3
votes
1answer
97 views

How do susceptible organisms prevent parasites from overcoming resistance?

Bt corn is genetically modified to kill borers, but "regulations require farmers to plant conventional varieties as well, which is intended to stop the borers becoming resistant." -Source How do ...
5
votes
1answer
183 views

Are quaternary protein monomers unique to a particular protein complex?

I know that quaternary protein structures are formed exclusively via non-covalent bonds. My biochemistry professor discussed a viral capsid that is essentially one quaternary structure with 240 ...
5
votes
2answers
174 views

Are there other mechanisms for mutation besides imperfect DNA replication?

I was reading http://www.askamathematician.com/2012/05/q-is-quantum-randomness-ever-large-enough-to-be-noticed/ and saw: [...] the evolution of entire species can be changed by a single mistake ...
9
votes
1answer
515 views

How does laser surgery correct accommodation problems?

When someone undergoes laser surgery to improve eyesight, how does it correct accommodation problems? Why does it not help presbyopia?
1
vote
0answers
37 views

How many pandemic H1N1 2009 virus sequences were submitted by the Indian NIV as of May 10, 2010? [closed]

The handout I was following is maddening. It says; "Go to the NCBI home page and select 'All Resources (A-Z)' and choose GenBank. Follow the NCBI Flu Resource link to determine how many pandemic H1N1 ...
8
votes
1answer
1k views

Is there a maximum amount of antibodies your body can keep?

I am wondering if you were theoretically able to get vaccinations or antibodies for any and every diseases and/or illness, would there be a limit to how many you can get and keep in your body at one ...
1
vote
2answers
2k views

Restriction Mapping of Plasmid Assignment

pUWL22 is a circular, double stranded, 10.5 kb plasmid. It contains a gene encoding an enzyme that confers ampicillin resistance in the host bacterium. Cloning into the kpn I and Sst I sites ...
4
votes
1answer
192 views

intravenous (IV) in the tail vein of an anaesthetized mouse

I trained myself to do intravenous injection on live mice. However, on anaesthetized mice you don't see the flux of your product showing that your injection was successful. In the same way, on live ...
13
votes
2answers
12k views

Possible? When a pregnant woman suffers an organ damage, fetus would send stem cells to the damage organ to help repair it?

I am quite sure that there is this blood-placental barrier between the mother and the baby so that nothing (except a type of antibody) can pass through it. But I remember reading somewhere that when ...
4
votes
2answers
697 views

Why is proteinase K digestion performed at 50 °C?

Many DNA isolation protocols use a Proteinase K digestion to remove proteins. This is often performed at 50 °C. Why is this?
1
vote
1answer
995 views

What are the positive and negative effects of insulin on cognitive function?

A UCLA study seems to imply that insulin interferes with cognitive function. The DHA-deprived rats also developed signs of resistance to insulin, a hormone that controls blood sugar and ...
3
votes
2answers
112 views

What risk to DNA does long-term exposure to low-dose radiation pose?

A new study from MIT scientists suggests that long-term exposure to low-radiation poses no risk of DNA damage for mice (it is also important to note that mice are unusually susceptible to cancer). So ...
6
votes
1answer
73 views

Question: Annotation search in scientific literature

In a scientific paper I have been studying ("Predicting Novel Human Gene Ontology Annotations Using Semantic Analys" S.Draghici et al., 2010), I have read that authors checked the accuracy of their ...
7
votes
3answers
384 views

Can protein structure be determined by X-Ray Diffraction in a single image?

I'm reading about the use of x-ray crystallography to determine protein structure. According to my book, data is collected at 30-360 angles (dependent on the symmetry of the protein). An illustration ...
9
votes
3answers
193 views

Does GFAJ-1 use Adenosine triarsenate as its energy currency?

Regarding the bacteria found in Mono Lake, CA that scientists believe uses or can use arsenic in its DNA backbone where life as we know it uses phosphorus (according to their experiments depriving the ...
5
votes
1answer
54 views

Why are some plants frost tender?

