3
votes
1answer
238 views

Are the byproducts of mammalian digestion simply depleted versions of the food or liquid consumed?

When mammals consume food and digest it or drink fluids that are then filtered by their kidneys, are the waste products generated simply depleted versions of what they consumed? Are there other ...
0
votes
1answer
91 views

How does the matter that makes up the fat of your fat cells ultimately leave your body--following weight loss?

I'd like to get some clarification on specifically how the matter from the fat reserves of the Adipocyte physically leaves the body. In other words, if you were to somehow follow every atom in the ...
1
vote
1answer
52 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 time)...
2
votes
2answers
173 views

How precise is EEG?

Imagine we want to read impulses within single neurons in the brain. Can we do that now for a single region within the brain? If not, what is the smallest region that can be monitored for an activity ...
2
votes
0answers
88 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?
4
votes
1answer
97 views

When do kinetochores attach?

I am really confused as to when kinetochores are attached to centromeres. Are they attached soon after replication or after condensation ?
1
vote
1answer
1k views

Does mitosis include cytokinesis?

I found that some books include cytokinesis within mitosis, but some other books I have referred to include only the dividing of the nucleus as mitosis and do not include cytokinesis. Can anyone help ...
1
vote
1answer
105 views

What stops the coagulation process?

Whenever there are minor/major injury to blood vessels, the platelets, fibrin, thrombin, etc. are recruited. They then seal the wound and block bleeding. What tells them that their job is done?
0
votes
2answers
116 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 ...
1
vote
1answer
86 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
1answer
220 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 ...
2
votes
1answer
198 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.
6
votes
1answer
4k 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 ?
1
vote
0answers
181 views

Why can't sodium butyrate be delivered orally in humans and other mammals?

I think I know why -- bioavailability problems but since I have no firm evidence to support this theory I thought I would ask the biology stackexchange community for their input. I'd like some firm ...
3
votes
1answer
127 views

Other than Acetylcarnitine what other orally-bioavailable Acetyl donors exist to assist in the conversion of CoA to acetyl-CoA?

I asked a question on bio stackexchange a few days from which I was hoping to be able to arrive at an answer for this question myself but I have had no such luck so now I am going to just ask outright:...
0
votes
1answer
79 views

Is forced cell growth related to apoptosis?

Could an instance of forced cellular growth cause some cells to have their self-destruct mechanisms to malfunction or 'turn off'thus preventing apoptosis?
0
votes
1answer
168 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 ...
2
votes
3answers
2k views

Genetics: pedigree following a rare trait autosomal recessive

I have two questions pertaining to this pedigree I believe it to be an autosomal recessive trait. The probability that individuals IV-1 and IV-2 would give rise to an affected individual would be: ...
7
votes
1answer
197 views

How significant is RNA degradation with removal of cap/polyA's in eukaryotes, or UTR's in prokaryotes?

Question is rather self-explanatory, but segmented into two parts. I'm attempting to make use of a repression system that employs cleaving RNA at specific areas with ribozymes with the intent of ...
3
votes
2answers
1k 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 time....
3
votes
2answers
328 views

Why don't plants get sunburned?

I just saw a video about the biology between sunburn, UVA and UVB and the different things we know about sunburn in humans. ( http://www.youtube.com/watch?v=ZSJITdsTze0 ) I wonder what keeps plants ...
2
votes
1answer
3k 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 ?
3
votes
1answer
1k views

Why do brain cells use shuttles that pass electrons from NADH to FAD?

Brain cells are cells require one of the highest amount of energy of any cell of body. So why do they use a shuttle which will transfer electrons from NADH produced in glycolysis to FAD(and there by ...
1
vote
1answer
53 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
81 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?
2
votes
1answer
1k 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 ...
4
votes
4answers
128 views

How to calculate extent of Sequence similarity [closed]

I had a problem that I was wondering if it could be solved by one of the techniques/algorithms used in bioinformatics to give the extent of similarity. I have a Problem Statement: we have a sensor (...
2
votes
1answer
76 views

observed luminescence in a piece of plaice

A plaice fish bought for human feed has been cleaned and cooked. Some parts of the raw body have been left out of the fridge at about 22°C for about 15 hours. During the following night a ...
4
votes
1answer
1k 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 ...
14
votes
4answers
11k views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
3
votes
3answers
916 views

How to calculate virus titre from qPCR

I harvested some lentivirus from 293T cells and want to titre the result. I infected 293T cells on a well plate with 400,000 cells per well which I infected with virus stock, and 1 in 10, 100 and 1000 ...
2
votes
3answers
87 views

Where can I find an at least Semi-Comprehensive list of what biochemical reactions Acetyl-CoA participates in?

