3
votes
2answers
752 views

Can any one reaction in a cell be at equilibrium?

I know that metabolism as a whole can never be at equilibrium (otherwise the cell is dead !) but I wonder whether a few reactions in the cell could be at chemical equilibrium at a given point of ...
6
votes
1answer
175 views

Why does radiation sickness cause hair to fall out?

As I understand it, radiation poisoning (acute radiation syndrome) is fatal because the radiation kills cells. However, why do victims experience hair loss at such an early stage in the process?
0
votes
1answer
283 views

Calcium for Humans: Supplements vs Fortified Sources

I am intolerant to meat and milk products, but purely natural foods don't contain enough calcium for the Recommended Daily Intake. Links 2 to 4 (but NOT 1) avouch a correlation between calcium ...
1
vote
1answer
656 views

What is 'calcium conductance'?

What is the meaning of calcium conductance in ion channels. I encountered this in the following text: It was established that the µ and δ opioid receptors open potassium channels, which results ...
3
votes
1answer
1k views

What happens when cells in your body run out of telomeres?

In my biology book I read about an experiment where the genes encoding telomerase were 'knocked out', but they could still live a normal life and no adverse effects were noticed until the 6th ...
2
votes
2answers
132 views

How did viruses learn to utilize the workings of a cell?

This is my first post here, so excuse me for its simplicity. Viruses can infiltrate a cell, overtake it and multiply. It has projecting fibers whose ends are shaped as kind of a "key" to a mobile ...
1
vote
2answers
2k views

Are mature RBCs prokaryotic?

Mature mammalian RBCs have all the characteristics of a eukaryotic cell except that they don't have a nucleus, they don't have any cell organelles. Does this mean that RBCs are classified as ...
1
vote
0answers
16 views

histamine inter-cellular and cytoplasmic binding site

I noticed that HRH (histamine receptor) has an inter-cellular and cytoplasmic binding site of anti-histamines which are equal in binding energy. Does anyone know what is the function of the well ...
6
votes
1answer
2k views

Why does the heart use lipids (and not glucose)?

Fetal hearts use glucose as their primary metabolic substrate. Adult hearts use free fatty acids, which are less efficient (require more $O_2$ to synthesize the same amount of ATP); however, during ...
1
vote
1answer
58 views

Adaptability in immune system

I read somewhere that recently some people are trying to use harmless bacteria that live symbiotically in humans to express some portions of antigens of the harmful ones. Some people have raised ...
1
vote
1answer
1k views

Is there a free alternative to Gelcompar for comparing banding patterns across multiple gels?

In order to run my microbial community samples from my experiments through DGGE, I was required to use multiple gels. Thus it is necessary to compare banding patterns across more than one gel. ...
2
votes
1answer
614 views

Molecular Evolution: Mrbayes never stops?

When I use my own data to build Bayesian phylogenetic trees using the software Mrbayes, after many generations, it never reaches stopping status (namely, the average standard deviation of split ...
3
votes
0answers
336 views

Virus titre and copy number of integration

If I need to preform a genome-wide high throughput screen using pooled shRNA library infection followed by deconvolution by deep sequencing, how would I determine the optimal infection rate at which ...
1
vote
1answer
135 views

Why are Taurine and Arginine essential components of the feline diet?

Taurine and arginine play a key role in the feline diet but I am unaware as to where exactly they fit in.
2
votes
0answers
70 views

Why is a nicotinamide-tryptophan combination used to treat affective episodes in a few older clinical trials?

At least one of the journal articles that reported on such clinical trials allured to the nicotinamide-tryptophan pathway that I assume must be related to the metabolism of tryptophan into serotonin ...
1
vote
1answer
273 views

L1 - L5 layers of the brain

I have read in some papers about the layers L1-L5 of the brain (e.g. in this paper). I could not find a definition of these layers. I have found information about the layers V1-V5 in the visual ...
2
votes
1answer
73 views

How correlated are proximally related CpG sites in human DNA?