Why do some plants have the ability to stand frost, while others can't? Does it have to do with the size of the water vacuoles in the plant cells?
7
votes
1answer
1k views

How does one calculate the resolution of a crystal structure?

Considering that I have a diffraction pattern of a crystal, how would I calculate the resolution of a structure in Angstroms? How does that value differ from the information that I would get from the ...
13
votes
1answer
490 views

How fast will cells lyse under hypotonic conditions?

Routinely, lysis of cells with hypotonic solutions is carried out along with some physical (douncing) or enzymatic (lysozyme) method to break open the cells. If one were not to do any of these and ...
9
votes
1answer
1k views

Will the “frog in boiling water not jumping out” work on warm blooded animals

There is the famous saying about a frog that is put in water that are slowly boiling will not jump out until it's too late. I realize it happens because of the frog's cold blood that adjusts to the ...
19
votes
1answer
270 views

Evolutionary origin and exogenous cues of ~28 day infradian rhythm?

The most obvious example of an approximately monthly biological cycle is the human menstrual cycle. My questions are the following: Is it known when and where this cycle or one like it arose? What ...
6
votes
1answer
185 views

Decreasing the alcohol proof and faster in hangover, why?

My russian friend says that the USSR agents used/use the trick that they offered the victim first vodka and then last wine. I have noted that this puts you faster to hangover: decreasing the alcohol ...
4
votes
1answer
56 views

What value type would a chromosome position be in a database or form?

I wanted to create a tool for some fields like SIFT, Phenotype, etc..so for example I know Phenotype will have "Text" values or SIFT will have some determined values from a drop down list...but what ...
1
vote
1answer
221 views

Human Body “Fat” Equilibrium

Here's my theory: If you consume x calories each day with y amount of caloric expenditure each day you gain zero weight, regardless of x and y being out of balance. If you then mechanically ...
4
votes
2answers
80 views

Genetic networks vs genetic architectures?

What is the difference between the terms genetic network and genetic architecture? I've heard both in a variety of contexts used by different people, so I am interested in what people think they mean, ...
7
votes
1answer
3k views

How do Proteins migrate in MES vs. MOPS

My gels look significantly different in MES (2-(N-morpholino)ethanesulfonic acid) and MOPS (3-(N-morpholino)propanesulfonic acid). That is to be expected. What I don't understand is why the simple ...
11
votes
3answers
313 views

Number of beneficial mutations cataloged?

I can see from Wikipedia that there are possibly thousands of harmful mutations that have been cataloged and linked to disease. There are also unnumbered neutral mutations. But, does anyone know how ...
5
votes
1answer
618 views

What generates variation in a species?

What is the biological mechanism behind the variation within sexually reproducing species? Obviously, the children are combinations, to differing degrees, of their parents. But how does the variation ...
6
votes
1answer
3k views

Molecularly, why can you straighten or perm hair?

I'm aware that hair can be curly because of the disulfide bond interactions in between cysteine amino acids in alpha-keratin filaments. However, I'm curious as to the biochemistry involved in ...
11
votes
1answer
532 views

How to reduce edge effects in cell-based high-throughput experiments?

In high-throughput experiments where cells are cultured, treated, stained, and imaged in 384-well microplates, I frequently see significant edge effects. For instance, the following plot shows cell ...
5
votes
1answer
99 views

In what ways, if any, does administration of rapamycin *not* mimic calorie restriction?

Numerous sources like this say that rapamycin increases lifespan. And mTOR antagonism appears to be a large part of this (mTOR antagonism also appears to be a large part of calorie restriction's ...
7
votes
1answer
197 views

Protein construct design

I am trying to create some constructs of a certain protein deleting well defined domains (at either terminus) to determine interaction regions with other proteins etc., 3 constructs with varying ...
7
votes
1answer
94 views

obesity risk and single gene polymorphisms

I read a fairly recent meta-analysis of studies into the association between adult obesity and polymorphisms of the FTO gene (Peng et al., 2011). The paper looked at 59 studies and found that "FTO may ...
1
vote
0answers
52 views

SAM and Reverse Complements [closed]

Assume a read aligner (such as e.g. BWA) is fed with a pattern P = GACT. Now, the text that ...
6
votes
1answer
295 views

How similar are Circulating Tumor Cells and Cancer Stem Cells?

