The Work of Gregor Mendel

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Genetics Noun

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[juh-net-iks]

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Genetics

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The scientific study of biological inheritance and how characteristics are passed from one generation to the next.

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Example: This diagram shows how different versions of a gene, called alleles (A, a), are located on chromosomes, creating homozygous (AA, aa) or heterozygous (Aa) pairs.

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Model System Noun

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[mod-l sis-tuhm]

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Model System

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An organism that is convenient to study and may help scientists learn about other species, including humans.

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Example: This diagram shows the steps scientists use to create and test a scientific model, starting with a question and ending with a published result.

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Fertilization Noun

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[fur-tl-uh-zey-shuhn]

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Fertilization

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The process during sexual reproduction where male and female reproductive cells join to produce a new cell.

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Example: This diagram shows a sperm cell combining with an egg cell in a process called fertilization, forming a zygote with genetic material from both parents.

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Self-pollination Noun

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[self-pol-uh-ney-shuhn]

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Self-pollination

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The process in which sperm cells fertilize egg cells from within the same flower, resulting in offspring with a single parent.

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Example: This diagram shows self-pollination, where pollen from a flower's anther fertilizes the stigma of the same flower.

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Cross-pollination Noun

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[kros-pol-uh-ney-shuhn]

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Cross-pollination

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The process of causing one plant to reproduce with another by transferring pollen to study traits from different parents.

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Example: A pollinator, like a bee, transfers pollen from one flower to the stigma of a different flower, which is essential for creating genetic variation.

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Trait Noun

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[treyt]

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Trait

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A specific, inherited characteristic of an individual organism, which can vary from one individual to another.

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Example: This diagram shows that a gene, which is a segment of a chromosome, determines a specific physical characteristic, known as a trait, like eye color.

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True-breeding Adjective

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[troo-breed-ing]

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True-breeding

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Describes organisms that are self-pollinating and consistently produce offspring with traits identical to themselves.

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Example: The diagram shows a cross starting with 'True-Breeding' parents, organisms that consistently produce offspring with the same trait, like the green pea (GG).

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Hybrid Noun

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[hahy-brid]

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Hybrid

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The offspring resulting from a cross between parents with different or contrasting characteristics.

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Example: This Punnett square shows a cross between two hybrid parents (Pp). The offspring with the 'Pp' genotype are hybrids, inheriting one dominant allele (P) and one recessive allele (p).

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P generation Noun

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[pee jen-uh-rey-shuhn]

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P generation

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The original pair of organisms in a genetic cross, also known as the parental generation.

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Example: This diagram shows the P generation (Parental generation) as the first step in a genetic cross, where a tall pea plant is crossed with a short one.

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F₁ generation Noun

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[ef-wuhn jen-uh-rey-shuhn]

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F₁ generation

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The first generation of offspring from a cross of the P generation, also known as the first filial generation.

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Example: This diagram shows that when a purple-flowered pea plant and a white-flowered pea plant (P generation) are crossed, all their offspring (F₁ generation) have purple flowers.