The erythema response of skin to ultraviolet radiation (UVR), i.e., the sunburn reaction, has long been known to correlate with skin color. Dark-skinned individuals are able to tolerate a longer sun exposure than light-skinned individuals. Skin color in humans is mainly determined by the quantity, quality, and distribution of the complex biopolymer, mel~ni1_1, and its organized form, the melanosome (1,2}; melanm IS thought to protect skin from the deleterious effects of UVR.
Answer:
hormones
Explanation:
An example of materials commonly released this way is hormones. These are chemical messengers that are sent to the pituitary gland where they are released directly into the bloodstream. The blood then carries the hormones to different organs and tissues of the body in order to exert their specific function which varies depending on the specific type of hormones being secreted.
They have a certain shape of active sites which only fit in certain substrates
See lock and key theoru
<span>Sunset, this is really similar to the question about molecular clocks you asked. The more closely related the three species are, the more similar the homologous proteins will be in each of the species.
Defining 'sequence similarity' is a little bit nuanced. It can refer either to the genetic code or the amino acid code. Because the genetic code is degenerate multiple codons code for the same amino acid - mutations in the gene don't result in mutations in the proteins when the mutated codon codes for the same amino acid as the unmutated codon.
Similarly, you can sort of think of some amino acids as being redundant. In some cases, replacement of one amino acid with another doesn't result in all that much change to the protein's structure or function. The result is, as species diverge and mutations build up, they build up preferentially in certain domains of the protein and more frequently involve replacement of one amino acid with one which is pretty much similar to it.</span>
During the regeneration stage of the calvin cycle:
- The remaining glyceraldehyde three-phosphate (G3P) molecules are converted into ribulose biphosphate (RuBP), a five carbon sugar that is combined with CO2
- The reaction is speeded up by RuBP carboxylase (rubisco), an enzyme that catalyzes the combination of CO2 and RuBP
