7
votes
1answer
53 views

Hamilton's derivation of direct fitness from his 1970 paper

In his 1970 paper "Selfish and Spiteful Behaviour in an Evolutionary Model", Hamilton uses Price's equation to derive his well-known rule $rb -c >0$. My question is about one of the steps in his ...
0
votes
1answer
59 views

What is the second phase of photosynthesis?

I really want to know what the second phase of photosynthesis (in the dark) is. I have a fair understanding of the first cycle where molecular oxygen is generated under the influence of light, but I ...
2
votes
1answer
43 views

How does steroid dependence occur?

I have seen on the internet that prolonged steriod treatment can result in the development of steroid drug tolerance leading to decreased hormone secretion. In turn this may lead to drug dependence, ...
5
votes
3answers
273 views

How many cells does the smallest animal have?

Note: question rewritten to prevent misunderstanding and make it more answerable I know that some small animals like C. elegans display surprising sophistication with a very small number of cells. ...
1
vote
1answer
52 views

C1q attachment to antibodies

After reading about complement pathway and the complement components, I was wondering, does the C1q component attach to the Fab fragment or to the Fc fragment? The pictures in Janeway's Immunobiology ...
0
votes
1answer
23 views

Can cfDNA testing distinguish results in the case of twins?

A fetus can now be screened for some of the more common genetic diseases and its sex determined from just a whole blood sample from the pregnant mother. Fetal DNA is abundant enough in the systemic ...
1
vote
0answers
28 views

What term describes insects that must eat protein to reproduce?

I know there is a specific term for insects that need to consume protein to produce viable eggs, as well as a term for those insects that don't need to consume protein to produce viable eggs.
3
votes
1answer
87 views

Why can blood group O be given to all blood groups?

Blood group O has antibodies against antigens A and B. Blood group A has A antigen. If someone with blood group A receives donor blood with group O, then anti-A antibodies in the donor blood should ...
3
votes
1answer
54 views

How fallible are DNA paternity tests?

Is it possible to get either a false positive or a false negative from a DNA paternity test and what would be the likely mechanisms behind this? For example, is it possible that a father's DNA could ...
0
votes
1answer
28 views

When do the spindle fibers attach to the chromosome

At what phase does this occur in mitosis (or even meiosis); some text books say prophase while others say metaphase.
1
vote
0answers
31 views

Is probability for double crossing over included in distance cM? [task]

We got this task: There are 3 genes (acb) on one chromosome (linked inheritance). Distance a-c = 12cM, a-b=16cM. Probability for double crossing-over (CO) is 0,6%. Find ratio of genotypes of ...
1
vote
0answers
26 views

Dopamine and other neurotransmitter release during music listening

A rather non-technical question here. Im looking for any studies that show a positive curve in respects to music sessions in humans and neurotransmitter release (specifically dopamine, epinephrine, ...
0
votes
1answer
48 views

What species of eagle pushes their young to teach them flying?

There are many references to eagle pushing their young off the nest to make them know how to fly, for example this motivational video. It is also described in this website: Let me show you "the ...
1
vote
2answers
56 views

Are there more true codes found in biology besides the central dogma?

I know each element of the central dogma is a code in the mathematical sense of finite-state machines. That is, DNA is transcribed into RNA, and RNA into proteins. What other examples are there of ...
0
votes
1answer
51 views

Supercomputer and undergraduates [closed]

Is it common for an undergraduate to run their thesis (evolutionary genomics) in a supercomputer? In my country, few supercomputers exist, but I'm not sure how it is for bachelors in the US or Europe. ...
1
vote
1answer
55 views

Growing E. coli at room temperature?

If I were to do a blue/white selection of transformed E. coli on LB agar ampicillin plates at room temperature (23⁰C) for about 2 days and 18 hours, will I run into the issue of satellite colonies or ...
2
votes
1answer
38 views

What equipment is needed to perform simple plant electrophysiology?

