Question

Normally the kinases are tightly regulated and are "on" only in the presence of what?

1) A second messenger
2) Two NR1 subunits and two NR2 subunits
3) Ca₂⁺
4) NR2B

Answer 1

Kinases are activated by specific factors, such as calcium ions. Ca²⁺ plays a crucial role in activating kinases, allowing them to phosphorylate target proteins and trigger cellular responses.

Step-by-step explanation:

Normally, kinases are tightly regulated and are "on" only in the presence of specific factors. One important factor that activates kinases is Ca²⁺, or calcium ions. When calcium ions are present, kinases can be activated and phosphorylate target proteins, thereby initiating various cellular responses.

For example, cyclic AMP (CAMP)-dependent kinase (A-kinase) is activated by CAMP and regulates many cellular pathways through phosphorylation of target proteins.