Genes, chromosomes and mutations

Grade 7 Science Worksheet

Circle the best answer.

1. 1.

   Ari traces a change in pea seeds. A piece of DNA is inserted in the SBE1 gene. What goes in the Protein box?

   • No starch-building enzyme is made
   • The same enzyme, made in a larger amount
   • Wrinkled seeds, the trait itself
   • A new enzyme that the seed made on purpose
2. 2.

   Esme asks what part of the pea cell the inserted piece changed. Which description fits the Gene box?

   • One gene, a short section of DNA
   • A whole chromosome, since a gene is bigger
   • The whole nucleus, since DNA is bigger
   • The seed shape, since a gene is a trait
3. 3.

   Jun reads about E. coli bacteria in a lab flask with citrate and little other food. A DNA change lets some bacteria use citrate. How is the change best described?

   • Harmful, since a DNA change breaks the cell
   • Helpful, since the bacteria can use a food
   • Helpful, since the bacteria planned the change
   • No effect, since the bacteria look the same
4. 4.

   Kira reads that a cucumber seedling has a DNA change. Its leaves have no chlorophyll and look pale. Chlorophyll absorbs light for making food. How is the change best described?

   • No effect, since a DNA change is tiny
   • Harmful, since the leaves cannot make food
   • Helpful, since pale leaves stay cooler
   • Harmful, since a mutation is a harmful change
5. 5.

   Luz reads that one DNA letter in a bean plant's gene changed, but the protein it makes is the same. The plant looks the same. How is the change best described?

   • Helpful, since the plant needed the new letter
   • Helpful, since a new letter gives a new trait
   • No effect, since the protein stays the same
   • Harmful, since the DNA letter changed
6. 6.

   46 chromosomes, in pairs. Milo reads that a human cell has 46 chromosomes in pairs, one of each pair from each parent. How many pairs are there?

   • 23 pairs, since each pair has two chromosomes
   • 92 pairs, since each parent gives 46 pairs
   • 46 pairs, since each chromosome is its own pair
   • 2 pairs, since there are two parents
7. 7.

   Noah reads that a fruit fly cell has 4 pairs of chromosomes. How many chromosomes is that in total?

   • 8 chromosomes, since each pair has two
   • 2 chromosomes, since a fly has two parents
   • 16 chromosomes, since each pair has four
   • 4 chromosomes, since a pair counts as one
8. 8.

   Pia reads that a rice plant cell has 12 pairs of chromosomes. Each chromosome is made of DNA and holds many genes. Which statement is correct?

   • It has 12 chromosomes, and each gene holds many
   • It has 24 chromosomes, each holding many genes
   • It has 12 chromosomes, and each holds many genes
   • It has 24 genes, and each holds many chromosomes
9. 9.

   A basil plant sits in a dim room. Ren wonders if the plant changes its DNA on purpose to use the dim light. Which answer is best?

   • Yes, a plant changes its DNA when it needs to
   • No, DNA changes happen by chance, not by need
   • Yes, dim light tells the DNA how to change
   • No, DNA stays the same for the plant's whole life
10. 10.

    A pea bed is dry. Tala asks if the dry soil makes the helpful DNA changes. Which answer is best?

    • Yes, dry soil makes changes that help
    • Yes, plants make the changes they need
    • No, dry soil cannot affect anything in a plant
    • No, a change comes by chance, helpful or not