5
votes
2answers
582 views

Effect of steroid hormone on specific cells?

As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why ...
5
votes
3answers
640 views

Evolution: How could all useful traits evolve simultaneously?

I have a basic question about evolution, for which I never found an answer. I understand how evolution works if we focus on one specific organ or trait. With each generation, some organism is more ...
5
votes
1answer
7k views

How do wild animals get rabies?

I can see the chain of spreading disease: Humans usually get rabies from domestic animals, those usually get it from wild animals, wild animals in their turn get from the other wild animals and here I'...
5
votes
1answer
2k views

How to avoid air bubbles while pipetting?

I get air bubbles while pipetting small volumes. How can I avoid them ?
5
votes
2answers
6k views

How do we know that everybody's DNA fingerprint is unique?

How do we know that everybody's DNA fingerprint is unique? I know, I know, everybody's DNA is unique. But when we do DNA fingerprinting, we're looking at very specific regions of high variability. ...
5
votes
2answers
5k views

On which strand does the promoter sit?

My book keeps giving different indicators as to whether the promoters are on the coding or template strand. It says the -35 region in prokaryotes must be on the coding strand. It also mentions, that ...
5
votes
3answers
128 views

Identifying whether ELISA kits are authentic or fake

What methods can be used to determine whether they are authentic or fake?
5
votes
4answers
1k views

Photosynthesis: What Powers the Splitting of Water?

The splitting of water is an endergonic (non-spontaneous) reaction, and thus would require energy (chemical work to be done) in order to happen. In Photosystem II, an enzyme catalyzes this splitting, ...
5
votes
1answer
105 views

Could murder be modeled as an infectious disease?

Background "When swine flu hit the population it spiked in certain areas and tapered off in neighboring regions, it hits hardest where people have least protection and this pattern is more ...
5
votes
1answer
2k views

What do the signs +/+ +/- mean in this image?

I don't understand what this graph is supposed to explain, especially what the signs +/+ or -/- mean. I just know it characterises some rats.
5
votes
1answer
308 views

Bee (?) identification

I live in Michigan. I just saw a bee that I think I've seen before, but only this time was I so struck by its uniqueness and - for lack of a better word - scariness. I'll describe it. It was ...
5
votes
2answers
348 views

Can PCR tubes be made of different materials than plastic?

Does it matter if I replace the PCR tube (usually made of plastic) with another material like aluminum, glass, or something similar?
5
votes
1answer
4k views

Why does blood come from mouth when people are shot in the chest area?

In almost every movie scene when a character is shot in the chest area, some blood comes from his mouth or sometimes even coughs blood before he dies. Are these kind of scenes realistic/possible? If ...
5
votes
2answers
173 views

How is gene expression estimated?

I'm reading this fantastic article on estimating body time: Molecular-timetable methods for detection of body time and rhythm disorders from single-time-point genome-wide expression profiles and one ...
5
votes
1answer
123 views

Can cirrhosis be caused by physical compression of the body?

On a random forum, a member speculated that their cirrhosis was caused by wearing tight-fitting clothing such as a girdle or corset. This leads me to the following question: Question: Can ...
5
votes
3answers
2k views

Why do some animals have 8 Limbs (e.g. Spiders, Octopuses)?

Octopuses have 8 tentacles, spiders have 8 legs. Is there something special about 8? It seems like an animal that needs 360° mobility has 8 legs.
5
votes
2answers
199 views

Are all known germs benign in small enough quantities? i.e. Why do we wash our hands?

We know that we wash our hands because germs can get into our body through the nose, the mouth, the eyes, cuts, etc. But I doubt we can completely clean our hands of germs every time we wash them, ...
5
votes
2answers
2k views

The probability of indirect human fertilization?

What is the probability of conception in situations when sperm isn't directly ejaculated into the woman's vagina, like: The man's or the woman's hands come into contact with sperm, for example when ...
5
votes
2answers
627 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?
5
votes
2answers
10k views

Why do we sweat after drinking water and running?

Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?
5
votes
1answer
3k views

What are tendons made of specifically

From what I read on wikipedia they are made of collagen. Collagen is just a protein. Right? How is this collagen structured (I imagine like fibers). Aren't there cells in this fibers as well? From ...
5
votes
2answers
268 views

Are there other mechanisms for mutation besides imperfect DNA replication?

I was reading http://www.askamathematician.com/2012/05/q-is-quantum-randomness-ever-large-enough-to-be-noticed/ and saw: [...] the evolution of entire species can be changed by a single mistake ...
5
votes
2answers
243 views

First pass protein structure prediction

I'm working with a protein that doesn't have any homology to other proteins so it will likely require ab initio structure prediction. However, since I don't work for a structure prediction lab and I ...
5
votes
2answers
566 views

What does the 34/70 in Saccharomyces pastorianus Weihenstephan 34/70 stand for?

I've searched everywhere. No Wikipedia page. No information on NCBI. I searched all occurrences of 34/70 in some primary research articles! The best I've found is this brewery forum where someone ...
5
votes
2answers
194 views

How to typeset gene regulatory networks

I have a relatively simply gene regulatory network I would like to visualize, complete with the common arrow and bar symbols used to show, respectively, which genes enhance or repress with other genes....
5
votes
1answer
107 views

What are the different ways an exon gets spliced?