Cytosine residues in DNA that can be methylated (i.e. CpG sites) are likely to be in the same methylation state if they are geographically (proximally) close together. I can only find one paper that ...
1
vote
1answer
147 views

how to clone a gene fragment in two direction as sense and antisense in vector

I have a sequence ATG GGG CCC TTT AAA TAA and want to use it as antisense RNA in my vector. How should I clone it? I am confused with the direction of my clone. I looking for the direction and ...
2
votes
1answer
63 views

Extract bacteria from compost?

I'm working on a project where I need to find certain cellulolytic bacteria. I was looking at this list : ...
1
vote
0answers
22 views

Do Total Gastrectomies leave individuals more open to infections from eating unsanitary food?

I ask this because the stomach plays a role in sterilising food and hence without one it follows that perhaps one would be more prone to getting intestinal infections.
4
votes
2answers
79 views

Reflexes & Pathologies including the Vagus Nerve

I only know the vasovagal reflex. I would really appreciate if someone could inform me about the other ones. About the pathologies, I already know the effects of direct nerve damage. I am talking ...
8
votes
1answer
66 views

What does the evidence suggest about how Neanderthals became extinct?

According to "Neanderthals: Facts About Our Extinct Human Relatives" (Szalay, 2013), Neanderthals dominated Europe during the last Ice Age, but may have died out before the arrival of Homo Sapiens ...
1
vote
1answer
53 views

Does sympathetic nervous system acts bilaterally for pupil dilation or other two sided organs?

The question might seem weird. Does sympathetic nervous system acts 'bilaterally' meaning if you shout to a person's left ear a loud noise (e.g. by headphones), will it activate sympathetic system ...
1
vote
1answer
73 views

Are there any bacteria that can receive ultrasound signals?

I'm looking for an example of bacteria that could receive ultrasound (at any ultrasound frequency) signal and possibly perform some (re)action afterwards.
1
vote
0answers
37 views

Root hair formation in Arabidopsis

In arabidopsis, 2 cell types arise in the root epidermis : root hair cells and hairless epidermal cells. The immature epidermal cells that are in contact with 2 underlying cells of root cortex ...
1
vote
1answer
42 views

Human defenses to toxoplasmosis

Toxoplasmosis modifies the rat's brain to make them love (and be eaten by) cats. It also infects ~30% of humans, and modifies traits in several bad ways (i.e. schizophrenia and increased reaction ...
6
votes
1answer
325 views

evolutionary reason behind sharing the same path for food and air?

What is the evolutionary reason behind sharing the same path for food and air? For example, we have a nose and lungs, yet they are linked by the pharynx, which is shared with the mouth and ...
1
vote
1answer
204 views

How to obtain bacteria samples?

Would anyone know how to go about obtaining samples of Salmonella or E. coli for purely educational purposes? Note: I just want to look at the stuff under a microscope.
3
votes
1answer
91 views

How do muscle relaxants work?

Do they act directly on the muscle and actually relax muscle tissue and ease spasms, or do they just prevent your brain from receiving signals that inform you of tight muscles? In the latter case, ...
3
votes
1answer
77 views

What's the mechanism for pain-induced swoon?

Is it true that people will pass out when subject to pain too much to bear, or there's no such threshold? What's the reason for passing out under acute pain, even if no physical injuries occur (e.g, ...
0
votes
2answers
101 views

Why can't cell division happen the other way around?

Mitosis in eukaryotes happen in this order: DNA replicates and then the cell divides. Why doesn't it happen in reverse order (i.e., cell divides and then replicates the DNA)? I am talking about ...
3
votes
1answer
179 views

Are human feces and urine merely a subset of the food and liquid we eat and drink?

In other words, does the body actually ADD ANYTHING TO urine or feces? As the food and drink makes its way from our mouth to our toilets, does the body add anything to it along the way? Or, is the ...
2
votes
0answers
72 views

Where are the gastralia (stomach ribs) attached?

