Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Fertilization generally occurs in the fallopian tube.
This is an example of negative feedback.
After a big meal, glucose levels in the bloodstream increases. The body recognises this change and goes through homeostasis, or the regulation of bodily state or internal environment.
The pancreas secretes insulin, which then binds to insulin receptors. This will result in the uptake of excess glucose from the bloodstream into cells and converted into glycogen to be stored in cells as energy storage molecules.
Since there is the counter effect of body (i.e. when blood-glucose concentration increases, the body sends a signal to decrease the blood-glucose concentration, this is called a negative feedback (instead of a positive feedback, which occurs if for e.g. the body signals cells to increase blood-glucose concentration even after blood-glucose concentration increased after a heavy meal).
Hope this helps! :)
Answer:
0.0139- frequency of heterozygotes in the population
Explanation:
Let q to the power of 2 represents the frequency of the homozygous recessive (aa) = 1/20000 = 0.00005
This, q = √q^2 = √0.00005 = 0.007
Since p + q = 1
p = 1 - 0.007 = 0.993
Using the formula: p^2 + 2pq + q^2
Where 2pq represents the frequency of the heterozygotes, thing we have
2 x 0.007 x 0.993
= 0.0139
