5
votes
1answer
346 views

Aren't antibiotic resistant probiotics dangerous?

Multidrug resistant probiotics are often recommended by doctors in various cases. But since bacteriae can easily exchange genes by conjugation or other means they could promote the drug resistance of ...
18
votes
2answers
1k views

Can rats pass on memories of a maze to their offspring?

A friend of mine told me once about a documentary movie he saw some years ago. On this movie he saw scientists talking about particular experiment. This experiment involved rats and probably ...
17
votes
4answers
2k views

Why are there exactly four nucleobases in DNA?

Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
4
votes
2answers
8k views

Calculating Protein Concentration from Kilo Units (KU)

I am looking to purchase Pyruvate Kinase from the Sigma Website, they state the volume in Kilo Units (KU) i.e. 1, 5 or 25 KU. It also states there are 350-600 units / mg protein. Does this mean one ...
6
votes
1answer
194 views

Is there a detectable amount of bacterial DNA in the blood of infected persons?

With which bacterial infection in humans has it been shown that bacterial DNA can be found in the blood? If any is found it is likely not to be very much, and even difficult to distinguish from ...
3
votes
1answer
1k views

SPINAL CORD: Do the axons from white matter synapse with the cell bodies in grey matter?

After wading through a sea of information, I understand the main differences between the white matter and grey matter of the spinal cord. I know that white matter contains myelinated axons in the ...
4
votes
1answer
928 views

Is ovum + ovum fertilization possible for human?

In humans is it possible to fertilize a ovum with another ovum from the same female subject? I already found some works in which the ovum is fertilized by a somatic cell (see e.g. this ), but I am ...
4
votes
0answers
69 views

effect of background selection on promoter regions compared to distant enhancers?

Has anyone looked at the effect of background selection on the levels of conservation of promoter regions compared to distant enhancers? Do promoter regions have a higher conservation due to ...
9
votes
1answer
3k views

When running gels what is the difference between constant volts or constant amps?

In general, you want to be consistent with running your gels either at constant volts or constant amps. However, it is very clear that during the progression of both PAGE and agarose gels, the free ...
6
votes
1answer
356 views

Photosynthetic Pigments vs. Chloroplasts

What is the difference between Photosynthetic Pigments and Chloroplasts? I know plants have both but Prokaryotes (Bacteria and Archeae) only have the former.
6
votes
2answers
439 views

What is the relationship between migraines and histamine?

A family member suffers from migraines so I have been reading a little around the subject. There seem to be any number of "triggers", but I have seen mention several times of the role of histamine ...
4
votes
1answer
303 views

How does a plant cutting develop roots?

Please correct me if my understanding is incorrect; I understand branch/stem, and root are composed of different types of cells. Yet in some plants (e.g. rose, bougainvillea) a cutting from the stem ...
10
votes
1answer
392 views

How does a jumping spider manage to “jump” on the ceiling?

I just witnessed a small jumping spider jump on some kind of louse or bed bug on the ceiling. How does it do that without falling? I have yet to find a high-speed-camera video of a jumping spider ...
5
votes
1answer
552 views

Total amount of CO₂ / Oxygen in Bloodstream in Humans

How much carbon dioxide and oxygen from/for respiration are in the bloodstream at any one time? (mass per litre of blood or similar) And would there be much more aside from the blood in tissue, e.g. ...
5
votes
2answers
4k views

Why do we sweat after drinking water and running?

Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?
5
votes
1answer
230 views

Are there any side-effects from a mosquitoes extinction?

Suppose that we have the ability to make mosquitoes extinct, what would the side-effect of such extinction be other than the fact that there won't be any mosquitoes left? Is it worth it to make ...
11
votes
3answers
279 views

Most suitable biodiversity index

I am conducting an investigation into the effect of two different grass management techniques (grazing vs. machine-mowing) upon floral biodiversity. I have collected my data and now need to process ...
2
votes
1answer
308 views

Will fruit/seed of a bonsai yield another bonsai plant/tree?

With practice one can create a bonsai; no complicated modification of the DNA in a high-end lab required. The bonsai will even beget bonsai fruit. What I am curious about is - if such bonsai fruit ...
8
votes
1answer
1k views

How does this illusion work?

I found this image on Google+ If you shake your head you can see a portrait of a person. Can anyone explain how the image is constructed in the brain?
0
votes
2answers
2k views

Autosomal Recessive Trait when skipping one generation

I learned recently that given a pedigree it is possible to tell whether a disease is autosomal recessive by observing if the trait skips a generation. If the disease does skip a generation, then the ...
5
votes
1answer
446 views

Primer Dimer / Hairpin Algorithms

What are the algorithms / methods in use for the calculation of primer dimers and hairpins? As an example, IDT's OligoAnalyzer tool will generate these analysis given particular sequences. The ...
10
votes
2answers
314 views

How deep in the soil can a seed be placed and still develop into a plant/tree?

The selected answer to How does a plant grow before photosynthesis is possible? indicates that a sprout grows beneath the soil using the food stored within the seed. Does this limited ready food ...
14
votes
1answer
193 views

Paralogous genes in genome-wide association studies?

Has anybody tested if paralogous genes are over-represented among the genes identified by genome-wide association studies (GWAS)? For example, if a GWAS study finds 200 genes associated to the ...
9
votes
1answer
402 views

Is it possible to lose synapses over time?

I mean, what if a person is for a long time submitted to conditions in which his mental capacities are not explored, are the synapses undone? I've heard that drugs may cause such an effect, but what ...
1
vote
1answer
2k views

What is the mIU unit as used in hCG hormone levels?

My girlfriend is in her very early pregnancy, and has provided several blood samples by now where the doctors measure her hCG levels. The hCG hormone level is measure in a unit called ...
4
votes
1answer
85 views

How would one describe the R-factor in crystallography?

