2
votes
1answer
243 views

How is transport of glucose into prokaryotic cells different from transport into eukaryotic cells?

I was reading page 92 of Fundamentals of Microbiology, 4th edition, which states In facilitated diffusion, the substance (glucose, for example) to be transported combines with a plasma membrane ...
2
votes
1answer
39 views

What are ways to compare the “costs” and “gains” of food production systems?

I'm looking for methodologies to compare the costs a food production requires with the gains it delivers (not in economic terms). I'm aware of energy returned on investment. Are there other methods ...
9
votes
3answers
702 views

How are our senses dimmed during sleep?

Our senses are not as sensitive during sleep compared to wake. There is an arousal threshold during sleep that only when it is overcome will it wake a person up. My question is how is this arousal ...
7
votes
1answer
2k views

Why aren't organelles considered alive?

I'm taking a 3-week Bio I summer course, and my textbook says the cell is the smallest/basic unit of life. I asked my professor why organelles aren't a living unit, and her reply was that they aren't ...
2
votes
1answer
419 views

Why is the blood pressure in the superior vena cava during inhalation less than during the exhalation?

For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart ...
4
votes
1answer
114 views

What are some examples of scaling laws in biology?

I've seen that metabolic rate scales logarithmically as function of mass for many animals over an extremely large span of parameters. What other scaling laws exist at the individual level?
2
votes
2answers
381 views

Why is a slow worm not considered a snake?

Slow worms are considered lizards as opposed to snakes, both are reptiles. Now I get that there are traits that distinguish them (eye lids, ears ...). But snake species themselves vary already quite a ...
6
votes
4answers
501 views

If Evolution Is In Progress, Why Fight Extinction?

Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of ...
3
votes
0answers
88 views

Why do ants dig surface paths?

A few days ago I observed a corridor built and used by ants that went over a path in fields: Why do they build it? It seems it doesn't bring any considerable protection from the surrounding ...
2
votes
1answer
804 views

Why is Sanger sequencing inferior for detecting SNPs in cancer cells?

I am familiar with Sanger sequencing, but at the level of an undergraduate. A lecturer of mine tried to describe Sanger sequencing as losing the sequence information in noise when used to detect ...
0
votes
1answer
66 views

SNPs mapping into protein

Starting a new project on protein-protein interactions and SNP analysis tool development. I would like to ask how does SNPs is mapped into protein? What does mapping means?
2
votes
1answer
43 views

Storing Apples at 30F?

This article about storing apples for the winter says: You do not want the apples' temperature to fall below 30°F (-1.1°C), however, because that will make them freeze and turn to mush when ...
4
votes
1answer
458 views

Breeding laboratory mice with cancer; how does this work?

It has recently been brought to my attention that live laboratory mice with specific cancer strains can be readily purchased for medical research. For example, the Jackson Laboratory sells mice with ...
1
vote
1answer
381 views

What is solid-phase bridge amplification?

During Illumina sequencing there is a step called bridge amplification by which DNA is amplified by isothermal enzymes. What is this stage, and how does it work?
5
votes
2answers
5k views

What's the difference between shotgun sequencing and clone based sequencing?

What are the main differences between shotgun sequencing and clone based sequencing?
7
votes
1answer
684 views

Does the human ear adapt to noise levels?

I have noticed lately that if I go to sleep, when I have my radio running, it is on lowest volume, I still consider it kind of loud. In the morning, when being on the edge of waking up, I hear the ...
1
vote
1answer
51 views

“Oblong to Allantoids” … Is it valid?

I read on the text book: The characteristic of Dinemasporium are: superficial, cupulate to Discoid conidiomata with brown satae, Phialid conidiogenous cells that give rise to hyaline, oblong to ...
1
vote
1answer
81 views

By what mechanism does elevated homocysteine level accelerate thrombin formation?

It has been stated that elevated homocysteine level accelerates thrombin formation. By what mechanism does this happen?
2
votes
2answers
212 views

By what mechanism does elevated homocysteine level cause endothelial dysfunction and damage?

It has been stated that elevated homocysteine level causes endothelial dysfunction and damage. By what mechanism does this happen? Why is it the endothel where elevated homocysteine causes problems? ...
0
votes
1answer
58 views

Does anyone know what marsupial this is? [closed]

I know what this is a marsupial, but i'm not quite sure which one. Any thoughts?
2
votes
1answer
52 views

How can I view modENCODE data faster?

I am trying to view several data tracks in the modENCODE GBrowse genomic browser. However, the site is so slow, it is practically unworkable. Is there a faster way to explore the data?
4
votes
1answer
306 views

How do sharks and other fish conserve and gain water in marine environments?

With the osmolarity of the average vertebrate being around 300mOsml, and salt water having an osmolarity of 1000mOsml, why does the water from the shark not leave to the salt water around it? I ...
3
votes
1answer
855 views

Is it possible for a person to become “reinfected” with the same strain of a virus?

If a person contracts a virus, viral conjunctivitis for example, is it possible for the individual to become "reinfected" with the exact same strain of the virus once the person has it treated and the ...
1
vote
1answer
50 views

Are there neuronal firing artifacts produced by head movement?

I'm experimenting with a consumer-grade ElectroEncephaloGram (EEG) sensor and have created the image below using the device. Because the sensor on the device does not use a suction cup, there are a ...
2
votes
1answer
90 views

Is RGB diode lighting okay for the eyes?

Is a light source giving off light composed of red, green and blue lights harmful to the eyes? Does it lack any important qualities that other artificial light sources, such incandescent lamps or ...
1
vote
2answers
202 views

Is it possible to print humans?

