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Many people eat shellfish called oysters - AQA - GCSE Biology Combined Science - Question 7 - 2018 - Paper 2
Question 7
Many people eat shellfish called oysters. An oyster has 20 chromosomes in each body cell. Which arrangement of chromosomes will a male oyster have in each body cel... show full transcript
Worked Solution & Example Answer:Many people eat shellfish called oysters - AQA - GCSE Biology Combined Science - Question 7 - 2018 - Paper 2
Step 1
Which arrangement of chromosomes will a male oyster have in each body cell?
Answer
The correct option for a male oyster is: One X and one Y chromosome and 9 pairs of other chromosomes. This indicates that male oysters possess one X chromosome and one Y chromosome, indicative of male sex determination in many species.
Step 2
Describe the type of cell division that produces gametes.
Answer
The type of cell division that produces gametes is called meiosis. During meiosis, the DNA is replicated, and the cell undergoes two rounds of division to produce four haploid cells, each containing half the amount of DNA of the original cell. These haploid cells are genetically distinct from one another.
Step 3
Suggest why the triploid oysters are not able to reproduce.
Answer
The triploid oysters are not able to reproduce because they have three sets of chromosomes. This abnormal number of chromosomes causes issues during meiosis, preventing proper pairing and separation of chromosomes, which is essential for gamete production.
Step 4
Explain why the triploid oysters grow more quickly than the diploid oysters.
Answer
Triploid oysters grow more quickly than diploid oysters because they do not allocate energy for reproduction. With no energy expended on reproductive processes, they can instead focus on growth, resulting in faster size increase and biomass accumulation.
Step 5
Suggest two environmental factors which may be causing this reduction.
Answer
- Rising water temperatures: Higher temperatures can lead to reduced oxygen levels in the water, affecting the survival and growth of oysters.
- Pollution in the water: Pollutants can be harmful to aquatic life and may lead to increased mortality rates in oyster populations.
Step 6
Give a reason why each factor may be causing the reduction in the population.
Answer
- Rising water temperatures can raise metabolic rates in oysters, causing stress and increased vulnerability to diseases, leading to higher mortality.
- Pollution can contaminate the habitat of oysters, leading to poor growth conditions and increased susceptibility to infections and diseases.
Step 7
Evaluate the production of triploid oysters for supermarkets and restaurants.
Answer
The production of triploid oysters for supermarkets and restaurants has both benefits and drawbacks. On the positive side, triploid oysters are available year-round, providing a reliable food source and higher culinary quality. They grow faster, which can increase profit margins for farmers and suppliers. However, the use of cytochalasins B raises health concerns due to its potential toxicity and links to cancer in animals, which may lead to consumer resistance and regulatory scrutiny. Overall, the benefits of availability and growth rate may outweigh the concerns if managed and communicated properly.