Chapter 12 terms

Question 1

mitosis

Answer 1

the division of the nucleus of a cell
Occurs in somatic cells only
Is coupled with another process called cytokinesis

Question 2

meiosis

Answer 2

a special type of division that can produce sperm and egg cells

Question 3

genome

Answer 3

All the DNA in a cell
can consist of a single DNA molecule (common in prokaryotic cells) or a number of DNA molecules (common in eukaryotic cells)

Question 4

chromatin

Answer 4

The DNA in cells that are not actively dividing

DNA and proteins loosely bound in nucleus

Question 5

chromosomes

Answer 5

Chromatin molecules in a cell are packaged into this once cell division begins

Question 6

gametes

Answer 6

(sex cells; sperm and ovum)

• • Have one set of chromosomes (haploid)
• • Human gametes have 23 chromosomes

Question 7

somatic cells

Answer 7

(all non-sex cells)

• • Have two sets of chromosomes (diploid)
• • Human somatic cells have 46 chromosomes

Question 8

ploidy

Answer 8

the number of chromosome sets in a cell

Question 9

haploid

Answer 9

one set of chromosomes per cell (N)

Question 10

diploid

Answer 10

two sets of chromosomes per cell
humans: haploid # = 23; diploid # = 46 or 23 homologous pairs
(2N)

Question 11

cohesins

Answer 11

Attaches duplicated chromosomes’ two sister chromatids along their lengths

Question 12

centromere

Answer 12

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

Question 13

replicated chromosome

Answer 13

In preparation for cell division, DNA is replicated and the chromosomes condense

Question 14

sister chromatid

Answer 14

Each duplicated chromosome has two of these (joined copies of the original chromosome), attached along their lengths by cohesins

Question 15

cytokinesis

Answer 15

the process by which the cytoplasm divides into two daughter cells (occurs during telophase of mitosis)
(the division of the cell)
–couples with mitosis

Question 16

cleavage

Answer 16

process animals undergo that begins with the formation of a contractile ring that constricts the cell at the midline forming an indentation
-cytokinesis occurs by this

Question 17

cleavage furrow

Answer 17

indentation formed by contractile ring that constricts cell at midline in cleavage process

Question 18

cell plate

Answer 18

forms during cytokinesis
-precursor structure to the cell wall formed by plants beginning to recruit cell wall materials to the middle of the cell

Question 19

cell cycle

Answer 19

the series of events that prepare a cell for division and also the division process itself
G1 “first gap”
S-phase “synthesis” 
G2 “second gap”
M-phase “mitotic phase”

Question 20

interphase

Answer 20

(cell growth and copying of chromosomes in preparation for cell division
consists of G1, S-phase, and G2

Question 21

mitotic spindle

Answer 21

a collection microtubules that orchestrates the movement of chromosomes during mitosis

Question 22

centrosome

Answer 22

the microtubule organizing center

-In animal cells, assembly of spindle microtubules begins in this

Question 23

aster

Answer 23

a radial array of short microtubules

Question 24

kinetochores

Answer 24

protein complexes that are connected to centromeres

Question 25

metaphase plate

Answer 25

midline of the cell | The replicated chromosomes are being directed towards this in prometaphase

Question 26

daughter cells

Answer 26

Most cell division results in daughter cells with identical genetic information, DNA

Question 27

binary fission

Answer 27

Bacteria and other prokaryotes reproduce through this process (division in half)

Question 28

cell cycle control system

Answer 28

The sequential events of the cell cycle are directed by a distinct cell cycle control system

Question 29

cell cycle checkpoints

Answer 29

where the cell cycle stops until a go-ahead signal is received G1 checkpoint G2 checkpoint M phase checkpoint

Question 30

cyclins

Answer 30

type of regulatory protein involved in cell cycle control

Question 31

cyclin dependent kinases (CDK)

Answer 31

type of regulatory protein involved in cell cycle control | - The activity of a Cdk rises and falls with changes in concentration of its cyclin partner

Question 32

maturation-promoting factor (MPF)

Answer 32

is a cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase