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Genetics and Heredity Practice Tests

These Grade 9 Biology practice tests explain how DNA, genes, chromosomes, and alleles carry information from one generation to the next. Questions cover Mendelian inheritance, Punnett squares, meiosis, mutations, pedigrees, genetic variation, and basic biotechnology.

Skills covered

  • Distinguishing DNA, genes, chromosomes, alleles, genotype, and phenotype
  • Applying dominant, recessive, homozygous, heterozygous, incomplete dominance, codominance, and sex-linked inheritance concepts
  • Using Punnett squares and probability to predict possible offspring genotypes and phenotypes
  • Connecting meiosis, crossing over, independent assortment, fertilization, and chromosome number to genetic variation
  • Interpreting mutations, pedigrees, karyotypes, natural selection, and introductory genetic engineering

How to use these practice tests

Start by identifying the gene, allele, chromosome, or inheritance pattern involved. For crosses, write the parental alleles and list the possible gametes before calculating the probability. Review each explanation to strengthen genetics vocabulary and evidence-based reasoning.

For more Grade 9 Science practice, return to the Grade 9 Science category.

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Grade 9 Genetics and Heredity Practice Tests

Practice Grade 9 Science questions about DNA, genes, chromosomes, alleles, Mendelian inheritance, Punnett squares, meiosis, mutations, pedigrees, and genetic variation.

Choose the best answer. Identify the genetic information or inheritance pattern, apply the relevant rule, and use probabilities carefully when interpreting crosses.

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

What are possible effects of a mutation?

Please select an answer first.

Correct answer: A

The correct answer is It can be neutral, harmful, or beneficial depending on context..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: A mutation may have different effects depending on the gene, environment, and whether the change affects function.
  3. Check the answer: The correct answer is It can be neutral, harmful, or beneficial depending on context..

A mutation may have different effects depending on the gene, environment, and whether the change affects function.

2. QuestionMultiple choice

What is a substitution mutation?

Please select an answer first.

Correct answer: B

The correct answer is A mutation in which one nucleotide is replaced by another..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: A substitution changes one nucleotide base for another and may or may not alter the resulting protein.
  3. Check the answer: The correct answer is A mutation in which one nucleotide is replaced by another..

A substitution changes one nucleotide base for another and may or may not alter the resulting protein.

3. QuestionMultiple choice

Why can a deletion mutation be especially disruptive to a protein-coding gene?

Please select an answer first.

Correct answer: C

The correct answer is It may shift the reading frame of the genetic message..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: If bases are deleted in a number not divisible by three, the reading frame can shift and alter many later codons.
  3. Check the answer: The correct answer is It may shift the reading frame of the genetic message..

If bases are deleted in a number not divisible by three, the reading frame can shift and alter many later codons.

4. QuestionMultiple choice

What does natural selection change in a population over generations?

Please select an answer first.

Correct answer: D

The correct answer is The frequencies of heritable alleles and traits..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Natural selection changes allele frequencies when heritable differences affect survival or reproduction.
  3. Check the answer: The correct answer is The frequencies of heritable alleles and traits..

Natural selection changes allele frequencies when heritable differences affect survival or reproduction.

5. QuestionMultiple choice

Which processes are important sources of genetic variation?

Please select an answer first.

Correct answer: A

The correct answer is Mutation and genetic recombination..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Mutation creates new alleles, while crossing over, independent assortment, and fertilization recombine existing alleles.
  3. Check the answer: The correct answer is Mutation and genetic recombination..

Mutation creates new alleles, while crossing over, independent assortment, and fertilization recombine existing alleles.

6. QuestionMultiple choice

What can a karyotype help identify?

Please select an answer first.

Correct answer: B

The correct answer is The number and general structure of an individual's chromosomes..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: A karyotype arranges chromosomes to examine their number and visible structure, including some chromosome abnormalities.
  3. Check the answer: The correct answer is The number and general structure of an individual's chromosomes..

A karyotype arranges chromosomes to examine their number and visible structure, including some chromosome abnormalities.

7. QuestionMultiple choice

What is the purpose of PCR in molecular biology?

Please select an answer first.

Correct answer: C

The correct answer is Making many copies of a selected DNA segment..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Polymerase chain reaction, or PCR, amplifies a specific DNA region so it can be analyzed.
  3. Check the answer: The correct answer is Making many copies of a selected DNA segment..

Polymerase chain reaction, or PCR, amplifies a specific DNA region so it can be analyzed.

8. QuestionMultiple choice

What is genetic engineering?

Please select an answer first.

Correct answer: D

The correct answer is The deliberate modification or transfer of genetic material..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Genetic engineering uses laboratory methods to alter DNA or move genetic material to achieve a desired outcome.
  3. Check the answer: The correct answer is The deliberate modification or transfer of genetic material..

Genetic engineering uses laboratory methods to alter DNA or move genetic material to achieve a desired outcome.

9. QuestionMultiple choice

Why is genetic variation important to a population?

Please select an answer first.

Correct answer: A

The correct answer is It provides differences that may help some individuals survive environmental changes..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Variation gives natural selection differences to act on and can increase the chance that some individuals persist when conditions change.
  3. Check the answer: The correct answer is It provides differences that may help some individuals survive environmental changes..

Variation gives natural selection differences to act on and can increase the chance that some individuals persist when conditions change.

10. QuestionMultiple choice

Which statement correctly compares genotype and phenotype?

Please select an answer first.

Correct answer: B

The correct answer is Genotype is genetic makeup; phenotype is the observable result of genes and environment..

  1. Identify the genetics concept: Determine whether the question asks about DNA, alleles, inheritance, meiosis, variation, or genetic evidence.
  2. Apply the inheritance principle: Genotype describes alleles, while phenotype describes observable traits produced through genetic and environmental interactions.
  3. Check the answer: The correct answer is Genotype is genetic makeup; phenotype is the observable result of genes and environment..

Genotype describes alleles, while phenotype describes observable traits produced through genetic and environmental interactions.

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