4
votes
1answer
139 views

Non-monotonic knock-out effects in prokaryotes

Typically, when performing gene-knockout, the experimenters select one gene to remove/replace-with-junk and then see if the prokaryote can still undergo fission. If it continues to reproduce then the ...
7
votes
1answer
136 views

Making penicillin using animals - specifically, a goat

In the scifi novel Lucifer's Hammer, one of the characters (a biologist, if I remember correctly) finds himself in a post-apocalyptic world and tries to make penicillin to save his own life. To do ...
3
votes
2answers
68 views

Is vision a vestigial sense for deep ocean species?

Sunlight doesn't penetrate beyond a couple of hundred feet from the surface of the ocean. Species that exist at greater depth probably live in a state of perpetual night; yet from a quick google image ...
3
votes
3answers
6k views

Evolutionarily speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
3
votes
0answers
104 views

Cheapest Way to Measure Germ Density

I would like to measure the surface density of Staphylococcus bacteria and Rhinoviruses (only those two, to be specific) within my home. What's the cheapest way? The textbook procedure is to: rub ...
6
votes
2answers
64 views

Predicting and identifying microbes and enzymes DNA sequence with metabolic prediction

Presently I am working on metagenomics of coal biomethenation by bacterial consortium. I have got the sequence result (Illumina). The sequence is huge and I can't predict anything from the sequence. ...
4
votes
1answer
333 views

What phenotypes can arise from gender-related aneuploidy?

Humans normally have 46 chromosomes (two copies - one from each parent - of each of the 24 chromosomes: [1:22] + [XX or XY]). Aneuploidy is an abnormal number of chromosomes - Down's syndromes is an ...
8
votes
2answers
289 views

Do antibiotics attenuate immune response on subsequent exposure to same bacteria?

A healthy immune response to a bacterial infection includes "memory" to permit the body to thwart subsequent exposure to same bacteria. What are the dynamics of using antibiotics on initial exposure ...
3
votes
3answers
171 views

What Defines a Food as Edible?

With many foods today containing chemicals, agents and preservatives etc... What biological criteria must a new food and its constituent components satisfy biologically, to be defined as edible? ...
2
votes
2answers
4k views

How do trees use Adhesion and Cohesion to move water against gravity?

I have an AP Bio class where I have to name 3 properties of water and I chose adhesion and cohesion for one of them. I'm having trouble finding out how exactly trees use adhesion and cohesion to move ...
13
votes
2answers
373 views

What kind of fruit is this?

Just spotted this fruit while walking to school. It's the size of a small coin.The taste is almost sour and tangy and somewhat sweet (I only tried one of them and very little of it). I admit, ...
3
votes
1answer
648 views

How long can a unicellular organism live without nutrition? What happens after that? Does it depend on the domain?

Say I have three unicellular organisms: a eukariote, a bacterium and an archaeon. If I cut off nutrition from them at the same time, how long will it take for them to die? What will their death look ...
6
votes
1answer
227 views

Have there been attempts to identify Chomsky's “language mutation” in humans?

I'm not versed in either biology or linguistics so please forgive any naiveties I may commit. I've learned that Noam Chomsky thinks that language is a result of a single genetic mutation in humans. ...
4
votes
1answer
1k views

What does vitamin B6 and B12 absorption depend upon?

I'm looking at my question about homocysteine metabolism and am doing a followup inquiry into vitamins B6(Pyroxidine) and B12(Cyanocobalamin). I've found this interesting bit about vitamin B12 and am ...
4
votes
1answer
97 views

In a vertebrate chimera, are particular organs homogenous genetically?

I have read that a chimera is an organism with two or more sets of DNA, with every cell having one of the sets. Is it possible and common for the two or more sets to be present in the cells of a ...
9
votes
2answers
280 views

Do twins “run in the family”?

My wife and I recently found out that we are going to have twins and so nearly everyone asks if we have a family history of twins. Now I know that the answer for me is that it doesn't matter—as ...
5
votes
3answers
237 views

Biological Pathway of Lipid Hypothesis

I've read a lot on both sides of the debate of low carb vs low fat diets trying to make some sense of what is being proposed. The lipid hypothesis runs roughly along the lines that we have lots of ...
4
votes
1answer
565 views

Are there any effects of elevated Cysteine levels on cognitive function?

