The algae make glucose by photosynthesis - AQA - GCSE Biology - Question 3 - 2021 - Paper 1
Question 3
The algae make glucose by photosynthesis.
Which two substances do the algae need for photosynthesis?
Tick (*) two boxes.
- Carbon dioxide
- Nitrogen
- Oxygen
- Wa... show full transcript
Worked Solution & Example Answer:The algae make glucose by photosynthesis - AQA - GCSE Biology - Question 3 - 2021 - Paper 1
Step 1
Which two substances do the algae need for photosynthesis?
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The two substances that algae need for photosynthesis are carbon dioxide and water.
Step 2
What is the source of energy for photosynthesis?
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The source of energy for photosynthesis is light.
Step 3
Which pyramid of biomass is correct for the food chain shown in Figure 4?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The correct pyramid of biomass for the food chain shown in Figure 4 is option (b).
Step 4
Calculate the percentage decrease in the biomass of adult herring between 1960 and 1970.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Given the biomass values, suppose it was 2.3 million tonnes in 1960 and 0.5 million tonnes in 1970. Using the formula:
percentagedecrease=(2.3(2.3−0.5))×100=78.26%≈78%
Step 5
Describe the change in biomass of adult herring from 1977 to 1990.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
From 1977 to 1990, the biomass of adult herring showed an increase. This can be attributed to the laws that were introduced to help in conservation efforts.
Step 6
Explain how the control of mesh size of fishing nets has helped to conserve stocks of herring.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The control of mesh size of fishing nets ensures that smaller, younger herring are not caught. This allows them to escape and reproduce, leading to a sustainable herring population.