Exons are produced by more than one mechanism, e.g. splicing out introns after transcription, if I remember correctly. Please list all mechanisms.
5
votes
1answer
345 views

What is the maximum altitude where humans can survive?

What is the highest altitude that a human can survive without being pressurized? Let's assume that oxygen and heat/insulation are not the limiting factors? Why I asked.
5
votes
3answers
270 views

What are the effects of removing CD4 receptors?

If the gene for the CD4 receptor was removed, would the person's immune system work normally? Could a new artificial receptor be substituted in place of CD4? Could HIV infection be prevented in this ...
5
votes
1answer
129 views

How do electrons destroy DNA bonds in radiation?

Malignant tumors can be treated by radiation therapy. Most commonly it's radiotherapy with photons, or protons and so on. The common denominator for both types is that the radiation creates electrons ...
5
votes
1answer
417 views

What is this Sacrificial Reproductive Strategy Called?

The reproductive strategy of salmon is 'suicidal'. Before breeding the males metamorph permanently into a form suited for the breeding season but unsuited for survival. The females devote so much of ...
5
votes
2answers
483 views

Evolution of endosymbionts?

Mitochondria and plastids in eukaryotes evolved through a process of endosymbiosis. How does an event like a eukaryote engulfing a bacteria, become a part of the genome? Some of these primitive ...
5
votes
1answer
288 views

How do steroids travel in the bloodstream?

Cholesterol, which is hydrophobic, cannot simply travel in the bloodstream, and instead is enclosed in lipoprotein (LDL, HDL). Steroids, which are derived from cholesterol, are also hydrophobic (right?...
5
votes
2answers
233 views

How does a virus reach its host, it is always passive? [closed]

We know that viruses are non motile and cannot metabolise, and that it enters the host cells via binding to the receptors. But how exactly it reaches the host (that is, how it go from the ...
5
votes
1answer
1k views

Where do amino acids get attached to tRNA and where is it synthesized?

Some very basic parts of transcription/translation seem to be left out in various literature. I can't find the answer to this anywhere: How exactly is tRNA synthesized? I realize that mRNA is ...
5
votes
2answers
209 views

Why is living muscle tissue seemingly able to restore its shape under force, while dead tissue is not?

When I press my finger, even with relatively little force, into beef or chicken (say, at a grocery store), the indentation remains. When I poke a cow with my finger, the indentation does not remain. ...
5
votes
2answers
222 views

The meaning of RNA-seq data

many papers I read mentioned "RNA-seq data". While searching for the meaning of this word, I could not find any layman's definition. As far as I understand, RNA-seq data is the complete RNA ...
5
votes
1answer
6k views

Why does high pH result in the denaturation of DNA?

In the Southern blot method, for example, a solution of NaOH is used to denature the DNA in the sample. I find this counterintuitive since I expected that $\text{Na}^+$ cations would neutralize the ...
5
votes
3answers
1k views

How does vasoconstriction/vasodilation change blood pressure?

Background: I am coming at this question from an electrical engineering background, and I feel like I am missing certain assumptions that are going into the statement found in my physiology textbook, "...
5
votes
1answer
990 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 ...
5
votes
1answer
127 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
5answers
97 views

Can an influenza virus carry other infectors with it?

This idea came to my mind when thinking about how many people become ill in many locations with similar symptoms (fever and rough cough) from Influenza. There are of course different types of ...
5
votes
1answer
2k views

Like other animals, why humans don't have species & breeds?

Like other animals, why don't humans have species & breeds ? Even my pet dog is one type of breed, but we (humans) lack breeds & species? What is the main reason?
5
votes
2answers
2k views

Why is the DNA codon table “equal” to the RNA codon table

Before anything else please pay attention of the double quotes on the "equal" in the title - I know they are not equal, but you will understand in a bit. If I look at the DNA codon table here or in ...
5
votes
2answers
613 views

How do you visualize RNA on a gel?

I have run an in vitro transcription reaction and produced some RNA of a single species and definite size. I would like to visualize it to check if the reaction worked. Can I do this on an agarose ...
5
votes
2answers
4k views

Why doesn't the human skin grow back exactly how it was before being damaged?

Very simple: Why (and how) is regenerated skin different from original ? As we know we lose skin cells that becomes the dust in out homes and it always grows back to full thickness right ? So when I ...
5
votes
2answers
308 views

How many different protein coding genes are in the Human Biome?

There are approximately 20k protein-coding genes found in the human genome. This number is presumably very small when considering all the genomes found in the diverse microbes associated with the ...
5
votes
1answer
5k views

What is the definition of a stringent/relaxed plasmid?

I have found a publication which proposes some definitions, including a definition for strict and relaxed replication. The definitions are: Relaxed control of plasmid replication. Relaxed control ...
5
votes
2answers
82 views

Standard Classification of Disease

I am working on a project for health center. It involves the creation of a database of all diseases. Currently I want to classify disease on the base of their category based on international standard. ...
5
votes
3answers
228 views

How easy is it to carry out de novo sequence assembly?

Today a colleague of mine asked the following question: " Assuming I need to build from 0, a chromosome of a fish, with short reads but no other reference whatsoever [de novo assembly]: ...
5
votes
2answers
3k views

Are Asians more genetically homogenous than other races?

I've heard that Asians (I'm not entirely sure which subgroup was being referred to) tend to be more genetically homogenous than other races, with people of African lineage being on the other end of ...

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