Genetics and Heredity Flashcards

Grade 10 · Science · Flashcards

Review essential vocabulary and concepts for Mendelian genetics and heredity.

Flashcards

Genetics: The scientific study of heredity and the variation of inherited characteristics.
Gene: A segment of DNA on a chromosome that codes for a specific trait; inherited from both parents.
Allele: An alternative form of a gene; each person inherits two alleles per gene (one from each parent).
Dominant allele: Expressed in the phenotype whenever present; written with a capital letter (e.g., T).
Recessive allele: Only expressed when two copies are present (homozygous recessive); written lowercase (e.g., t).
Genotype: The allele combination an organism carries for a given trait (e.g., TT, Tt, tt).
Phenotype: The observable expression of the genotype, shaped by genes and environment.
Homozygous: Both alleles for a gene are the same (TT = homozygous dominant; tt = homozygous recessive).
Heterozygous: Two different alleles for a gene (Tt); the dominant phenotype is expressed.
Punnett square: A diagram for predicting the probability of genotypes and phenotypes in offspring of a cross.
Incomplete dominance: Heterozygote shows an intermediate phenotype (blend); neither allele fully dominates the other.
Sex-linked trait: A trait whose gene is located on a sex chromosome (usually X); more often expressed in males (XY).