SB9: All the Questions I got wrong

Question 1

Describe the biological consequences on organisms that live in water if the water becomes polluted. (4)

Answer 1

• more bacteria /fungi /microorganisms
• decomposition
• less oxygen
• fish die/ animals die
• eutrophication

Question 2

Explain the possible consequences of deforestation for the water cycle. (2)

Answer 2

• less transpiration/ less water loss from plants
• less cloud formation
• less precipitation

Question 3

Deforestation also affects the carbon cycle. Explain these effects. (4)

Answer 3

• less photosynthesis
• more carbon dioxide in the air/ less carbon dioxide taken out of the atmosphere
• less consumption of plants
• less decomposition/ decay
• burning of trees produces carbon dioxide

Question 4

Farmers use crop rotation to reduce the need to add nitrate fertilisers to the soil. Plants such as peas and beans have a mutualistic relationship with nitrogen-fixing bacteria. Explain why farmers use these plants in their crop rotation cycle. (3)

Answer 4

To increase nitrate levels (1) as nitrogen fixing bacteria lives in roots (1) and this bacteria produces nitrates (1) from nitrogen gas (1)

Question 5

Plants cannot use nitrogen directly from the air but need it to make proteins. Explain how plants get the nitrogen they need to make protein. (3)

Answer 5

• plants use nitrates, fertilisers / compost,
• nitrogen fixation
• nitrification
• absorption through nodes
• active transport

Question 6

Explain how plants use the nitrates from the soil. (2)

Answer 6

used to make protein (1) for growth (1)

Question 7

Describe how the over-use of nitrate fertilisers can cause eutrophication. (4)

Answer 7

• nitrates leak into water (1)
• algae grow on surface (1)
• underwater plants stop photosynthesising (1)
• plants die (1)
• decomposers feed off dead plants (1)
• using oxygen in respiration (1)

Question 8

Name one type of organism that is a decomposer

Answer 8

Bacteria

Question 9

Many animals excrete urine that contains urea. Some soil microorganisms use the enzyme urease to change urea to ammonium ions and carbon dioxide. Describe how ammonium ions can be converted to nitrate ions in the soil (2)

Answer 9

• Nitrifying bacteria (1)
• convert the ammonium ions into nitrates (1)

Question 11

Give one effect of adding too much nitrate into the soil

Answer 11

Eutrophication

Question 12

Name an advantage of assessing air quality using blackspot fungi

Answer 12

• easy to see whether leaves are infected
• doesn’t require special equipment

Question 13

Explain the relationship between light intensity and daisy plants, given that when light intensity increases, so does the daisy population (3)

Answer 13

• higher light intensity = more photosynthesis
• causing faster growth and reproduction
• therefore, as light intensity increases, daisy plants increase

Question 14

Describe how fish are farmed (2)

Answer 14

• Fish are kept in pens/ ponds/ tanks (1)
• fed and kept healthy until they are caught (1)

Question 15

One reason why not all energy is transferred between trophic levels is because certain molecules cannot be digested. Give two other reasons why (2)

Answer 15

• respiration
• active transport
• not eaten