Circulating Tumor Cells (CTCs) are linked with metastasis and their presence can be used to indicate the onset of metastatic cancer. Likewise, the Cancer Stem Cell (CSC) hypothesis suggests that ...
29
votes
1answer
2k views

Is the “Great Pacific Garbage Patch” beneficial for marine wildlife?

A study was just released by researchers at Scripps Institute of Oceanography revealing a drastic increase in the amount of plastic adrift in the Pacific Ocean. According to the paper, the amount of ...
22
votes
1answer
389 views

How does a cell know its size?

Cells come in all sorts of sizes. How do they regulate their cell size to the point where similar cell types have a fairly mono-disperse size distribution? Reasked from ...
3
votes
1answer
262 views

Predicting progeny of recessive mutations using recombination

I was asked this question on a test and got it wrong, but I'd like to know how to do it. The answers are shown in the blanks below: You are studying two recessive mutations in the fruit fly D. ...
15
votes
2answers
236 views

Can methylation from DNA get copied to RNA during transcription?

Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
13
votes
2answers
251 views

Percentage of genome devoted to regulating gene expression

Recently I've been studying the p53 tumor suppressor gene as a model for regulation of gene expression. It's amazing how many different post-translational modifications are known to regulate p53 ...
7
votes
1answer
82 views

How do nuclear receptors locate each other to form a DNA loop?

Nuclear receptors can influence transcription far up- or downstream from their own binding sites by looping DNA (Rubina et al.; J Mol Bio 2004). I am not sure how exactly the receptors first attach ...
8
votes
1answer
93 views

Why doesn't yearly screening for lung cancer decrease mortality rates?

In a large trial, screening yearly for lung cancer hasn't reduced mortality rates. Why is this? Isn't cancer best treatable when caught early? Is this because lung cancer is hard to treat anyway, ...
8
votes
1answer
4k views

Primary function of the enzyme lipoprotein lipase

I read here and here that the function of lipoprotein lipase is to facilitate fat uptake and storage in adipose tissue. Could anyone provide a slightly more expanded explanation, without going into ...
4
votes
1answer
117 views

What exactly is meant by the expression “differentially expressed”?

As far as I've seen, this expression is almost always used in relation to gene expression profiling. Unfortunately, I have no background in this area. Can someone please explain this in layman terms?
16
votes
2answers
5k views

How do the brain and nerves create electrical pulses?

I have heard that information is sent between the brain and peripheral nerves via electrical pulses or signals, but I don't understand how they create them in the first place.
12
votes
1answer
972 views

Why do neurons die so quickly (relative to other cells) when deprived of oxygen?

This question could be considered a follow-up question to Why is a lack of oxygen fatal to cells?, although the top answer there does not address why damage starts to pop in. The answer says this: ...
11
votes
1answer
787 views

Does bioluminescence occur in humans too?

I read that Japanese researchers have developed very sensitive camera that recorded bioluminescence in humans; is it possible and if so what is the mechanism behind it?
4
votes
0answers
44 views

Determine which gene is in the middle complementation [duplicate]

Possible Duplicate: Crossing mutant strains on minimal media problem I'm studying this problem for my genetics final: My Attempt: The answer for part B is met2 and the answer for part C ...
9
votes
2answers
157 views

Are there any structures in mammals that are used only by males?

There are examples of structures which only serve a purpose in females, but it seems like the opposite could also be true. Are there any structures which exist in both mammalian sexes and only serve a ...
10
votes
2answers
196 views

Did we first have swimming birds or flying birds?

Looking at the swimming birds building nests just across my garden, I suddenly wondered how evolution came to swimming birds and whether flying birds started swimming or whether swimming bird like ...
-4
votes
1answer
234 views

DNA chip contains a complete set of random hexanucleotide (6-mers) probes? (Solve) [closed]

can you tell me how to find solution to this question A DNA chip contains a complete set of random hexanucleotide (6-mers) probes. Out of the 4^6 = 4096 probes, how many will form perfect ...

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