Answer:
A. Molecular changes such as extracellular signals on extracellular ligands can result in quick changes in cell behaviour. One example is insulin. Upon insulin binding on the receptor on the cell membrane, the cell release GLUT4 transporters (for muscle cells) to increase uptake of glucose.
B. Slow changes in cell behaviour can be observed for other lipophilic hormones or intracellular receptors such as glucocoortoid or estrogen which reacts with receptors in the cells.
C. Insulin is required to maintain a constant blood glucose level and hence levels of insulin has to be mediated in correspondence to the blood glucose levels. Fast acting signalling is thus required for homeostasis of blood glucose levels. Where for such lipophilic hormones such as steriods, glucocortoid, these hormones tend to have a longer lasting effect and hence results in a slow change.
The bottleneck effect occurs when the majority of a population is destroyed due to natural disasters or human activity's. This reduces the size of the gene pool resulting in smaller variations from bird to bird. Gene mutation is the permanent change in the DNA or gene. Stabilizing selection occurs when genetic diversity decreases and the majority of the population stabilizes on a specific trait. The Founder effect occurs due to a smaller population leaving a larger population. This leaves the smaller population with smaller genetic variations. The correct answer is the Founder effect.
The answer is B: contains mostly cellulose; forms the outer layer of animal cells
