Meiosis, Gametogenesis, and Genetics

Gametes

haploid sex cells produced in the gonads of animals and the flowers of plants

prophase/prometaphase I

synapsis

crossing over- leads to genetic diversity

metaphase I

homologous pairs line up

anaphase I

homologous pairs split

similarities and differences between mitosis and meiosis

mitosis produces 2 identical “daughter” cells from a “single” parent cell

meiosis produces cells that are genetically unique from the parent and contain only half as much DNA

how many divisions are there in meiosis?

2

how many divisions are there in mitosis?

1

why are there 2 divisions in meiosis, but only 1 in mitosis?

cells need to divide twice in meiosis to have half the genetic material

polar bodies are…

not functional, but egg cells are functional

how many eggs are produced during oogenesis?

1

how many sperm are produced during spermatogenesis?

4

allele

variation of a gene

gene

distinct sequence of nucleotides forming part of a chromosome

what do genes code for?

proteins

homozygous

same zygote

BB. bb

heterozygous

different zygote

Bb

letters refer to the

gametes

genotype

genetic components that contribute to the phenotype of an organism

Bb, BB

phenotype

physical trait (black eyes)

males in pedigrees

square

females in pedigrees

circle

those affected in pedigrees are

colored in (square/circle is not white)

the sex chromosome is the

23rd pair

female sex chromosome

XX

male sex chromosome

XY

karyotype

photograph of an individual’s chromosomes

synapsis

fusion of chromosomes at the start of meiosis

haploid

presence of a single set of chromosomes in an organism's cells

diploid

containing two complete sets of chromosomes, one from each parent

crossing over

the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring