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?

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

   Bo reads that seeds without the enzyme hold less starch and more sugar, then take in water and dry. What goes in the Trait box?

   • Wrinkled seeds, since they shrink as they dry
   • Wrinkled seeds, since the seeds chose the shape
   • Round seeds, since extra sugar fills the seed
   • Round seeds, since the gene is still in the cell
3. 3.

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

   • A whole chromosome, since a gene is bigger
   • The whole nucleus, since DNA is bigger
   • The seed shape, since a gene is a trait
   • One gene, a short section of DNA
4. 4.

   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?

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

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

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

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

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

   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, dim light tells the DNA how to change
   • No, DNA stays the same for the plant's whole life
   • Yes, a plant changes its DNA when it needs to
   • No, DNA changes happen by chance, not by need
9. 9.

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

   • No, a change comes by chance, helpful or not
   • Yes, plants make the changes they need
   • No, dry soil cannot affect anything in a plant
   • Yes, dry soil makes changes that help
10. 10.

    A new DNA change helps one pea plant in a dry bed. Zee asks why that plant has it. Which explanation fits?

    • The plant made the change because the bed was dry
    • A DNA change gives a plant a helpful new trait
    • A chance change; dry soil showed it helps
    • The dry soil put the change into the seed