Yes, there is the wikipedia definition, but how would one explain this concept to a non structural biologist?
1
vote
0answers
46 views

Where can I find approximate rates of sequestration of CO₂ for different species of algae? [on hold]

For a study, I want to compare the rates of CO₂ sequestration and fixation of a few different species of algae. I could not find any data on the sequestration rates. Any pointers to where I can find ...
4
votes
2answers
112 views

Sequencing from PCR

As far as I understand it, PCR can be used to make many copies of one gene. My question is, is it possible to sequence DNA after PCR and is it easier than sequencing it via other methods. If it is ...
1
vote
0answers
26 views

Photosynthesis/Plants Question [duplicate]

Possible Duplicate: How long will a vegetable live for after being harvested? Exactly when do plants "die," as in stop functioning to live? If, for example, you pick a plant and start to ...
4
votes
0answers
49 views

Is it possible to repopulate lactase in the stomach? [duplicate]

Possible Duplicate: Can an adult without genetic lactase persistence still develop a tolerance for dairy foods? In my younger years, I don't seem to have a problem drinking milk. Nowadays, ...
10
votes
7answers
3k views

How did the first self replicating organism come into existence?

When people try to explain evolution, they tell me that evolution is a cumulative result of mutations & natural section of the more superior individuals of a particular species. I think I'm fairly ...
1
vote
0answers
109 views

Properties and life cycle of chondrocytes and tenocytes [closed]

Questions regarding chondrocytes and tenocytes: Do these cells replicate, or are they regenerated from mature stem cells? How often are these cells regenerated? How long do they live? Do they ...
3
votes
3answers
202 views

Extreme examples of protein translation/use coupling/decoupling?

What are known extreme examples of protein translation/effect coupling/decoupling? For example, examples of proteins that are immediately used at the time the have been translated and vice versa, ...
19
votes
1answer
1k views

Why do ants live so long?

I was surprised to learn that worker ants in some species live many years. I would have expected a lifespan of a few weeks or months (which is apparently the case for many species). What factors ...
6
votes
2answers
3k views

How do I deal with sticky and viscous samples from cell lysates?

To check a protein expression I pelleted a small amount of E. coli before and after induction and lysed them by redissolving them in SDS-PAGE loading buffer and heating them to 95 °C for 1 minute. ...
3
votes
1answer
59 views

What are treatable foetal conditions during pregnancy?

What are different foetal conditions during pregnancy that could be treated with appropriate prenatal genetic testing? I only know that pregnant women are encouraged to take certain supplements to ...
5
votes
2answers
2k views

What is the appropriate method to send a strain?

We are planning to send an ecoli strain to another lab. What is the appropriate way to do so. No MTA is required but the options seem to be using filter paper or sending a glycerol stock on dry ice.
9
votes
2answers
382 views

Is there any recent evidence for the aquatic ape theory of human evolution?

aquatic ape theory suggests that many features that distinguish humans from their nearest evolutionary relatives emerged because the ancestors of humans underwent a period when they were adapting to ...
7
votes
1answer
1k views

Why is the Kakapo more attracted to humans than its own kind?

The Kakapo can be seen in this video by BBC. It is said that the species is strongly sexually attracted to humans. Why could this be the case?
2
votes
1answer
62 views

variation in expression accounted for a SNP — what's a usual percent?

I am reading a GWAS paper that found a SNP associated to predisposition to colon cancer and was assessed for gene expression of the nearby gene. They found that the genotype accounted for 55% of the ...
5
votes
1answer
120 views

Is it possible to sequence only the 16S rRNA component? If so, how?

There have recently been several papers on using 16S rRNA as a way of identifying species (here, and here). I'm wondering if it's possible to sequence either just that subunit of the ribosome or just ...
4
votes
1answer
356 views

T7 promoter leakiness

Can a gene be expressed under the T7 promoter in an E. coli strain (e.g. DH5 alpha), which does not have the T7 polymerase gene encoded in its genome? In other words, is T7 promoter leaky? To be ...
11
votes
1answer
1k views

Why does hair turn grey or white, and why does it happen later for some?

The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some ...
2
votes
1answer
487 views

Why does ampicillin in solution turn yellow?

I have a universal tube with 10 mg mL-1 ampicillin. When I got it, it was supposed to be sterile. It was opened for approximately 20 minutes for an experiment and has since been standing around sealed ...
1
vote
0answers
346 views

Appropriate methods for triteration? [closed]

What is the appropriate method to pipetting up and down mammalians cells to sufficiently break up clumps. This should also keep in mind the issues from Pipetting damage on cells. Visually one can see ...
5
votes
1answer
121 views

Is there any reason the common housefly continues to return to an area?

This might come off as a really silly question. But I'm wondering (especially in the case of food) if there is any reason a fly would continue to try and sit on top of a piece of food even after ...
4
votes
2answers
219 views

Is Homo sapiens the only species capable of prioritization?

Just what the title states--given an absurdly large number of assignments to perform in a limited time-frame we usually attempt to do the most important ones first. Is this ability to define and ...
5
votes
1answer
362 views

Do all plants photosynthesize with equal efficiency?

Just what the title states. Given identical, necessary and favourable conditions (Probably nutrients, humidity, and light but what I mean is all necessary requirements are fulfilled) - Is ...
14
votes
2answers
813 views

Impact of Alan Turing's approach to morphogenesis

Shortly before his untimely passing, the computing pioneer Alan Turing published his most cited paper The Chemical Basis of Morphogenesis (1952). The central question for Turing was: how does a ...
11
votes
2answers
2k views

Why do only only two sexes exist for animals?

Why, from the natural selection point of view, do only two sexes exist for animals?

15 30 50 per page