Genetics and Heredity Basics
Key vocabulary, Punnett square ratios, and inheritance patterns from Mendel to sex-linked traits.
Keyboard Shortcuts
💡 Pro tip: Use keyboard shortcuts for faster studying!
Study Smart Tips for Genetics and Heredity Basics
Master these concepts using proven study techniques that actually work:
Active Recall
Test yourself before flipping each card to strengthen memory retention
Spaced Repetition
Review difficult cards more frequently than easy ones
Multiple Sessions
Break study time into shorter, focused sessions
Explain Aloud
Verbalize answers to reinforce understanding
Questions Covered in This Set
10 cards to master
Allele
A version (variant) of a gene — e.g., a purple allele or a white allele for flower color.
Genotype vs. phenotype
Genotype is the pair of alleles carried (PP, Pp, pp); phenotype is the visible trait (purple or white flowers).
Homozygous vs. heterozygous
Homozygous = two identical alleles (PP or pp); heterozygous = two different alleles (Pp).
What ratios come from a Pp × Pp cross?
Genotype 1 PP : 2 Pp : 1 pp; phenotype 3 dominant : 1 recessive (75% purple, 25% white).
Mendel's Law of Segregation
The two alleles of a gene separate during meiosis so each gamete carries only one allele — the reason Punnett squares work.
What is a test cross and what does it show?
Crossing an unknown dominant individual with a homozygous recessive (Pp × pp gives 1:1) to reveal whether it is PP or Pp.
Incomplete dominance
The heterozygote is a blend: red (RR) × white (WW) snapdragons → all pink (RW); pink × pink gives 1 red : 2 pink : 1 white.
Codominance
Both alleles show fully and separately — roan cattle have distinct red and white hairs, not pink.
Why are sex-linked traits more common in males?
X-linked genes sit on the X chromosome; males (XY) have only one X, so a single recessive allele (X^c Y) is expressed with no second X to mask it.
Polygenic traits
Traits like height, skin color, and eye color controlled by many genes, producing a smooth range instead of two categories.
