2
votes
1answer
56 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
179 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 ...
4
votes
1answer
141 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 ...
5
votes
1answer
85 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
71 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 ...
5
votes
3answers
214 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 ...
0
votes
2answers
196 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
43 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
145 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
73 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 ...
1
vote
2answers
37 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, ...
5
votes
1answer
195 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 ...
4
votes
2answers
174 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
54 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+ ...
5
votes
1answer
92 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
640 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
295 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
129 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
23 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
282 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 ...
14
votes
1answer
292 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
187 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
121 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 ...
3
votes
1answer
38 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. Nano-assembly of Graphene seems like a potentially excellent target for the technology. Have any research/full-blown labs worked on this? Any ...
5
votes
1answer
623 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
31 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
1k 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 ...
5
votes
1answer
119 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 ...
4
votes
2answers
232 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
88 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 ...
16
votes
9answers
6k 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?
1
vote
1answer
55 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
64 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 ...
1
vote
0answers
38 views

What genetic distance model should be used when calculating genetic differences in Arelquin?

I'm using Arelquin to look at the genetic structure between a number of different populations. I want to compare the populations by producing pairwise FST values, however I don't know what model for ...
0
votes
0answers
28 views

what's the vascular cambium?

is the vascular cambium equivalent to interfascular cambium or intrafascular cambium? isn't the vascular cambium similar to the intrafascular cambium because both occur inside the vascular bundle
10
votes
1answer
481 views

Cloning and Telomeres

I read that the length of telomeres in Dolly was shorter, because the DNA was taken from an old sheep. Shorter telomeres may lead to early aging. What is happening now with cloning? Do we use a ...
5
votes
1answer
45 views

Is there any conclusive study relating the food consumed and the occurrence of acne?

The internet says a million things about what to eat and what not to in case of acne. For instance: Refrain from dairy products. Refrain from food heavy in unsaturated fat. Refrain from too much ...
3
votes
3answers
78 views

Identifying a tree with an image

I have trouble identifying a tree that I saw on a vacation. This is the image: I would like to know the name of the tree, I only know that its not European.
6
votes
1answer
54 views

Can plants grow under extreme (>1%) carbon dioxide concentrations?

Related to but distinct from this question due to the concentrations involved. While small carbon dioxide concentration increases can positively impact plant growth under some circumstances and at ...
1
vote
0answers
54 views

How organized is the inside of a cell? [closed]

I know cells have many ways of organizing and controlling what goes on inside their membranes. But just how ordered or chaotic is it inside a cell? Here's a few thoughts I had. Consider the ...
1
vote
0answers
39 views

Superpatients for Cancer resistance

I was reading an article on MIT Technology review about superpatients for low cholesterol that got me thinking whether such patients exist for cancer. The article is ...
3
votes
1answer
167 views

How do CO₂ and carbonic acid (H₂CO₃) work in buffering the blood?

Been struggling with this for the past few days even after reading half of the acid base tutorial here, if someone could help me that'd be great. What I don't understand is how HCO3- is supposed to ...
1
vote
0answers
145 views

The skin color of bonobos

Why is that bonobos skin color on the areas not covered by hair are dark throughout life unlike the chimpanzee?
6
votes
2answers
227 views

Advantage of opponent color?

Opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner (source). What is ...
1
vote
1answer
56 views

About the apoptosis mechanisms in a cell

The apoptosis mechanisms in a cell are like a type of 'self-destruction mechanism': is this correct? As with any type of complex system with various necessary functions, if it has a set of ...
6
votes
1answer
174 views

The origin of molecular machines

DNA holds genetic information and holds the key to the evolution of living organisms. Transcription and translation mechanisms enable living cells to process information encoded in DNA. To that end, ...
8
votes
2answers
253 views

Why don't we see turbulence in the aorta even in normal situations?

I read about the Windkessel effect. Then I read about pulse pressure waves getting reflected from the periphery. If the pulse pressure wave is reflected during diastole and at the same time blood is ...
3
votes
3answers
818 views

If ants have an antibiotic gland, how can they spread hospital infections?

Wikipedia describes how antibiotics are produced in ants: "Metapleural glands ... are responsible for the production of an antibiotic fluid that then collects in a reservoir ... also referred ...
1
vote
1answer
126 views

What's the meaning of 'plasma' in 'plasma membrane'?

I wonder why is it called plasma membrane - what's the biological meaning of the word 'plasma'?
0
votes
0answers
75 views

I brought a hibernating yellow jacket queen into my house accidentally. What will happen?

There was apparently a hibernating yellow jacket queen in my stack of firewood outside. An hour or so after bringing in the firewood, we saw the queen fly off into the house, where we can't find her. ...

15 30 50 per page