meiosis

Question 1

what is meiosis?

Answer 1

a cell division where gametes are produced

Question 2

what are gametes?

Answer 2

sperm or oocytes

Question 3

what is a diploid?

Answer 3

a cell with 2 copies of chromosomes

Question 4

how many pairs of chromosomes do humans have?

Answer 4

23

Question 5

what is a replicated chromosome?

Answer 5

a chromosome with 2 identical sister chromatids

Question 6

what is a haploid?

Answer 6

a cell with a single copy of each chromosome

Question 7

what is a single stranded chromosome?

Answer 7

a chromosome that was previously a sister chromatid and a centromere

Question 8

what is a homologous chromosome?

Answer 8

pair of similar not identical chromosomes

Question 9

mitosis

Answer 9

produces 2 cells, each containing 46 chromosome, daughter cells are identical to the original parent cells, cells are diploid, cell division occurs 1 time

Question 10

meiosis compared to mitosis

Answer 10

produces 4 cells containing only 23 chromosomes, daughter cells are genetically different from parent cells, cells are haploid

Question 11

what is the spermatogonia?

Answer 11

each contains 23 pairs of chromosomes total 46 and they are diploid, stem cells that help produce sperm, divide by mitosis and produce a primary spermatocyte

Question 12

what do sustentacular cells do?

Answer 12

support, protect, and nourish the developing sperm

Question 13

what are the primary spermatocytes?

Answer 13

has 23 pairs of chromosomes that are diploid, divide by meiosis, after finishing the first meiotic division it forms secondary spermatocytes

Question 14

what are secondary spermatocytes?

Answer 14

contains 23 chromosomes only that are haploid, after they finish the 2nd meiotic division, they produce spermatids

Question 15

what are spermatids?

Answer 15

immature sperm that contains 23 chromosomes only that are haploid, spermatids develop into sperm

Question 16

what is sperm?

Answer 16

will shed cytoplasm from the spermatid and develop the head, mid piece, and tail

Question 17

what is the acrosome cap?

Answer 17

enzymes on the head of sperm

Question 18

what is the head?

Answer 18

the head of sperm contains nucleus and DNA

Question 19

what is the midpiece?

Answer 19

contains mitochondria

Question 20

what is the SRY gene?

Answer 20

region of Y chromosome that initiates a cascade of genes to induce the development of the testis

Question 21

what happens when a gonad has the SRY gene?

Answer 21

germ cells in the medulla proliferate to form the testes

Question 21

what happens when a gonad doesn’t have the SRY gene?

Answer 21

germ cells in the cortex proliferate to form the ovaries

Question 22

prophase 1

Answer 22

double stranded chromosomes pair up, crossing over occurs

Question 23

what is crossing over and what does it do?

Answer 23

genetic material is exchanged between homologous chromosomes creating genetic diversity

Question 24

metaphase 1

Answer 24

pairs of homologous chromosomes form two lines in the middle of the cell, the side where the sperm and egg chromosomes go for each pair is random, and spindle fibers attach to replicated chromosomes

Question 24

anaphase 1

Answer 24

pairs of homologous chromosomes are separated and pulled to opposite ends of the cell, each chromosome is still replicated and not pulled apart

Question 25

telophase 1

Answer 25

cell finishes 1st meiotic division producing 2 daughter cells, daughter cells each have 23 replicated chromosomes each chromosome contains 2 sister chromatids, parent cells had 23 pairs of chromosomes but daughter cells have only 23 chromosomes total

Question 25

metaphase 2

Answer 25

replicated chromosomes align at the center of the cell

Question 26

prophase 2

Answer 26

replicated chromosomes gather, crossing over does not occur since there are no homologous pairs of chromosome

Question 26

telophase 2

Answer 26

4 cells produced each have 23 with single stranded chromosomes each chromosome has 1 chromatid, cytokinesis begins, 4 cells are gametes

Question 27

anaphase 2

Answer 27

sister chromatids pulled apart to opposite ends of the cell, become single stranded chromosomes

Question 28

what is trisomy?

Answer 28

an extra copy of a chromosome. 3 instead of 2

Question 29

what is monosomy?

Answer 29

a single copy of a chromosome, absence of one of two sets of chromosomes