Chapter 4

Question 1

Cellular respiration

Answer 1

Glucose molecules are oxidized

Products are water, CO2, heat and ATP

Centre of all metabolism

Question 2

Overall change in energy of cellular respiration

Answer 2

-2870kJ/ mol glucose rather by composition or cellular respiration

Question 3

Respiration steps

Answer 3

1) Glycolysis- 10 steps- cytoplasm
2) Pyruvate oxidation- 1 step- mitochondrial matrix
3) Krebs cycle- 8 steps- mitochondrial matrix
4) Electron transport and chemiosmosis- multistep process ON inner mitochondrial membrane

Question 4

Obligate aerobe

Answer 4

Can not live without oxygen

Question 5

Substrate level phosphorylation

Answer 5

Formation of ATP by the direct transfer of a phosphate group from a siubstrate to ATP

Happens in glycolysis and krebs cycle

Forms ATP directly without O2

Pi and energy come from substrate

Question 6

Oxidative phosphorylation

Answer 6

Forms ATP using energy transferred indirectly from a series of redox reactions

Happens in ETS via chemosmosis

Energy comes from oxidation of NADH and FADH2

Question 7

Metabolic rate

Answer 7

The amount of energy that is expended per unit time in an organism

Question 8

Basal metabolic rate (BMR)

Answer 8

The metabolic rate of an organism at rest. Accounts for 60-70% of human activities

Question 9

Anaerobic respiration

Answer 9

Uses an inorganic molecule other than oxygen as the final oxidizing agent. Uses electron transport system

Question 10

Fermentation

Answer 10

Uses an organic compound as the final oxidizing agent to produce energy

Question 11

Beta oxidation

Answer 11

A process in which fatty acids are broken down into acetyl-CoA through catabolism

Question 12

ATP contains ___ kJ/ mol

Answer 12

31

Question 13

Uncoupling electron transport

Answer 13

The energy released is turned into thermal energy used to regulate body temperatures instead of being used as ATP

Question 14

What does cellular respiration do?

Answer 14

Extracts energy from food.

Question 15

Glycolysis

Answer 15

10 steps. in glycolysis 1 glucose is turned into dihydroxy phosphate and 2 glyderaldehyde 3 phosphate molecules (steps 1-5, initial energy investment phase)

The 2 G3P molecules both form pyruvate in glycolysis 3 (steps 6-10, energy payoff phase)

Question 16

When glycolysis forms pyruvate what does it do?

Answer 16

Diffuses into mitochondrial membrane through a transport protein

Question 17

Pyruvate oxidation

Answer 17

1) Pyruvate is decarboxylized
2) Pyruvate looses e- by being oxidized by NAD+ and produces an acetyl group
3) Acetyl group reacts with the sulphur atoms of coenzyme A and produces acetyl co-A

Question 18

Citric acid cycle (basics)

Answer 18

Acetyl Co-A —–> Citrate (6C) —–> oxaloacetote

Question 19

Proton motive force

Answer 19

moves protons because of a chemical gradient of protons across a membrane

Question 20

Proton gradient

Answer 20

A difference in proton (H+) concentration across a membrane

Question 21

Chemiosmosis

Answer 21

A process in which ATP is synthesized using the energy of an electrochemical gradient and the ATP synthase enzyme

Question 22

Actual yield

Answer 22

30 ATP because:

1) Some H+ leak through inner membrane
2) Some H+ in revision are used by cell for other activities
3) Some cells use less efficient glycerol- phosphate shuttles

Aerobic respiration is still much more efficient than glycolysis

Question 23

Theoretical yield of cellular respiration

Answer 23

38 ATP (41%)

Question 24

Protein catabolism

Answer 24

Amino group is removed: deamination in the liver

The remaining carbon skeletons enter various components of glycolysis or krebs cycle

Question 25

Lipid catabolism

Answer 25

Triglycerides divide into glycerol and fatty acids

Glycerol may be converted to glucose (may result in acetone in diabetics)

Fatty acids undergo beta oxidation in the matrix (removal of 2C acetyl groups)

Acetyl groups combine with CoA to from acetyl CoA

Question 26

Energy comparisons

Answer 26

A 12C carbohydrate produces 20% less ATP than a 12C fatty acid

Fats are less dense than carbohydrates

Fats produce 2X the amount of NRG per gram of carbohydrates

Question 27

Lactate fermentation

Answer 27

Pyruvate reacts with NADH and is converted directly into lactate and regenerates NAD+.

Question 28

Alcohol fermentation

Answer 28

Pyruvate is oxidized, producing ethanol

Question 29

Lactate threshold

Answer 29

The level of exercise intensity at which lactate concentration increases sharply increases