I'm looking at this diagram of homocysteine metabolism and see two distinct pathways that the amino acid may get metabolized to: with vitamin B12 it gets converted back into methionine, while with B6 ...
4
votes
1answer
84 views

Bugs' love for light

Do bugs love light bulbs because they resemble the stars or is it the sun? How do they sense the bulb? What is the purpose of this "brightophilia" that has evolved in insects?
1
vote
1answer
57 views

What is the role of Homocysteine in cognitive function?

I'm looking at this link : Homocysteine and cognitive impairments and am looking for more information on specific cognitive impairments associated with elevated levels Homocysteine. That article is ...
3
votes
2answers
399 views

What is an organism?

The definition of an organism Wikipedia gives is An organism is any contiguous living system. I understand that these are not organisms according to this definition: A bird and a tree it's ...
4
votes
1answer
318 views

What causes instinctive behaviour?

Some actions, almost behaviour, exist that are common across a species. For instance, based on personal observation, human babies try to taste anything new they encounter until they are a few score ...
10
votes
2answers
27k views

How many human cells are there in our body, on average?

How many human cells are there in our body, on average? Wikipedia says 1013: Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in ...
12
votes
1answer
809 views

What did Richard Feynman contribute to molecular biology?

Some time ago, I read James Gleick's "Genius: The Life and Science of Richard Feynman", a wonderful biography of Feynman and, by extension, most of modern physics. In this book, the author mentions ...
3
votes
0answers
107 views

How does a plant decide when to grow a branch? [duplicate]

As a plant grows, at some point the first branch forms. As it continues, branches grow new branches, and so on, in a seemingly random way. Is it random, or is it driven by the environment (heat or ...
3
votes
2answers
149 views

Is it possible to correctly identify presence of Y chromosome with external physical test only?

I asked a question related to the third sex, and I came to know that its always possible to categorize a human to male or female with presence of Y chromosome. Now, I have another question. Is there ...
3
votes
4answers
1k views

Can the third sex be categorized as Male or Female?

Hijra are people who have a penis (not sure if sexually active) but look much like a female (perhaps for some feminine biological property). Wikipedia says they are "physiological males who have ...
3
votes
0answers
104 views

RMSD during conformational transition in proteins

When I was investigating the differences between protein structures obtained by X-ray crystallography and NMR spectroscopy, I found the paper [1] compairing structures of several proteins resolved ...
1
vote
2answers
553 views

What is the most complex plant form?

At school we were told on scale of 0 through 1000 the animal kingdom ranges from amoeba the simplest/primitive being at 0, and Humans the most complex animals at 1000; what are the equivalent ...
10
votes
6answers
1k views

Human evolution: Where *exactly* did the first human come from, whose parents were not?

Layman here. So I have never really quite understood this facet of human evolution, (or any other for that matter), in that, I understand the evolutionary process, but I get lost on the 'border' ...
5
votes
3answers
2k views

How did butterflies evolve to have eyes on their wings?

Some butterflies, such as the UK native Peacock butterfly (Google Image Search) have markings on their wings that look just like eyes, complete with a white fleck to imitate a convex, transparency ...
4
votes
2answers
463 views

Under what circumstances will a human neuron divide?

I read somewhere that a mature neuron loses its ability to divide, except for very specific situations. I was unable to find the description of those situations. What are they? (I'm sorry I'm not ...
7
votes
2answers
164 views

Is it possible for parasitic wasp to alter the behaviour of it's host after emerging from it?

I know that parasitic wasp larvae could live for a long time inside their alive host (eg. caterpillar), but I always thought that they kill the host when they eventually get out of it. But once I've ...
9
votes
1answer
115 views

E. coli values for [enzymes], [metabolites] and kinetic rates

In my attempt to create a metabolic model of E. coli, I have found a comprehensive list of metabolic reactions and their stoichiometry. The one I am currently using is E. coli model iJO1366 (more ...
3
votes
3answers
1k views

Are there verbs for “undergo mitosis” and “undergo meiosis”?

