Answer:
(C) 10 times more acidic than distilled water.
Explanation:
The pH scale is logarithmic, meaning a pH difference of one is a difference of 10 times.
Answer: Substances that are protein based cannot cross the lipid cell membrane, but can exert their effect by binding to the proteins based receptors present on the lipid bilayer.
Explanation:
Hormones such as calcitonin , Parathyroid hormone and pituatry horomones are proteins and water soluble.They cannot cross lipid bilayer but can bind to ligand binding protein receptors.
These receptors are protein macromolecules that are specific in nature for specific hormones.
After binding to the receptors, these hormone-recpetor complexes activate second messengers and regulate the downstream effects.
Answer: 1. Cyclin-dependent kinases.
2. The activation process is in two steps: binding of cyclin to cdk and then phosphorylation of cdk cyclin.
3. They are activated when cdks sends signals to cell that is pass already into the next stage of the cell cycle.
4. They are inactivated by the combination of P21 and Thr-14/Tyr-15 phosphorylation after uv induced DNA damage.
5. Changes are seen in target protein level when cdks level rises.
6. The targets are protein that promotes cell divisions.
Explanation:
