Mendel's Monohybrid Cross (Biology Exam 2: Genetics)

Inheritance

the biological mechanism through which traits are passed from parents to offspring.

Blending inheritance

an early idea that offspring are a smooth blend of parental traits, dismissed by Mendel's findings.

Particulate inheritance

the theory that inheritance involves discrete units (genes) that are passed on independently.

Gregor Mendel

Austrian scientist whose experiments with pea plants established the foundations of genetic theory.

Cross-fertilization

the fertilization that occurs between gametes from different individuals, enhancing genetic diversity.

Self-fertilization (selfing)

a reproductive strategy where an organism fertilizes its own eggs, leading to offspring with the same genetic traits.

Character

a category of observable features (e.g., flower color) that can vary between individuals.

Trait

a specific variation of a character, such as red or white flower color.

True-breeding variety

organisms that produce identical offspring when self-fertilized, ensuring trait consistency across generations.

Reciprocal cross

a genetic cross that tests the effect of parents’ alleles by switching the male and female parents.

Monohybrid

a cross between two organisms that differ in one specific trait.

Parental (P) generation

the generation utilized to produce the F1 generation, often consisting of true-breeding individuals.

First filial (F1) generation

the first generation of offspring resulting from the P generation cross.

Second filial (F2) generation

the result of crossing individuals from the F1 generation, demonstrating further inheritance patterns.

Monohybrid cross

a genetic cross involving a single trait with two alleles, often represented in a Punnett square.

Gene

a segment of DNA responsible for a specific trait or function.

Locus

the specific physical location of a gene on a chromosome, important for genetic mapping.

Allele

a variant form of a gene that may result in different traits.

Genotype

the genetic constitution of an individual, reflecting its alleles.

Phenotype

the visible or expressed characteristics of an individual resulting from the genotype.

Dominant allele

allele that manifests its effect in the phenotype even in the presence of a recessive allele.

Recessive allele

allele that only shows its effect if the organism is homozygous for that allele.

Dominant trait

a trait that is expressed when at least one dominant allele is present.

Recessive trait

a trait that is only expressed when two recessive alleles are present.

Homozygous genotype (AA/aa)

an organism with two identical alleles for a trait.

Heterozygous genotype (Aa)

an organism with two different alleles for a trait, affecting their phenotype.

Law of Segregation

Mendel's principle stating that allele pairs separate during gamete formation.

Genotypic ratio

the ratio of different genotypes that result from a genetic cross.

Phenotypic ratio

the ratio of different phenotypes observed in the offspring of a genetic cross.

Punnett square

a diagram used to predict the genetic outcomes of a cross between two organisms.

Test cross

the cross of an individual with an unknown genotype to a homozygous recessive individual to determine the unknown genotype's contribution.