PencilGo

Grade 7 · Science

7th grade Genotype, phenotype and offspring ratios worksheet

6 printable versionsOn Level10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

When it’s done, scan the sheet with your phone and PencilGo marks it and picks the next one. Create a free account

Version
Print

Genotype, phenotype and offspring ratios

Grade 7 Science Worksheet

NameDate

Circle the best answer, or write your answer on the line.

  1. Bo makes a Punnett square for Ii × Ii pea plants. As a fraction in simplest form, what is the chance an offspring is II?

  2. Esme makes a Punnett square for AA × Aa pea plants. As a fraction in simplest form, what is the chance an offspring is AA?

  3. Jun studies a Gg × Gg pea cross. What is the ratio of genotypes in the offspring?

    • 1 GG : 1 Gg : 1 gg
    • 1 GG : 2 Gg : 1 gg
    • 2 GG : 2 gg
    • 3 green : 1 yellow

  4. Kira studies an Ii × ii pea cross. What is the ratio of genotypes in the offspring?

    • 1 inflated : 1 constricted
    • 3 Ii : 1 ii
    • 1 Ii : 1 ii
    • 1 II : 2 Ii : 1 ii

  5. Luz studies an AA × Aa pea cross. What is the ratio of genotypes in the offspring?

    • Each offspring axial
    • 1 AA : 2 Aa : 1 aa
    • 3 AA : 1 aa
    • 1 AA : 1 Aa

  6. Milo studies the same kind of cross, Gg × Gg. What ratio of pod colors is expected?

    • 3 green : 1 yellow
    • 1 green : 3 yellow
    • 1 green : 1 yellow
    • 1 GG : 2 Gg : 1 gg

  7. Noah studies an Ii × ii pea cross. What ratio of pod shapes is expected?

    • 1 inflated : 1 constricted
    • 3 inflated : 1 constricted
    • Each pod constricted, as each box has an i
    • 1 Ii : 1 ii

  8. Pia studies an AA × aa pea cross. What flower positions are expected in the offspring?

    • All Aa, with no look given
    • 3 axial : 1 terminal
    • All axial, each plant Aa
    • All terminal, since each plant carries a

  9. Tala's pea plant has narrow, constricted pods. Which genotype must it have?

    • II, since it has two letters
    • Ii or ii, since each has an i
    • ii, since constricted is recessive
    • Ii, since it is mixed

  10. Zee crosses two pea plants with axial flowers, and some offspring have terminal flowers. What are the parents' genotypes?

    • AA and AA, since both look axial
    • AA and Aa, since one looks axial
    • Aa and Aa
    • aa and aa
PencilGopencilgo.com

7th grade Genotype, phenotype and offspring ratios worksheet – printable
Print: 123456

About this worksheet

Genotype, phenotype and offspring ratios. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can tell a genotype (letter pair) from a phenotype (the trait you see) and name homozygous and heterozygous pairs.
  • I can give a genotype ratio (1 : 2 : 1) and a phenotype ratio (3 : 1) from the same square, and a genotype's chance as a fraction in simplest form.
  • I can predict how many of many offspring have one genotype, and explain why a dominant look can hide a recessive letter.

Standard: MS-LS3-2

Words to know

genotype: The letter pair for a gene, such as Gg

phenotype: The trait you can see, such as green pods

homozygous: Two of the same letter: GG or gg

heterozygous: Two different letters: Gg

genotype ratio: How many boxes have each letter pair, such as 1 GG : 2 Gg : 1 gg

phenotype ratio: How many boxes show each look, such as 3 green : 1 yellow

axial / terminal: Flowers along the stem / flowers at the stem tip

Common mistakes

Your child swapped genotype and phenotype. The genotype is the letter pair (Gg); the phenotype is the trait you can see (green pods).

Your child thought a plant with one recessive letter (such as Gg) shows the recessive trait. One dominant letter is enough for the dominant trait to show.

Your child gave a ratio of looks when asked for letter pairs, or the other way round. Gg × Gg gives 1 GG : 2 Gg : 1 gg, which is 3 green : 1 yellow.

Questions parents ask

What is the most common mistake with genotype, phenotype and offspring ratios?

Your child swapped genotype and phenotype. The genotype is the letter pair (Gg); the phenotype is the trait you can see (green pods).

Are these 7th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More grade 7 science

See all grade 7 science

Every sheet you scan goes into your child’s record: dated, marked and ready for the year-end portfolio. Homeschool records

Ready for easier practice?

Print a sheet, scan it when it’s done, and PencilGo picks the next one.

Create a free account