A genetic form of "night blindness" (i.e. poor vision in dim light) is caused by mutations in genes encoding rhodopsin kinase (R
K) and arrestin. The mutations reduce the dynamic range of light perception, and the affected individuals have a prolonged light response and adapt very slowly to low light (when entering a dark theater room, for example). Which of the following mutations do you expect to be the cause?A. Loss-of-function RK mutations and loss-of-function arrestin mutations B. Loss-of-function RK mutations and gain-of-function arrestin mutations C. Gain-of-function RK mutations and loss-of-function arrestin mutations D. Gain-of-function RK mutations and gain-of-function arrestin mutations
Answer: The answer is A - Loss-of-function RK mutations and loss-of-function arrestin mutations
Explanation:
RK is Rhodopsin Kinase. Rods which are photoreceptors (along with cones) for providing vision to the eyes contain a receptor-protein called Rhodopsin. When light hits the rhodopsin some changes occur which generate electrical signals that are carried through the optic nerve to the brain.
Mutation in Rhodopsin kinase is associated with night blindness
Humans with defects in RK, or its downstream regulator arrestin, have a prolonged light response, incapable of adapting quickly to sudden drops in ambient light intensity
Yes, it does, but not the way people think. it doesn't gain it from the weight of all the people. the earth takes mass from elsewhere, as our population continues to grow.
"Periodic drought causes an abrupt decrease in vegetation" is the one among the following that <span>is caused by the modification of density–independent factors. The correct option among all the options that are given in the question is the second option or option "B". I hope the answer has helped you.</span>
