2
votes
1answer
43 views

Cosmid genomic library, or genomic cosmid library?

Which usage is better for referring to a "cosmid library of genomic DNA fragments"?
2
votes
4answers
153 views

How does mutation cause natural selection? and is it common in protists or prokaryotes?

Why is it inevitable that evolution by mutations alone should be a common cause of evolutionary change in most natural populations? And do you expect mutation-driven evolution to be more common in ...
5
votes
1answer
123 views

Is a sequential double transformation acceptable?

Standard protocol states having two compatible vectors being transformed simultaneously during the same procedure. I've come across a situation in which transforming one vector, obtaining results, and ...
2
votes
0answers
1k views

What are the roles of guanidine-HCl and ethanol in binding of DNA to silica?

I'm trying to understand how exactly the binding to silica gel (in kits) step works and I cannot find any papers which provide an explanation of the physics or chemistry; especially on the way that ...
10
votes
3answers
4k views

Was the mitochondrion or chloroplast first?

I still don't know if the mitochondrion or chloroplast was first? I've looked for it on the internet and in various books but haven't found anything. Does anyone have the answer and a theory which ...
2
votes
1answer
95 views

Life on other planets [duplicate]

first of all I'm not sure if I should post this here or in the astronomy stack. I think biologist are more likely to answer my question. To make it short: Why when looking for any sort of life on ...
1
vote
1answer
79 views

What does min mean?

I read that "trp operon is located at 27 min on E.coli chromosome." What does "min" mean ?
1
vote
1answer
167 views

How do Gram + bacteria use a proton gradient for F-type ATPase?

Does anyone know of any papers showing how Gram positive Fermiculates or Actinobacteria use a H+ gradient for an F-type ATPase, It seems impossible since there is no outer LPS membrane to maintain ...
1
vote
1answer
30 views

Property of E.coli harboring F element

From Genetics by Ursula Goodenough E.coli harboring an F element are endowed with a number of phenotypic traits : 1.They are sensitive to infection by ssRNA phages and certain ssDNA phages. ...
1
vote
2answers
101 views

Effect on fitness of mutations

What is the distribution/probability density function (PDF) of impacts on fitness of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...
1
vote
1answer
40 views

Dominance/recessivity of new mutations

What is the distribution/probability density function (PDF) of recessivity/dominance of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...
1
vote
1answer
70 views

Additive genetic variance with $n$ loci

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
1
vote
1answer
109 views

Additive genetic variance with $n$ alleles

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
3
votes
1answer
60 views

Brainbow fluorescence labeling technique

I have this picture describing the Brainbow system here: The paper I am reading says it uses Cre-lox recombination to express a certain color. If the cell in question was expressing a yellow ...
1
vote
2answers
70 views

In what ways can mechanisms of apoptosis be damaged?

How many ways can an Apoptosis mechanism be made disfunctional or irreparably damaged? If a cell has damaged Apoptosis mechanisms and it divides will its daughter cells have such damage?
1
vote
1answer
89 views

People say the cardiac cycle depends on blood pressure? How so?

I know what the cardiac cycle is. There are two phases diastole and systole. One is the relaxed, and the other is the contracted form of the heart. The diastole is where blood is pumped to the ...
2
votes
2answers
106 views

Role of Melatonin in Circadian Rhythm

Melatonin regulates the wake-sleep cycle by causing drowsiness and lowering body temperature, but which specific chemical pathways lead to this drowsiness?
1
vote
3answers
84 views

Does DNA influence death (e.g. by cell aging)

I know that we age because of errors in the cell replication process and these errors eventually leads to death. If we exclude environmental factors, are there any other factors that can cause these ...
5
votes
2answers
167 views

Real time PCR normalization algorithm

When performing normalization of real time PCR results, I found two ways of doing it: In my lab they follow the next layout: $\text{Efficiency}^{-(CT\ _{\large\text{interest gene}} - CT ...
1
vote
1answer
39 views

Nervous System : Organ or Gland Failure

If an organ was to start failing, not total failure, such as the thyroid gland, is it possible that the fault may not lie in the failure of the organ but in the nerve signals coming from the brain?
1
vote
1answer
29 views

Nervous System : Signal Translation

If a device were created to monitor the nervous signals from the heart, including stable heartbeats, rapid heartbeats, etc., and this device were capable of transmitting the "stable heartbeat" to the ...
1
vote
1answer
38 views

Nervous system : Nerve signals [duplicate]

If the electrical signals from all the various organs throughout the body eventually connect to the nerves in the spinal column traveling up to the brain, how does the brain differentiate the ...
1
vote
1answer
59 views

Nervous system: Pain and Pleasure?

If you have a constant pain in your body, why does a greater pain or pleasure make you not feel the original pain?
2
votes
1answer
54 views

Cloning a gene of an organism with an nonsequenced genome

What would be the best protocol to clone a gene about 5kb in size? The genome is not sequenced, but the gene itself very similar to orthologous genes of organisms with known sequences.
1
vote
1answer
89 views

Do chickens always lay eggs?

http://de.wikipedia.org/wiki/Hühnerei says it takes up to 24 h for a chicken to produce an egg. Is that dependent on the chickens nutrition, i.e., if it does not get enough food or the wrong kind, ...
1
vote
1answer
127 views

building intelligent structure with random evolution requires series of non useful steps

In order to build an intelligent design such as a bridge or a mechanical watch, you need a series of non useful steps. As far as I understand, in random evolution theory, the "intelligence" involved ...
1
vote
1answer
1k views

How do ants spontaneously grow wings?

