slide 3

Question 1

cell division

Answer 1

The ability of organisms to produce more of their own
kind distinguishes living things from nonliving matter.
The continuity of life is based on the reproduction of
cells, or cell division

Question 2

In unicellular organisms,

Answer 2

division of one cell

reproduces the entire organism.

Question 3

Multicellular organisms depend on cell division for

Answer 3

• Development from a fertilized cell
• Growth
• Repair

Question 4

cell cycle

Answer 4

the

life of a cell from formation to its own division.

Question 5

Cell division

Answer 5

is a controlled process resulting in

genetically identical daughter cells

Question 6

Cells duplicate their genetic material

Answer 6

before
they divide, ensuring that each daughter cell
receives an exact copy of the genetic code

Question 7

genome

Answer 7

All the DNA in a cell constitutes the cell’s genome

Question 8

A genome can consist of

Answer 8

a single DNA molecule
(common in prokaryotic cells) or a number of DNA
molecules (common in eukaryotic cells)

Question 9

chromosomes.

Answer 9

DNA molecules in a cell are packaged into

chromosomes.

Question 10

chromatin

Answer 10

The combined DNA and protein complex is called chromatin

Question 11

Every eukaryotic species has a characteristic number of
chromosomes. Chromosomes come in pairs with one of
each pair inherited from each parent

Answer 11

Humans have 23 pairs

= 46 chromosomes

Question 12

sister chromatids.

Answer 12

During cell replication each chromosome is duplicated. It is
connected to its copy. These connected copies of the
chromosome are called sister chromatids

Question 13

The centromere

Answer 13

is the narrow “waist” of the
duplicated chromosome, where the two
chromatids are most closely attached

Question 14

The two sister chromatids separate and move into

two nuclei before the cell divides into two

Answer 14

Once separate, the chromatids are chromosomes

Question 15

Eukaryotes have two types of cells

Answer 15

Somatic cells

and gametes

Question 16

Somatic cells

Answer 16

– typical cells of the body, contain the

full genome, the full set of chromosomes

Question 17

Gametes –

Answer 17

reproductive cells including sperm and

eggs, contain half the chromosomes in somatic cells

Question 18

meiosis.

Answer 18

Gametes (sperm and eggs) are produced by a

variation of cell division called meiosis

Question 19

Meiosis yields

Answer 19

nonidentical daughter cells that have
only one set of chromosomes, half as many as the
parent cell.

Question 20

The cell cycle of somatic cells consists of

Answer 20

• interphase

- mitotic (M) phase

Question 21

Interphase

Answer 21

(cell growth and copying of

chromosomes in preparation for cell division)

Question 22

Mitotic (M) phase

Answer 22

(mitosis and cytokinesis)

Question 23

interphase (about 90% of the cell cycle) can be

divided into subphases

Answer 23

– G1 phase (“first gap”)
– S phase (“synthesis”)
– G2 phase (“second gap”)
The cell grows during all three phases, but
chromosomes are duplicated only during the S phase.

Question 24

interphase (about 90% of the cell cycle) can be

divided into subphases

Answer 24

– G1 phase (“first gap”)
– S phase (“synthesis”)
– G2 phase (“second gap”)
The cell grows during all three phases, but
chromosomes are duplicated only during the S phase.

Question 25

Mitosis

Answer 25

the division of duplicated chromosomes

Question 26

Mitosis is conventionally separated into five phases

Answer 26

``` – Prophase – Prometaphase – Metaphase – Anaphase – Telophase ***Cytokinesis overlaps the latter stages of mitosis. ```

Question 27

G2 of interphase

Answer 27

Chromosomes have been duplicated but aren’t condensed. Two centrosomes have formed that will organize the mitotic spindle.

Question 28

The mitotic spindle is

Answer 28

``` a structure made of microtubules that controls chromosome movement during mitosis. ```

Question 29

An aster

Answer 29

(a radial array of short microtubules) extends from each centrosome in the spindle

Question 30

Prophase:

Answer 30

Chromatin is condensed into discrete duplicated chromosomes that appear as pairs of identical sister chromatids joined at their centromeres.

Question 31

Prometaphase:

Answer 31

Nuclear envelope fragments. Each of the two sister chromatids of each duplicated chromosome has a kinetichore protein to which the microtubules of the spindle attach.

Question 32

Metaphase

Answer 32

The chromosomes are aligned at the metaphase plate, a plane equal distance from the two centrosomes.

Question 33

Anaphase

Answer 33

Sister chromatids of each pair separate and move towards opposite centrosomes. The cell elongates as the microtubules not attached to kinetichores lengthen

Question 34

Telephase

Answer 34

Two daughter nuclei form in the cell. The chromosomes become less condensed. Spindle microtubules are depolymerized.

Question 35

cleavage

Answer 35

In animal cells, cytokinesis occurs by a process | known as cleavage, forming a cleavage furrow

Question 36

In plant cells, a cell plate

Answer 36

forms during cytokinesis

Question 37

binary fission.

Answer 37

Prokaryotes (bacteria and archaea) reproduce by | a type of cell division called binary fission

Question 38

In binary fission, the chromosome replicates | (beginning at an origin of replication),

Answer 38

and the two daughter chromosomes actively move apart. The plasma membrane pinches inward, dividing the cell into two

Question 39

Regulation of the Cell Cycle

Answer 39

``` The frequency of cell division varies with the type of cell. These differences result from regulation at the molecular level. Cancer cells manage to escape the usual controls on the cell cycle. ```

Question 40

cell cycle control system

Answer 40

The sequential events of the cell cycle are directed by a distinct cell cycle control system, which is similar to a clock. The cell cycle control system is regulated by both internal and external controls. The clock has specific checkpoints where the cell cycle stops until a go-ahead signal is received

Question 41

Regulation of the Cell Cycle For many cells, the G1 checkpoint seems to be the most important.

Answer 41

If a cell receives a go-ahead signal at the G1 checkpoint, it will usually complete the S, G2 , and M phases and divide

Question 42

G0 phase.

Answer 42

If the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state called the G0 phase

Question 43

An example of an internal signal is that kinetochores not attached to spindle microtubules send a molecular signal that delays anaphase

Answer 43

External signals include growth factors, proteins | released by cells that stimulate other cells to divide

Question 44

Cancer cells do not respond normally to the body’s | control mechanisms

Answer 44

Cancer cells may not need growth factors to grow and divide, rather they . – may make their own growth factor – may convey a growth factor’s signal without the presence of the growth factor – may have abnormal cell cycle control