ASVAB CampGenetics, Heredity and Evolution flashcards
8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.
Rule · 1/8
DNA base-pairing rules, and what changes in RNA?
In DNA, A pairs with T and G pairs with C. RNA uses uracil (U) in place of thymine, so a DNA A is matched by U in messenger RNA.
Term · 2/8
Genotype versus phenotype
Genotype is the pair of alleles an organism carries (e.g. Ff). Phenotype is the observable trait (e.g. freckles). Different genotypes like FF and Ff can share a phenotype, and environment also shapes phenotype.
Term · 3/8
Homozygous versus heterozygous
Homozygous: two identical alleles (RR or rr). Heterozygous: two different alleles (Rr). Homo means same, hetero means different.
Formula · 4/8
Cross two heterozygotes (Aa x Aa) with complete dominance: what ratios result?
Genotypes 1 AA : 2 Aa : 1 aa. Phenotypes 3 dominant : 1 recessive, so each offspring has a (25%) chance of showing the recessive trait.
Formula · 5/8
How do you find the probability that two independent events both happen?
Multiply: . Example from two Bb parents: first child bb and second not bb is . Each birth is independent.
Term · 6/8
Mitosis versus meiosis
Mitosis: two identical diploid cells for growth and repair. Meiosis: two divisions giving four genetically different haploid cells (gametes). In humans, 46 chromosomes become 23 in each gamete.
Term · 7/8
Natural selection versus genetic drift
Selection: heritable variation that affects survival or reproduction makes favored alleles more common. Drift: allele frequencies change by chance, strongest in small populations (founder and bottleneck effects).
Common trap · 8/8
Why can't a father pass an X-linked allele to his son?
A father gives his Y chromosome to every son and his X to every daughter. So sons get their X from the mother; every daughter of an affected father receives his allele.