Chapter 3: Bioenergetics

Question 1

What is the definition of Metabolism?

Answer 1

Sum of all chemical reactions in the body

Question 2

Define Bioenergetics.

Answer 2

Biology of energy exchange; process of converting foodstuff into biologically usable energy

Question 3

What are Anabolic Reactions?

Answer 3

Synthesis/build up (e.g., glucose → glycogen)

Question 4

What are Catabolic Reactions?

Answer 4

Degrade/break down (e.g., glycogen → glucose)

Question 5

What are Endergonic Reactions?

Answer 5

Must consume energy to proceed

Question 6

What are Exergonic Reactions?

Answer 6

Give off energy (e.g., glucose → water & CO₂)

Question 7

What are Coupled Reactions?

Answer 7

Linked reactions where energy from one reaction drives another

Question 8

Define Oxidation in chemistry.

Answer 8

Removing electron from a molecule (losing electron)

Question 9

What is a reducing agent?

Answer 9

Molecule that donates electron

Question 10

Define Reduction in chemistry.

Answer 10

Adding electron to a molecule (gaining electron)

Question 11

What is an oxidizing agent?

Answer 11

Molecule that accepts electron

Question 12

What are important molecules in energy transfer?

Answer 12

• NAD⁺/NADH: Oxidized form (NAD⁺), Reduced form (NADH)
• FAD/FADH: Oxidized form (FAD), Reduced form (FADH)

Question 13

What are Enzymes?

Answer 13

Catalysts that regulate speed of chemical reactions

Question 14

What do enzymes lower?

Answer 14

Activation energy required to initiate reactions

Question 15

Do enzymes cause reactions or change products?

Answer 15

No

Question 16

Describe the structure of enzymes.

Answer 16

Large protein molecules with unique shape and active sites

Question 17

What forms when an enzyme binds to a substrate?

Answer 17

Enzyme-substrate complex

Question 18

What clinical relevance do enzymes have?

Answer 18

Released into blood when tissue is damaged (e.g., lactate dehydrogenase, creatine kinase)

Question 19

How do most enzymes end?

Answer 19

With the suffix ‘-ase’

Question 20

What do Kinases do?

Answer 20

Add phosphate group (phosphorylation)

Question 21

What do Dehydrogenases do?

Answer 21

Remove hydrogen atoms

Question 22

What do Oxidases catalyze?

Answer 22

Oxidation-reduction reactions involving oxygen

Question 23

What do Isomerases do?

Answer 23

Rearrange atoms within substrate molecules

Question 24

What factors affect enzyme activity?

Answer 24

• Temperature (optimal temperature for maximum activity)
• pH (optimal pH for maximum activity)

Question 25

What are the types of Carbohydrates?

Answer 25

* Monosaccharides * Disaccharides * Polysaccharides

Question 26

What is the energy provided by carbohydrates?

Answer 26

1g = 4kcal

Question 27

What is Glycogen?

Answer 27

Storage form of glucose in muscle and liver

Question 28

What is Glycogenesis?

Answer 28

Glucose → Glycogen (enzyme: Glycogen Synthase)

Question 29

What is Glycogenolysis?

Answer 29

Glycogen → Glucose

Question 30

What are the types of Fats?

Answer 30

* Fatty acids * Triglycerides * Phospholipids * Steroids

Question 31

What is the energy provided by fats?

Answer 31

1g = 9kcal

Question 32

What is Lipolysis?

Answer 32

Triglycerides → Fatty Acids

Question 33

What is Lipogenesis?

Answer 33

Fatty Acids → Triglycerides

Question 34

What are proteins composed of?

Answer 34

Amino acids (9 essential, 11 nonessential)

Question 35

What is the energy provided by proteins?

Answer 35

1g = 4kcal

Question 36

What can some amino acids be converted to?

Answer 36

Glucose or used as metabolic intermediates

Question 37

What is ATP?

Answer 37

Energy currency of the cell

Question 38

What is the reaction of ATP to release energy?

Answer 38

ATP → ADP + P + energy (enzyme: ATPase)

Question 39

What are the limited stores of ATP in muscle?

Answer 39

~80-100g

Question 40

What is the ATP-PCr System?

Answer 40

Anaerobic (no oxygen required) and most rapid method

Question 41

What tasks does the ATP-PCr system support?

Answer 41

High intensity, short duration tasks (<10 sec)

Question 42

What is the reaction in the ATP-PCr system?

Answer 42

PCr + ADP → ATP + Cr (enzyme: Creatine Kinase)

Question 43

What is Glycolysis?

Answer 43

Anaerobic pathway that occurs in sarcoplasm

Question 44

What does glycolysis fuel?

Answer 44

High-intensity tasks ~30 sec

Question 45

What is produced per glucose molecule in glycolysis?

Answer 45

* 2 ATP * 2 NADH * 2 Pyruvate OR 2 Lactate

Question 46

What are the two phases of glycolysis?

Answer 46

* Energy investment: 2 ATP required (if starting with glucose) * Energy generation: 4 ATP produced

Question 47

What is the rate limiting enzyme in glycolysis?

Answer 47

Phosphofructokinase (PFK)

Question 48

What happens in aerobic glycolysis?

Answer 48

Pyruvate → Acetyl CoA (if O₂ available)

Question 49

What happens in anaerobic glycolysis?

Answer 49

Pyruvate → Lactate (if O₂ unavailable)

Question 50

What is Oxidative Phosphorylation?

Answer 50

Aerobic (requires oxygen)

Question 51

What are the two components of oxidative phosphorylation?

Answer 51

* Citric Acid Cycle (Krebs Cycle) * Electron Transport Chain

Question 52

What occurs in the Citric Acid Cycle?

Answer 52

Occurs in mitochondria and removes electrons from substrates

Question 53

What is produced per pyruvate in the Citric Acid Cycle?

Answer 53

* 3 NADH * 1 FADH * 1 ATP

Question 54

What is the rate limiting enzyme in the Citric Acid Cycle?

Answer 54

Isocitrate dehydrogenase

Question 55

What is the ATP yield from NADH in the Electron Transport Chain?

Answer 55

2.5 ATP

Question 56

What is the ATP yield from FADH in the Electron Transport Chain?

Answer 56

1.5 ATP

Question 57

What is the final electron acceptor in the Electron Transport Chain?

Answer 57

Oxygen

Question 58

What is the total ATP yield from one glucose molecule (aerobic)?

Answer 58

32 ATP (33 if starting with glycogen)

Question 59

Break down the ATP production from one glucose molecule.

Answer 59

* Glycolysis: 2 ATP * Pyruvate→Acetyl-CoA: 0 ATP * Citric Acid Cycle & Electron Transport Chain: 30 ATP