8
votes
1answer
166 views

Is it plausible that eukaryotic organelles like flagella and cilia are the result of endosymbiosis with spirochetes?

This was a claim by Lynn Margulis explained over at this link. The sense organs of vertebrates have modified cilia: The rods and cone cells of the eye have cilia, and the balance organ in the ...
5
votes
1answer
691 views

The genetic and physiological origins of laughter?

This Wikipedia article defines laughter in many terms, such as... "a visual expression of happiness, or an inward feeling of joy" and "a part of human behavior regulated by the brain, ...
14
votes
3answers
462 views

What is the most difficult feature to explain evolutionarily? [closed]

I wonder what are examples of organs/structures/behaviours/cooperation that evolutionary biologists themselves find most difficult to explain -- to explain how they could appear evolutionarily -- ...
1
vote
0answers
97 views

How to find Dmax (genetics problem) [closed]

My attempt: I'm not sure this is right but this is what i did. I found the allele frequencies to be: A=0.4 B-0.3 a=0.1 b=0.2 I think to find Dmax I just multiply the two alleles with the larges ...
2
votes
0answers
38 views

How much does a human brain's metabolic rate vary? [duplicate]

Possible Duplicate: How does brain energy consumption depend on mental activity? Our brains consume about 20% of our energy when we're at rest. How variable is a human brain's energy ...
5
votes
1answer
560 views

Is it true that newborn babies don't produce tears while crying? Why?

Well, I was just going through an article on eye, where in fun facts it was mentioned that newly born (for initial 1 to 3 months) babies do not produce tear while crying. Actually, I have found this ...
20
votes
1answer
2k views

How long do your eyes need to adapt to darkness and reach full contrast?

I heard you should wait some time until your eyes adapt to darkness and are able to see smallest luminosity differences, otherwise you might overlook faint objects in the ocular. Are there any rules ...
8
votes
1answer
105 views

Why can't we breed watermelons without any remaining seeds in the flesh?

Watermelon is just starting to come in season in the northeastern U.S., and having a seedless watermelon is convenient. The only downside is, the "seedless" almost always still have the immature, ...
8
votes
1answer
197 views

Finding DNA from Amino Acid sequence problem

My attempt: First I took the single letter AA codes and made them amino acids. So, the first one is Trp which is 5'-UGG-3'. From this I got the DNA sequence 3'-CCA-5'. However, the correct ...
15
votes
1answer
354 views

How fast does the rotor in ATP synthase spin?

I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
11
votes
3answers
365 views

How did the human brain evolve?

A common question posed is, "how did the eye evolve?", because the eye is so complex. However, this has been answered rather clearly and there are several examples around the world of animals in ...
4
votes
1answer
261 views

Finding exons in DNA problem

My attempt: I looked for the TACs because I thought this would be AUG in mRNA and ultimately Methionine (the start codon). But apparently, that's not how you do this problem. Im confused because ...
6
votes
2answers
616 views

What is the main general difference between Mitosis and Meiosis?

I found such a clause: The general principle is that mitosis creates somatic cells and meiosis creates germ cells. However, I cannot agree. Each gametogonium needs to go through mitosis before ...
7
votes
1answer
175 views

Why is the Patellar reflex not triggered when the tendon is extended slowly?

I have been previously told that the Patellar reflex (knee-jerk-reaction) exists to prevent the hyper-extension of the patellar tendon. Yet if the impact to the tendon is delivered slowly - i.e. by ...
6
votes
4answers
186 views

Genetic effects on personality

It is said that genes are partly responsible for the choices we make in our life; our genes help to create our environment, and then that environment can influence our personality. So, beside genes, ...
18
votes
1answer
1k views

Why do stars disappear when I look at them?

I've noticed that when I'm out at night stars seem to vanish when I focus on them. I assume the reason is physiological and not astronomic. Why does this happen? I would expect that things would be ...
8
votes
1answer
1k views

Does the use of “var”, “x”, and/or “ssp” in a scientific name provide specific information?

