Membranes and Solute Transport

1. What type of molecule in the membrane structure creates the barrier? What type of molecule performs most of the membrane functions?
2. Why do most solutes need assistance from a membrane protein in order to cross the membrane?
3. What factors must be considered in order to decide whether or not solute transport is favorable?
4. Why are carriers saturable when channels aren't?
5. How are the proteins required for primary and secondary active transport alike, and how are they different?
*6. How do the faces of the bilayer differ from each other?
7. How are the types of integral membrane proteins different from each other?
8. What is the equation for ΔG of transport across the membrane? How does the concentration factor (R T ln [c₂/c₁]) change when the direction of transport across the membrane changes? How does the charge factor (Z F ΔV) change when the direction of transport across the membrane changes?
9. What are the characteristics of ion channels?
*10. How many binding sites does the K⁺ ion channel have, and how is it selective?
11. What are the characteristics of carriers?
12. What must a primary active transport protein be able to do that secondary active transport proteins don't have to do?
13. What is the cycle of steps used by the Ca²⁺ ATPase to move Ca²⁺ across the membrane?

Biosignaling

1. What is biosignaling, why is it needed, and what are its characteristics?
2. For each biosignaling method we study, how does the receptor respond?
3. What makes a signal end? What is desensitization, and how does it occur?
4. How does a cell restore its pre-signal internal environment?
5. How do biosignaling pathways differ from each other?
6. What are the domains of a receptor?
7. How does the nicotinic acetylcholine receptor function? What happens as a result?
How are the results reversed?
8. How does a 7tm receptor function?
9. What are the subunits of a G protein, and what does each do? How is a G protein activated, and how is it inactivated?
10. What reaction does adenylyl cyclase (AC) catalyze? How is its product removed from a cell?
11. What are the subunits of inactive protein kinase A (PKA), and how is PKA activated?
12. What happens if a different G protein (not G_s) is activated?
13. For all three receptors (nicotinic ACh, 7tm, and insulin), which molecules are proteins and which are not? Which proteins are enzymes, and what reactions do the enzymes catalyze?

Bioenergetics

1. What is the relationship between ΔG and ΔG°'? Between ΔG°' and K_eq?
2. What is the significance of ΔG°' being additive?
3. What is the role of ATP in the cell? (Is it used for storing energy or for transferring energy?)
4. Why is ATP a "high energy" molecule? In general, what are the characteristics of high energy molecules?
5. What is the relationship between ΔG°' and ΔE°'? Why are oxidation-reduction reactions covered in biochemistry?
6. What is the equation that relates ΔG°' to K_eq?
7. In what ways does ATP participate in reactions?
8. What are the reactions catalyzed by nucleoside diphosphate kinase (NDP kinase) and by adenylate kinase? What reaction is catalyzed by pyrophosphatase?
9. What is the difference between H⁺, H, and H^-? What is the half reaction to reduce NAD⁺?
10. What is the equation that relates ΔG°' to ΔE°'?
11. Given two half reactions, how can you write a spontaneous whole reaction, and calculate ΔE°' and ΔG°' for the spontaneous reaction?

Glycolysis

1. How is the structure of glucose changed by the reactions in the preparation phase of glycolysis?
2. Which glycolysis reaction is the committed step, and what does "committed step" mean?
3. How is glyceraldehyde-3-phosphate changed during the reaction catalyzed by GAPDH? How is it changed, overall, during the reactions of the payoff phase of glycolysis?
4. What happens to pyruvate during fermentation? Why?
5. Why are the fermentation products of skeletal muscle cells different from yeast cells?
6. What is the overall reaction for glycolysis? What is the overall reaction for the preparation phase? For the payoff phase? What is the net energy yield per glucose from glycolysis?
7. What is the reaction catalyzed by hexokinase, and why is it important?
8. What is the reaction catalyzed by PFK-1, and why is it important? What does PFK-1 mean?
9. What is the reaction catalyzed by GAPDH, and why is it important? What are the steps of this reaction?
10. What is the reaction catalyzed by pyruvate kinase? What is the mechanism for the reaction?
11. What happens to pyruvate in anaerobic yeast cells? What enzymes are required, what is the intermediate, and what is the net energy yield per glucose as a result?
12. What happens to pyruvate in anaerobic skeletal muscle cells? What enzyme is required, and what is the net energy yield per glucose as a result?

Gluconeogenesis

top of page