According to this news, scientists can use stem cells to print objects. So say theoretically, is there any possibility to print human beings?
2
votes
2answers
290 views

DNA replication Okazaki fragments

I understand multiple origin bubbles; DNA polymerase only synthesizes DNA from 5' to 3' and all that. But what I don't understand is why it has to be in fragments. Yes, DNA is anti parallel, and so ...
2
votes
1answer
316 views

Will lipid molecules 'flip-flop' over a membrane without the use of an enzyme?

All of the references to this I can find refer to enzymes like Flippase making it 'easier' or 'more likely' that the translocation will occur, rather than actually make it possible. The following is ...
9
votes
2answers
1k views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
2
votes
1answer
111 views

Why is elevated homocysteine considered a risk factor for angina?

Elevated homocysteine levels are listed among risk factors for angina. How is homocysteine related to the heart? Or the coronary arteries? How do these relationships make it a risk factor for angina? ...
2
votes
2answers
45 views

Can stress echocardiography show coronary blood flow difference before and after exercise?

Stress echocardiography means a pair of cardiac ultrasound imaging examinations, before and after exercise. I assume that coronary blood flow is increased after exercise. Is cardiac ultrasound ...
2
votes
1answer
310 views

By what mechanism does an obstructed bile duct cause excess fat in the stool?

By what mechanism does an obstructed bile duct (for example gallstones) cause steatorrhoea (excess fat in the stool)?
5
votes
1answer
372 views

What could account for an apparent loss of mass at death?

An interesting tidbit floating around the internet these days is that Dr. Duncan MacDougall apparently weighed people shortly before and after death, and found an average of a 21 gram discrepancy, to ...
3
votes
0answers
38 views

Can I purify polyhydroxyalkanoates by heating the cells extensively?

Traditional methods of purifying polyhydroxyalkanoates (PHAs) and other bioplastics made by bacteria involve washing the cells with harsh chemicals or strong bases.I'm interested in maintaining the ...
4
votes
1answer
65 views

How can I save bacillus strains on filter paper without an -80 degree freezer?

I want to save my bacillus strains but I don't have access to a -80 degree freezer. What are possible alternatives?
5
votes
2answers
168 views

How does a pinched nerve cause pain (at the molecular level)?

Is this due to pressure differentials in the surrounding tissue? (Is it possible to have a pinched nerve without compression of the surrounding tissues, and does this cause pain?) What are the ...
9
votes
2answers
2k views

Why is saltatory conduction faster than continuous conduction?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
4
votes
4answers
25k views

How long human can survive with just drinking water everyday

Can humans live without eating food, just by drinking water? How long can we survive just by drinking water everyday?
1
vote
1answer
48 views

Introductory text for primatology

I'm looking for a book that provides a good overview of primatology, one aimed more at researchers rather than a popular science book. Ideally, I'd like something with an ethology/ecology angle with ...
5
votes
4answers
3k views

How long can a naked human survive on Mars?

How long can a naked human survive at the surface of the Mars planet? For instance, let's say a worker's base takes fire while he sleeps, and he has to run to the emergency building 200 meters away ...
3
votes
1answer
337 views

What is an epistasis group?

I have been trying to wrap my head around the concept of epistasis for a couple of days now, and I think I understand it, at least at a basic level, but I still don't understand some of the ways that ...
2
votes
1answer
50 views

The Eye, and Camera Lenses

How do near sightedness, farsightedness, and normal sightedness work? If the eye is accustomed to one small focal point, how can it manage a wall of light? And also, how does it process the small ...
4
votes
1answer
146 views

Does biofuel production by microalgae need an extra source of CO₂?

It is necessary to have extra source of CO2 i.e. from a nuclear reactor or factory chimney to produce bio-fuel by microalgae or is it able to do it with the normal CO2 density in the atmosphere?
1
vote
2answers
62 views

Which X-Y chromosomes have the developmental genes for mammals?

I know that for a given mammal, half the chromosomes come from father and half from mother. This is typically denoted as x-y. I've recently read about "toolkit" genes that control how a cell develops ...
0
votes
0answers
244 views

Relationship between biomass and net primary productivity [on hold]

I want to do validation on simulated net primary productivity. But I don't have measured NPP data, Eddy covariance flux measurement data. I have only field measurement biomass data. So can I directly ...
3
votes
2answers
110 views

Highly spherical Radiolaria; does this image accurately depict the organism?

If I understand correctly, Cenosphaera spp. is a type of Radiolaria, which is a type of zooplankton. The following is an image of Cenosphaera spp. is from the supplementary material (Figure S2) of ...
5
votes
1answer
171 views

Why are certain aneuploidies more common?

Certain aneuploidies such as trisomy-21 (Downs syndrome), trisomy-18 (Edward syndrome), Turner syndrome (XO) etc are more common than others. I had a vague thought that it is related to chromosome ...
2
votes
0answers
84 views

What is the mechanism by which Melatonin increases dream vividness and intensity in humans?

I'm looking at the wikipedia article on Melatonin and noticed that it mentions vivid dreaming caused by melatonin. I have the "Melatonin and the Biological clock" pamphlet referenced in the article, ...
4
votes
2answers
360 views

Does bleach destroy RNAse activity, and if so, how does it do it?

I am working with RNA samples, and I'm trying to be very careful about RNAse contamination. I have some questions about bleach, though. Some people say that a solution of bleach is enough to destroy ...
5
votes
2answers
2k views

Is wiping with RNAse Zap enough to destroy RNAse activity?

From the RNAseZap MSDS, it is an SDS at some unknown concentration, maybe with some NaOH? Some other links suggest there is some NaOH as well. The Ambion site states that RNAseZap destroys RNAse ...

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