Exam 3

Point Mutation

is a change in a single nucleotide in the DNA sequence. This can result in a different amino acid being incorporated into a protein or can have no effect if the changed nucleotide still codes for the same amino acid (due to redundancy in the genetic code).

Silent Mutation

a type of point mutation that does not change the amino acid sequence of a protein. Because of the redundancy in the genetic code, some changes in the nucleotide sequence do not affect the overall protein produced.

Missense Mutation

a point mutation that results in the substitution of one amino acid for another in a protein. This can have varying effects on the function of the protein depending on where and how the amino acid change occurs.

Nonsense Mutation

a point mutation that changes an amino acid codon into a stop codon, leading to premature termination of protein synthesis. This usually results in a nonfunctional protein.

Frameshift Mutation

occurs when nucleotides are added or deleted from the DNA sequence, which shifts the reading frame of the gene. This can result in an entirely different and often nonfunctional protein.

Mismatch Repair

is a cellular mechanism that corrects errors that occur during DNA replication, specifically those that lead to base pair mismatches.

Excision Repair

is a DNA repair mechanism that removes damaged or incorrect nucleotides and replaces them with the correct ones using the complementary strand as a template.

Redundant/Ambiguous in Genetic Code Context

multiple codons can code for the same amino acid, which provides a buffer against mutations in the DNA sequence.

Genotype

genetic constitution of an organism, typically focusing on specific alleles of interest. An individual can be homozygous (AA or aa) or heterozygous (Aa) for a certain gene affecting flower color.

Phenotype

observable physical or biochemical characteristics of an organism, determined by both genotype and environmental influences.

Allele

variant form of a gene that can exist at a specific locus on a chromosome.

Trait

a specific characteristic or feature of an organism, which can be influenced by one or more genes.

Homozygous

An organism is [ BLANK ] at a given locus when it has two identical alleles for a trait.

Heterozygous

An organism is [ BLANK ] at a specific locus when it has two different alleles for a trait.