What exactly does it mean when a plant has a scientific name that specifies a vairety, for example Nothofagus solandri var. cliffortioides, or when the name includes an "x", as in Populus ...
6
votes
1answer
348 views

How Do Adherent Cells In Culture Attach To A Plastic Dish?

I am particularly interested in MC3T3-E1 cells (mouse fibroblasts), which are adherent cells. Are hemidesmosomes involved in anchoring the cells to the plastic dish? What (if any) other molecules are ...
0
votes
1answer
78 views

If inhibiting S6 kinase decreases protein translation, then could inhibiting S6 kinase could possibly slow down long-term potentiation in neurons?

From http://en.wikipedia.org/wiki/P70S6_kinase... Phosphorylation of S6 induces protein synthesis at the ribosome. P70S6 kinase is in a signaling pathway that includes mTOR (the mammalian ...
5
votes
1answer
179 views

Why isn't the p16-INK4a gene involved in apoptosis expressed in heart or liver tissues?

New York Times article explains how killing p16-INK4a positive senescent cells can help keep the surrounding cells vigorous. So here's my question: why is p16-INK4a expressed in most cells other than ...
8
votes
2answers
219 views

What are the frequency ranges of most marine mammal vocalizations?

I am trying to determine a list of frequency ranges into which marine mammal vocalizations fall. Ideally, I would like a list showing where the most popular marine mammal vocalizations fall, followed ...
8
votes
1answer
54 views

Downloadable worldwide database of disease statistics?

I am looking for a downloadable database of disease statistics. I have emailed the good folks over at HealthMap, but they haven't gotten back to me yet. As far as I can tell, their data relevant to ...
6
votes
2answers
222 views

Is there such thing as a generic “metabolic type”?

A while ago I picked up a book called "Eat right for your metabolic type". The book discussed the effects of the endocrine system on the overall shape and the speed of metabolism. The book outlined ...
2
votes
1answer
126 views

What are the effects of combining rapamycin with dietary restriction?

Are the effects additive or subadditive? In many ways, rapamycin acts like a CR mimetic, but even CR can only go so far.
7
votes
1answer
182 views

Linkage and LD: quantitative or qualitative?

My understanding is that the concept "genetic linkage" can be expressed in quantitative form, like: A predisposing gene X was found in close genetic linkage to Y. ...
7
votes
1answer
99 views

How can I normalize mRNA samples for sequencing?

Is there an easy, inexpensive, not too labor intensive way to normalise mRNA samples so that even though one loses information of gene expression levels, each of the transcripts in the transcriptome ...
2
votes
0answers
86 views

Has anybody used Evrogen's DSN-normalization protocol for cDNA normalization? [closed]

I found the link to a commercial product by Evrogen to normalise cDNA samples for gene discovery projects here: http://www.evrogen.com/technologies/normalization.shtml The most up-to-date reference ...
6
votes
1answer
676 views

Does anyone have any TOPO directional cloning tips? [closed]

I'm just about to start working on a TOPO cloning after I couldn't get it to work with standard restriction/ligation. Does anyone have any tips for TOPO cloning?
7
votes
1answer
44 views

Which functional annotations could be useful?

Analyzing a genome, for a generic gene, which functional annotations (e.g from Gene Ontology) can help understanding its meaning/function or, at least, provide helpful informations? Annotations of ...
4
votes
1answer
194 views

Automatic cropping of collimated digital X-ray images

Do you have any suggestions for a library which offers an algorithm to crop digital X-ray images automatically? We receive full-size images (43x43cm) from a detector, independent of the collimator ...
9
votes
2answers
34 views

Resources for finding all drugs of a certain class

I may be embarking on a project involving a fairly extensive healthcare records data set, looking for the use of a particular type of drug (for example, "Proton Pump Inhibitors"). But these drugs are ...
11
votes
3answers
484 views

Human disease and associated phenotype database?

Does anyone know of any good databases that contain symptoms for diseases and other ailments in humans? I've tried working with UMLS, but thats been impossible to work with. I've also tried working ...
7
votes
2answers
26 views

What data / tools exist for mapping of disease trends?

I was just looking at the Google Flu Trends map. Google Insight could be used to gain similar information for other trends in disease keyword searches. I started wondering how valid are keyword ...
7
votes
1answer
130 views

How exactly does long-term tension (over months) build up in the ligaments, tendons, muscles?

And is there any basis for believing that massage relieves that tension?
13
votes
2answers
139 views

Relationship between our microbiome and personalized nutrition

Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
5
votes
4answers
416 views

Could someone recommend an introductory book on epidemiology? [closed]

I'm hoping to learn the basics of epidemiological methods, terminology, etc. I come from a background in statistical economics, and I'm moving into the economics of public health. I don't know if ...
6
votes
1answer
2k views

Purpose of poly(A)+ RNA?

I am learning RNA-seq analysis. I always encounter this phase "poly(A)+ RNA". After searching, I got this: "Most messenger RNAs contain a poly(A) tail, while structural RNAs do not. Poly(A) selection ...
7
votes
1answer
95 views

Can one dendrite pass through another?

While tracing dendrites on EyeWire I encountered the following situation. They belong to an Orientation Selective Ganglion Cell. It's the first dendrite I've noticed with such a clear 'hole' in it, ...
4
votes
1answer
164 views

From inflammation to sickness and depression: when the immune system subjugates the brain

Recently, some research, for example this article has proposed that inflammation can cause innate immune cells to produce pro-inflammatory cytokines that act on the brain to cause sickness behaviour. ...
5
votes
2answers
2k views

Primer design for introduction of restriction sites flanking a gene of interest

I am wondering what the correct method for primer design to introduce restriction sites. Specifically between two methods. 1) Primer first partially hybridises to the gene, has a mis-match where the ...
7
votes
1answer
4k views

Difference between strand-specific and not strand-specific RNA-seq data

I would like to ask the difference between strand-specific and not strand-specific dataset. As far as I know, strand-specific data means that we know which strand the transcript is from. I do not ...
6
votes
0answers
58 views

Using the IMGT/GENE-DB service to find RSS

I'm trying to get the data for the Human and Mouse 12 and 23 Recomination Signal Sequences (RSS), to run a classification algorithm on it. I'm not a biologist, so I apologise in advance for my ...
3
votes
1answer
89 views

Majority of transcripts are from sense strand?

I am wondering whether majority of transcripts are transcribed from the 5'->3' strand? Because I encounter a lot of expressions like "anti-sense transcripts". Could anybody help clarify this? Thanks.
8
votes
1answer
1k views

Effects of beer on muscle recovery after exercise

I noticed it several times that when I drink beer (even one bottle) after some heavy workout, the next day my muscles are more stiff than other times, and not the same way... Is it because that ...
3
votes
1answer
72 views

Is it harmful for someone to consume things full of bacteria if they don't get physically sick from the bacteria at all?

Or as another example - what if you touch a surface that's contaminated with potentially pathogenic bacteria (like the ones at ...
2
votes
0answers
57 views

Are there examples of PTMs that add different chemical groups (and mass) to different amino acids?

I'm talking about this type of post-translational modifications. What I'm interested in is not whether some modifications can only occur on specific amino acids (that's clear), but if the nomenclature ...
2
votes
2answers
88 views

Consensus codon optimization by organism

Does a public database exist that contains this information? I'm trying to make a simple gene annotation program that will let me input a DNA sequence and then optimize it based on one of these tables ...
1
vote
1answer
86 views

Generating custom human DNA sequences based on traits such as eye colour?

I'm wondering if it would be possible to create software (unless some already exists, but I couldn't find any) to generate human DNA (the base pairs on the double helix) containing genes representing ...
2
votes
0answers
82 views

Mouse meta-globin mRNA problem

This is an mRNA strand of mouse meta-globin: 5'-ccccagauacggaauucgaau-3' A) Which small RNA (below) is most likely to regulate expression of meta-globin? ...
4
votes
2answers
60 views

Main methods used to predict functional annotations in GO

Can someone provide me some information about the main method used to predict the inferred electronic annotations in Gene Ontology?

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