3
votes
2answers
264 views

Do women experience more bonding hormones than men after sex?

Does Oxytocin (or any other bonding hormone) increase more so for women than for men after sex? Someone told me that it increases 4-fold for men and 12-fold for women (unconfirmed). Is there any ...
3
votes
1answer
115 views

Are there any air-plants with parts that are edible for humans?

Are any air plants (Tillansia sp.) safe for humans to eat? I haven't been able to find whether or not there are. Pineapple is in the same family (Bromeliaceae), but isn't an air plant.
3
votes
1answer
310 views

Is there any size limit to the amount of information a human (or other) brain can hold

Im not sure how this would ever be tested but is there a limit to how much the brain can 'hold' before it reaches capacity ? I guess this could also be interpreted in terms of memory, as how well ...
3
votes
2answers
86 views

The move from RNA to DNA and the necessity of reverse transcriptase

In this piece about giant viruses and the origin of life, in the context of the move from RNA world to DNA world, virologist Valerian Dolja states: In order to move from RNA to DNA, you need an ...
3
votes
2answers
139 views

How is information sent from limbs to the brain exactly?

Say you have a needle, and you poke a very specific area on your left thumb. A signal gets sent from that nerve up your spine and into your brain. How does the brain know exactly where this signal ...
3
votes
1answer
35 views

What is the reason behind more severe proteinuria in nephrotic syndrome than in nephritic syndrome?

Why is there less protein loss via urine in case of nephritic syndrome than in case of nephrotic syndrome?
3
votes
2answers
81 views

How does guanidium denature DNA?

Guanidium salts like (G-isothiocyanate) disrupt the hydrophobic interactions inside a protein or nucleic acid and denature it. What happens when hydrophobic interactions in DNA are broken? (I don't ...
3
votes
1answer
67 views

How does the counter current mechanism concentrate urine?

The movement of ions like sodium into the interstitial space causes water to passively diffuse out the descending loop of Henle. How does this concentrate the urine? The solvent is removed at one ...
3
votes
1answer
1k views

What is a suicide plasmid?

What is a suicide plasmid? Example: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737453/ mentions a "suicide vector". See also ...
3
votes
1answer
172 views

How does chromosome cross-over occur?

I have heard that during meiosis, homologous chromosomes from each parent "cross-over", which enables the off-spring to inherit some alleles from the mother and some alleles from the father. The ...
3
votes
4answers
117 views

how we don't breathe nitrogen when it makes the most of air?

How we don't breathe nitrogen when it makes the most of air? Why we are always tend to breathe oxygen,not hydrogen and nitrogen?
3
votes
1answer
98 views

How to maximize lung oxygen intake?

What method of breathing provides a sudden surge of oxygen into the lungs filling it as full as possible in volume and density. Deep breaths? Shallow breaths? Breaths taken while bent over? Deep ...
3
votes
1answer
105 views

Why basement membrane thickens in diabetes mellitus?

Untreated diabetes mellitus may lead to blindness and kidney failure because the basement membrane of small blood vessels in these organs thickens due to increased production of collagen and laminin. ...
3
votes
1answer
67 views

How does regurgitated food go to the 3rd stomach chamber instead of going to the 1st?

Ruminants are known for their regurgitation of food; the food goes through the 1st and 2nd stomach chambers, then returns to the oral cavity in cuds. The cuds then come back into the stomach, but this ...
3
votes
2answers
151 views

How can CI repressor both activate and repress $P_{RM}$ promoter found in $\lambda$ phage?

I'm reading a paper where the authors constructed a toggle switch that uses bidirectional $P_R/P_{RM}$ promoter found in the $\lambda$ phage. There are 3 binding sites - $O_R1$, $O_R2$, $O_R3$ - ...
3
votes
2answers
97 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
3
votes
2answers
238 views

How was the Huntington's disease gene's location found?

I read in the book "Why we get sick." by Nesse and Williams that: Steady detective work and fabulous luck have enabled geneticists to pinpoint the Huntington's gene on the short arm of ...
3
votes
2answers
44 views

Tapeworms and their effect on humans

I've read that some people in some countries actually use tapeworms as a form of losing weight. What are the dangers to these people?
3
votes
1answer
363 views

How do I get a brighter DNA bands

I've been trying to a good contrast for my DNA bands, however I haven't been so successful. I've been running the ladders only to make sure I get a good contrast before further experimentation. I ...
3
votes
1answer
50 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 ...
3
votes
1answer
43 views

How do B memory cells provide immunological memory? Do they differentiate into plasma cells?

My text book doesn't say anything about how B memory cells actually ensure a faster response the second time the antigen is encountered. My guess is that they differentiate into plasma cells which ...
3
votes
3answers
92 views

Why do 6-8% of diphtheria patients do not develop natural immunity after being affected?

I am thinking of why some patients do not have natural immunity after exposure to the A-B toxin of diphthria. I think the A-B exotoxin is the key factor causing this disease and should trigger memory ...
3
votes
1answer
75 views

Chaos theory and population cycles

I have just begun to read about Chaos theory and have come across the statement that "Period three implies chaos." My question: Does any odd period imply chaos or only 3? If so, how can populations ...
3
votes
1answer
84 views

Why is Turner syndrome rarer than Klinefelter syndrome?

