Membrane & Axoplasmic Transport (Exam 1)

Question 1

What are the 2 types of neuron membrane receptor proteins?

Answer 1

1) transport receptor proteins
2) GPCRs

Question 2

Transport receptor proteins facilitate the movement of ions directly through the protein. What are the 2 types?

Answer 2

channel and carrier proteins

Question 3

What are GPCRs?

Answer 3

-loop in and out of the membrane 7x
-do not directly facilitate movement of ions through the receptor
-activation initiates a cascade of reactions inside a cell

Question 4

What are the 3 types of channel transport proteins?

Answer 4

1) ligand gated (activated by a chemical/neurotransmitter)
2) voltage gated (activated by a change in membrane voltage)
3) leaky channels (always open)

Question 5

Carrier transport proteins undergo a change in shape to move a substance through the membrane. Some require ATP so this is called __________________. Some do not require ATP energy, so this is called ____________________

Answer 5

active transport, facilitated diffusion

Question 6

What are the 4 examples we went over in class for primary active transport pumps?

Answer 6

1) sodium potassium pump
2) calcium pump (in and out)
3) chloride pump (out of cell)
4) hydrogen pump (H+ into vesicles)

Question 7

The sodium potassium pump, pumps how many sodium out and potassium in?

Answer 7

3 sodium out, 2 potassium in

Question 8

Which term is used to describe how much stuff is in a solution?

Answer 8

osmolarity (water will move towards the higher osmolarity)

Question 9

What is a hypotonic solution?

Answer 9

solution has less solute conc. (lower osmolarity) than the cytoplasm inside the cell

Question 10

A cell placed in a hypotonic solution will cause a cell to ___________ bc the the cytoplasm of the cell will have a higher conc. of solutes than the hypotonic solution and the water will move from the solution into the cell

Answer 10

swell

Question 11

What is a hypertonic solution?

Answer 11

solution has a higher solute concentration (osmolarity) than the cytoplasm inside the cell

Question 12

A cell placed in a hypertonic solution will cause a cell to ___________ bc the solution will have a higher concentration of solutes than the cytoplasm of the cell and water will move out of the cell

Answer 12

shrink

Question 13

In axoplasmic transport, substances travel to and from soma along microtubules (aka neurotubules), which are held together by ______ proteins. Axoplasmic transport requires 2 ATP dependent motor proteins

Answer 13

tau

Question 14

What does anterograde transport carry?

Answer 14

-components to maintain axon plasma membrane
-new organelles
-enzymes necessary for neurotransmitter synthesis
-large molecule neurotransmitters

Question 15

What does retrograde transport carry?

Answer 15

-old organelles to be recycled
-NGF
-microorganisms such as viruses like herpes, rabies, and poliovirus

Question 16

Transection of an axon will lead to anterograde degradation of the portion of the axon that is distal to the injury site. The postsynaptic cell/tissue innervated by the injured axon can also undergo degeneration if there are no other synapses on that cell/tissue. What is this called?

Answer 16

Wallerian degeneration

Question 17

What happens with CNS axon injuries?

Answer 17

-axon stump distal to the injury site will die within a few days
-no system to self-repair

Question 18

What happens with PNS axon injuries?

Answer 18

-axon stump distal to the injury site will often repair
-repair is due to function of Schwann cells
-the axon proximal to the injury will sprout new growth
-the key to regeneration is aligning the transected stumps
-schwann cells differentiate and begin phagocytizing debris
-at the same time, schwann cells around the distal stump proliferate and secrete trophic factors (nerve growth factor) promoting growth of the severed distal axon
-the proximal transected axon grows sprouts
-schwann cells form rows between the axon stumps
-growth cones of the sprouting axons find their way along these rows of schwann cells to reunite and regenerate