Crocodiles and some dinosaurs have a second set of ribs between the sternum and pelvis called gastralia. Where are the gastralia attached to the rest of the skeleton?
1
vote
1answer
94 views

Complementarity of cDNA

Strictly speaking, what is the definition of cDNA? This confuses me, since usually it is said to refer to DNA that is complementary to mRNA. Is this correct? Is it restricted to mature mRNA? I ...
3
votes
1answer
2k views

Why is FADH2 made instead of NADH in one of the reaction of Krebs cycle?

FADH2 is made in conversion of Succinate to Fumarate. Why is this so ? Why not NADH ?
2
votes
2answers
94 views

Why does the mixture of infant formula with saliva provide an ideal breeding ground for disease-causing micro-organisms?

From: http://www.nal.usda.gov/wicworks/Topics/FG/Chapter4_InfantFormulaFeeding.pdf Discard any infant formula remaining after a feeding. The mixture of infant formula with saliva provides an ideal ...
0
votes
1answer
104 views

How does the enzyme Dicer function in the RISC complex?

I know that the RISC (RNA-induced silencing complex) is one of the primary complexes involved in gene regulation through RNAi. What I want to know is, what role exactly does Dicer play in this ...
4
votes
1answer
726 views

How to secrete a recombinant protein from E. coli?

What are some secretory pathways that can be used to secrete a recombinant bacterial enzyme from E. coli? I have a recombinant protein (29kDa) that I will express in E. coli BL21 cells. For now I ...
2
votes
1answer
62 views

How do you differentiate between SR protein and SR-like protein?

What are the criteria that the researchers use to choose whether a protein is an SR protein or and SR-like protein?
1
vote
1answer
1k views

Why in some cells is GTP made in citric acid cycle and in some ATP?

In many animals GTP is produced in citric acid cycle. While in plants,bacteria and some animals ATP is produced. Why is this so ? What is the advantage ?
1
vote
1answer
50 views

Where can I find pdb files for macromolecules like receptors?

I have tried going to the RCSB website and quite frankly it was useless since when I looked up receptors like say the metabotropic glutamate receptor 2 (mGluR2) I got no helpful results.
2
votes
1answer
687 views

Is there any advantage of having a mitochondria for aerobic respiration?

If we consider the pathway of breakdown of glucose which includes glycolysis, the citric acid cycle and the electron transport chain, all these processes takes place in some prokaryotes and ...
3
votes
1answer
431 views

What hair color will result in someone inheriting both blond and ginger genes?

Both the genes for blond hair and ginger hair are recessive, so they need both parents to give the same gene for it to take affect. What happens when a person has 1 copy of a recessive gene and ...
7
votes
2answers
597 views

Does every human eye see the same visible spectrum?

It is said that human eye can see light with wavelength approximately between 400nm and 700nm. Are these upper and lower bounds same for every human? If not, what are the means and standard ...
7
votes
2answers
329 views

How does the body measure dehydration?

What, physically, does the body do to measure it? I assume it's measured by how how turgid or plasmolysed certain 'sample cells' are, or water concentration in the blood, What is the way they use to ...
3
votes
3answers
1k views

What makes urine smell acrid?

Occasionally, after someone's been, there is an awful acrid smell lying about long after them. What causes this? The food that they've eaten? Urea less dilute due to dehydration? If it helps I've ...
1
vote
2answers
376 views

Amount of Heterozygosity

How many loci in the human genome are heterozygous? How about other species? EDIT: I was wondering, considering for example the whole world population, how many of the human genes actually have two ...
14
votes
2answers
8k views

Why do people have antibodies against other blood types?

The ABO blood type divides each blood type according to whether they have the "A" and "B" antigen(s) (AB has both, O has none). People also have antibodies against the antigens they don't have (AB has ...
0
votes
1answer
87 views

Creating expression template from PCR: What annealing temperature to use?

I am creating a transcription template for expression in PURExpress and was confused about the annealing temperature to use. I have two primers with the T7 promoter and an RBS on the forward primer ...
0
votes
1answer
397 views

Strongest muscle of Human Body

Which is the strongest muscle of human body ? Confusion b/w Masseter muscle (Muscle of Jaw) and Tongue and Muscle of Heart and Muscle of Uterus.

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