AP Biology Flashcards: Mutations
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
Are all mutations harmful?
No, mutations are not always harmful. Their effects on an organism can be beneficial, neutral, or detrimental.
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Are all mutations harmful?
No, mutations are not always harmful. Their effects on an organism can be beneficial, neutral, or detrimental.
Explain the relationship between mutations and natural selection.
Mutations introduce genetic variation, which can alter phenotypes. Natural selection then acts on these phenotypes, and genetic changes that enhance survival under environmental pressures can be selected for.
What is nondisjunction?
Nondisjunction is an error that can occur during mitosis or meiosis. It results in changes to the chromosome number, which can affect the phenotype.
What is a mutation?
A mutation is an alteration in a DNA sequence. This change can affect the protein produced and the resulting phenotype.
How do mutations contribute to genetic variation?
Mutations alter DNA sequences, creating new alleles and genetic diversity. They are a primary source of the variation that can be subject to natural selection.
Besides direct DNA sequence changes, what is another way cellular errors can alter an organism's genetic makeup?
Errors in mitosis or meiosis, such as nondisjunction, can result in changes to the total number of chromosomes in an organism.
Genotype
The genetic makeup of an organism based on its DNA sequence. Changes in genotype, such as mutations, can lead to changes in phenotype.
A mutation occurs that enhances an organism's ability to survive in its environment. What is the likely outcome for this mutation over time?
Because the genetic change enhances survival, it will likely be selected for by environmental pressures, leading to an increase in its frequency in the population.
Phenotype
The observable traits of an organism that result from its genotype. Phenotypes are subject to natural selection.
What are the primary causes of random mutations?
Random mutations can be caused by errors that occur during DNA replication or repair, or by external factors.
How does a change in genotype lead to a change in phenotype?
A change in the DNA sequence (genotype) can alter the protein that is produced. This modified protein can then lead to a change in an organism's observable traits (phenotype).