ch. 10 cell reproduction

Question 1

how do prokaryotic cells divide?

Answer 1

by binary fission

Question 2

how do eukaryotic cells divide?

Answer 2

by mitosis or meiosis

Question 3

what is the result of mitosis?

Answer 3

formation of 2 daughter cells

Question 4

what forces the cell to divide in binary fission?

Answer 4

formation of a septum

Question 5

what happens during binary fission?

Answer 5

-circular chromosome replicates, beginning at an origin and proceeding bidirectionally
-new chromosomes move to opposite ends (poles) of the cell

Question 6

what are chromosomes composed of?

Answer 6

chromatin (complex of DNA and proteins)

Question 7

what are the two types of chromatin?

Answer 7

heterochromatin and euchromatin

Question 8

what must happen to chromosomes to allow best sorting and separation?

Answer 8

they must be condensed

Question 9

what is the nucleosome ?

Answer 9

DNA wrapped around a core of 8 histone proteins spaced 200 nucleotides apart

Question 10

what does further coiling create?

Answer 10

30nm fiber or solenoid

Question 11

what holds radial loops of chromatin fiber in place? what are they aided by?

Answer 11

scaffold proteins; condensing proteins

Question 12

most cells have how many versions of each chromosome?

Answer 12

2

Question 13

what does diploid mean?

Answer 13

two sets of chromosomes

Question 14

where does each pair of homologous chromosomes come from?

Answer 14

one from mother and one from father

Question 15

what are homologous chromosomes?

Answer 15

chromosomes that have similar genes (alleles) at identical locations along the DNA molecule

Question 16

what are sister chromatids?

Answer 16

replicated chromosomes

Question 17

where are sister chromatids connected? what connects them?

Answer 17

centromere; cohesion protein

Question 18

what is mitosis?

Answer 18

cell division in which all of the chromosomes are replicated, followed by a single division done in a manner that creates two identical 2N cells from a single 2N cell

Question 19

what process is used for somatic cell division?

Answer 19

mitosis

Question 20

what does mitosis create?

Answer 20

two identical 2N cells

Question 21

what is somatic cell division?

Answer 21

clonal or multicellular

Question 22

what are the 5 main phases of the cell cycle?

Answer 22

1. G1 (gap phase 1)
2. S (synthesis)
3. G2 (gap phase 2)
4. M (mitosis or meiosis, depending on cell type)
5. C (cytokinesis)

Question 23

what composes interphase?

Answer 23

G1, S phase, and G2

Question 24

what happens during Sphase?

Answer 24

DNA replication; 2 sister chromatids are produced from each chromosome

Question 25

what happens during G1?

Answer 25

cell growth

Question 26

what happens during G2?

Answer 26

chromosomes condense

Question 27

what is the centromere?

Answer 27

the region of the DNA that sister chromatids share

Question 28

what holds sister chromatids together at the centromere?

Answer 28

cohesion proteins

Question 29

where are kinetochore proteins?

Answer 29

attached at the centromere

Question 30

what do the microtubules attach to?

Answer 30

the kinetochore

Question 31

what are centrioles and what are their function?

Answer 31

microtubule-organizing centers that replicate and move to each end (pole) of the cell

Question 32

what are the five stages of mitosis in the correct order?

Answer 32

1. prophase 2. prometaphase 3. metaphase 4. anaphase 5. telophase

Question 33

what happens during prophase?

Answer 33

-chromosomes further condense -centrioles move to each pole -spindle apparatus is assembled -nuclear envelope dissolves

Question 34

what happens during prometaphase?

Answer 34

-chromosomes become attached to the spindle apparatus by their kinetochores -a second set of microtubules is formed from the poles to each kinetochore -microtubules begin to pull each chromosome toward the center of the cell

Question 35

what happens during metaphase?

Answer 35

-microtubules pull the chromosomes to align them at the center of the cell - sister chromatids line up with centromeres on the metaphase plate (imaginary plane through the center of the cell)

Question 36

what happens during anaphase?

Answer 36

-removal of cohesin allows the centromeres to separate -microtubules pull sister chromatids toward the poles -in anaphase A the kinetochores are pulled toward the poles -in anaphase B the poles move apart

Question 37

what happens during anaphase a?

Answer 37

the kinetochores are pulled toward the poles

Question 38

what happens during anaphase b?

Answer 38

the poles move apart

Question 39

what happens during telophase?

Answer 39

-spindle apparatus disassembles -nuclear envelope forms around each set of sister chromatids -chromosomes begin to uncoil -nucleolus reappears in each new nucleus

Question 40

what is cytokinesis?

Answer 40

the cleavage of the cell into halves

Question 41

what do animals use for cytokinesis?

Answer 41

a cleavage furrow

Question 42

what do plants use for cytokinesis?

Answer 42

a cell plate

Question 43

what are cyclins?

Answer 43

proteins produced in synchrony with the cell cycle

Question 44

what are cyclin-dependent kinases (Cdks)?

Answer 44

enzymes that drive the cell cycle; activated only when bound by a cyclin

Question 45

what do cyclin dependent kinases activate and how?

Answer 45

activate target proteins by phosphorylation

Question 46

what happens at the G1/S checkpoint?

Answer 46

cell “decides” to divide

Question 47

what happens at the G2/M checkpoint?

Answer 47

cell makes a “commitment” to mitosis

Question 48

what happens at the late metaphase (spindle) checkpoint?

Answer 48

cell ensures that chromosomes are attached to the spindle before dividing

Question 49

what do growth factor do?

Answer 49

trigger intracellular signals that override cell controls that otherwise inhibit cell division

Question 50

what is cancer?

Answer 50

a failure of cell cycle control resulting in runaway cell division

Question 51

what two genes can cause cancer when mutated?

Answer 51

tumor-suppressor genes and proto-oncogenes

Question 52

what is the function of tumor-suppressor genes?

Answer 52

normally prevent division in cells containing mutations

Question 53

what is the function of proto-oncogenes?

Answer 53

normally code for growth factors or signal transduction proteins that promote normal cell division

Question 54

what happens to Proto-oncogenes when mutated?

Answer 54

become oncogenes and cause runaway cell division rather than normal (controlled) cell division (oncogenes can also cause cancer when they are introduced into a new cell (e.g., viral oncogenes))