Answer:
sickle cell anemia is caused by a mutation in the hemoglobin beta (or HBB) gene and it leads to a single change in amino acid sequence. this gene is located on chromosome 19
Explanation:
In DNA<span>, the code letters are A, T, G, and C, which stand </span>for<span> the chemicals </span>adenine<span>, thymine, guanine, and cytosine, respectively. In base pairing, </span>adenine always pairs<span> with thymine, and guanine </span>always pairs<span> with cytosine.</span>
Answer:
"GFP contained in synaptic vesicles moved into the synaptic cleft by exocytosis."
Explanation:
Synaptic vesicles are small membrane sacs that carry neurotransmitters from the cell body where they are produced, to the presynaptic membrane of the terminal button where they are released. The release zone of the presynaptic membrane contains voltage-dependent calcium channels. When an action potential depolarizes the presynaptic plasma membrane, 
-channels open, and flows into the nerve terminal to trigger the exocytosis of synaptic vesicles, thereby releasing their neurotransmitters into the synaptic cleft
Answer:
The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells.
Explanation:
Blood-brain barrier
It is a very selective semipermeable membrane , hence allow some specific substance to pass via it . This barrier separates the extracellular fluid in the central nervous system and the circulating blood from the brain .
<u>The barrier is composed of the endothelial cells .</u>
Passive diffusion is shown in this system , and allows molecules like the water , glucose , amino acid to pass .
It regulates the chemical composition of the fluid of brain cell .
