C1.2 Cell respiration HL

Question 1

Role of NAD in Cell Respiration

Answer 1

NAD acts as a hydrogen carrier in cell respiration, essential for redox reactions, and facilitates the transfer of electrons during oxidative phosphorylation

Question 2

Glycolysis Overview

Answer 2

Glycolysis is the first step of cell respiration, occurring in the cytoplasm, where glucose is converted into two pyruvate molecules

Question 3

Phases of Glycolysis

Answer 3

Four phases: Phosphorylation (ATP investment), Lysis (splitting glucose), Dehydrogenation (reducing NAD), and ATP Formation (substrate-level phosphorylation)

Question 4

Conversion of Glucose to Pyruvate

Answer 4

Glucose undergoes a 10-step process in glycolysis, resulting in the formation of two 3-carbon pyruvate molecules

Question 5

Redox Reactions in Glycolysis

Answer 5

Redox reactions in glycolysis involve the transfer of electrons and hydrogen, crucial for converting NAD to NADH and generating ATP

Question 6

Define anaerobic respiration

Answer 6

Cellular respiration without oxygen, converting glucose to energy (ATP)

Question 7

Role of glycolysis in anaerobic respiration?

Answer 7

Produces ATP and NADH by converting glucose to pyruvate without oxygen

Question 8

Lactic acid fermentation in humans?

Answer 8

Converts pyruvate to lactate, regenerating NAD+, enabling ATP production without oxygen

Question 9

Alcohol fermentation in yeast?

Answer 9

Converts pyruvate to ethanol and CO2, used in brewing and baking

Question 10

Anaerobic respiration by-products in yeast?

Answer 10

Ethanol and carbon dioxide, key for alcoholic drinks and dough rising

Question 11

Link Reaction: Net Products for Each Glucose?

Answer 11

2 ATP, 4 NADH, 2 Acetyl CoA

Question 12

Initial Step of Krebs Cycle?

Answer 12

Acetyl CoA + Oxaloacetate = Citrate

Question 13

Krebs Cycle: Oxidative Decarboxylation?

Answer 13

CO2 removed, NAD reduced to NADH, Citrate oxidized

Question 14

ATP Generation in Krebs Cycle?

Answer 14

Substrate-level phosphorylation

Question 15

FAD’s Role in Krebs Cycle?

Answer 15

Hydrogen carrier, becomes FADH2

Question 16

Electron Transport Chain

Answer 16

Series of proteins in mitochondria transferring electrons from NADH/FADH2 to oxygen, creating ATP

Question 17

Chemiosmosis

Answer 17

Proton movement across mitochondrial membrane via ETC, driving ATP synthesis

Question 18

NAD’s role in ETC?

Answer 18

Donates electrons to ETC, essential for proton gradient and ATP production

Question 19

Oxidative phosphorylation

Answer 19

ATP creation process involving electron flow through ETC to oxygen

Question 20

Function of ATP synthase?

Answer 20

Enzyme synthesizing ATP using proton motive force.

Question 21

Role of oxygen in aerobic respiration?

Answer 21

Oxygen is the final electron acceptor in the electron transport chain, forming water, which is essential for the continuation of aerobic respiration

Question 22

Carbohydrates’ function in respiration?

Answer 22

Carbohydrates like glucose undergo glycolysis and the Krebs cycle to produce ATP, with glucose being the primary respiratory substrate

Question 23

Lipids vs. carbohydrates in respiration?

Answer 23

Lipids, split into glycerol and fatty acids, contribute to more ATP production. Glycerol enters glycolysis; fatty acids become acetyl CoA for the Krebs cycle.

Question 24

Energy yield: lipids vs. carbohydrates?

Answer 24

Lipids generate more energy (39.4 kJ/g) than carbohydrates (15.8 kJ/g) as respiratory substrates

Question 25

Why aren’t lipids used in anaerobic respiration?

Answer 25

Lipids require oxygen for breakdown in the Krebs cycle and are unsuitable for anaerobic respiration, which lacks oxygen