Positron Emission Tomography scan of the brain of cocaine addicts showed that the drug affects how the brain use glucose. Cocaine users' brain cannot use glucose efficiently and there are also reduced metabolic activity in other areas of the brain.
Answer:
Epistasis
Explanation:
In epistasis, the interaction between genes is inimical, such that one gene masks or interferes with the expression of another. “Epistasis” is a word coined of Greek roots that mean “standing upon.” The alleles that are being masked or silenced are said to be hypostatic to the epistatic alleles that are doing the masking. The cause of the biochemical basis of epistasis is a genetic pathway in which the expression of one gene is dependent on the function of a gene that precedes or follows it in the pathway.
The example of epistasis given is the pigmentation of mice. we were told that "if a mouse has two recessive alleles for coat color, it is always albino no matter what the genotype of other genes involved in coat color"
Let say recessive allele (rr), it is always albino irrespective of other type of other genes, this is true in the stance that epistasis can be reciprocal such that either gene, when present in the dominant (or recessive) form, expresses the same genotype.
Velocity is how fast the river is moving, the Volume is how much is in the river!
Tissue damage activates nociceptors or pain receptors in the skin. A signal is sent to the peripheral nerve to the spinal cord where neurotransmitters or chemical messengers are released. It activates other nerves to pass signal to the brain. The signals are relayed to the somatosensory cortex for sensation, frontal cortex for thinking and limbic system for emotional response.
Hello there.
<span>Regulation of the cell cycle is dependent upon cyclins and cyclin-dependent kinases. The key(s) that allows a cell to progress beyond the restriction point is (are)
</span><span>c. cyclin A and Cdk2.
</span>
