Chpt 3 Study Questions

Question 1

3 major components of cell structures function?

Answer 1

Cell membrane (sarcolemma)- separates cells from extracellular environment

Nucleus- i. holds genes that regulate protein synthesis

Cytoplasm- contains organelles (mitochondria), fluid part of cell

Question 2

Concept of coupled reactions?

Answer 2

Exothermic reaction has to release energy to power an endothermic reaction

Question 3

Define: Bioenergetics, Endergonic reaction, Exergonic reaction

Answer 3

Bioenergetics: process of converting food into energy

Endergonic: reaction that requires energy

Exergonic: reaction that releases energy

Question 4

Role of enzymes as catalysts?

Answer 4

Enzymes lower the activation energy, which is the energy required to drive a reaction

Question 5

Where do glycolysis, Kreb’s cycle, and oxidative phosphorylation take place in cell?

Answer 5

Glycolysis: cytoplasm

Kreb’s: mitochondrial matrix

Oxidative phosphorylation - mitochondria

Question 6

Define glycogen, glycogenolysis, glycolysis

Answer 6

Glycogen- stored glucose in liver and muscle

Glycogenolysis- glycogen to glucose

Glycolysis- i. glucose broken down by enzymes - produces pyruvate & 4 ATP, 2 net because 2 were needed to power the reaction

Question 7

What are high-energy phosphates?

Meaning of “ATP is the universal energy donor?”

Answer 7

• High energy phosphates is ATP. Adenine, ribose, & 3 linked phosphates.
• Serves to couple the energy released from the breakdown of foodstuffs into a usable form of energy required by ALL cells

Question 8

Define aerobic and anaerobic

Answer 8

-Aerobic: Requires O2; oxidative phosphorylation

-Anaerobic: Doesn’t require O2; PC breakdown and glycolysis

Question 9

Briefly discuss the function of glycolysis in bioenergetics. What role does NAD+ play in glycolysis?

Answer 9

-Glycolysis is an anaerobic pathway used to transfer bond energy from glucose to rejoin Pi to ADP and convert to pyruvate or lactic acid.

-NAD is the hydrogen acceptor

Question 10

Discuss the operation of the Krebs cycle and the electron transport chain in the aerobic production of ATP.

What is the function of NAD+ and FAD in these pathways?

Answer 10

-Kreb’s cycle converts pyruvate to Acetyl-CoA and then oxaloacetate from CHO, fats, and proteins to produce energy in forms of ATP, NADH, and FADH2. Electron transport chain uses hydrogen in NADH and FADH2 to form ATP by coupling Pi to ADP.

-NAD+ and FAD are electron carriers to be used in the ETC.

Question 11

What is the efficiency of the aerobic degradation of glucose?

Answer 11

34% efficient, 66% lost due to heat

Question 12

What is the role of oxygen in aerobic metabolism?

Answer 12

Oxygen acts as the final acceptor of H+ to form water

Question 13

What are the rate-limiting enzymes for the following metabolic pathways? ATP-PC system? Glycolysis? Krebs cycle? Electron transport chain?

Answer 13

-ATP-PC system: creatine kinase

-Glycolysis: phosphofructokinase

-Krebs cycle: isocitrate dehydrogenase

-ETC: cytochrome oxidase

Question 14

Briefly discuss the interaction of anaerobic versus aerobic ATP production during exercise

Answer 14

-Anaerobic ATP production: during short, high intensity activities

-Aerobic ATP production: during long, low-to-moderate intensity activities

Question 15

Discuss the chemiosmotic theory of ATP production.

Answer 15

-ETC results in pumping of H+ ions across inner mitochondrial membrane

Question 16

Briefly discuss the impact of changes in both temperature and pH on enzyme activity.

Answer 16

-Temperature: small rise in body temp. increases enzyme activity. Too high and it degrades enzymes

-pH: change from optimal pH(~7) reduces enzyme activity. Exercise can lead to lactic acid and pH change.

Question 17

Discuss the relationship between lactic acid and lactate.

Answer 17

-Lactate is the conjugate base of lactic acid. Lactic acid is produced in glycolysis