12
votes
2answers
2k views

How was birth control realized in ancient days? [closed]

In ancient days, there were no birth control methods like condoms or contraceptive pills available. How did they control pregnancy?
2
votes
2answers
176 views

What is the cause of colours of nail

Why the nails are of white colour from bottom? then why they are pink and again white in the end?
3
votes
0answers
45 views

Do High Triglycerides Invalidate Tests for Infections?

Blood donation websites tell you to avoid eating fats a few days before the donation, because when there is a lot of fat in the blood, they can't test for infectious diseases and must discard the ...
2
votes
1answer
241 views

Are there histones present in the cytoplasm?

In this paper the authors depleted core histone heterodimers H3-H4 at 90 % from the cytoplasm of Xenopus oocytes. They state that their concentration is in the order of 6 uM. My question is, are ...
2
votes
0answers
55 views

Do genetic modifications exist to enhance the taste of tomatoes?

GM tomatoes seem less tasty. Has there been any research on GMOs with regard to taste? Can scientists introduce a gene to, let's say, tomatoes, which would enhance the flavour? If not, why?
3
votes
1answer
75 views

Hodgin-Huxley model for a single neuron

I am viewing (through edX ) an introduction course to computational neuroscience. In the second lecture, the Hodgin-Huxley model is considered. I am going over some of the questions and have ...
-1
votes
1answer
63 views

Why do aquatic animals smell so bad? [closed]

Many have experienced the "fishy" smell prevalent with seafood, but why do aquatic animals smell so bad? Is it because of salt water?
12
votes
3answers
3k views

Why do humans find baby animals cute?

Why do humans find baby animals like cats, dogs, ... so cute? As these are potential competitors (when grown up!) or even natural enemies (like e.g. tigers, leopards, ..), the protection instinct (...
5
votes
4answers
317 views

Why can't you just take a vitamin? Why you need a healthy diet on top of that?

From what I understand, your body needs certain amounts of vitamins and minerals to maintain health. Why can't we just take enough pills to obtain these vitamins and minerals?
4
votes
1answer
45 views

What determines the thickness of Cornea?

In eye-operations such as Lasik and Femto, the thickness of cornea is key decision factor whether the operation is feasible. A normal thickness is between 500-600 µm. Cornea consists of a very special ...
14
votes
3answers
3k views

Help identify this worm-like thing

Many instances of this worm-like creature were found in a water system for a mountain cabin in the Sierra Nevada mountains of the US, in late June / early July. The water system collects water from ...
1
vote
1answer
85 views

Plasmid gene knockout

How do delete a single gene encoded in an operon on a plasmid using E. coli? Could you use the same principle as when knocking out a gene from the bacterial chromosome which is e.g. suicide vector-...
5
votes
0answers
77 views

Understanding F-statistics in population genetics

I am reading a classical Weir and Cockerham 1984 paper about Fst estimation. At the beginning (first page, right column), they define 3 statistics. $F$ is the correlation of genes within individuals ...
5
votes
2answers
163 views

Exhalation while holding breath

If you inhale to your maximum capacity and hold your breath for an extended period of time, it begins to feel uncomfortable; slowly releasing your breath at this point seems to provide relief from ...
0
votes
1answer
56 views

Critical discussion: Gene expression and systems biology allows us to understand the control of complex traits

I'm having a bit of trouble tackling this question. Any help on what I should write about or the points I should mention would be much appreciated. I keep seeing articles about eQTL and QTL are these ...
6
votes
2answers
4k views

How is membrane capacitance related to the increased speed of saltatory conduction?

Here is the original question which inspired my question. As explained by the answers there, the reason saltatory conduction in myelinated neurons is faster than non-myelinated conduction is because ...
5
votes
2answers
176 views

Need some good resources to learn about Protein function and structure

I'm taking a course on biochemistry at edx. Since I'm a computer science student, I'm having some trouble in understanding many biochemical concepts. While the first module was just fine, I found the ...
3
votes
1answer
42 views

Which hydrophobicity scales are best for detecting transmembrane regions, and why?

There are many hydrophobicity scales for protein analysis. Broadly, I gather the differences between them are from the experimental method to acquire the data and the normalisation (or lack thereof) ...
6
votes
1answer
424 views

How can bats hear such high frequencies?

I attended a talk that glossed over some biology as it was talking about a certain protein. The speaker mentioned humans can hear up to, often less than 20kHz frequencies, whereas bats can hear up to ...
8
votes
1answer
128 views

Why do humans require vitamin B12 supplementation while herbivores do not?

This question came about from reading the comments of this (very unclear) question, which the author did not properly clarify. Vegans are often recommended to take vitamin B12 supplements, as the ...
1
vote
0answers
26 views

Do animals commit suicide? [duplicate]

Do we have documented cases of animals purposely and consciously trying to end their own life? What leads to animal suicide, and is it preventable? I've heard mixed answers from various biologists. ...
11
votes
1answer
1k views

Why do chickens not try to get up if laid on their backs?

I've seen a few videos about chickens being laid on their backs for a few seconds after which the chickens stay in that position until they are turned over. Comments around the video suggested that ...
6
votes
1answer
177 views

Are there any theories why such an imbalance in chirality of molluscs?

Most gastropods exhibit sinistral (right hand) winding of their shells. But very few species are anti sinistral. Have there been any theories as to why such a great difference?
3
votes
1answer
72 views

What determines the pathway of a neurological signal?

My question is about the neurological signals. In our body when a signal, for example a hearing signal from hair cells, is built, it goes through a lot of neurons and it passes a lot of synapses. I am ...
7
votes
0answers
111 views

What is basis of multifunctionality of “master glands” in the endocrine system?

