2
votes
1answer
68 views

What are the distinctive structural features of single- or double-stranded xRNA, or where can I find them?

I am interested in the structural differences caused by benzopurines and benzopyrimidines at the oligonucleotide level between RNA and xRNA, both in single-stranded and double-stranded form. I am ...
5
votes
1answer
282 views

How quickly can the human heart rate rise and fall?

How quickly can the human heart rate rise and lower? For example lets say a human heart rate is rested and is at 60BPM and that person is suddenly scared to trigger their fight or flight reaction. ...
2
votes
2answers
218 views

Filamentous algae - what exactly am I looking at?

I have just taken some images with my light microscope at 400x of (what I think is) some form of filamentous algae from a local pond. Now, I think I am looking at a single cell (centre) with some ...
7
votes
2answers
121 views

A mathematician's confusion regarding parametric $t$ tests for gene expression data

I'm a mathematician trying to test some things on gene expression data, and I'm thus skimming over various articles such as Sotiriou et. al. to understand what is typically done with such data sets. ...
19
votes
6answers
870 views

How is evolution possible in contemporary humans?

I would like to know if evolution is continuing to happen in modern humans, assuming things like existence of the nuclear family structure, fidelity to one partner, etc. It seems to me the answer ...
6
votes
1answer
468 views

$S_{0.5}$ vs $K_m$ values in enzyme kinetics

What is the difference between $S_{0.5}$ values and $K_m$ values in enzyme kinetics?
5
votes
1answer
219 views

What evolutionary pressures pushed Galápagos tortoises to mature so slowly and live so long?

I read that they take up to 40 years (in the wild) to reach the age of reproduction and are thought to live over 100 years, with one in captivity reaching over 170 years. Can someone explain in ...
4
votes
2answers
1k views

Advice on Cell Biology texts by Alberts

I am currently reading "The Chemistry of Life" by Rose. It's a great book (to me as a lay reader at least) and an interesting topic so I am interested in pursuing some of the further reading he ...
2
votes
1answer
155 views

What are the biochemical interactions between human body and Polyethylene?

Our waterways and oceans are showing increased levels of plastic contamination. These plastics are breaking down into smaller pieces. When one goes to the beach and plays in the surf they often ...
2
votes
2answers
2k views

What is the purpose of measuring both VS (volatile solid) and TS (total solid)?

In the biogas process you often measure Volatile solid and Total solids. Can any one explain these concepts more accurately and why it is interesting to look at these properties. The biogas process ...
9
votes
1answer
1k views

What's the name of the fibrous strands that hold the seeds in a pumpkin?

If you cut open a pumpkin, the seeds are suspended inside the pumpkin by some fibrous, slimey strands. You can see them in the middle of this sliced-open pumpkin: I'm writing a post for the ...
5
votes
1answer
546 views

Using ion-exchange chromatography to purify DNA from a cell extract - Is DNA more negatively charged then RNA?

When applying this method we have a glass or plastic column of resin which is positively charged. Then we pour cell extract into the column in order to capture the negatively charged particles which ...
4
votes
1answer
66 views

Parse PDB using DSR-PDB Library

I'm trying to parse ATOM section of a PDB file. I'm using the dsr-pdb library for this purpose. I've encountered a problem. This library interprets CD1 atom of ILE ...
2
votes
1answer
88 views

What does self-preservation stem from? [closed]

Self-preservation, or preservation anyway, probably happens throughout the animal kingdom, and perhaps through the plant kingdom as well (some plants/trees, apparently, produce chemicals to repel ...
6
votes
2answers
108 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
1answer
381 views

What makes an animal/species suitable for domestication/training?

Humans have domesticated all manner of creatures during the course of their civilization - dogs, horses, several types of cattle, varieties of birds, and perhaps others too. A prerequisite for an ...
4
votes
2answers
296 views

Were there lifeforms before LUCA?

