Energy for Muscular Activity

Question 1

What is ATP?

Answer 1

ATP (adenosine triphosphate) is the body’s main energy molecule used for muscular and metabolic activity.

Question 2

What are the three systems that regenerate ATP?

Answer 2

1) Phosphocreatine system
2) Anaerobic glycolytic system
3) Aerobic oxidative system

Question 3

What is ATP hydrolysis?

Answer 3

The breakdown of ATP into ADP and phosphate, releasing energy.

Question 4

What is ATP turnover?

Answer 4

The continuous breakdown and resynthesis of ATP in the body.

Question 5

What triggers muscle contraction besides neural input?

Answer 5

Energy from ATP is required to power cross-bridge cycling.

Question 6

Where is ATP stored in the muscle?

Answer 6

In small amounts directly within the muscle fibers.

Question 7

How long does the phosphocreatine system last?

Answer 7

Approximately 7–12 seconds.

Question 8

Is the phosphocreatine system anaerobic or aerobic?

Answer 8

Anaerobic (does not require oxygen).

Question 9

What limits the phosphocreatine system?

Answer 9

The amount of stored phosphocreatine in the muscle.

Question 10

What is the primary use of the PC system?

Answer 10

Short bursts of high-intensity effort (e.g., sprints, jumps).

Question 11

When does the anaerobic glycolytic system become active?

Answer 11

When PC stores are depleted and oxygen is insufficient.

Question 12

What is the main fuel for the anaerobic glycolytic system?

Answer 12

glucose or glycogen

Question 13

Where does anaerobic glycolysis occur?

Answer 13

In the sarcoplasm (cytoplasm) of muscle cells.

Question 14

What are the by-products of anaerobic glycolysis?

Answer 14

Lactic acid, 2 ATP, pyruvate, and hydrogen ions.

Question 15

What causes muscle fatigue in anaerobic metabolism?

Answer 15

Accumulation of hydrogen ions (↓ pH) from lactic acid.

Question 16

How long can the anaerobic system provide energy?

Answer 16

20 seconds to 3 minutes.

Question 17

What is the primary energy system for 800m running?

Answer 17

Anaerobic glycolytic system.

Question 18

Where does the aerobic oxidative system take place?

Answer 18

mitochondria

Question 19

What are the inputs for the aerobic system?

Answer 19

Oxygen, carbohydrates, and fats.

Question 20

How many ATP are produced per glucose molecule aerobically?

Answer 20

36 ATP.

Question 21

What are the by-products of aerobic metabolism?

Answer 21

water and carbon dioxide

Question 22

What is the most efficient energy system for long-duration activity?

Answer 22

aerobic oxidative system

Question 23

What is the Krebs Cycle?

Answer 23

A cycle in the mitochondria that produces ATP from carbohydrates, fats, and proteins.

Question 24

What is the Cori Cycle?

Answer 24

A cycle in the liver that converts lactic acid back to glucose.

Question 25

What is required for the aerobic system to function optimally?

Answer 25

Sufficient oxygen, mitochondria, and enzymes.

Question 26

How much ATP can one fat molecule yield?

Answer 26

Approximately 460 ATP.

Question 27

What system dominates after 3 minutes of exercise?

Answer 27

The aerobic oxidative system.

Question 28

What limits aerobic energy production?

Answer 28

Lung capacity, blood flow, oxygen availability, and metabolic enzyme function.

Question 29

What does training do to mitochondrial content?

Answer 29

increases size, number, and efficiency (up to 250%).

Question 30

How much can glycogen storage increase with training?

Answer 30

up to 200%

Question 31

How does training improve oxygen delivery?

Answer 31

By increasing capillaries and myoglobin (up to 80%).

Question 32

How does training increase fat usage?

Answer 32

By storing more fat in muscle and improving fat metabolism.

Question 33

What adaptations reduce lactate accumulation?

Answer 33

Enhanced aerobic capacity and increased lactate clearance.

Question 34

How is lactate eliminated more efficiently?

Answer 34

Through increased blood flow and metabolism in liver, heart, and inactive muscles.

Question 35

What is VO₂ max?

Answer 35

The maximal oxygen consumption per minute per kg of body mass.

Question 36

What are three factors that influence VO₂ max?

Answer 36

1) Cardiac output 2) Oxygen carrying capacity 3) Muscle oxygen extraction

Question 37

What macronutrients provide energy?

Answer 37

Carbohydrates, fats, and proteins.

Question 38

What is the primary fuel at rest?

Answer 38

A 50:50 mix of carbohydrates and fats.

Question 39

What fuels are used in prolonged, less intense exercise?

Answer 39

Mainly fats.

Question 40

What test is used to assess anaerobic system power?

Answer 40

Wingate test (anaerobic alactate and lactate systems).

Question 41

What is the main determinant of energy system demand during activity?

Answer 41

The type and intensity of the activity (e.g., sprinting vs. gardening).

Question 42

What process reforms ATP from ADP and phosphate?

Answer 42

ATP resynthesis.

Question 43

Why does ATP need to be regenerated quickly during exercise?

Answer 43

Because the body's stored ATP is used up rapidly in active muscles.

Question 44

What is the role of food molecule breakdown in ATP production?

Answer 44

It provides the energy required to recombine ADP and phosphate to form ATP.

Question 45

Which system is also called the anaerobic lactate system?

Answer 45

Anaerobic glycolytic system.

Question 46

What determines how long each energy system can supply energy?

Answer 46

The availability of substrates (e.g., PC, glucose, oxygen) and the intensity of the activity.