chapter 4-sexual cell reproduction

Question 1

daughter cells contain…

Answer 1

half the number of chromosomes from their parent (1N)

Question 2

the process of creating haploid cells enables species to…

Answer 2

maintain a constant chromosome number from generation to generation.

Question 3

what happens when haploid cells fuse during fertilization?

Answer 3

diploid cells form containing parental chromosome number (2N)

Question 4

what is meiosis 1 known as?

Answer 4

reduction division

Question 5

what happens in meosis 1?

Answer 5

• chromosome number is reduced by one half

- homologous paired chromosomes separate to opposite ends

Question 6

what is segregation?

Answer 6

when homologous paired chromosomes separate to opposite ends

Question 7

what happens in crossing over?

Answer 7

genetic material exchanges= greater diversity

Question 8

what happens in meiosis 2?

Answer 8

• separation of the sister chromatids

- 4daughter cells from original parent cell

Question 9

what is gametogenesis?

Answer 9

it’s the process in which sex cells are formed

Question 10

gametogenesis in males:

Answer 10

single cell produces 4 identical sperm cells all capable of fertilazation

Question 11

gametogenesis in females:

Answer 11

a single cell produces three polar bodies containing 1N chromosomes but very little cytoplasm
=not used in fertilization
4th cell = ootidreceives most of the cytoplasmic material =used for fertilazation.

Question 12

what is nondisjunction?

Answer 12

the failure of the separation of sister chromatids or homologous chromosomes

Question 13

when does nondisjunction occur?

Answer 13

when homologous chromosomes move to the same pole during meiosis

Question 14

result of nondisjunction?

Answer 14

one daughter cell = missing one chromosome, the other carrying an extra

Question 15

list some disorders

Answer 15

trisomy-3 copies of a chromosome
(Down syndrome=extra chromosome in #21)

monosomy- carries a single chromosome rather than a homologous pair(Turner syndrome=carries only x)

Question 16

why is cell division important?

Answer 16

growth,repair, reproduction

Question 17

chromosomes?

Answer 17

long threads of genetic material found in the nucleus of a cell

Question 18

chromatids?

Answer 18

single stands of a chromosome

Question 19

centromeres?

Answer 19

structures that hold chromatids together

Question 20

centrioles?

Answer 20

small protein bodies that are in the cytoplasm of an animal cell

Question 21

spindle fibers?

Answer 21

protein structures that divide chromosomes during cell division

Question 22

what happenes in prophase?

Answer 22

spindle fibers act as guide wires for attachment and movement of the chromosomes during division

Question 23

what happenes in metaphase?

Answer 23

chromosomes composed of sister chromatids move towards the center of the cell

Question 24

what happenes in anaphase?

Answer 24

centromeres divide and chromatids move to opposite poles

Question 25

what happenes in telephase?

Answer 25

chromosomes lengthen and intertwine.spindle fibers dissolve. nuclear membrane forms around each mass of chromatin.

Question 26

what is Interphase?

Answer 26

cell activity between cell divisions. cells grow, carry out chemical activities that sustain life. cells produce protein to prep for mitosis

Question 27

what is cytokinesis?

Answer 27

division of cell cytoplasm must provide organelles for each of the new cells

Question 28

what is cloning?

Answer 28

identical offspring are produced from a single cell or tissue.

Question 29

What is the process of meiosis?

Answer 29

it is the process by which sex cells are formed