BIO STUDY

Notes

BIO STUDY SHEET: Meiosis + Mendel + Punnett Squares (Complete) 1) Big Picture: Why Meiosis Exists ● Meiosis = “reduction division” (Greek meion = less) ● It cuts chromosome number in half ● Parent cell → daughter cells with half the chromosomes ● Purpose: so fertilization doesn’t double chromosomes every generation Key Terms ● Diploid (2n): two of each chromosome type (pairs of homologs) ● Haploid (n): one of each chromosome type ● Gametes: sperm and eggs (haploid) ● Zygote: fertilized egg (diploid) Why chromosome number stays the same across generations ● Sperm (n) + Egg (n) → Zygote (2n) ● If sperm/egg weren’t haploid, chromosome number would increase every generation 2) Chromosomes, Homologs, and Ploidy Homologous chromosomes ● A pair of chromosomes that: ○ look similar ○ carry the same genes ○ can have different alleles Maternal vs Paternal ● Maternal chromosome = from mom ● Paternal chromosome = from dad Example Cell in the lesson ● Has 3 types of chromosomes → n = 3 ● Diploid means two of each type → 2n = 6 total chromosomes Allele comparison in that cell ● At gene C, maternal and paternal had same allele ● At genes A and B, maternal and paternal had different alleles Unrepli...