What is the minimum needed equipment to perform simple plant electrophysiology? I am looking for some simple experiments that I could run at home for learning. Ideally, I would transfer the skills to ...
3
votes
1answer
47 views

Fecundity per woman in early humans

The average fecundity per woman varies a lot from country to country. I call average fecundity per woman the average number of born children per woman. In Homo sapiens, what was the average fecundity ...
5
votes
1answer
48 views

Miscarriage in early humans

Today, about 10 to 20 percent of known pregnancy end in miscarriage. Pregnancy is a biological process that has been very well studied by medicine. As a result, modern medicine helps a lot to prevent ...
7
votes
1answer
43 views

Survival curve in early humans

The survival curve/function describes the probability of a given individual to survive to age $x$. In humans, today's survival function is very much influenced by medicine. This leads me to wonder ...
2
votes
0answers
22 views

How does the population fitness changes after a change in mutation rate

The mean population fitness as given by mutation load theory depends only on the genome-wide mutation rate ($U$). My question is: how many generations is needed to reach a new mutation load ...
7
votes
3answers
97 views

Which fruit compounds affect the speed of fructose absorption?

Blood fructose levels are not regulated by insulin in the human body. This means that the body absorbs pure fructose very fast, and it raises the blood fructose levels rapidly. Do fruits/ vegetation ...
1
vote
2answers
91 views

What triggers programmed cell death in humans (from outside the cell)?

What triggers programmed cell death in humans? Is it decided by the brain (for the entire body)? Or is it a local decision of a cell by its environment? Something else? I realize that there might be ...
1
vote
1answer
29 views

Why does renal artery stenosis lead to activation of Renin-Angiotensin system?

To my current understanding, stenosis or narrowing of the arteries would mean higher blood pressure, similar to atherosclerosis. So the Renin system should be suppressed to counter the high blood ...
2
votes
1answer
64 views

Production of processed Insulin in bacteria

Genetically-engineered bacteria are used to produce insulin in industry, but as far as I know, the bacteria can produce only proinsulin. Why is that? What happens in the human body in order to make ...
0
votes
0answers
29 views

How to measure concentrations of different metals from the environment?

Suppose that different kind of metals and chemicals (e.g. magnesium, sodium, copper) got transmitted to environment e.g. as a cause of an accident. How would measure the levels of those metals and ...
0
votes
0answers
6 views

awakening effects of light

I tried reading by light from a neighbouring room and felt sleepier than if my own lights were on. Is there a formula for the intensity of light vs physiological preparation for sleep(calcium, ...
-1
votes
0answers
19 views

On average, what's the coldest temp. a person can survive in and for how long? [duplicate]

Please do not mention this question as it has no good answers. I would like to know the external atmospheric temperature and for how long within these ranges can a human survive. For example, how ...
6
votes
1answer
76 views

What's the worst that can happen from too much sleep deprivation? Can you die?

It is well known that sleep deprivation causes considerable discomfort in humans (and has even used as a form of torture), but nevertheless there have been people who went through protracted sleep ...
3
votes
1answer
27 views

IgA complement activation

Recently, I have been reading Janeway's immunobiology and had a question on immunoglobin A. I read that IgA activates the complement pathway using the Fab fragment of the IgA. How does IgA do that? I ...
0
votes
1answer
39 views

Taste of salt water

I had a question relating to chemistry and biology, so please tell me if this is suited better for the Chemistry website. My question was, if water dissolves salt by separating the two ions, the Na+ ...
4
votes
1answer
41 views

Are there any known health benefits / risks from milliampere current (0.1-2 mA) on forehead?

This is about devices like that sold by foc.us that allows user to apply a small current on a specific part of the forehead. For the sake of this question I use the foc.us "gamer" model as example. ...
10
votes
1answer
557 views

Dreadnoughtus: Why are new taxa named using Dog Latin?

Once upon a time, binomial nomenclature was expected to follow Latin rules: the genus had to be a noun and the species had to be an adjective that agreed with the genus according to Latin rules of ...
4
votes
5answers
121 views

Are There Rules for How Proteins Are Formed?

