4.4 Bioenergetics

Question 1

What is the word equation for photosynthesis?

Answer 1

Carbon dioxide + water → glucose + oxygen (in the presence of light)

Question 2

What is the chemical equation for photosynthesis?

Answer 2

6CO2 + 6H2O → C6H12O6 + 6O2

Question 3

What type of reaction is photosynthesis?

Answer 3

Endothermic reaction

Question 4

Where does the energy for photosynthesis come from?

Answer 4

Light energy from the environment

Question 5

Where does photosynthesis occur in the plant?

Answer 5

In the chloroplasts

Question 6

What are the chemical symbols for the key substances in photosynthesis?

Answer 6

CO2, H2O, O2, C6H12O6

Question 7

What factors affect the rate of photosynthesis?

Answer 7

Temperature, light intensity, carbon dioxide concentration, and amount of chlorophyll

Question 8

How can the rate of photosynthesis be measured?

Answer 8

By measuring oxygen production or CO2 uptake, e.g., using pondweed

Question 9

What is a limiting factor in photosynthesis?

Answer 9

A factor that restricts the rate when it is in short supply

Question 10

(HT) What does the inverse square law relate to in photosynthesis?

Answer 10

Light intensity and distance: light intensity ∝ 1/distance²

Question 11

(HT) Why are limiting factors important for greenhouse economics?

Answer 11

To optimise growth conditions and maintain profit

Question 12

What is the required practical for photosynthesis?

Answer 12

Investigate the effect of light intensity on the rate of photosynthesis using pondweed

Question 13

What are the five main uses of glucose in plants?

Answer 13

Respiration, converted to starch, used to make fats/oils, cellulose, amino acids

Question 14

What is needed alongside glucose to make amino acids?

Answer 14

Nitrate ions absorbed from the soil

Question 15

What is respiration?

Answer 15

An exothermic reaction that transfers energy for living processes

Question 16

What is the word equation for aerobic respiration?

Answer 16

Glucose + oxygen → carbon dioxide + water

Question 17

What is the chemical equation for aerobic respiration?

Answer 17

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 18

What is the word equation for anaerobic respiration in muscles?

Answer 18

Glucose → lactic acid

Question 19

Why does anaerobic respiration transfer less energy?

Answer 19

Because glucose is only partially broken down

Question 20

What is the word equation for anaerobic respiration in yeast?

Answer 20

Glucose → ethanol + carbon dioxide

Question 21

What is anaerobic respiration in yeast called?

Answer 21

Fermentation

Question 22

What are three uses of energy from respiration?

Answer 22

Building larger molecules, movement, keeping warm

Question 23

What changes occur during exercise?

Answer 23

Increased heart rate, breathing rate, and breath volume

Question 24

What happens if muscles don’t get enough oxygen during exercise?

Answer 24

Anaerobic respiration occurs, causing lactic acid buildup and oxygen debt

Question 25

What is oxygen debt?

Answer 25

Extra oxygen needed to remove lactic acid post-exercise

Question 26

(HT) How is lactic acid removed?

Answer 26

It is transported to the liver and converted back to glucose

Question 27

What is metabolism?

Answer 27

The sum of all chemical reactions in a cell or body

Question 28

What is energy from respiration used for in metabolism?

Answer 28

To drive enzyme-controlled synthesis of molecules

Question 29

List five examples of metabolic processes.

Answer 29

1) Glucose to starch/glycogen/cellulose, 2) Lipid formation, 3) Amino acid synthesis, 4) Respiration, 5) Breakdown of proteins to urea