a) Apple trees show genetic variation:
(i) State one possible cause of genetic variation in apple trees - Edexcel - GCSE Biology - Question 8 - 2023 - Paper 1
Question 8
a) Apple trees show genetic variation:
(i) State one possible cause of genetic variation in apple trees.
(ii) The colour of an apple is an observable characteristi... show full transcript
Worked Solution & Example Answer:a) Apple trees show genetic variation:
(i) State one possible cause of genetic variation in apple trees - Edexcel - GCSE Biology - Question 8 - 2023 - Paper 1
Step 1
State one possible cause of genetic variation in apple trees.
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Answer
One possible cause of genetic variation in apple trees is mutation, which refers to changes in the DNA sequence that can result in different traits.
Step 2
Which is the term for an observable characteristic?
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Answer
D phenotype
Step 3
Name the type of reproduction that produces genetically identical organisms.
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Answer
Asexual reproduction
Step 4
Give one advantage and one disadvantage of growing genetically identical apple trees.
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Answer
An advantage of growing genetically identical apple trees is that they ensure uniform fruit quality and characteristics, which can be beneficial for commercial production. A disadvantage is that they may be more susceptible to diseases, as a pathogen can easily spread through genetically identical plants.
Step 5
Devise a method to find the optimum pH of an enzyme that breaks down starch.
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Answer
To find the optimum pH for the enzyme that breaks down starch, prepare several test tubes with starch solution at different pH levels (using buffer solutions). Then, add a fixed amount of enzyme solution to each test tube and incubate them at a suitable temperature. After a set time, add iodine solution to each tube to check for starch presence. The test tube with the least color change (indicating the least starch is present) shows the optimum pH for the enzyme activity.
Step 6
Explain why this enzyme would not work at pH 10.
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Answer
Enzymes are highly sensitive to pH levels, and each enzyme has an optimum pH range. At pH 10, the enzyme's active site may undergo denaturation or change shape, rendering it ineffective at catalyzing its specific reaction.
