Year 10 Science · Unit 1 · Lesson 2

DNA Structure and Function

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Learning Goals

Warm Up

Because… chain

Fill in the missing effects. Each cause leads to the next step in the chain.

DNA has a specific base sequence in a gene
→
The amino acid sequence is determined
→
A specific protein is produced
→
The protein carries out its function in the cell
→

Overall outcome:

Your Turn

Real-world context

A gene contains the base sequence ATGCGATCG. Scientists studying this gene found that it is expressed in skin cells but switched off in brain cells, even though both cell types carry identical DNA. This selective gene expression is controlled by chemical tags on the DNA and histones (proteins that pack DNA).

(a) Write the complementary DNA strand for the sequence ATGCGATCG. Use base pairing rules (A–T, G–C).

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(b) Using your knowledge of how DNA stores genetic information, explain why the same DNA sequence can produce different proteins or have different effects in a skin cell versus a brain cell.

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Show What You Know

1. In your own words, describe the relationship between a codon, an amino acid, and a protein. Why does the specific order of bases in DNA matter?

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2. A gene contains the base sequence ATGCGATCG. This sequence acts as a code that determines the order of amino acids in a protein. If just one base in this sequence changed, for example, the first A became a T, explain how this could affect the protein produced by the gene and why even a small change can have large consequences.

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Wrap Up

In one sentence, what was the main idea of this lesson?

HSCScience · Year 10 Science · Unit 1 · Lesson 2 · Apply Worksheet