Answer:
Explanation:
A. Cancer cells are cancerous because they divide all the time. Normal cells stop dividing once there's enough of them but cancer cells divide when not required as well. Therefore, if Ras is mutated it will always be "on" which means it will activate the pathway which will lead to division of cells i.e. cells divide to multiply their numbers so more cells will be made. Normally, cells only multiply whne there's the growth factor present to activate the whole pathway, but since Ras is mutated it doesnt need the growth factor to activate the pathway, it automatically always activates the pathway even in absence of growth factor.
B. It is highly unlikely that the proposed drug will have a useful effect. This is because mutant Ras protein of this type behaves as though it is constantly "on". Ras acts downstream of the receptor, i.e. first you have the reception of growth factor in receptor, then the ras gets activated. However, the activating mutation makes its effect felt (Ras is activated no matter if there's a growth factor or not), which is why mutant Ras is always active and no longer dependent on the receptor for activation.
Therefore, blocking the ability of the receptor to dimerize and activate Ras will probably not have an effect on cells containing the mutant Ras protein as it does not inhibit the activity of mutated Ras protein.
(Check out the Ras/Ref/MEK/Erk pathway for better understanding of how significant role Ras protein plays in cell proliferation i.e. division)
There are four types of plate boundaries:
Divergent boundaries -- where new crust is generated as the plates pull away from each other.
Convergent boundaries -- where crust is destroyed as one plate dives under another.
Transform boundaries -- where crust is neither produced nor destroyed as the plates slide horizontally past each other.
Plate boundary zones -- broad belts in which boundaries are not well defined and the effects of plate interaction are unclear.
Answer:
optimum temperature
Explanation:
the embryological and anatomical conditions for human reproduction depends on hormones and enzymes, these enzymes are protein in nature so any alternation in temperature will cause these proteins to be denatured hence compromising reproduction processes in humans.
In areas with high winds and lower levels of moisture, the coyote brush hugs low to the ground surface forming a cover over dunes. The coyote brush is a plant growing in a chaparral biome being able to withstand extreme heat conditions. The coyote brush adaptation to its environment is one of the most unique characteristic of this plant.
B. Net movement in osmosis is from areas of higher concentration to areas of lower concentration. Net movement in diffusion occurs from areas of higher concentration to areas of lower concentration.