This question got me thinking about something. LUCA is the last universal common ancestor of all current living organisms, which is a very different definition from the first-ever living organism. Is ...
3
votes
1answer
291 views

What is the known maximum ranging distance of a bat's sonar?

Bats are known to navigate by using echo-location. How far away can a bat detect an object by its sonar?
6
votes
3answers
295 views

Are there genes in humans from the common ancestor of all organisms?

How long ago can human genes be traced? Are there any genes that go back unchanged to the beginning of life on Earth? And if so, how many?
1
vote
1answer
780 views

Why do drugs which are hormones have long half-life?

Hormones normally have short half-life. How is it possible that they have long-life in drugs?
7
votes
1answer
769 views

What determines the colors and patterns of a clam shell?

Earlier this week I was looking at some bivalve shells that had ornate patterns which ranged in color from a light orange-pink to a deep orange-red. Here is an image I found online that seems to be of ...
18
votes
3answers
41k views

What is the difference between orthologs, paralogs and homologs?

These three terms are often misused in the literature. Many researchers seem to treat them as synonyms. So, what is the definition of each of these terms and how do they differ from one another?
2
votes
1answer
889 views

Why does high-voltage mostly shock a person, and even small current kill?

This may be the wrong forum to ask. For instance several people are known to have survived a direct lightning strike; albeit the number of fatalities are probably far larger. Anyway, I found myself ...
2
votes
1answer
88 views

Reattaching body parts

Is there any living organism that has the ability to remove and reattach body parts at will? I'm not talking about regeneration (like in starfish). Say I'm chasing prey, and I decide that my tail ...
7
votes
1answer
894 views

Are there any solitary species of ant or termite?

The social insects consist of the ants, the bees, and the termites, which live in colonies rather than living solitary. But I've heard that there are some species of bee which are solitary and don't ...
4
votes
1answer
128 views

Are there any websites offering graphs for the light absorption of different enzymes?

I have found graphs for the light absorption of water, haemoglobin, lipids, melanin, etc., but I am having a hard time finding graphs about enzymes. Are there any websites or other reference sources ...
4
votes
1answer
336 views

Genetic engineering for insulin production

In order to put human DNA inside a bacteria in order to have it create Insulin, from what type of cell would you need to take the gene for insulin? I thought it should be from any somatic cell, since ...
1
vote
1answer
211 views

Why must the alcohol decolorizer be used for 30 seconds or less for Gram staining?

I had today a class in microbiology and my teacher said that the Decolorizer component is the critical one and cannot be more than 30 seconds. The decolorizer has alcohol in high concentration, my ...
4
votes
1answer
1k views

Conversion rate of topical Retinol to Retinoic Acid (Tretinoin)?

I'm wondering if someone out there has more information than me. Retinoids have well known metabolic pathways in vivo, and it's usually something like: ...
8
votes
2answers
81 views

Should we be looking for extra-terrestrial life on comets?

I have just read What elements are a possible basis for life? and I find myself wondering whether instead of seeking advanced life-forms at remote locales a La SETI, and perhaps fundamentally ...
5
votes
2answers
403 views

What were the mammal ancestors like 65 million years ago?

What we know about our mammal ancestors that were alive (and survived) at the extinction event 65 million years ago?
3
votes
1answer
208 views

Amount of neurons in the heart

Finding numbers for the amount of neurons in the brain is quite easy. Finding them for other human organs is harder. How many neurons are there in the human heart?
5
votes
3answers
203 views

Can children restore brain cells?

By "children" I mean young people at the age of 10 or lower. I know that the adult brain cannot restore brain cells, but what about children? I mean, the brain must develop from a few cells to a 90 ...
2
votes
1answer
440 views

Can the RNA in the HIV virus make viral enzymes without entering the nucleus?

