Lecture 9A

Question 1

Making an egg or sperm

Answer 1

Cells that will go through meiosis: diploid germ cells

Cells that are the products of meiosis: haploid gametes (egg, sperm)

interphase (exactly like interphase before mitosis) –> Cell division: meiosis –> cytokinesis

Question 2

Homologous chromosomes

Answer 2

Carry genes affecting the same attributes (ex eye color) one from mom, the other from dad

Question 3

Diploid & Haploid

Answer 3

Number of SETS OF CHROMOSOMES

Diploid cell: has 2 sets of chromosomes: 2n
Human somatic cells: 46 chromosomes: 2 sets of 23
Female:
1 complete set of 23
chromosomes from mom: 1-22 + X
1 complete set of 23 chromosomes from dad: 1-22 + X
Male:
1 complete set of 23
chromosomes from mom: 1-22 + X
1 complete set of 23 chromosomes from dad: 1-22 + Y

Haploid cell: has 1 set of chromosomes: 1n
Gametes: Sperm cells or ova (eggs) are haploid
22 autosomes + an X (in a human egg)
22 autosomes + either X or Y (in a human sperm cell).

Question 4

Zygote & all somatic cells are

Answer 4

Zygote & all somatic cells are diploid (2n)
23 chromosomes in egg (1-22 + X) +
23 chromosomes in sperm (1-22 + X or Y)
= 46 chromosomes: 23 homologous pairs

After fertilization you have a single cell called a zygote. In it’s nucleus are 46 chromosomes