Unit: 2 - metabolic rate

Question 1

Metabolic rate is the rate at which an organism uses energy, typically measured in joules or calories per unit of time.

Answer 1

What is metabolic rate?

Question 2

What are the main methods for measuring metabolic rate?

Answer 2

1. Oxygen consumption: Measuring the rate at which oxygen is used by the organism.
2. Carbon dioxide production: Measuring the rate of CO₂ output.
3. Calorimetry: Direct or indirect methods to measure heat production.

Question 3

What is direct calorimetry?

Answer 3

A method that measures the total heat produced by an organism, usually in a calorimeter.

Question 4

What is indirect calorimetry?

Answer 4

A method that estimates metabolic rate by measuring oxygen consumption and/or carbon dioxide production.

Question 5

How does body size affect metabolic rate?

Answer 5

Smaller organisms have a higher metabolic rate per unit of body mass due to a larger surface area-to-volume ratio, requiring more energy to maintain body temperature.

Question 6

What factors can influence metabolic rate?

Answer 6

Age

Sex
Activity level
Hormones (e.g., thyroxine)
Environmental temperature

Question 7

Why is oxygen delivery important for metabolism?

Answer 7

Oxygen is required for aerobic respiration, where it serves as the final electron acceptor in the electron transport chain, enabling efficient ATP production.

Question 8

What are the main components of oxygen delivery?

Answer 8

1. Respiratory system: Supplies oxygen to the blood.
2. Circulatory system: Transports oxygenated blood to tissues.
3. Hemoglobin: Carries oxygen in the blood.

Question 9

How does hemoglobin aid oxygen delivery?

Answer 9

Hemoglobin binds oxygen in the lungs and releases it to tissues with low oxygen concentrations

Question 10

What is the Bohr effect?

Answer 10

The Bohr effect describes how hemoglobin’s oxygen affinity decreases in the presence of high CO₂ levels or low pH, enhancing oxygen delivery to tissues.

Question 11

How does cardiac output affect oxygen delivery?

Answer 11

Increased cardiac output (heart rate × stroke volume) delivers more oxygen-rich blood to tissues, supporting higher metabolic rates.

Question 12

What happens during anaerobic conditions when oxygen delivery is insufficient?

Answer 12

Cells rely on anaerobic respiration, producing ATP less efficiently and generating lactic acid as a byproduct.

Question 13

How do myoglobin and hemoglobin differ in oxygen delivery?

Answer 13

Myoglobin, found in muscle cells, has a higher affinity for oxygen than hemoglobin, providing a reserve for oxygen during intense activity.