I have just started reading about the endocrine system and I am having some difficulty understanding the basis of distribution of glands and associated hormones. I am using multifuntionality to ...
0
votes
0answers
140 views

What is the reason our body stops producing collagen/elastin?

Stops producing elastin at around 14 years old. Collagen -- at 25-30. What is the reason?
1
vote
0answers
148 views

Were we able to create vitamin B12 in past?

All herbivores produce vitamin B12 de novo. Gorillas, for example, are "vegans" so I suppose some human ancestor was also herbivore. Have we ever been B12 self-producers? If so, why have we lost that ...
1
vote
0answers
48 views

Which taxonomic classification schemes are most accepted?

Since the taxonomic classification schemes followed by universities around the world are different I wish to know which are the most accepted classification schemes till date concerning the following ...
0
votes
1answer
35 views

Is 100% accuracy in DNA sequencing possible?

I would like to obtain a complete genome of a canine (with mitochondrial DNA too) at 100% accuracy. Is it even possible with the current technology? The source I have is potential degraded, i.e. dried ...
4
votes
2answers
350 views

How do you store membrane proteins?

We're producing some membrane proteins and they aren't amenable to freeze thaws even when we add glycerol. The proteins are solubilized in detergent above the cmc so they should be in micelle form in ...
2
votes
1answer
54 views

Physiology of tricuspid and bicuspid(mitral) valves

The tricuspid and bicuspid valves are atrioventricular valves. Both are valves that prevent backflow of blood pumped from the atria to the ventricles. However, the former has 3 "flaps" while the ...
4
votes
2answers
263 views

How does decreasing surface tension of lipids help to emulsify them?

According to my chemistry book, water has higher surface tension than lipids. But in my biology book it is written that "the gall forms an emulsion of water and lipids by lowering the lipid's surface ...
0
votes
0answers
29 views

Book recommendation on the human muscle system

I would like to learn more about the exact mechanism behind our movements, especially about what happens during intense training when anaerobic state arises.
4
votes
0answers
51 views

Negative association between habitat quality and reproductive success in birds

I'm looking for bird studies that have found either a negative correlation or no correlation between habitat quality and reproductive success. Or in other words, bird studies that have found that ...
6
votes
1answer
145 views

What is the biochemical explanation for tingling and burning sensation in brain due to certain food?

Consumption of mustard (spicy English Mustard), wasabi and horseradish based food dressings usually result in a burning, tingling or freezing sensation in the brain/scalp and nostrils as the vapour ...
5
votes
0answers
107 views

How does an organism know when to stop growing, whether it is already on the outermost layer? [closed]

When a multicellular organism is under its development how does the current outermost layer of cells "know" that they should not divide furthermore, as their bodyplan coded into DNA is already ...
1
vote
2answers
80 views

Referencing the homologous chromosomes

There exist a co-ordinate system from chromosomes like "12p11.3". In this system, first integer range from 1 to 23 i.e it takes homologous chromosomes as a pair. If we want to distinguish among ...
5
votes
0answers
73 views

Why do some medicines induce sleep? [closed]

I have seen lot of people sleep or say that they are feeling sleepy after taking some medicines. Why? I mean, if a medicine acts on some cell of the body because that cell has got its receptors and ...
1
vote
1answer
150 views

Choosing the best assay for my experiment? [closed]

Which of the following assays can be used to determine whether cell death specifically due to apoptosis has occurred in a given cell sample? Choose all that apply. WST-1 Assay Caspase Colorimetric ...
0
votes
2answers
402 views

Evolution of insects, spiders and jellyfish

Well we all learned at school the classic evolutionarily theory ...
2
votes
0answers
201 views

Skin extra sensitive to heat after burn

I just got my finger burnt (first degree burn $\Rightarrow$ I didn't even bother to bear the wound). It didn't hurt much, even when I pressed the wound. However, when exposed to heat (hot water, but ...
8
votes
1answer
662 views

Do butterflies pass over migration patterns to their offspring?

So, earlier, I read online (http://io9.com/butterflies-remember-a-mountain-that-hasnt-existed-for-509321799) that Monarch butterflies veer east during their southward migration to avoid a mountain ...
4
votes
2answers
235 views

How do researchers map root systems of plants?

For example, here is a picture of the root systems for some prairie grasses: (Click image for higher-resolution PDF) from: http://www.conservationresearchinstitute.org/educational-offerings.html How ...
1
vote
1answer
112 views

Design arbitrary degenerate primers (with non-binding criteria)

I would like to design a number of arbitrary degenerate primers (primers with variable bases, e.g. NGATWGCTSATNGC) for a TAIL-PCR. I would like to be able to ...
0
votes
0answers
135 views

Cut-off values for LD, LOD and D-prime as algorithmic input

I created an algorithm to generate SNPs for random people of different descents - based on HapMap data. While this works good, there is something else I want to take into consideration. So if a SNP ...
2
votes
0answers
79 views

Efficient algorithm to calculate various population divergence statistics

Intro and description of the data I am simulating the evolution of very long DNA sequences. The model works well, is performant and will output data in the following kind of fasta format ...
3
votes
1answer
42 views

Application of Latin names for Taxonomy

The current taxonomy has family names like Canidae and Felidae. But Felidae has sub families like Felinae and Pantherinae. Roaring cats and non-roaring cats. My question is based on the fact that we ...
0
votes
1answer
73 views

At what saltiness will water simply pass through us?

If water has a low salt content, it hydrates us. When water has too high salt concentration, like sea water, it drains water out of us instead when we drink it. At what salt concentration would water ...
6
votes
1answer
107 views

Did any dinosaur molt?

Like snakes or lizards, did any dinosaur molt ? if yes, have we any proof of it ?

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