Unit 9: meiosis and menstrual cycle (honors only)

Question 1

meiosis

Answer 1

a kind of cell division which creates eggs and sperm

Question 2

tetrad

Answer 2

pairs of homologous chromosomes which form in prophase I of meiosis

Question 3

haploid

Answer 3

cells with only one set of chromosomes (made by meiosis)

Question 4

diploid

Answer 4

cells with two sets of chromosomes (made by mitosis)

Question 5

crossing over

Answer 5

when “legs” of the chromosomes touch and cross and swap DNA.

Only occurs while chromosomes are in tetrads.

Creates greater genetic variation in egg and sperm cells.

Question 6

How many sperm or egg cells are produced by one round of meiosis?

Answer 6

4 sperm

1 egg (other three cells are not used)

Question 7

Compare and contrast mitosis and meiosis.

Answer 7

Both are types of cell division. Both use the spindle and chromosomes. The have the same phases. Mitosis happens all over the body, but meiosis is only the ovaries or testes. Mitosis produces 2 diploid cells; meiosis produces 4 haploid cells. Mitosis has 1 round of cell division; meiosis has 2. Only meiosis has tetrads.

Question 8

Follicle

Answer 8

The cell which helps the egg cell develop.

Later becomes the corpus luteum.

Produces estrogen in the ovary.

Question 9

estrogen

Answer 9

A hormone released by the follicle in the ovary.

Causes the uterine lining to grow.

Stimulates the brain to release LH and FSH.

Question 10

estrogen and progesterone

Answer 10

Hormones produced by the corpus luteum in the ovary.

Causes the uterine lining to stay thick.

Inhibits the brain.

Question 11

PMS and menstruation

Answer 11

Caused by a drop off of hormones, especially estrogen and progesterone.

The lining of the uterus is shed.

Question 12

ovulation

Answer 12

When the ovary releases an egg into the Fallopian tube.

Caused by high levels of brain hormones (LH and FSH).

Happens about half way through a woman’s cycle.

Question 13

corpus luteum

Answer 13

The left over follicle.

Produces estrogen and progesterone in the ovary.

Question 14

How do a fetus and birth control pills prevent ovulation?

Answer 14

Both release estrogen and progesterone, inhibiting the brain, which does not produce LH or FSH, so ovulation doesn’t occur.

Question 15

Why do teenager girls have longer and heavier periods than other women?

Answer 15

Teens have higher hormone levels because they are going through puberty. (Those hormones also cause pimples and mood swings.)

Question 16

Answer 16

tetrads crossing over

Occurs during prophase I or metaphase I of meiosis

Question 17

LH and FSH

Answer 17

Lutinizing Hormone and Follicle Stimulating Hormone

Produced by the pituitary gland in the brain.

Trigger ovulation.