Armatus
  • Member for 9 years, 9 months
  • Last seen this week
  • Heidelberg, Germany
Why do we like salt?
Accepted answer
28 votes

In developed countries we usually consume enough salt (sodium to be exact) without actually adding table salt to food. Everything can become toxic when consumed in excess - even water - and when we ...

View answer
How fast does the rotor in ATP synthase spin?
Accepted answer
21 votes

According to "Resolution of distinct rotational substeps by submillisecond kinetic analysis of F1-ATPase" (Yasuda et al., Nature, 2001), ATPase rotates at 130 revolutions per second when saturated ...

View answer
Why don't teeth glow?
19 votes

Firstly, phosphorus does not exhibit phosphorescence on its own (don't let words mislead you, they often don't mean what they seem like): See http://en.wikipedia.org/wiki/Phosphorescence#Materials and ...

View answer
Could hydrogen replace oxygen in cellular respiration?
16 votes

No, hydrogen could not replace oxygen because it has entirely different characteristics. The most important one is probably its electronegativity - oxygen 'pulls' electrons much 'stronger' than ...

View answer
Can humans survive without consuming life?
14 votes

Your question is phrased somewhat ambiguously as to whether you're asking about the theoretical possibility, the feasibility, or the practical ability in everyday life. 1) Theoretically, yes. It is ...

View answer
Why aren't organelles considered alive?
12 votes

The definition of life is a controversy in itself, and as it is simply a word that can be understood by everyone however they wish, there is no "correct" definition. It is thus not really possible to ...

View answer
The genetic and physiological origins of laughter?
12 votes

I recommend this article: The Evolution and Functions of Laughter and Humor: A Synthetic Approach by M Gervais and DS Wilson, 2005, University of Chicago Press. For your question about the origin, ...

View answer
If life is discovered on another planet, will it likely be classified using the current domain/kingdom/phylum system?
Accepted answer
11 votes

Background There are basically three highest taxonomic levels: bacteria, archaea and eukaryotes. Many sources distinguish only prokaryotes and eukaryotes, subdividing prokaryotes into bacteria and ...

View answer
What does the term 'bioavailability' mean?
Accepted answer
11 votes

Bioavailability is a concept which applies to nutrients and drugs which pass through first-pass metabolism, i.e. orally (and to some extent nasally) consumed substances. Anything absorbed in the gut ...

View answer
Is a fatty acid a polymer?
10 votes

In the IUPAC Gold Book, IUPAC defines a polymer as follows: A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, ...

View answer
Why does blood come from mouth when people are shot in the chest area?
Accepted answer
10 votes

Substances such as blood trigger the Cough reflex, so if for any reason blood accumulates in the airways, it will be ejected this way. If you have a look at chest anatomy, you can see how this could ...

View answer
Why do some people find vegetables so repellent when evolutionarily they should find them an attractive and thus tasty food?
10 votes

Evolution is not that simple. There is no selective pressure for a feature if it does not ultimately in some way benefit reproduction or the offspring. Vegetables are healthy for us now because we ...

View answer
Is it possible for a person to become "reinfected" with the same strain of a virus?
Accepted answer
9 votes

The nature of infectious agents is that they transmit between organisms. This means that they have reservoirs outside a single host, and hence of course encountering the exact same strain twice is ...

View answer
How best to count bees entering and leaving a hive to measure hive activity?
9 votes

One thing that's certain is that the activity of bees varies according to time of day, so more important than how long you record for is probably at what time you record. If you always record at the ...

View answer
Number of reading frames in nucleotide sequence
Accepted answer
9 votes

Every nucleotide sequence has six possible reading frames, because each codon (determining one amino acid) consists of a base triplet (3 frames), and there is a complementary strand which could be ...

View answer
Does one neurotransmitter travel all the way through the nervous system?
9 votes

You've got a few things mixed up here: A signal may travel down a pathway, passing through several neurons (e.g. around 4-8). However, this signal is not always in the same form: From one end of a ...

View answer
Which blood vessel carries the most impure blood?
Accepted answer
9 votes

It's the renal artery because it will contain everything from the liver as you describe plus all waste accumulated on the way from the liver to the kidney. Here it gets filtered, so there cannot be a ...

View answer
The evolution of dogs through domestication and artificial selection
9 votes

According to Serpell, 1995 (http://books.google.co.uk/books?id=I8HU_3ycrrEC, page 8), wolf bones in association with human bones have been found from as early as the middle pleistocene (126,000–781,...

View answer
If a mother had a child with her own son, could a paternity test yield positive result for the son's father?
Accepted answer
8 votes

Let's approach some different methods of distinguishing parents: 1: The Y chromosome. These are passed down from father to son. Therefore, if the baby is male, its Y chromosome will be the same as ...

View answer
In which order did the cells of the immune system evolve?
Accepted answer
8 votes

As I'm lucky enough to have access to that article, I'm going to extract whatever I can find to answer your question. To begin with, innate immunity must have evolved first - we can see it at almost ...

View answer
What causes random long white body hairs?
Accepted answer
8 votes

Since it's been so long, I guess a rushed speculative answer might be at least an idea. DNA gets damaged randomly all the time, and repair mechanisms are in place to fix it. When the damage is too ...

View answer
What is the function of the RNA primer in DNA replication?
8 votes

In simple terms: Function of the RNA primer: DNA polymerases need a double-stranded DNA region to which they can attach in order to begin copying the rest of the DNA strand. In order to provide this ...

View answer
What is the functional difference between hemoglobin and ferritin?
Accepted answer
8 votes

Hemoglobin is the protein of erythrocytes (red blood cells) which has ferrous ions (Fe2+) bound in its subunits. These are able to keep oxygen bound which enables the cell to transport oxygen through ...

View answer
Gametes of two different species
Accepted answer
8 votes

Daniel's answer excellently explains the issue in an understandable fashion, though you may have been looking for a more cell biological approach. According to Immunological aspects of sperm ...

View answer
Could we transmit smells electronically?
8 votes

In expansion to biocs' excellent answer, I would like to highlight some practical limitations of this. Suppose we did manage to create a huge database of exact chemical mixtures which produce all ...

View answer
What's the Evolutionary Purpose of Religion?
7 votes

In terms of genetic evolution, religion itself cannot really be considered to have an evolutionary advantage or disadvantage, as it is not anchored in any genes. This means that it is not an ...

View answer
How do neurons form new connections in brain plasticity?
Accepted answer
7 votes

I haven't read anything particularly about dendrites being reshaped, though I would expect them to be as flexible as other parts of the cells. The more commonly discussed topic (in my literary ...

View answer
How are proteins formed?
Accepted answer
7 votes

Essentially, yes, "proteins that we consume form new proteins that are different". The processes are each of them topics for themselves. In short, consumed proteins are digested by peptidases (...

View answer
What controls the size of breasts?
Accepted answer
6 votes

The known factors seem to be mainly oestrogen and genetic (although I haven't been able whatsoever to find detail on what genes): Manning et al (1997): Breast asymmetry and phenotypic quality in women....

View answer
What causes knuckle "popping" and the feeling of relief that comes from it?
6 votes

Nobody really knows where it comes from. The currently most popular theory is that pulling the joint apart leads the gases in the joint's cartilage to accumulate and form a bubble which then pops when ...

View answer