The diagram shows a section of a DNA molecule - Edexcel - GCSE Biology - Question 5 - 2016 - Paper 1
Question 5
The diagram shows a section of a DNA molecule.
(a) (i) Complete the sentence by putting a cross (✓) in the box next to your answer.
The two scientists who first ma... show full transcript
Worked Solution & Example Answer:The diagram shows a section of a DNA molecule - Edexcel - GCSE Biology - Question 5 - 2016 - Paper 1
Step 1
Complete the sentence by putting a cross (✓) in the box next to your answer.
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Answer
The two scientists who first made an accurate model of DNA were D Watson and Crick.
Step 2
State the term used to describe the shape of a DNA molecule.
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Answer
The term used to describe the shape of a DNA molecule is 'double helix'.
Step 3
Describe two ways that a DNA molecule is changed by mutation.
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Answer
Substitution Mutation: This occurs when one base in the DNA sequence is replaced with another base. For example, if adenine (A) is replaced by guanine (G), it may lead to a change in an amino acid in a protein.
Deletion Mutation: This type of mutation results when one or more bases are removed from the DNA sequence. Such a deletion can result in a frameshift, altering the reading frame of the genetic code and potentially leading to a nonfunctional protein.
