chapter 10 - meiosis and sexual life cycles

Define

A) genetics

B) heredity

C) genes

A) The scientific study of heredity and variation

B) transmission of traits from one generation to the next

C) units of heredity that are made up of segments of DNA

What are karyotypes? how are they prepared?

somatic cells in metaphase are halted in cell division and stained for observation

What are the three origins of genetic variability?

3 mechanisms that contribute to genetic variation: crossing over, independent assortment of chromosomes and random fertilization

what are chiasmata?

point at which crossing over occurs, to produce recombinant chromosomes

crossing over

• occurs between 2 non-sister chromatids of homologous chromosomes during prophase I

• produces recombinant chromosomes

what are recombinant chromosomes?

new unique chromosomes that combine genes inherited from each parent into a single chromosome

how does the independent assortment of chromosomes during metaphase I contribute to genetic variability?

homologous chromosomes orient randomly during metaphase I, leading to many possible gametes depending on orientation

which 3 events are unique to meiosis?

1. synapsis and crossing over

2. specific arrangement of paired homologous
   chromosomes (tetrads), instead of individual replicated
   chromosomes in metaphase I

3. homologous chromosomes, instead of sister
   chromatids separate in anaphase I