0654_2017_O/N_QP_21_Biology

1.What is homeostasis?

• the maintenance of the body’s external environment

• the maintenance of the body’s internal environment

• the processes that produce heat in the body

• the removal of wastes from the body

2.What is excretion?

• breakdown of materials in kidney cells

• chemical reactions in liver cells

• removal of undigested food from the gut

• removal of waste products

3.What could deforestation cause?

• a decrease in carbon dioxide levels and a decrease in flooding

• a decrease in carbon dioxide levels and an increase in flooding

• an increase in carbon dioxide levels and a decrease in flooding

• an increase in carbon dioxide levels and an increase in flooding

4.Which statements about X chromosomes in humans are correct?B

• A

• B

• C

• D

5.A child blows into a rubber balloon.

What is the percentage of oxygen inside the balloon?

• 0%

• 4%

• 16%

• 21%

6.The maternal blood leaving the placenta is different in composition from that arriving.

What are those differences?

• A

• B

• C

• D

7.When a suspension of powdered milk is completely digested by a protease enzyme it becomes clear.

The graph shows the time taken for a mixture of protease and powdered milk to clear at different temperatures.

What is this enzyme’s optimum temperature?

• 5 °C

• 37 °C

• 40 °C

• 50 °C

8.What is the equation for photosynthesis?

• 6CO2 + 6H2O → C6H12O6 + 6O2

• 6CO2 + C6H12O6 → 6O2 + 6H2O

• 6O2 + 6H2O → C6H12O6 + 6CO2

• 6O2 + C6H12O6 → 6CO2 + 6H2O

9.The diagram shows a section through a villus.

What is the function of structure X?

• to absorb amino acids from the intestine

• to absorb fatty acids from the intestine

• to transport enzymes to the intestine

• to transport water to the intestine

10.Why do food chains usually have fewer than five trophic levels?

• All the carnivores consume herbivores.

• The energy passed on reduces from one trophic level to the next.

• There is less protein in each individual higher up the chain.

• There is only one producer in each chain.