Answer:
All of those answer are correct.
Yes, this is true, and it is actually one of the organisms driving evolution! Some organisms develop mutations that are actually beneficial (better eye-sight, for example) and they're more likely to pass those to their children that individuals without those mutations!
I'm not completely sure, but I'm fairly certain that the answer is B.
Answer:
The order must be K2→K1, since the permanently active K1 allele (K1a) is able to propagate the signal onward even when its upstream activator K2 is inactive (K2i). The reverse order would have resulted in a failure to signal (K1a→K2i), since the permanently active K1a kinase would be attempting to activate a dead K2i kinase.
Explanation:
- You characterize a double mutant cell that contains K2 with type I mutation and K1 with type II
mutation.
- You observe that the response is seen even when no extracellular signal is provided.
- In the normal pathway, i f K1 activat es K2, we expect t his combinat ion of two m utants to show no response with or without ext racell ular signal. This is because no matt er how active K1 i s, it would be unable to act ivate a mutant K2 that i s an activit y defi cient. If we reverse the order, K2 activating K1, the above observati on is valid. Therefore, in the normal signaling pathway, K2 activates K1.
Answer:
e. The animal was endothermic and had a high metabolic rate
