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1.2 What happens in cells (and what do cells need)?

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Question 19

H

Scientists studied the DNA of a species of plant.

a.

A section of DNA contains 2700 bases in total, counting both strands.

Calculate the maximum number of amino acids this section of DNA could code for.

[2]

b.

The DNA in one cell of the plant contains a total of 6.4 × 10⁹ bases. 29.3% of these bases are A.

Calculate the number of bases in one cell that are G.

Give your answer in standard form to 2 significant figures.

[3]

c.

A student says:

'If the DNA of two species has the same percentage of each base, the two species must make the same proteins.'

Explain why the student is wrong.

[2]

Markscheme

1.2 What happens in cells (and what do cells need)? Questions

GCSE
Biology
1.2 What happens in cells (and what do cells need)?

184 exam-style questions on OCR GCSE Biology 1.2 What happens in cells (and what do cells need)?, covering 1.2.1 Structure of DNA, 1.2.2 Nucleotides and complementary bases, 1.2.3 Protein synthesis, 1.2.4 DNA structure and the proteins made, 1.2.5 Investigating enzymatic reactions, and 1.2.6 Mechanism of enzyme action. Each one has a worked solution and a mark scheme showing where the marks go.

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