Genes, chromosomes and mutations

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

2. 1.

   Bo reads the same chart and table. Which line explains why strain P stays at 100 on sugar Z?

   • Its chromosome is too small to hold the whole gene
   • Its gene has a mutation that harmed its cells
   • It chose not to change its gene as sugar Z came
   • Its protein cannot use sugar Z, so no growth
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 change harmed it, and the table shows Q losing many cells
   • Q's gene is its growth, and the table shows the gene growing
   • Q's changed gene gives a protein using sugar Z, so Q grows
   • P's gene changed as well, and the table shows P growing slowly
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: a changed gene is not counted as a mutation
   • Yellow petals: the same protein gives the same trait
   • Brown petals: any changed letter changes the protein and trait
   • Brown petals: the plant chose a new color to match
5. 4.

   Kira finds a changed DNA letter in one leaf cell of a violet pea plant. Seeds from the plant grow into plants without the change. Which explanation fits?

   • A leaf cell does not form seeds, so no seed gets it
   • A gene is a trait, so leaf cells have no genes to change
   • The plant undid the change to protect its seeds
   • The change was harmful, so the seeds could not grow
6. 5.

   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 copied the letter from the soil
   • The seedling chose the letter to grow faster
   • A leaf change spreads through the plant into its seeds
   • The change arose in a cell that formed the seed
7. 6.

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

   • Change S changed the trait, as a changed letter does
   • Change T harmed the plant, so the claim is correct
   • S and W did not harm, so the claim is wrong
   • Change W is a trait, so it is a gene, not a mutation
8. 7.

   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: the petal color itself. Chromosome: holds many genes
   • Gene: a section of DNA. Chromosome: one single gene
   • Gene: a section of DNA. Chromosome: holds many genes
9. 8.

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

   • There is no flaw, since living things change DNA to fit
   • The change must have been harmful to the bacteria
   • Changes come by chance; sugar only showed which grew
   • Bacteria have no DNA, so they cannot change it
10. 9.

    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 mutation: a DNA change made a new allele
    • A new chromosome: the plant grew a second chromosome
    • A trait: the dwarf trait is the gene itself
11. 10.

    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 chromosomes, since a parent gives one of each pair
    • 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