If the provirus was not formed yet, can the virus make viral enzymes? (I know that it already has some, but supposing it doesn't)
5
votes
2answers
61 views

Flow cytometry issues

I'm having problems with data analysis here. I have flow cytometry data being collected on a Fortessa, and when I import them into FlowJo 8.7, all of my fluorescence values are systematically 10X ...
1
vote
1answer
241 views

What does “cellular” mean in this context?

I came across a confusing word when I was reading a Scientific American story, “Controversial Spewed Iron Experiment Succeeds as Carbon Sink” (by David Biello). It goes like this: “One key to the ...
2
votes
2answers
361 views

What does “delineate” mean in this context?

I was reading a Scientific American story, “Controversial Spewed Iron Experiment Succeeds as Carbon Sink” (by David Biello), when I came across this sentence: “The problem for scientists is that ...
14
votes
1answer
205 views

Has the human 7-day week had any impact on the evolution of species?

Most (if not all) industrialized countries follow a 7-day work week now, such that we are bound to follow a certain weekly trend in matters such as pollution generation, where to go (e.g. stay in town ...
2
votes
1answer
516 views

Has the age at which menopause occurs changed throughout history?

I was reading recently that the age of menarche has decreased in the last 150 years, and was wondering if the age of menopause in humans has also changed recently? Would there be selective pressure ...
8
votes
1answer
4k views

Why can't humans drink sea water?

Why can't humans drink sea water? It would seem to be a huge evolutionary advantage for an animal to be able to drink sea water rather than have to rely on fresh water, and it's provably not ...
7
votes
1answer
87 views

Do antisense transcripts have different names than their sense strand transcripts?

I want to find which genes in the human genome can potentially be complementary to a transcript that could act as antisense transcript inhibtion? Are cis-NATs (naturally occuring anti-sense ...
5
votes
1answer
2k views

Does the light color spectrum and frequency matter for photosynthesis?

Do plants grow differently when given sun light, wolfram lamp, fluorescent light, LED light, infrared, ultraviolet, x-ray, unfocused laser and stroboscope?
2
votes
0answers
21 views

How to seek information on the duration of biological entrainment processes in mammals? [closed]

This is a question that is a little bit hard to define for me. I'm interested in learning more about times of "attractor/entrainment" processes that may take place in the body/brain of mammals, and ...
8
votes
2answers
931 views

Scoring sequence against position weight matrix

I have a weight matrix of length 20 x 15 (amino acids x sequence positions). Each element of my weight matrix is a relative probability If I have a sequence say "AAPGTGASMHSGLLW" how would I score it ...
3
votes
1answer
337 views

Can Naegleria fowleri enter through the eyes ( example rinsing/splashing eyes with water)

I understand that it primarily enters the body through the nose by by "feeding on the olfactory neurons in the nose" as answered here in a different question. Would the nerve cells in the eyes present ...
5
votes
1answer
97 views

Does the Heart Require Gold?

I distinctly remember an episode of NOVA from the early 1980’s that concerned itself with gold. One of the points that was made was that there are trace amounts of gold in the human body, ...
4
votes
2answers
2k views

Why does alcohol cause the hemolysis of RBC in a large proportion?

I had today an experiment that we put 95% alcohol to the blood which made it completely transparent so hemolysis must have occurred. I started to think about the reasons. I think that this is because ...
7
votes
1answer
760 views

Does drinking coffee have negative effects?

From what I collected, coffee is a magical potion that lets you feel energetic, and essentially not-sleepy. But are there any tradeoffs? I mean, if it was so beneficial, wouldn't the human body ...
3
votes
1answer
26 views

Mutation in axillary buds of trees overcoming self-incompatability?

I seem to recall from either reading or lecture that there have been instances of trees that are self-incompatible accumulating enough mutations in an axillary bud that the resulting branch was able ...
5
votes
2answers
1k views

Does cooking or ripening reduce the concentration of solanine in nightshade?

I recall a story from one of my Botany professors where he encountered a woman picking Solanum dulcamara (nightshade) berries. When he asked her what she was doing with them, she responded that her ...

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