Chapter 10 - How Cells Divide

Question 1

Bacteria divide by:

Answer 1

binary fission

Question 2

Replication of bacteria begin at the:

Answer 2

origin of replication

Question 3

What forms to divide the cell into 2 cells?

Answer 3

a septum

Question 4

linear chromosomes

Answer 4

Eukaryotic chromosomes

Question 5

chromatin

Answer 5

a complex of DNA and proteins

Question 6

heterochromatin

Answer 6

not expressed

Question 7

euchromatin

Answer 7

expressed regions

Question 8

DNA wrapped around a core of 8 histone proteins

Answer 8

nucleosome

Question 9

What holds a nucleosome together?

Answer 9

histone proteins

Question 10

Further coiling of a nucleosome creates the 30-nm fiber or_______

Answer 10

solenoid

Question 11

The particular array of chromosomes of an organism

Answer 11

karyotype

Question 12

Chromosomes must be ___________ before division.

Answer 12

replicated

Question 13

Replicated chromosomes are connected to each other at their ________.

Answer 13

kinetochores

Question 14

Complex of proteins holding replicated chromosomes together

Answer 14

cohesin

Question 15

2 copies of the chromosome within the replicated chromosome

Answer 15

sister chromatids

Question 16

What phases of the cell cycle are considered interphase?

Answer 16

G1 (gap phase 1), S (synthesis), G2 (gap phase 2)

Question 17

What are the 5 main phases of the Eukaryotic Cell Cycle?

Answer 17

G1
S
G2
M
C

Question 18

G1 (gap phase 1)

Answer 18

time of cell growth

Question 19

S phase

Answer 19

synthesis of DNA (DNA replication); 2 sister chromatids are produced

Question 20

G2 (gap phase 2)

Answer 20

chromosomes condense

Question 21

Proteins of the kinetochore are attached to the _________.

Answer 21

centromere

Question 22

Microtubules attach to the ____________.

Answer 22

kinetochore

Question 23

During G2 the chromosomes undergo ___________, becoming tightly coiled.

Answer 23

condensation

Question 24

Microtubule-Organizing Centers

Answer 24

centrioles

Question 25

5 Phases of Mitosis

Answer 25

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

Question 26

What happens during Prophase of Mitosis?

Answer 26

- chromosomes continue to condense and become visible - centrioles move to each pole of the cell - spindle apparatus is assembled - nuclear envelope dissolves - chromosomes appear as two sister chromatids held together at the centromere

Question 27

Prometaphase:

Answer 27

- 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 28

Metaphase of Mitosis:

Answer 28

-microtubules pull the chromosome to align them at the center of the cell

Question 29

Imaginary plane through the center of the cell where the chromosomes align.

Answer 29

metaphase plate

Question 30

Anaphase of Mitosis:

Answer 30

- removal of cohesin proteins - centromeres separate - microtubules shorten and pull sister chromatids toward the poles

Question 31

Telophase of Mitosis:

Answer 31

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

Question 32

Cleavage of the cell into equal halves.

Answer 32

cytokinesis - in animal cells-produces a cleavage furrow - in plant cells-forms a cell plate between the nuclei - in fungi and some protist-mitosis in nucleus, division of nucleus with cytokinesis

Question 33

How many check points control the cell cycle?

Answer 33

3

Question 34

What are the three checkpoints the control the cell cycle?

Answer 34

1. G1/S checkpoint 2. G2/M checkpoint 3. late metaphase (spindle) checkpoint

Question 35

What happens at the G1/S checkpoint?

Answer 35

the cell "decides" to divide

Question 36

What happens at the G2/M checkpoint?

Answer 36

the cell makes a commitment to mitosis

Question 37

What happens at the late metaphase (spindle) checkpoint?

Answer 37

the cell ensures that all chromosomes are attached to the spindle

Question 38

Proteins produced in synchrony with the cell cycles that regulate passage of the cell through cell cycle checkpoints.

Answer 38

cyclins

Question 39

Enzymes that drive the cell cycle.

Answer 39

cyclin-dependent kinases (Cdks)

Question 40

_______ activates the proteins that remove cohesin holding sister chromatids together.

Answer 40

anaphase-promoting complex (APC)

Question 41

Growth factors:

Answer 41

- can influence the cell cycle - trigger intracellular signalling systems - can override cellular controls that otherwise inhibit cell division

Question 42

platelet-derived growth factor (PDGF)

Answer 42

triggers cells to divide during wound healing

Question 43

Two kinds of genes can disturb the cell cycle when they are mutated:

Answer 43

1. tumor-suppressor genes | 2. proto-oncogenes

Question 44

Tumor-suppressor genes:

Answer 44

prevent the development of many cells containing mutations; ex. p53 halts cell division if damaged DNA is detected

Question 45

Proto-oncogenes:

Answer 45

- some encode receptors for growth factors, some encode signal transduction proteins - become oncogenes when mutated