On hot summer nights we get flocks of ants that have grown wings (from what I know to migrate nests). It appears the wings are not permanent, but are grown for a temporary purpose. From what I ...
2
votes
1answer
132 views

Substitute 25mM dNTPs mix with 10mM dNTPs

I need to make a solution of multiple compounds, one of them is dNTPs. The recipe calls for 20 μl 25 mM dNTPs in a 1250 μL master mix. Unfortunately I do not have it available at that concentration, ...
2
votes
1answer
64 views

Stomach Virus : How does it affect the bacteria of the intestines?

When you have a stomach virus and it causes extreme bowel movements to the point of almost pure stomach acid, does this kill off the bacteria in our intestinal tracks?
1
vote
2answers
181 views

Advantages of pain sensation?

The hazards of congenital insensitivity to pain (CIP) are well-known. This question is about the obverse: what selective advantage, if any, does the normal sensation of pain confer? I'm thinking of ...
3
votes
1answer
77 views

Significance of lipids in biological membranes…?

Membranes are specifically designed by lipids to maintain internal hydrophilic environment in narrow range.There are hydrophobic amino acids among naturally occurring 20 amino acids and as well as ...
0
votes
1answer
33 views

Can inhibition of lymphocytes migration be a direct cause of chronic inflammation?

Here is the original slide: I am thinking about the "cord factor" sentence in a more general case. Assume you inhibit Leucocytes migration. How does this lead to accumulation of macrophages in the ...
0
votes
1answer
70 views

How can a recessive allele propagate until they manifest?

Suppose a specific gene has two possible alleles. In a given population all members have only the dominant one. By a mutation on member receives the first recessive allele of that population. Is it ...
1
vote
1answer
43 views

Cells created using differently aligned proteins

I remember reading that scientist were making cells (I assume bacteria), that used differently oriented proteins to create a whole new class of life. Because apparently right and left aligned proteins ...
3
votes
1answer
89 views

Function of heparin and dextran sulfate for removing proteins

From this article : The reaction was terminated and the histones, and most nonhistones, were removed by adding the nuclease-treated chromosomes to a solution containing dextran sulfate (2 ...
3
votes
1answer
34 views

Changing time and rpm of centifuge

Inspired by this question, I want to ask a question about centrifugation. Suppose a protocol says : 10 min at 2500 rpm . Can we instead centifuge for 5 min at 5000 rpm or 20 min at 1250 rpm ?
1
vote
1answer
74 views

Missing 4$H_2O$s (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $H_2O$ molecules. Generally, cellular respiration is written thus : $C_6H_{12}O_6 + ...
1
vote
1answer
214 views

What is the biological reason that some viruses cause sore joints (eg flu)?

Frequently I have experienced sore joints during a bad bout of influenza. I understand that during time of sickness, white blood cells are deployed in the blood stream. I also believe that white blood ...
1
vote
2answers
24 views

Concerning Apoptosis

What if cellular growth and repair is 'forced' to occur repeatedly in a region where it wouldn't normally happen , if the biological area was 'healthier'. Could this more aggressive cellular growth ...
3
votes
2answers
61 views

Is half-a-tablet of X a substitute for a tablet of X/2?

This may be anecdotal. At the pharmacy earlier, the prescription called for a drug with X mg of the target chemical. The pharmacy however only had stock of a higher potency of the same brand. E.g. ...
10
votes
1answer
433 views

E coli cotransformation efficiency

What is the E coli transformation efficiency for 2 plasmids? Are any studies that have looked at the correlation between number of plasmids transformed and transformation efficiency? Is there a ...
3
votes
1answer
635 views

Does yeast grow on LB agar plates?

I would like to grow E coli cells on cellophane on top of LB plate, and then grow yeast cells on the same LB plate. Does (or how well) yeast grow on LB plates? Is there a composition media that can be ...
1
vote
1answer
57 views

Why can't my body deal with cold-sores

I am not a biologist, but I have always wondered why my body hasn't learnt to deal with the HSV-1 virus. I understand it reamins dormant for a while and things like stress or the common cold can ...
0
votes
1answer
69 views

Fibrinous inflammation, exudate and scarring in monotonous movements and ageing

I have palpated many hard organs during my work and studies. I have seen many young and old people who have hard organs, like very hard shoulder - very common. I have interviewed some of them, some ...
1
vote
0answers
17 views

Which kit provides the highest yield and purity of extracted DNA from FFPE tissue samples?

I'm looking to extract DNA for sequencing from FFPE (Formalin fixed paraffin-embedded) tissue samples. I'd like to use a commercial kit that provides a high yield of good quality DNA.
5
votes
1answer
76 views

Burns' “To a mouse” - what species of mouse?

What's the most likely mouse species Robert Burns is referring to in his poem "To a Mouse, on Turning Her Up in Her Nest with the Plough". Burns farmed near Ayr, which is on the Firth of Clyde in ...
1
vote
1answer
181 views

Plastid and mitochondria

I am not biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is difference between plastid, chloroplast and mitochondria? Are there any plant ...
2
votes
1answer
42 views

Knockout Rat Phenotype Database?

Is there a database where I might list the phenotype of a certain rat knockout and/or search for other similar phenotypes? There is a International Mouse Phenotyping Consortium, which has the goal ...
2
votes
1answer
598 views

What can cause the bloating in high protein diet of Whey proteins?

I am thinking what can cause the swelling of gastrointestinal system i.e. bloating after high protein diet of Whey proteins. Liver does breaks those proteins to branched chain amino acids (BCAA), ...
1
vote
1answer
333 views

Can SIRS occur without Sepsis from Infection?

I am thinking this figure It suggests me that there has to be Sepsis that infection can lead to SIRS. I am thinking particularly the pathogenesis of Cryptococcus neoformans where respiratory ...

15 30 50 per page