2. Bioenergetics

Question 1

What is the general equation for photosynthesis?

Answer 1

Carbon dioxide + Water → Glucose + Oxygen

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Question 2

What are the key processes in photosynthesis?

Answer 2

Light is absorbed by chlorophyll.

Carbon dioxide and water are converted into glucose.

Oxygen is released as a by-product.

Question 3

What factors can limit the rate of photosynthesis?

Answer 3

Temperature
Carbon dioxide
Light

Question 4

How can greenhouses enhance conditions for photosynthesis?

Answer 4

By controlling temperature, carbon dioxide concentration, and light intensity.

Question 5

What are the uses of glucose produced in photosynthesis?

Answer 5

• Used for respiration
• Converted into starch for storage
• Used to produce fats or oils for storage
• Used to produce cellulose for cell walls
• Used to produce proteins

Question 6

How do plants produce proteins?

Answer 6

Plants use glucose and nitrate ions absorbed from the soil to produce proteins.

Question 7

How do carbon dioxide and water enter the plant?

Answer 7

Carbon dioxide enters leaves through stomata, and water is absorbed by roots.

Question 8

What increases the surface area for absorption in roots and leaves?

Answer 8

Root hairs increase root surface area; flattened shape and internal air spaces increase leaf surface area.

Question 9

How do stomata function in plants?

Answer 9

Stomata allow carbon dioxide in and oxygen out, and control water loss.

Question 10

What are the functions of xylem and phloem in plants?

Answer 10

Xylem transports water and mineral ions from roots to leaves (transpiration stream).

Phloem transports dissolved sugars from leaves to rest of the plant (translocation).

Question 11

What is the structure and function of the human heart?

Answer 11

The heart pumps blood around the body, has four chambers (right/left atria, right/left ventricles), and contains muscle tissue.

Question 12

What is the role of a pacemaker in the heart?

Answer 12

A group of cells in the right atrium control the natural resting heart rate.

Question 13

What causes coronary heart disease and how is it treated?

Answer 13

Fatty material buildup narrows coronary arteries; treated with stents to keep arteries open.

Question 14

What is the function of blood in the human body?

Answer 14

Transports substances like oxygen, carbon dioxide, nutrients, and wastes to and from cells.

Question 15

How does the body use enzymes in digestion?

Answer 15

Enzymes catalyze the breakdown of large food molecules into smaller, absorbable molecules.

Question 16

What is the equation for aerobic respiration?

Answer 16

Glucose + Oxygen → Carbon dioxide + Water
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Question 17

What changes occur in the body during exercise?

Answer 17

Increased heart rate, increased breathing rate and depth, and conversion of glycogen to glucose.

Question 18

What is anaerobic respiration and when does it occur?

Answer 18

Respiration without oxygen, producing lactic acid; occurs when oxygen is insufficient during intense exercise.

Question 19

What are the products of anaerobic respiration in plants and some microorganisms?

Answer 19

Ethanol and carbon dioxide.

Question 20

What is the equation for anaerobic respiration in muscles?

Answer 20

Glucose → Lactic Acid
C₆H₁₂O₆ → 2C₃H₅O₃

Question 21

How does the alveoli structure facilitate gas exchange?

Answer 21

Provides a large surface area and is richly supplied with blood capillaries for efficient gas exchange.

Question 22

What is the transpiration stream in plants?

Answer 22

The movement of water from the roots through the xylem and out of the leaves.

Question 23

What is translocation in plants?

Answer 23

The process by which phloem tissue carries dissolved sugars from the leaves to other parts of the plant.

Question 24

What are the two main types of circulatory systems in humans?

Answer 24

One for the lungs (pulmonary circulation) and one for all other organs (systemic circulation).

Question 25

What are the primary functions of red blood cells?

Answer 25

To transport oxygen from the lungs to the organs and tissues.

Question 26

What is the function of white blood cells?

Answer 26

To form part of the body’s defense system against microorganisms.

Question 27

What role do platelets play in the blood?

Answer 27

They help blood to clot at the site of a wound.

Question 28

How does the body ensure blood flows in the correct direction within the heart?

Answer 28

Valves in the heart prevent backflow and ensure blood flows in the correct direction.

Question 29

What are the main differences between arteries and veins?

Answer 29

Arteries have thick walls with muscle and elastic fibers, while veins have thinner walls and often have valves to prevent backflow.

Question 30

What is the role of capillaries in the circulatory system?

Answer 30

Capillaries are narrow, thin-walled vessels where the exchange of substances between blood and body tissues occurs.

Question 31

What does blood plasma transport?

Answer 31

Carbon dioxide from organs to the lungs, soluble products of digestion from the small intestine to other organs, and urea from the liver to the kidneys.

Question 32

What is the process of blood clotting?

Answer 32

A series of enzyme-controlled reactions result in the conversion of fibrinogen to fibrin, forming a network of fibers that trap blood cells and form a clot.

Question 33

Why is blood typing important?

Answer 33

To ensure compatibility during blood transfusions and to prevent adverse reactions.

Question 34

What is the purpose of bile in digestion?

Answer 34

Bile neutralizes stomach acid and emulsifies fats to increase the surface area for lipase enzymes to act upon.

Question 35

What is the function of hydrochloric acid in the stomach?

Answer 35

It creates an acidic environment in which stomach enzymes work most effectively.

Question 36

How do intercostal muscles and the diaphragm contribute to breathing?

Answer 36

Intercostal muscles and diaphragm contract to increase thorax volume for inhalation and relax to decrease thorax volume for exhalation.

Question 37

What is the function of mechanical ventilators?

Answer 37

To assist or replace spontaneous breathing in patients with respiratory failure.

Question 38

What happens to the heart rate and breathing during exercise?

Answer 38

Both heart rate and breathing rate increase to supply muscles with more oxygen and glucose, and to remove carbon dioxide.

Question 39

What causes muscle fatigue during anaerobic respiration?

Answer 39

The build-up of lactic acid in muscles during anaerobic respiration.

Question 40

What is an oxygen debt?

Answer 40

The extra oxygen required after exercise to oxidize and remove lactic acid accumulated during anaerobic respiration.

Question 41

What are the main types of enzymes involved in digestion and their functions?

Answer 41

Amylase: Breaks down starch into sugars.
Protease: Breaks down proteins into amino acids.
Lipase: Breaks down lipids into fatty acids and glycerol.

Question 42

What is a negative pressure ventilator and how does it work?

Answer 42

A negative pressure ventilator causes air to be “drawn” into the lungs by creating a vacuum around the chest, leading to inhalation.

Question 43

What is a positive pressure ventilator and how does it work?

Answer 43

A positive pressure ventilator forces air into the lungs by increasing the air pressure in the patient’s airway during inhalation.