A cell is the smallest LIVING unit in a body. An atom is the smallest "nonliving" unit.
Answer:
B
Explanation:
A doesn't make sense
c at night plant use oxygen and not carbon
Answer:
a. It is a hormone that acts upstream in the signaling pathway (i.e., acting as a ligand by binding to cell receptors)
b. Dopamine-mediated pathways
Explanation:
It is well known that many cellular transduction pathways are activated via binding of signaling molecules (ligands) to receptors capable of triggering signaling cascades into the cell. For example, dopamine is a signaling hormone (neurotransmitter) involved in diverse brain processes (i.e., motor control, emotional response, etc). It is a neurotransmitter that binds to dopamine receptors and then stimulates the enzyme adenylate cyclase in a process that subsequently activates the production of the second messenger cyclic adenosine monophosphate (cAMP). Finally, cAMP acts as an intracellular signal transductor that play roles in many biological processes by transferring into the cell the effects of dopamine.
<span>A human skin cell contains 46 chromosomes. A frog sperm cell contains 12 chromosomes. Which pair of numbers shows the chromosome number of a normal gamete from each of these species
</span><span>Human 23; frog 12</span>