Quiz #2 (1996): Cell Physiology
1. Which of the following is TRUE?
Ligand-gated ion channels show enzyme-like kinetics of ion transport.
The Na+/K+ ATPase is found on the basolateral membrane of transport epithelial cells.
Internal cellular organelles lack transport proteins.
Carriers cannot mediate active transport.
Voltage-gated ion channels show enzyme-like kinetics of ion transport.
2. Protein Kinase A (A-kinase) differs from Protein Kinase C (C-kinase) in that only A-kinase:
hydrolyzes ATP
phosphorylates substrate proteins
is activated by cyclic AMP
is activated by diacylglycerol (DAG)
is a part of a G-protein-linked signaling pathway
3. The "signal" of the signaling mechanism for segregation of secretory and membrane proteins is:
a second messenger
an integral membrane protein
a short polypeptide sequence
a protein phosphorylation reaction
a hormone
DATA FOR THE NEXT TWO QUESTIONS:
A hypothetical cation Y++ is present in the cytoplasm of a cell at 100 mM and is present in the surrounding extracellular fluid at 10 mM. The cation is not actively transported across the cell membrane.
4. What is the equilibrium potential for Y++ ?
- 60 mV
+ 60 mV
+ 30 mV
- 30 mV
None of the above is correct.
5. If the actual membrane potential is measured and found to be +100 mV, in which direction will Y++ move, and what will be the driving force(s) for its movement?
into the cell, driven only by the electrical force
into the cell, driven both by the concentration and electrical forces
out of the cell, driven only by the electrical force
out of the cell, driven both by the concentration and electrical forces
neither in nor out of the cell, because the concentration and electrical forces are in