unit 3: cell division

Question 1

the miotic phase of the cell cycle involves a pair of processes called . . .

Answer 1

mitosis and cytokinesis

Question 2

the division of the nucleus that results in two identical nuclei

Answer 2

mitosis

Question 3

the division of the cytoplasm that results in two daughter cells

Answer 3

cytokinesis

Question 4

a protein structure that moves chromosomes

Answer 4

spindle

Question 5

when does the spindle form

Answer 5

during the prophase stage of mitosis and meiosis I

Question 6

when do chromosomes separate into sister chromatids

Answer 6

anaphase of mitosis and meiosis II

Question 7

what regulates the cell cycle

Answer 7

checkpoints

Question 8

what happens if a checkpoint fails

Answer 8

uncontrolled division, which leads to cancer

Question 9

what happens at the G1 checkpoint

Answer 9

checks for cell size and DNA damage and invloves external signals

Question 10

what happens at the G2 checkpoint

Answer 10

checks for replicated DNA and DNA damage

Question 11

what happens at the M checkpoint

Answer 11

checks if the sister chromatids are correctly connected to the spindles

Question 12

during which phase of mitosis does the M checkpoint occur

Answer 12

metaphase

Question 13

what is miotic division used for

Answer 13

growth, regeneration, and asexual reproduction

Question 14

what are homologous chromosomes

Answer 14

chromosomes that are the same size, contain the same genes, and pair for meiosis

Question 15

which chromosome is not homologous

Answer 15

the y chromosome

Question 16

what is a karyotype

Answer 16

a diagram of chromosomes present in a cell, organized in homologous pairs that are usually color coded

Question 17

humans have how many chromosomes and how many pairs

Answer 17

46 chromosomes and 23 pairs

Question 18

what do sex chromosomes code for

Answer 18

sex (male or female)

Question 19

what are genes

Answer 19

sections of DNA that code for one or more related proteins or functional RNA

Question 20

what are alleles

Answer 20

different forms of the same gene

Question 21

what is ploidy

Answer 21

the number of chromosome sets present in the nuclei of eukaryotic cells

Question 22

haploid

Answer 22

single chromosome set (n)

Question 23

diploid

Answer 23

2 chromosome sets (2n)

Question 24

polyploid

Answer 24

more than 2 chromosome sets (3n, 4n, 5n, etc)

Question 25

what is meiosis

Answer 25

a type of cell division involved in sexual reproduction that results in four different nuclei that are each half of the original ploidy (ex: 2n to n)

Question 26

how many times does cytokinesis occur during meiosis

Answer 26

two

Question 27

when does DNA replication occur

Answer 27

during the s phase of interphase

Question 28

what is synapsis

Answer 28

the pairing of homologous chromosomes

Question 29

what is recombination (crossing over)

Answer 29

paired homologous chromosomes exchange segments of chromatin with each other

Question 30

what can cause genetic variation

Answer 30

independent assortment, fertilization, recombination, and mutations

Question 31

independent assortment

Answer 31

the independent and random alignment of homologous pairs during meiosis I

Question 32

fertilization

Answer 32

process in sexual reproduction in which male and female reproductive cells join to form a new cell generating an incredible amount of genetic variation

Question 33

recombination

Answer 33

process that occurs during meiosis I that produces chromosomes with different combinations of alleles than those found in the parent organism

Question 34

which type of reproduction is more efficient for producing offspring

Answer 34

asexual

Question 35

nondisjunction

Answer 35

an error that occurs during meiosis or mitosis in which chromosomes are incorrectly distributed to the daughter nuclei

Question 36

meiosis I

Answer 36

- chromatin condenses into a compact form and chromosomes are visible - synapsis and recombination occur - chromosomes line up at the equator - chromosomes are separated

Question 37

meiosis II

Answer 37

identical to mitosis

Question 38

prophase

Answer 38

- chromatin condenses into a compact form and chromosomes are visible under a microscope - spindles form

Question 39

prometaphase

Answer 39

- nuclear envelope breaks down giving the spindle access to chromosomes - spindles attach at the kinetochore protein that forms around the centromere of the chromosome

Question 40

metaphase

Answer 40

spindles pull chromosomes in both directions causing them to line up along the equator of the cell

Question 41

anaphase

Answer 41

- chromosomes separate into sister chromatids making them their own chromosome - spindles pull newly formed chromosomes to the edge of the cell - cytokinesis starts and the cell begins to stretch into an oval shape