1
vote
1answer
2k views

Can food swallowed when a person is upside down reach the stomach?

If a person positions himself upside down and swallows food, will it reach the stomach against gravity? If so how?
1
vote
1answer
17k views

Can white eggs be considered as non-vegetarian? [closed]

I am basically a vegetarian and I find it very difficult to get an actual biological answer for this question on search engine. There are couple of links which discuss these argument but can not be ...
1
vote
1answer
962 views

What's the difference between life expectancy of cigarette smoker and general population?

Some say that smoking cigarettes will shorten lifespan. By how many years is the lifespan of a typical smoker shortened? What are the common cause(s) of death among smokers? Are there any known ...
0
votes
0answers
44 views

Western blot extrange band

I performed a WB using plasma rats and monkeys samples with anti ubiquitin K-48 antibody. In every sample the antibody binds something and it appears a specific band that seems to be 71kDa. When I ...
0
votes
1answer
39 views

Do plants need O₂ to consume energy they've stored via sugar?

This question came up as I work my way through the answers to another question I just asked. My understanding is that plant photosynthesis looks something like this (though with lots more going on ...
0
votes
3answers
192 views

can recessive alleles produce codominance?

Maybe I'm confused by the term "codominance", but I wondering if codominance only occurs with two dominant alleles. Can two recessive alleles produce codominance in an individual? Likewise, can two ...
0
votes
1answer
672 views

Static in limbs

I have noticed that while sitting in the Sukhasan posture(picture below) for a long time, my feet suddenly become all stiff and i am unable to move it. What I deduce from the experience is that it is ...
0
votes
1answer
79 views

Is forced cell growth related to apoptosis?

Could an instance of forced cellular growth cause some cells to have their self-destruct mechanisms to malfunction or 'turn off'thus preventing apoptosis?
-1
votes
1answer
122 views

What do the names of Immunoglobulin subtypes mean? [closed]

What is the exact meaning and full form of IgM IgG IgA etc? What is the rationale behind the names of the isotypes, if there is one? For example, what does "M" mean in IgM?
71
votes
2answers
9k views

Can HIV be transmitted via mosquitos?

It is known that HIV is usually transmitted by direct blood or body fluid contact between an infected individual and a healthy person (like blood transfusion or needle sharing): Suppose a mosquito ...
41
votes
1answer
31k views

Why Does Salt Water Help Sore Throats?

I am having some trouble understanding how salt water, a simple solution, could so effectively remove the pains of a sore throat. I do believe that the answer is closely related to hypo/hyper-tonic ...
54
votes
2answers
2k views

Is there any evidence that sexual selection may lead to extinction of species?

Darwin suggested that sexual selection, especially by female choice, may counter natural selection. Theoretical models, such as a Fisherian runaway process, suggest that evolution of preference and ...
48
votes
4answers
3k views

Why do smaller mammals move intermittently?

I was watching a nice little video on youtube but couldn't help but notice how snappy smaller animals such as rats and chipmunks move. By snappy I mean how the animal moves in almost discrete states ...
35
votes
2answers
2k views

Can brain cells move?

I was discussing this with my brother. I'm pretty sure I read somewhere that they can move. Thanks EDIT: By movement I mean long distance migration (preferably within the brain only).
27
votes
2answers
1k views

Why doesn't blood remain on a mosquito's proboscis in quantities that could spread blood-borne diseases?

We know that HIV can't be transmitted by mosquitos, and nor can other highly virulent viruses that are transmitted through blood and bodily fluid exchanges, such as Ebola (thankfully!). Marcus Junius ...
17
votes
8answers
12k views

Why have humans evolved much more quickly than other animals?

Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel. Meanwhile, a lion is still a lion and a ...
16
votes
2answers
514 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
9
votes
6answers
501 views

Introductory literature for synthetic / systems biology?

I'm a computer engineer (MsC Computer Engineering) who's looking to switch into the field of synthetic / systems biology. I've got a comprehensive layman's understanding of evolution, genetics, ...
22
votes
3answers
4k views

Is there any use of CO₂ in human body?

We all know CO₂ as a waste product of metabolism . Does CO₂ have any helpful role , apart from having a role in pH of blood ?
20
votes
1answer
641 views

Natural examples of XOR functions at the cellular level

We can often think of cells as a sort of circuit on macromolecules, and can show that they can accurately and robustly implement functions like $\text{MAJ}(x_1,...,x_n)$ (return $1$ if more than half ...
35
votes
2answers
728 views

Is there evidence that some non-human species perform sexual selection based primarily on intelligence? How do they do this?

I'm a biology amateur, but it seems like sexual selection is almost always performed based on physical characteristics, the outcome of physical contests, or some sort elaborate courtship. But do any ...
27
votes
3answers
45k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
21
votes
1answer
4k views

What is the criticality of the ribosome binding site relative to the start codon in prokaryotic translation?

In prokaryotic translation, how critical for efficient translation is the location of the ribosome binding site, relative to the start codon? Ideally, it is supposed to be -7b away from the start. ...
18
votes
4answers
5k views

Are mitochondria dead?

