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9th grade Multiple alleles: ABO blood types worksheet

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Multiple alleles: ABO blood types

Grade 9 Science Worksheet

NameDate

Circle the best answer.

  1. Read this first

    ABO alleles (model)

    itemrule
    IA and IBcodominant
    IA and IBeach dominant to i
    irecessive allele

  2. Ari reads the allele rules. Which list holds every genotype that gives type A?

    • IAIA, IAi and IAIB
    • Just IAIA
    • IAIA and IAi
    • IAi and ii

  3. Bo reads the allele rules. Which list holds every genotype that gives type B?

    • IBIB, IBi and IAIB
    • IBi and ii
    • IBIB and IBi
    • Just IBIB

  4. Table

    Model plant colors (model data, not a real plant), 3 rows. Columns: allele, rule. Row 1: P, purple, dominant to Y and w. Row 2: Y, yellow, dominant to w. Row 3: w, white, recessive.

  5. Esme reads the rules for a model plant. Which list holds every genotype with yellow flowers?

    • YY and Yw
    • YY, Yw and PY
    • Yw and ww
    • Just YY

  6. Kira fills the square for model parents with genotypes IAIB and ii. What is the ratio of types A : B : AB : O?

    • 2 A : 0 B : 2 AB : 0 O
    • 0 A : 0 B : 0 AB : 4 O
    • 1 A : 1 B : 1 AB : 1 O
    • 1 A : 1 B : 0 AB : 0 O

  7. Luz fills the square for model parents with genotypes IAi and IAi. What is the ratio of type A to type O?

    • 1 : 3, for type A : type O
    • 1 : 2 : 1, for IAIA : IAi : ii
    • 1 : 1, for type A : type O
    • 3 : 1, for type A : type O

  8. Model data: Milo counts 400 offspring from parents with genotypes IAi and IBi. About how many are expected to be type AB?

    • 300 (3 boxes of 4)
    • 133 (1 box of 3)
    • 100 (1 box of 4)
    • 200 (2 boxes of 4)

  9. Model data: Pia counts 120 offspring from parents with genotypes IAi and IAi. About how many are expected to be type A?

    • 90 (3 boxes of 4)
    • 60 (the two IAi boxes)
    • 30 (just the IAIA box)
    • 40 (1 box of 3)

  10. Table

    ABO alleles (model), 2 rows. Columns: item, note. Row 1: alleles in the population, IA, IB and i. Row 2: one genotype, a pair of alleles, order ignored.

  11. Ren reads the ABO card. How many different genotypes are possible with the alleles IA, IB and i?

    • 3 (one for each allele)
    • 9 (IAi and iIA counted twice)
    • 6 (each pair, order ignored)
    • 4 (one for each type)

  12. Table

    Six ABO genotypes (model), 2 rows. Columns: item, note. Row 1: genotypes, IAIA, IAi, IBIB, IBi, IAIB and ii. Row 2: rules, IA and IB are codominant, and each is dominant to i.

  13. Tala reads the card. How many different blood types do the six genotypes give?

    • 4 (types A, B, AB and O)
    • 3 (one for each allele)
    • 2 (one for each dominant allele)
    • 6 (one for each genotype)

  14. Table

    Model plant colors (model data, not a real plant), 3 rows. Columns: allele, rule. Row 1: P, purple, dominant to Y and w. Row 2: Y, yellow, dominant to w. Row 3: w, white, recessive.

  15. Zee reads the rules for a model plant with three alleles. How many genotypes and how many flower colors are there?

    • 6 genotypes and 4 flower colors
    • 6 genotypes and 3 flower colors
    • 3 genotypes and 3 flower colors
    • 6 genotypes and 6 flower colors
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9th grade Multiple alleles: ABO blood types worksheet – printable
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About this worksheet

Multiple alleles: ABO blood types, six genotypes and four phenotypes. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can say that a gene can have more than two alleles in a population (ABO has three: IA, IB and i), and that each genotype is still a pair, so one individual carries two.
  • I can name the type that a genotype gives: IAIA and IAi give type A, IBIB and IBi give type B, IAIB gives type AB, and ii gives type O.
  • I can say why: IA and IB are codominant (both show in IAIB), each is dominant to i, and i is recessive (it shows only as ii).
  • I can list every genotype that gives one type (type A: IAIA and IAi), and I know a type does not need two matching alleles.
  • I can fill and read a 2 by 2 square for IAi × IBi, IAIB × ii and IAi × IAi, and turn it into a type ratio (1 A : 1 B : 1 AB : 1 O, then 1 A : 1 B, then 3 A : 1 O), not mixing it up with the genotype ratio.
  • I can find the chance of type O (1 in 4 from IAi × IBi; 0 from IAi × IAIB) and an expected count out of a model total (a fourth of 400 is 100).

Standard: HS-LS3-3

Words to know

multiple alleles: A gene with more than two alleles in a population

allele: One form of a gene, such as IA, IB or i

genotype: The pair of alleles one individual carries

phenotype: The type or look that shows, such as type A

codominant: Both alleles show at the same time in a heterozygote

dominant, recessive: The allele that shows when present, and the one that shows only as a pair

heterozygous, homozygous: Two different alleles in the pair, and two matching alleles

Punnett square: A grid of every equally likely way two parents' alleles can pair up

Common mistakes

Your child treated the recessive allele (i here, w for the model plant) as if it were dominant, so a genotype such as IAi looked like type O. A recessive allele shows only as a pair. Ask your child what IAi shows.

Your child expected IA and IB to mix into one in-between look. They are codominant, so both show side by side. Ask your child what IAIB shows.

Your child thought IA hides IB (or the other way round), so only one type shows. Neither is dominant over the other, so both show. Ask your child what IAIB shows.

Questions parents ask

What is the most common mistake with multiple alleles: abo blood types?

Your child treated the recessive allele (i here, w for the model plant) as if it were dominant, so a genotype such as IAi looked like type O. A recessive allele shows only as a pair. Ask your child what IAi shows.

Are these 9th 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.

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