Acetyl-CoA has a number of biochemical roles in the body and I'm curious as to whether anybody knows where I can find at least a semi-comprehensive list (i.e. comprising all the major roles in the ...
0
votes
1answer
739 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.
4
votes
2answers
184 views

How long can C. Tetani survive in soil?

Clostridium tetani (C. tetani) is a bacterium commonly found in soil and is excreted in the faeces of many animals (both mammals and birds) and serves, by means of the exotoxin, tetanospasmin, causes ...
1
vote
2answers
846 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 ...
1
vote
1answer
79 views

Why to choose a grammar from a lot of grammars that can describe structure of proteins? [closed]

Why do we choose a grammar from a lot of grammars that can describe structure of proteins? Usually, there are a lot of (maybe infinite) grammars that can describe one language. Why do we choose a ...
2
votes
3answers
711 views

How is the mRNA transported out of the endoplasmic reticulum?

In eukaryotes the nuclear envelope is continuous with the ER, so what helps it out of that?
3
votes
1answer
93 views

Domains in cell membrane

How is movement of proteins and lipids between different domains of cell membrane prevented? Why is the noncytosolic layer not able to do lateral movements between domains but cytosolic layer is able ...
2
votes
1answer
2k 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 ...
-1
votes
1answer
509 views

I think evolution has goal [closed]

Richard Dawkins says evolution doesn't have any goal. But I think evolution has one. At the end evolution creates intelligent being. If we find another earth like planet evolution sould have the same ...
0
votes
1answer
39 views

What are some possible causes that might explain why the global temperature has remained relatively constant in the last decade? [closed]

First - I do not know if this is the best site to pose this question. However, stack exchange does not appear to have an ecology sub-site. That said, this appears to be the most appropriate place ...
5
votes
2answers
690 views

Could be an union/synergy between Math, Computer Science and Marine Biology?

I'm studing for my bachelor's degree in Natural Science and I have to chose the path for my future life. I have to chose the right kind of graduate studies. Since I love computer science, maths and ...
2
votes
3answers
162 views

Why are things conscious?

I've been referred to here from http://philosophy.stackexchange.com/questions/8052/why-are-things-conscious. Could you guys help out? Here's the question: What is the reason for animals or more ...
0
votes
1answer
57 views

Function of ER in reviewing mutated proteins

At least in the case of Cystic Fibrosis it happens that a mutant protein (which could actually function!) is held in the ER because the ER detects it as misfolded. Does this happen in every type of ...
1
vote
1answer
199 views

Why are fibroblast used so commonly in cell biology?

Fibroblasts are some of the most commonly used cells in cell biology. What are the properties of those cells which makes them commonly used ?
3
votes
1answer
275 views

Why are centrioles aligned at 90 degree with each other?

The centrioles are aligned at 90 degree with each other. What is the function of this?
3
votes
2answers
13k views

How do plant cell divide without centrioles?

Most plants do not have centrioles , so What organelle lets them multiply?
1
vote
0answers
49 views

What are the characteristic structures of bacillus M. tuberculosis and what they cause?

I answered to this question: In most forms of the disease, the bacillus M. tuberculosis spreads slowly and widely in the lungs, causing the formation of hard nodules (tubercles) in the ...
5
votes
1answer
207 views

Identification of this fly?

So I find these flies every year in my mulch, and I've never seen them anywhere else. The mulch becomes full of their larvae, which I feed to my toad and lizards. There are so many that you can hear ...
8
votes
1answer
262 views

Genetic Drift: Models, assumptions and empirical observations

There two main mathematical models to describe the process of genetic drift are Moran model and Wright-Fisher model. My questions concern the assumptions of these models, the existence of other ...

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