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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 does a dominant allele do in a simple dominant-recessive model?

Please select an answer first.

Correct answer: A

The correct answer is It can determine the phenotype when at least one copy is present..

  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: A dominant allele can contribute to the dominant phenotype in a heterozygous genotype.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

A dominant allele can contribute to the dominant phenotype in a heterozygous genotype.

2. QuestionMultiple choice

When is a recessive phenotype usually expressed in a simple model?

Please select an answer first.

Correct answer: B

The correct answer is When an organism has two recessive alleles for the 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: A recessive phenotype is expressed when the genotype contains two recessive copies, such as aa.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

A recessive phenotype is expressed when the genotype contains two recessive copies, such as aa.

3. QuestionMultiple choice

What does homozygous mean?

Please select an answer first.

Correct answer: C

The correct answer is Having two identical alleles for a gene.

  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: Homozygous genotypes contain matching alleles, such as AA or aa.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Homozygous genotypes contain matching alleles, such as AA or aa.

4. QuestionMultiple choice

What does heterozygous mean?

Please select an answer first.

Correct answer: D

The correct answer is Having two different alleles for a gene.

  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: A heterozygous genotype contains different alleles, such as Aa.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

A heterozygous genotype contains different alleles, such as Aa.

5. QuestionMultiple choice

If B is dominant for black fur and b is recessive for white fur, what phenotype is expected for BB?

Please select an answer first.

Correct answer: A

The correct answer is Black fur.

  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: BB contains two dominant B alleles, so the dominant black-fur phenotype is expected in this simple model.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

BB contains two dominant B alleles, so the dominant black-fur phenotype is expected in this simple model.

6. QuestionMultiple choice

If T is dominant for tall stems and t is recessive for short stems, what phenotype is expected for Tt?

Please select an answer first.

Correct answer: B

The correct answer is Tall stems.

  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: Tt contains one dominant T allele, so the dominant tall phenotype is expected in this simple model.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Tt contains one dominant T allele, so the dominant tall phenotype is expected in this simple model.

7. QuestionMultiple choice

What is the purpose of a Punnett square?

Please select an answer first.

Correct answer: C

The correct answer is To organize possible allele combinations and predict their probabilities.

  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: A Punnett square models possible allele combinations from the parental gametes; it predicts probabilities, not guarantees.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

A Punnett square models possible allele combinations from the parental gametes; it predicts probabilities, not guarantees.

8. QuestionMultiple choice

In the cross Aa × aa, where A is dominant, what percentage of offspring are expected to have the recessive aa genotype?

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 Aa parent can pass A or a, while the aa parent can pass only a, giving two aa outcomes out of four equally likely combinations.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

The Aa parent can pass A or a, while the aa parent can pass only a, giving two aa outcomes out of four equally likely combinations.

9. QuestionMultiple choice

In the cross AA × aa, what genotype is expected for all offspring?

Please select an answer first.

Correct answer: A

The correct answer is 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: The AA parent contributes A and the aa parent contributes a, so every offspring receives Aa in this simple cross.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

The AA parent contributes A and the aa parent contributes a, so every offspring receives Aa in this simple cross.

10. QuestionMultiple choice

Why can siblings have different traits even when they have the same two biological parents?

Please select an answer first.

Correct answer: B

The correct answer is They can receive different combinations of alleles from the parents..

  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: Different allele combinations and other biological processes can make siblings genetically different.
  3. Check the evidence: Use the allele information, cross, family pattern, or observation to select the scientifically supported answer.

Different allele combinations and other biological processes can make siblings genetically different.

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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.