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10 Gregor Mendel used pea plants in plant breeding experiments - Edexcel - GCSE Biology - Question 10 - 2020 - Paper 1
Question 10
10 Gregor Mendel used pea plants in plant breeding experiments. He discovered the basis of genetic inheritance. (a) He cross-bred tall pea plants with short pea p... show full transcript
Worked Solution & Example Answer:10 Gregor Mendel used pea plants in plant breeding experiments - Edexcel - GCSE Biology - Question 10 - 2020 - Paper 1
Step 1
Explain why the offspring are all tall.
Answer
The offspring are all tall because they inherit the dominant allele for tallness (A) from the tall parent plants. Since the short plants are homozygous recessive (aa) and the tall plants contributing at least one dominant allele (A), all offspring receive the tall phenotype.
Step 2
Give two reasons why the parent pea plants were grown in a warm, closed greenhouse.
Answer
- A warm environment helps promote optimal growth and flowering for the pea plants.
- A closed greenhouse can reduce the risk of pest infestations and disease, ensuring better conditions for cross-pollination.
Step 3
Predict, using the Punnett square, the percentage probability that this cross will have offspring that produce green-coloured peas.
Answer
To predict the outcome, we set up the Punnett square for two heterozygous parents (Aa x Aa):
| A | a | |
|---|---|---|
| A | AA | Aa |
| a | Aa | aa |
From the Punnett square, 1 out of 4 squares results in aa, which represents green-coloured peas. Thus, the percentage probability is 25%.
Step 4
Explain one advantage to pea plants of using sexual reproduction to produce offspring.
Answer
One advantage of sexual reproduction is genetic diversity. This diversity allows pea plants to adapt to changing environments and resist diseases, which can improve the chances of survival in varying conditions.
Step 5