Question

Which of the following carry messages from the receptor to the inside of the cell? primary messengers secondary messengers both a and b none of the above

Answer 1

Ans) Secondary messenger

Explaination:

The binding of a messenger to a receptor located on the
outside of the plasma membrane generates a "second
messenger" inside the cell. This second messenger
becomes responsible for insuring that the cell gets the message by initiating changes in cell function.

Ans) a, b, c

Explaination:

The blood–brain barrier restricts the passage of pathogens, the diffusion of solutes in the blood, and large or hydrophilic molecules into the cerebrospinal fluid (CSF), while allowing the diffusion of hydrophobic molecules (O₂, CO₂, hormones) and small polar molecules and also allows the passage of some molecules by passive diffusion, as well as the selective transport of molecules such as glucose, water and amino acids that are crucial to neural function.