In the video "What is Life? Is Death Real?", the subject of mitochondria is raised at 2:58. At 3:12, the narrator says "[mitochondria] are not alive any more: they are dead." What currents of thought ...
16
votes
3answers
632 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 -- ...
12
votes
10answers
1k views

A good book for history of biology/biotechnology for lay people

I have many friends who are interested in Biology and want to know more about the subject in general (like a history of biology, from Darwin's theory, to DNA structure discovery, to the human genome ...
11
votes
2answers
799 views

How does the genetic code evolve?

After looking at this question, some other questions poped in my mind. The DNA code is redundant, there are 20 amino acids for 64 possible nucleotide combinations. Therefore some amino acid are coded ...
9
votes
3answers
137 views

Intuitive explanation for Kin- and Group- selection

It is known from theoretician in the field of kin selection that kin selection (inclusive fitness theory) and group selection are actually two sides of the same coin. In other words, these two ...
38
votes
2answers
2k views

How do cockroaches resist the effects of ionizing radiation?

Cockroaches are very hardy insects. It is known that, among other things, they are able to withstand bursts of ionizing radiation that would kill a human being. The explanations of this observed ...
28
votes
2answers
6k views

Why do tattoos persist if body cells are regularly renewed?

I am not quite sure if it is true, but I read somewhere that within 7 years all the body's cells are replaced with new ones. I am not quite sure if it is cells or atoms. If it is then why do tattoos ...
19
votes
1answer
275 views

Why do you die if you cannot breathe?

I was wondering what the actual reason for death by suffocation is. Obviously it is related to oxygen deprivation. But what is the underlying cause of death? Is it due to insufficient oxygen for ...
19
votes
2answers
1k views

Do plant-animal cross races exist?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
18
votes
1answer
3k views

Do insects' muscles become stronger with exercise?

I am curious to know if insect muscles become stronger with exercise, because I have seen many insects get tired out, but I have never seen one get stronger. They always seem to become permanently ...
17
votes
3answers
1k 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 ...
13
votes
1answer
431 views

Do fake wasp nests actually fool wasps?

I have seen fake wasp nests sold as a deterrent against wasps and similar insects. Do they really work? Is there some scientific evidence for it? A related link: ...
13
votes
1answer
1k views

What light intensity starts melatonin release in humans?

I'm interested in whether any studies have determined the intensity of light at eye level that starts melatonin release in humans. I know that: melatonin release is suppressed by blue light with ...
10
votes
5answers
1k views

Can the human brain be reduced to a binary system?

Does the brain really function like a computer as in, ultimately every response is related to a binary sequence based on whether particular neurons fire or not?
10
votes
1answer
225 views

Does stress physically age our body?

Going by the assumption that stress eventually triggers a flight/fight response, and the subsequent realization that flight/fight puts the body in a system of readiness to use it's available resources ...
9
votes
1answer
664 views

When does weak selection produce qualitatively different results from strong selection?

In evolutionary game theory, it is typical to model organisms as having a base fitness that is modified slightly by the game interaction. The ratio of the game effect versus the base fitness ...
9
votes
3answers
886 views

Do memories have mass?

If it were possible to live forever, would our brains grow infinitely with the number of memories that we store? Or would we remove old memories as we create new ones?
8
votes
2answers
501 views

What does fitness really mean?

Fitness is certainly the most important concept in the theory of evolution. My question does not have to do with practical measures of fitness but with the theoretical definition of it. I am a bit ...
8
votes
1answer
2k views

Disadvantages of unihemispheric sleep

Is is well known fact that marine mammals and some birds can sleep with one brain hemisphere at a time, since it's essential for their survival. However, at least in my opinion, such mechanism would ...
7
votes
2answers
276 views

How many ATP are formed?

What is the number of ATP molecules formed during the photosynthetic processes which consume 8 molecules of $\text{H}_2\text{O}$ due to noncyclic electron transport and subsequent ...
7
votes
1answer
3k views

On average how many genes / alleles do people share?

I am curious about how much more a child can be alike to one parent than the other. If a child were to inherit all the alleles that are shared between both parents from one parent, but inherit all ...
7
votes
1answer
1k views

Smallest unit on which selection can act

Traditionally, the individual was considered to be the smallest unit on which Natural Selection (NS) acts. Today, we usually consider the gene as being the unit of NS. Of course, we should also ...
6
votes
2answers
117 views

How are Genetic Circuits Modelled?

I've read a recent Nature Methods paper by Moon T.S. et al, in which a synthetic genetic circuit consisting of layered logic gates was created. For example, the paper, a circuit is modelled in Figure ...
5
votes
2answers
1k views

What are we missing about the real workings of the evolutionary process? [closed]

As a scientist (and a computer scientist at that) my view is that if we cannot simulate a process we have not understood it properly. I have been following the interesting field of Artificial Life for ...
3
votes
1answer
164 views

How does sepsis affect heart function?

I have intuition that sepsis with infection can cause: spastic functioning of heart during systole heart working spontaneously in snatches during systole atrial fibrillation first contraction of ...
36
votes
3answers
1k views

How does the sensitive plant detect vibrations?

The sensitive plant (Mimosa pudica) is a remarkable little plant whose characteristic feature is its ability to droop its leaves when disturbed: Apparently, this ability to droop rests on the cells ...
28
votes
2answers
5k 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 ...

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