Genes, chromosomes and mutations

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

2. 1.

   Ari's class reads the chart and the growth table. Which claim and reason fit what the data show?

   • Harmful: a changed gene breaks the protein in strain Q
   • No effect: strain Q is the same kind of bacteria as strain P
   • Helpful: strain Q planned the change when sugar Z appeared
   • Helpful: the changed gene lets strain Q use sugar Z
3. 2.

   Esme writes a sentence that uses both the chart and the table. Which sentence is correct?

   Use the picture in question 1.

   • Q's gene is its growth, and the table shows the gene growing
   • P's gene changed as well, and the table shows P growing slowly
   • Q's changed gene gives a protein using sugar Z, so Q grows
   • Q's change harmed it, and the table shows Q losing many cells
4. 3.

   Jun reads that a sunflower gene has one changed letter but makes the same protein. What goes in the Trait box, and why?

   • Yellow petals: the same protein gives the same trait
   • Brown petals: the plant chose a new color to match
   • Yellow petals: a changed gene is not counted as a mutation
   • Brown petals: any changed letter changes the protein and trait
5. 4.

   Luz finds the same changed DNA letter in every cell of a seedling, but not in the leaves of either parent plant. Which explanation fits?

   • The seedling chose the letter to grow faster
   • The seedling copied the letter from the soil
   • A leaf change spreads through the plant into its seeds
   • The change arose in a cell that formed the seed
6. 5.

   Milo claims that every DNA change harms a plant. Which response uses the chart to find the flaw?

   • S and W did not harm, so the claim is wrong
   • Change T harmed the plant, so the claim is correct
   • Change W is a trait, so it is a gene, not a mutation
   • Change S changed the trait, as a changed letter does
7. 6.

   Noah says the gene for petal color is the petal color, and a chromosome is one big gene. Which response corrects both parts?

   • Gene: bigger than a chromosome. Chromosome: a thread of DNA
   • Gene: a section of DNA. Chromosome: holds many genes
   • Gene: a section of DNA. Chromosome: one single gene
   • Gene: the petal color itself. Chromosome: holds many genes
8. 7.

   Pia says that when a dish ran low on food, the bacteria changed their DNA to use a new sugar. What is the flaw?

   • Bacteria have no DNA, so they cannot change it
   • Changes come by chance; sugar only showed which grew
   • The change must have been harmful to the bacteria
   • There is no flaw, since living things change DNA to fit
9. 8.

   Pea plants have a tall form and a dwarf form of one height gene. Different forms of a gene are called alleles. Ren asks how a new form arose. Which claim and reason fit?

   • A need: the plant changed its gene to grow shorter
   • A trait: the dwarf trait is the gene itself
   • A mutation: a DNA change made a new allele
   • A new chromosome: the plant grew a second chromosome
10. 9.

    Tala reads that a pea plant cell has 7 pairs of chromosomes. One of each pair comes from each parent. Which claim and reason fit for one parent?

    • 7 pairs, since each parent gives whole pairs
    • 14 chromosomes, since each parent gives both of each pair
    • 28 chromosomes, since each parent gives two sets of 14
    • 7 chromosomes, since a parent gives one of each pair
11. 10.

    Zee reads that a dog cell has 39 pairs of chromosomes. One of each pair comes from each parent. Which claim and reason fit for one parent?

    • 78 chromosomes, since the puppy's cells have 78 in total
    • 39 chromosomes, since a parent gives one of each pair
    • 20 chromosomes, since a parent gives about half of 39
    • 39 pairs, since each parent gives whole pairs of them