Turner syndrome occurs in 1-1000 to 1-5000 females, and Klinefelter syndrome occurs in 1-500 to 1-1000 males. Why is Turner so rare even though they both are caused basically by the same mechanism?
3
votes
1answer
355 views

Is the complement system a part of innate or adaptive immunity

I've been reading about the complement system, as part of the human immune system. The complement system is introduced as part of the article on innate immunity on Wikipedia. This classification makes ...
3
votes
1answer
142 views

Sporophyte and gametophyte

My textbook says that in both groups of seedless plants (vascular plants, non-vascular plants) the gametophyte is a free-living plant, independent of the sporophyte. I don't understand this statement ...
3
votes
3answers
75 views

Is there a downloadable list of all species along with their traditional classification?

I'm looking for a downloadable list of all known (or better said, online documented) species in this straightforward format, as an example the European Frog: Kingdom: Animalia Division: Chordata ...
3
votes
2answers
112 views

Modern immunology textbooks

I am looking for recommendations to good textbooks introducing modern immunology. Review articles, preferably modern (post 2000) would also be useful. Please, include a brief comment with each book ...
3
votes
2answers
178 views

Why are antibodies so expensive?

The amplification on vector transgenic microorganisms and the subsequent purification does not seem that complicated. Also, what are the processes that biotechnological industries follow, in detail, ...
3
votes
1answer
43 views

Where can I find a full genealogy of human cell types?

It is said on Wikipedia, that the precursor of blastocyst is a morula, and that the precursor of morula is a zygote. This gives us the part of genealogy tree of cell types. Unfortunately, no full ...
3
votes
1answer
896 views

What is the definition of “dry weight” and “dry cell weight”?

As I understand it, the dry weight of something is its weight minus the weight of its water content. Is this the definition? What about dry cell weight?
3
votes
2answers
359 views

Microscope recommendation for an amateur?

I am a mathematics student looking for a hobby and this has come up as a potential hobby. Thus I am interested in buying a high-magnification microscope that is within the limits of my budget. My ...
3
votes
2answers
3k views

How does extracellular potassium ion concentration and calcium ion concentration affect the excitability of a cell?

When extracellular $K^+$ concentration increase by a certain amount, excitability of cells is higher because the resting potential shifts toward a higher equilibrium potential of $K^+$, therefore ...
3
votes
1answer
52 views

Euthyrodism and goitre

I read in Tortora and Derrickson that goitre is associated with euthyrodism. How is that possible?
3
votes
1answer
60 views

Alternating Ovulation

I have often heard that right and left ovaries alternate in releasing ovum. Is it always true? What controls this rhythm? Is it simply because the other ovary is unresponsive to LH or FSH? If so, ...
3
votes
1answer
287 views

Negative value on linear gene expression in microarrays

I am starting to use microarrays and maybe this is a dumb question: Using Illumina microarrays, linear gene expression can be negative? Or maybe some artefacts have been introduced? And, in this ...
3
votes
1answer
57 views

What is the cause of the spots on this leaf?

On a hiking trip to the Alps I found trees whose leaves showed those spots you see on the picture. I am curious about what the cause is. Higher resolution pictures of front and back side.
3
votes
3answers
70 views

Would Bubling Oxygen Through “Dead Zones” Like A Fish-Tank Make Much Difference?

I am a dilettante when it comes to dead zones. I realize that they vary from fleeting algal blooms to continuous dead zones. For the continuous dead zones it would seem to me that adding a "bubbler" ...
3
votes
1answer
56 views

Does a large effective population size result in faster decay of linkage disequilibrium (LD)?

I am thinking about an invasive species that was introduced into North America just a few (<20) generations ago. Using microsatellite genotypes (105 loci), I have identified almost no significant ...
3
votes
1answer
64 views

Difference in reptile inner ear and otosclerosis

In reptiles, the sound is conducted from the tympanic membrane to the inner ear by a single bone. In the disease otosclerosis the stapes of humans become fused to the other middle ear bones( or to ...
3
votes
1answer
1k 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 ?
3
votes
1answer
139 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 ...
3
votes
1answer
829 views

Neuromediator, Neuromodulator, Neurotransmitter?

Of these three words, perhaps Neurotransmitter is the most obvious. I took a look at Wikipedia page for Neuromodulation and found that this is pretty similar to Neurotransmitter too. I guess ...
3
votes
2answers
2k views

Why do kefir grains stop growing in soy milk?

Kefir is a fermented milk drink made with kefir grains. It usually is prepared by inoculating cow, goat or sheep milk with kefir grains. I would like to prepare the drink with soy milk, which worked ...
3
votes
3answers
194 views

What exactly is the neural receptive field?

Neural receptive fields map the spatial or temporal distribution of the data to individual neuron excitation, if I understand correctly, but I do not understand if receptive fields (especially in the ...
3
votes
1answer
124 views

Differences between right and left handed people

Are there any articles reporting any significant differences in behavior, attitudes, intelligence, appearance, etc., between right and left handed people?
3
votes
1answer
162 views

Precursor miRNA and a mature miRNA

What is the main difference between a precursor miRNA and a mature miRNA? It is often the case that we have more than one precursor miRNA but only one mature miRNA. The miRNA-seq data contains only ...
3
votes
1answer
920 views

How does a virus take control over the host cell?

When the virus integrates its DNA with the hosts and enters the lytic pathway, do the viral proteins that produced destroy the cells DNA? Do they deactivate it? Also does the cell function in the same ...
3
votes
1answer
115 views

Are any organisms known to use meiosis I to create non-identical offspring asexually?

So, there are numerous species of animals who use parthenogenesis, but to my knowledge the reproduction is clonal. That is, the offspring are identical to the mother. Are there any documented cases ...
3
votes
1answer
76 views

Understanding these SNP annotations

I am looking at the PharmaPGKB database for SNPs and trying to understand what the following annotation means: rs1801131 at 1:11854475 in CLCN6, MTHFR (VIP) Ok, ...

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