36
Really interesting question: The lethal yellow mutation (also abbreviated Ay) affects the agouti signalling protein which plays a major role in pigmentation. Heterozygous expression of it leads to the dominant expression of pheomelanin (which is yellow), causing the mice to express this color (among other effects). To understand why it is homozygous ...
22
Wow, as an astrophysicist who has just logged into biology SE for the first time, I didn't think I'd have a question I could immediately answer.
You are correct about the Sun's output, so what about the lion.
If the lion is in its usual passive state, i.e. lying around as shown in your picture, then you would not go far wrong in treating them as black body ...
14
I looked at the original paper, Blank and Goodman "DNA is a fractal antenna in electromagnetic fields" Int J Radiation Biology, 87:4, 409-415, DOI:10.3109/09553002.2011.538130.
To be honest I can't give concrete reasons to doubt it, but here are a few things that raise my suspicions:
it is a review article that relies heavily on self-citation (15/50 ...
11
The paper's description is poor, but they seem to be describing an encoding where each of 20 possible amino acids are associated with a position within a string of 20 bits, e.g. alanine with offset 0, cysteine with offset 1, etc. With that representation, one amino acid residue within a window is encoded by a string of 20 bits, 19 of them being 0 and the ...
10
Protein structures, which can be obtained from protein crystals or from concentrated solutions of pure protein via NMR, are arguably the primary source of knowledge that we have about how genes perform their function on the molecular level.
I've added a link to RCSB.org above - they write up a story on an important protein structure monthly(?) - its a ...
9
This is the data for a few cell types:
Cell type Total G1 S G2 M Ref
----------------------------------------------------------
Neuro2a 9 2 5 1.5 0.5 [1]
Hela 16.2 7.7 7.2 0.8 0.5 [2]
A549 18 7 7.5 2.5 1 [3]
MCF7 21.3 9 9.3 ...
9
There is one book that will perfectly suits your needs:
A biologist's guide to Mathematical Modeling in Ecology and Evolution, by Sally Otto
It is a very good book that is very easy to understand and in the meantime goes pretty far (It ends with the use of diffusion equation in Evolutionary Biology). I highly recommend it.
It covers:
How to create a ...
9
Yes, various intracellular membranes do have potential differences, but as you can imagine they are more difficult to measure experimentally, so in general data on this is scarce.
Summary
Mitochondrial membrane: 150mV-180mV with negativity on the matrix side. Seth et al 2011
Endoplasmic reticulum membrane: 75-95mV with negativity in the ER. Qin et al 2011, ...
8
If you google "sperm chemotaxis sucrose" you learn some things of interest. Notably, wikipedia's article on sperm chemotaxis indicates that the important chemoattractants for sperm (the things that attract sperm via chemotaxis) are various signaling molecules given off the by the egg.
It is not clear why you would necessarily think that sucrose would ...
8
There are lots of biological clocks, or clocks made of biological components. The circadian clock is an important, though complicated, example. There are excellent engineered clocks that form some of the neatest examples of systems / synthetic biology. See for example Elowitz & Leibler's "repressilator" (link, link). The basic idea in all of these is to ...
7
You can find biochemical pathways on KEGG pathway for example.
KEGG PATHWAY is a collection of manually drawn pathway maps representing our knowledge on the molecular interaction and reaction networks for:
1. Metabolism
Global/overview Carbohydrate Energy Lipid Nucleotide Amino acid Other amino Glycan
Cofactor/vitamin ...
7
Is the standard Lotka-Volterra (LV) model an exact fit for insulin-glucose (IG) dynamics? No. Can a similar model built on the same principles capture most of the essential features of the IG dynamics? Absolutely.
How to capture most of the insulin-glucose dynamics using a slightly modified Lotka-Volterra model
We can figure out how to change the LV ...
7
I believe that there is only one drawing in the first edition of On the Origin of Species, and it is Darwin's. Any good edition such as the fascimile edition with an introduction by Ernst Mayr, will include this drawing. I'm not sure about other editions of the Origin or other books of Darwin's. However, maybe you don't need to buy anything. Darwin ...
7
In my experience neither is preferred.
When simply presenting a protein sequence, e.g. in the context of a database of proteins encoded by a genome, then the one-letter code tends to be used.
When showing an alignment of a DNA sequence with the encoded protein sequence both can be used, although personally I prefer the one-letter code for this too ...
6
I am surprised Janeway's Immunobiology is not listed here:
Murphy K. Janeway's Immunobiology. 8th ed. New York: Garland Science; 2011.
It is very comprehensive, accessible and goes beyond any graduate course I know. Most immunology researchers I know have a copy of this handy somewhere in their office. A particular highlight are the very clear illustration....
6
There are a number of more recent papers dealing with phylogenetic methods in reconstructing language history as well, including work by Colin Renfrew and Quentin Atkinson.
Here are two recent high-profile papers. Unfortunately, both are still behind paywalls, but even reading the list of papers they cite / that cite them would be a great way to answer your ...
6
Below is a Python script that might help you to get started (apologies if it fails the Pythonic test - it works!). It uses the Entrez part of the Biopython library. The script sets up a query, in this case yeast AND Saccharomyces against the pmc database. Also note that this script uses the 2 step process that NCBI likes you to use - the first part of the ...
6
Unix and Perl to the Rescue by Keith Bradnam and Ian Korf is an excellent introductory book and guide for bioinformatics (Linux and Perl) in genomics. It includes exercises and starts with the very fundamentals. You will still need some basic understanding of genetics and biology though.
6
The topic you describe is very interesting and known as "species selection." Some traits exist that not only affect the reproductive success of individuals, but also affect the diversification rate of the entire species, either through affecting the extinction rate, the speciation rate, or both.
To give you an example, I'll summarize this paper by Goldberg ...
6
There are two possibilities for searching for scientific articles:
The first one is to use PubMed, a database which has been set up by the National Institute of Health in the US. It contains about 25 Million journal articles. All articles in this database are coming from peer-reviewed journals.
The other one is to use Google Scholar, which is better when ...
6
I don't work in ecology, but my first thought is that I would not expect any relationship whatsoever between diversity and biomass. Biomass simply means the combined mass of all life on the planet. If that mass consists of one extremely fat goat the size of the moon, or several trillion different organisms doesn't make a difference, mass is mass.
Now, it ...
5
Quantitative descriptions of leaf shape used as diagnostics are hard to come by. There are numerous qualitative descriptions (lyrate, cordate, acicular, etc.), and I think this fits within the example you give that "the laminar shape for this species is mainly ovate." But actual quantitative ranges as you mention (e.g., that the L:W ratio of Acer lies within ...
5
I would recommend The selfish gene by Richard Dawkins. It is targeted at a scientifically interested audience, but well written and recognized by the scientific community.
http://amzn.com/0199291152
5
I always wondered this myself, but the structure of a protein can end up being quite important for a number of reasons. Most relate to the fact that protein function often depends on specific domains, and while a protein may have multiple functional domains it is important for all domains to be properly aligned and constructed in three-dimensional space. ...
5
In human cells it takes about 20 s to make a 20,000 dalton enzyme.
Assuming that the cells concerned are already making mRNA for the enzyme, there will be two main factors:
(1) The time taken to synthesize the polypeptide
(2) Any time taken to fold the protein
(If the enzyme is secreted from the cell there will also be the time taken for the protein to ...
5
Where I studied, every undergrad read Campbell Biology. You can start it as a non-specialist but you will not be one at the end..
5
There are various types of Mushroom identification Sites. you can take help from:
Mushroomexpert
Rogersmushrooms
MycoKey 4.0
Source: MycoKey 4.0
5
Check out Fig. 7 in the document at http://ipubli-inserm.inist.fr/bitstream/handle/10608/4343/MS_1991_3_263.pdf . The caption says: "Castration of a 23 day fetus. [Mother's] womb is open, the rear end of the fetus is pulled out, a flank incision is performed, and the testicle, located on the mesonephros, is exposed, then cut. After bilateral testicular ...
5
The sun will win until you have enough lions to form a star sized mass.
Assuming that your lions have an average mass of 200kg, which is probably pretty close, 1 trillion lions has a mass of 2×1014 kg, which is pretty close to the mass of Remus, a moon around the asteroid Sylvia. The mass of the sun is about 2×1030 kg.
So your lions would have enough mass ...
5
Beginning Perl for Bioinformatics by Jim Tisdall http://shop.oreilly.com is quite good, in my opinion, and his sequel, Mastering Perl for Bioinformatics is also great. The focus is largely, but not exclusively genomics.
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