Exam 1 Practice Questions: Genetics & Evolution Vocabulary Flashcards

35 vocabulary flashcards covering key terms from genetic variation, meiosis, natural selection, and evolutionary mechanisms.

DNA mutation

A change in the DNA sequence of a gene; the ultimate source of new alleles and genetic variation.

Genotype

The genetic makeup of an organism; the specific alleles it carries.

Phenotype

The observable traits or characteristics of an organism.

Allele

A version or variant form of a gene.

Gene

A DNA sequence that codes for a trait.

Variation

Differences in traits or allele combinations within a population.

Alternative splicing

The process by which different exons are joined to produce multiple mRNA transcripts from a single gene.

Protein isoforms

Distinct protein products produced from a single gene via alternative splicing.

Diploid

An organism with two sets of chromosomes; two alleles per gene in somatic cells.

Haploid

An organism or cell with one set of chromosomes; one allele per gene in gametes.

Somatic cell

A non-reproductive body cell; typically diploid.

Gamete

A reproductive cell (sperm or egg) that is haploid and carries one allele per gene.

Homozygous

Having two identical alleles for a given gene.

Heterozygous

Having two different alleles for a given gene.

Dominant allele

An allele that is expressed in the phenotype when present in at least one copy.

Recessive allele

An allele expressed in the phenotype only when two copies are present (homozygous recessive).

Silent mutation

A nucleotide change that does not alter the amino acid sequence due to codon redundancy.

Meiosis

Cell division that halves the chromosome number and introduces variation via crossing over and independent assortment.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis.

Independent assortment

Random orientation of homologous chromosome pairs during meiosis, increasing genetic diversity.

Gene pool

The total collection of genes and alleles in a population.

Mutation (source of new alleles)

A change in DNA that creates new alleles; the ultimate source of genetic variation.

Genome

The complete set of genetic material in an organism.

Human Genome Project

A project that mapped the entire human genome to identify genes and their variations.

Natural selection

A process where traits that increase survival and reproduction become more common over generations.

Evolution

A change in allele frequencies in a population over generations.

Fitness

An organism’s relative ability to survive and reproduce in a given environment.

Sexual selection

A form of natural selection driven by mating preferences or competition for mates.

Intersexual selection

Mate choice by individuals of one sex influencing the genetic makeup of the other sex.

Intrasexual selection

Competition within one sex for access to mates.

Directional selection

Selection that favors one extreme phenotype over others.

Stabilizing selection

Selection that favors intermediate phenotypes and reduces variation at extremes.

Disruptive selection

Selection that favors extreme phenotypes over the intermediate.

Genetic drift

Random changes in allele frequencies, especially in small populations, due to chance.

Gene flow

Movement of alleles among populations via migration, which can increase or decrease genetic variation.