Proteins are formed by stringing together different amino acids. Different amino acids have different properties (such as being attracted to or repelled by water, positively or negatively charged, ...
5
votes
1answer
80 views

Are There Exceptions to Animal Cells not Having Cell Walls?

In the January Issue of SciAm (discussing Haemophilia): When damage occurs to blood vessels, exposure of the blood to collagen in the cell walls and material released by the cells triggers the ...
2
votes
1answer
18 views

Relative sweetness

I have noticed that when I eat something sweet, then afterwards, I eat something else that is sweet, the second sweet food is not as sweet as it usually is. I am pretty sure many others have a similar ...
3
votes
1answer
191 views

Why isn't the insertion of a single nucleotide destructive for DNA?

As far as I know proteins are built by sequentially reading triplets of nucleotides. But if at a certain point a nucleotide is inserted in the sequence, the following sequence of triplets is ...
12
votes
1answer
131 views

Do species other than humans have distinct daily feeding patterns?

I have a general interest in complex adaptive systems and I have found that nature and the organisms within it is a perfect natural case of a rich adaptive system with a lot of possibilities for ...
4
votes
4answers
140 views

Are there known examples where an evolved mechanism “echoes” one originally provided by the environment?

Short summary I am a researcher in origins of life, a field that deals with hypotheses about evolutionary processes that took place before LUCA (the last universal common ancestor), and with the ...
2
votes
1answer
18 views

Concentration of degenerate primers should you dilute to?

I'm a little embarrassed to ask but when you have for example four degenerate primers and the end protocol says that the final primer concentration should be 10 µM working stock, should you make the ...
2
votes
1answer
24 views

Has any research lab done serious work to engineer new bacteria which assemble graphene wafers?

I was thinking about crazy uses for engineered bacteria. Graphene seems like a potentially excellent target for the technology. Have any credible labs worked on this? Any papers on it? What would be ...
4
votes
1answer
82 views

Besides hemoglobin, what proteins are present in red blood cells?

I knew that mature red blood cells (RBCs) lacked nuclei, but I wasn't aware until just now that they also lacked ribosomes and mitochondria. Most cells in the human body all contain a common laundry ...
4
votes
1answer
27 views

Is there a risk of localised die-off when plants bud too early?

I've been taking a few walks in the countryside in Scotland and England this winter (end of December 2014). Some parts of England haven't had any frosts yet, which is very unusual, and it's been ...
4
votes
3answers
170 views

Why is mRNA needed in the Protein translation?

The original question was to predict the basic requirements for information storage. Then the discussion moved to why is it necessary to include mRNA in the protein translation process. Why can't ...
3
votes
1answer
55 views

What is an operon?

What is an operon in a eukaryotic cell, and how does it regulate the expression of genes? I've already read Wikipedia, but it is not enough clear to me. Unfortunately my knowledge in genetics are very ...
5
votes
2answers
128 views

Phylogenetics and the Tree of Life

As far as I understand, evolution is nowadays pretty much analyzed through phylogenetic trees, that is cladograms. These are constructed using the available records and taking some key structures and ...
6
votes
1answer
72 views

Blood cells penetration

Is there a type of blood cell that can reach all other body cells? By "reach", I mean to "touch" the surface of the target cell. If we look at the red blood cell for example, that moves in blood ...
13
votes
9answers
5k views

Why didn't the polar bear change its color from white to black during evolution to absorb heat?

Polar bears are white in color and white color is not a good absorbant of heat. Why then didn't they evolve a black color to absorb more heat?
0
votes
1answer
39 views

how to reconcile PDB structures' sequences via Uniprot references?

i’m trying to reconcile structures in PDB entries with their sequences as reported in their chemList.polymer.dbref entries. E.g.: considering structures for HIV ...
3
votes
1answer
34 views

Why are canines not nauseated by similar foodstuffs/state of decay as human beings?

I am continually surprised at the items my pet dog is willing to ingest. I understand part of the consumption is driven by nutritional instincts (licking salty liquids such as sweat) or nurturing ...

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