B4

Question 1

Word equation for photosynthesis

Answer 1

Carbon dioxide + water —light—> glucose + oxygen

Question 2

Symbol equation for photosynthesis

Answer 2

6CO2 + 6H2O ——> C6H12O6 + 6O2

Question 3

What type of reaction is photosynthesis and why?

Answer 3

Endothermic reaction in which energy is transferred from the environment to the chloroplasts by light.

Question 4

How do plants use glucose? (5)

Answer 4

1. Respiration. 2. Making cellulose. 3. Making amino acids. 4. Stored as oil and fats. 5. Stored as starch.

Question 5

What are 4 limiting factors for photosynthesis?

Answer 5

1. Light intensity. 2. Carbon dioxide concentration. 3. Temperature. 4. Amount of chlorophyll.

Question 6

How would you gain maximum profit in greenhouses? (3)

Answer 6

1. Put lots of light on. 2. Have a high temperature but not too high so that the enzymes denature. 3. Have lots of CO2.

Question 7

Required practical activity 6: investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed. (4)

Answer 7

1. Set up a light (LED is better) and ruler and pondweed. 2. Turn light on and set a set time for pondweed to photosynthesise and count oxygen bubbles. 3. Change the distance of pondweed to light and repeat. 4. Control variable: temperature and same type of light and time.

Question 8

What do plants use to make proteins?

Answer 8

Nitrate ions that are absorbed from the soil.

Question 9

What kind of reaction is respiration?

Answer 9

An exothermic reaction which is continuously occurring in living cells.

Question 10

What do organisms need energy for? (3)

Answer 10

1. Chemical reactions to build larger molecules. 2. Movement. 3. Keeping warm.

Question 11

What is the word equation for aerobic respiration?

Answer 11

glucose + oxygen –> carbon dioxide + water + energy

Question 12

What’s the symbol equation for aerobic respiration?

Answer 12

C6H12O6 + 6O2 —> 6CO2 + 6H2O

Question 13

What is the word equation for anaerobic respiration in animals?

Answer 13

glucose —> lactic acid + (a little) energy

Question 14

What is the word equation for anaerobic respiration in plants?

Answer 14

glucose —> ethanol + carbon dioxide + (a little energy)

Question 15

What’s aerobic respiration in yeast cells called?

Answer 15

Fermentation

Question 16

How is fermentation important?

Answer 16

Economic importance in the manufacture of bread and alcoholic drinks.

Question 17

Why does the body - when exercising - increase the heart rate; breathing rate and breath volume?

Answer 17

It needs more energy and needs to supply the muscles with more oxygenated blood.

Question 18

What is oxygen debt?

Answer 18

Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.

Question 19

What happens to the lactic acid?

Answer 19

Blood flowing through the muscles transports the lactic acid to the liver where it is converted back into glucose.

Question 20

What is metabolism?

Answer 20

Metabolism is the sum of all the reactions in a cell or the body

Question 21

What does metabolism include? (5)

Answer 21

1. Conversion of glucose to starch and glycogen and cellulose. 2. The formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids. 3. The use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins. 4. Respiration. 5. Breakdown of excess proteins to form urea for excretion.