From my experience on SE sites, I believe this is the right site to ask this question under "terminology". I've been trying to find out whether English has one-word verbs for "undergo mitosis" and ...
4
votes
1answer
90 views

Determining if a Protein Model Contains a Backbone Clash

I have an ensemble of homology models of a protein, and I now wish to remove those models which have backbone clashes. I could obviously check by eye but this is subjective and probably will not be ...
8
votes
1answer
92 views

Predators faking to be not hungry?

I believe that there are predator/prey combinations where the prey can easily spot that the predator is not hungry and will not try to flee from it. I’m thinking, for example, of gazelles who will ...
5
votes
2answers
1k views

What would cause proteins to get stuck in the stacking layer of a SDS-Page gel

Typically when proteins aggregate, they will get stuck at the top of the well. However, we're seeing some protein aggregate in the stacking layer even when we're treating the loading volume with DTT. ...
18
votes
3answers
8k views

Why do cockroaches flip over when they die?

This question has always mystified me since young. For beetles, I can reason that they flip over because they have a higher centre of gravity causing them to be in unstable equilibrium when they tuck ...
5
votes
3answers
140 views

Do dogs have something different about their physiology that allows them to pant without hyperventilating?

I was wondering this as I considered how effective panting would be for humans as a means of cooling.
1
vote
1answer
33 views

Could silicon oil block Na+ ion channels in the membrane of an axon and prevent Na+ influx?

Could silicon oil block Na+ ion channels in the membrane of an axon and prevent Na+ influx? I have been wondering if Na+ influx could have been a diluting factor in anterograde fills. If so, could ...
8
votes
3answers
202 views

What would need to be discovered to prove there is extraterrestrial life?

Curiosity is on the Martian surface and is equipped with a slew of laboratory equipment. What would Curiosity need to discover to prove there is or has been life on Mars? Would it have to find DNA (or ...
7
votes
1answer
283 views

Do mosquitoes need to pump blood out of the host?

Many species of mosquitoes have bloodsucking females. When they bite a host, do they need to pump? Or does the sheer blood pressure combined with capillary action suffice to make the blood rush into ...
4
votes
1answer
91 views

Why isn't there any repulsive force between Na+ and K+ disrupting thier roles in transmembrane voltage/ action potentials

Pretty self explanatory question. I have a basic grasp on the "How" and "Why" of Reversal/Action Potential in and between neurons, but this question lingers.
5
votes
1answer
316 views

What are the units of enzyme activity?

I was looking at this graph of turnip peroxidase activity and I saw that they use units of 1/sec for enzyme activity. What does this unit intuitively represent and how is it calculated?
9
votes
1answer
2k views

Why is GTP gamma S non hydrolyzable?

GTP gamma S is routinely used in studies of G proteins to stably activate the G protein. Comparing the structures of GTP gamma S and GTP, the Sulphur atom replaces the Oxygen attached to the leaving ...
1
vote
0answers
68 views

When should endocytosis inhibitors be used in cell binding assays?

I'm beginning to do some cell-binding assays and I would like for my proteins to not be endocytosed by my mammalian cells. Typical suggestions are for the cells to be kept on ice and that the binding ...
4
votes
1answer
81 views

Is there an advantage to having cellulite

There are many ads nowadays advertising cellulite removal, and it causes me to wonder if there is an advantage to having cellulite or if it is just a result of too much fat unevenly spread? Is it ...
4
votes
2answers
421 views

Does making yogurt from non-pasteurized milk work against possible disease bacteria?

In the past, when there was no pasteurization, could making yogurt from milk lower the chance of getting infected by bovine tuberculosis (or other diseases from infected milk)? For example, would ...
6
votes
2answers
1k views

Why do DNA and RNA have the functions they have?

I know that there are two most important directions of genetic information transfer in living organisms: DNA->DNA and DNA->RNA. The first is replication, and the second is transcription. I wonder if ...

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