is to cause allergy ! In whatever texts I have seen it is written that IgE is important to cause allergies but what is the beneficial function of IgE ? Why was it ...
1
vote
0answers
39 views

What are the mechanisms of disabling extrinsic control of heart?

I started this thread by thinking this question but I developed it further below What is the mechanism maintaining refractory period of pacemakers? My conjecture is that the mechanism is the ...
5
votes
3answers
166 views

Is it possible to have life in vacuum?

I just got struck by curiosity now: Intuition says no, but I've never had confirmation of it.
0
votes
0answers
33 views

Which reflex arcs work in Heart with extrasystoles?

I am researching what is triggering the extrasystoles - initial idea from this thread about Which ionic channels of Pacemakers can work in very low frequencies in extrasystole? I am interested in the ...
0
votes
1answer
31 views

Which ionic channels of Pacemakers can work in very low frequencies in extrasystole?

At frequency 0-3 Hz. Like computer processors which can work at low frequencies and controlling under- and overvoltage. Normal most significant channels are Ca2+ and K+ that are changing. However, I ...
6
votes
2answers
296 views

Is there a biological reason for spreading food intake into breakfast-lunch-dinner?

I keep hearing over an over how humans can satisfy their entire daily caloric need in one sitting at a fast food restaurant. At the same time I'm looking at the kitchen plates, cups, etc, and they ...
6
votes
1answer
198 views

Task-dependent “reversed” handedness: why use left hand for some tasks? How is it controlled by the brain?

I am right-handed. Which means that when I hammer down a nail, I hold the nail in my left hand, with which I can hold it straight and at a controlled position. This is true in situations where the ...
9
votes
1answer
124 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and ...
2
votes
1answer
2k views

Why do three nucleotides code for one amino acid? Why not 5 nucleotides? [duplicate]

We all know why there are 3-base codons, and why there aren't any 2-base codons. But why is there not a 4-base a 5-base codon?
5
votes
3answers
506 views

Evolution: How could all useful traits evolve simultaneously?

I have a basic question about evolution, for which I never found an answer. I understand how evolution works if we focus on one specific organ or trait. With each generation, some organism is more ...
2
votes
0answers
150 views

Why does IUCN classify pistachio as a “Near Threatened” species?

When reading the Wikipedia entry on pistachio, I noticed that IUCN has classified the plant under "Near Threatened". On looking up its entry at IUCN, I see that its population is trending downwards, ...
2
votes
1answer
202 views

Troubleshooting for Agarose Gel Electrophoresis

SI ran my 2% agarose gel on constant voltage (100 V). For a few times it worked at CV but, after a week or so the machine would automatically switch to constant current by itself. And this only ...
2
votes
1answer
76 views

Are there any fungi that can digest humic acids?

Humic acids are a complex group of organic substances, that are generally known to be hardly biodegradable. Fungi as agroup are known for breaking down complex organic matter like cellulose or lignin. ...
1
vote
2answers
84 views

Is Sinus node conduction necessary for heart beating?

Assume a patient with previous cardial infaction which SA node not possible to activate action potential anymore. However, SA trying to beat unsuccessfully repeatedly waisting energy. Therefore, I ...

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