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Grade 7 Science · Genetics and Heredity

Grade 7 Genetics and Heredity Practice Test

Build Grade 7 Science skills with five 10-question practice tests on DNA, genes, chromosomes, alleles, traits, Punnett squares, mutations, variation, and heredity.

Genetics and Heredity Practice Tests

These Grade 7 Science practice tests use original questions to build genetics and heredity skills. Students practice DNA, genes, chromosomes, alleles, genotype, phenotype, dominant and recessive traits, Punnett squares, pedigrees, mutations, genetic variation, gene expression, and environment-trait relationships.

Skills covered

  • Explaining how DNA, genes, chromosomes, and alleles relate to one another
  • Distinguishing genotype, phenotype, homozygous, heterozygous, dominant, and recessive patterns
  • Using Punnett squares and probabilities to model possible inherited traits
  • Interpreting pedigrees and evidence from family or twin studies
  • Explaining mutations, genetic variation, gene expression, and selective breeding
  • Separating inherited information from environmental effects and acquired changes

How to use these practice tests

For each question, identify the genetic structure or inheritance pattern first. When a cross is given, list the possible allele combinations and remember that probability predicts expected outcomes rather than guaranteeing the result for one individual or family.

For more Grade 7 Science practice, return to the Grade 7 Science category.

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Grade 7 Genetics and Heredity Practice Tests

A 10-question Grade 7 Science practice test on DNA, genes, chromosomes, alleles, traits, Punnett squares, mutations, variation, and heredity.

Read each genetics question carefully, identify the inheritance pattern or genetic structure, and choose the answer supported by the given evidence.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

What genotypes are possible from the cross Aa × Aa?

Please select an answer first.

Correct answer: A

The correct answer is AA, Aa, and aa.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Each parent can contribute A or a, producing AA, Aa, or aa combinations.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Each parent can contribute A or a, producing AA, Aa, or aa combinations.

2. QuestionMultiple choice

In the cross Aa × Aa, what is the expected probability of aa?

Please select an answer first.

Correct answer: B

The correct answer is 25 percent.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: The four equally likely combinations are AA, Aa, Aa, and aa, so one of four is aa.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

The four equally likely combinations are AA, Aa, Aa, and aa, so one of four is aa.

3. QuestionMultiple choice

In the cross Aa × Aa, where A is dominant, what percentage of offspring are expected to show the dominant phenotype?

Please select an answer first.

Correct answer: C

The correct answer is 75 percent.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: AA, Aa, and Aa show the dominant phenotype, which represents three of four possible combinations.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

AA, Aa, and Aa show the dominant phenotype, which represents three of four possible combinations.

4. QuestionMultiple choice

In the cross Tt × tt, where T is dominant, what percentage of offspring are expected to be tall?

Please select an answer first.

Correct answer: D

The correct answer is 50 percent.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: The Tt parent can contribute T or t and the tt parent contributes t, giving Tt and tt in equal proportions.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

The Tt parent can contribute T or t and the tt parent contributes t, giving Tt and tt in equal proportions.

5. QuestionMultiple choice

Which statement correctly compares genotype and phenotype?

Please select an answer first.

Correct answer: A

The correct answer is Genotype is the allele combination, while phenotype is the observable trait..

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Genotype describes genetic information; phenotype describes the trait that is observed or measured.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Genotype describes genetic information; phenotype describes the trait that is observed or measured.

6. QuestionMultiple choice

How can the environment affect phenotype?

Please select an answer first.

Correct answer: B

The correct answer is Environmental conditions can influence how a genetic trait appears..

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Nutrition, temperature, light, and other conditions can influence how genetic information is expressed.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Nutrition, temperature, light, and other conditions can influence how genetic information is expressed.

7. QuestionMultiple choice

What is codominance?

Please select an answer first.

Correct answer: C

The correct answer is A pattern in which both alleles are fully expressed in the phenotype.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: In codominance, both allele effects appear, such as distinct features shown together rather than blended.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

In codominance, both allele effects appear, such as distinct features shown together rather than blended.

8. QuestionMultiple choice

What is incomplete dominance?

Please select an answer first.

Correct answer: D

The correct answer is A pattern in which the heterozygous phenotype is intermediate between the two homozygous phenotypes.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Incomplete dominance produces an intermediate appearance in the heterozygous condition.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Incomplete dominance produces an intermediate appearance in the heterozygous condition.

9. QuestionMultiple choice

What does a pedigree diagram help researchers study?

Please select an answer first.

Correct answer: A

The correct answer is How a trait may be inherited through several generations of a family.

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Pedigrees use symbols and relationships to track the appearance of a trait across generations.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Pedigrees use symbols and relationships to track the appearance of a trait across generations.

10. QuestionMultiple choice

Why does a probability from a Punnett square not guarantee the exact outcome in a small family?

Please select an answer first.

Correct answer: B

The correct answer is Random allele combinations can differ from the expected ratio in a small number of offspring..

  1. Identify the heredity concept: Determine whether the question asks about DNA, genes, chromosomes, alleles, traits, probability, mutations, or variation.
  2. Connect genes and traits: Expected ratios become more reliable across many trials; a small family can differ by chance.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Expected ratios become more reliable across many trials; a small family can differ by chance.

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Frequently asked questions about Grade 7 Genetics and Heredity

What is the difference between genotype and phenotype?

Genotype is the allele combination an organism has, while phenotype is the observable or measurable trait that results from genetic information and environmental influences.

Does a Punnett square guarantee the trait of one offspring?

No. A Punnett square predicts probabilities for possible allele combinations. The actual result for one offspring can differ from the expected ratio by chance.

How many questions are on this page?

The page includes five mini tests with 10 questions each, for 50 Grade 7 Genetics and Heredity questions in total.