DNA & Genes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The Code Inside You: DNA and Genes

Science · The Human Body · ages 12-14
Name ______________________   Date ____________

  1. What best describes a protein-coding gene?

    • A whole chromosome
    • A section of DNA that codes for a protein
    • A type of protein found in muscles

  2. In DNA's double helix, which base does adenine (A) always pair with?

    • Guanine (G)
    • Thymine (T)
    • Cytosine (C)

  3. CRISPR is a tool that can cut and edit DNA sequences.

    Circle one:   True   False

  4. Your body makes thousands of different proteins. Where do the instructions for each one come from?

    • Genes in DNA hold instructions to build them
    • All proteins come from the same one gene
    • Proteins are built without any DNA instructions

  5. A strand of DNA reads A-C-C-T-G. What bases pair with it, in order, on the opposite strand?

    • T-G-G-A-C
    • A-C-C-T-G
    • G-A-A-C-T

  6. Why does germline editing, changing DNA in eggs, sperm, or embryos, worry some scientists?

    • The changes could be passed down to future generations
    • It always cures every disease instantly
    • It has no effect on the DNA sequence

  7. A gene's DNA strand is 20 bases long. How many bases are on its complementary (partner) strand?

    Answer: ______________

  8. A student says: 'DNA only has two bases, so it's like a two-letter code.' What is wrong with this claim?

    • DNA has no bases at all
    • DNA has four bases but they never pair up
    • DNA actually has four bases: A, T, C, and G
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Answer key

For grown-ups. Fold this page away before handing over the rest.

The Code Inside You: DNA and Genes W1-mt_0sELh0MYWb-s1

  1. A section of DNA that codes for a protein · A gene that codes for a protein is a specific stretch of DNA. It holds the instructions to build a protein.
  2. Thymine (T) · A always bonds with T, and C always bonds with G. That is the base-pairing rule.
  3. True · CRISPR locates a specific spot in DNA, cuts it, and lets scientists edit the sequence there.
  4. Genes in DNA hold instructions to build them · Protein instructions come from genes in DNA. One gene can be used in more than one way, so it can help make different proteins.
  5. T-G-G-A-C · Match each base to its one partner: A to T, C to G, C to G, T to A, G to C. That gives T-G-G-A-C.
  6. The changes could be passed down to future generations · Germline edits can be inherited, so any mistake, or any change people disagree about, could pass on to children who never chose it.
  7. 20 · Every base on one strand pairs with exactly one base on the other strand, so both strands end up the same length.
  8. DNA actually has four bases: A, T, C, and G · DNA's code uses four bases, and they pair up in fixed partners: A with T, C with G.
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