Chapter 8

Question 1

asexual reproduction

Answer 1

1. offspring from a single parent

2. offspring and parent are genetically identical

Question 2

sexual reproduction

Answer 2

1. offspring from two parents

2. offspring is a unique combination of genes from two parents

Question 3

binary fission

Answer 3

1. chromosome duplicates and moves to opposite poles
2. cell elongates
3. cytoplasm divides

Question 4

chromatin

Answer 4

loosely packed DNA and proteins

Question 5

chromosomes

Answer 5

condensed, chromatin present immediately before cell division

Question 6

sister chromatids

Answer 6

both sides of a chromosome each containing the SAME genetic information

Question 7

centromere

Answer 7

area where sister chromatids are attached

Question 8

cell cycle

Answer 8

series of events extending from the time a cell is formed until it divides into two

Question 9

phases of cell cycle

Answer 9

interphase, mitosis, cytokinesis

Question 10

interphase

Answer 10

G0: non-dividing phase (heart and brain)
G1: cell grows in size, function
S: DNA synthesis (replication) occurs
G2: Cell continues to grow and prepare for division

Question 11

mitosis (M)

Answer 11

nuclear division

Question 12

cytokinesis

Answer 12

cytoplasm division

Question 13

events of mitosis

Answer 13

prophase
prometaphase
metaphase
anaphase
telophase

Question 14

prophase

Answer 14

spindle is forming, centrioles migrate to opposite ends of the cell

Question 15

prometaphase

Answer 15

chromosomes form, nucleolus and nuclear membrane disperse

Question 16

metaphase

Answer 16

spindle fully formed, chromosomes aligned single file with centromeres at metaphase plate

Question 17

anaphase

Answer 17

chromosomes separate at centromere, move towards opposite poles, cell elongates

Question 18

telophase

Answer 18

cell elongation continues, nucleolus and nuclear envelope reform, chromatin forms

Question 19

events of cytokinesis

Answer 19

Animal cells - ring of microfilaments contracts into cleavage furrow
Plant cells - vesicles fuse into a membranous cell plate which develops into a cell wall

Question 20

anchorage dependence

Answer 20

being in contact with a solid surface

Question 21

density-dependent inhibition

Answer 21

cells stop dividing when they touch each other

Question 22

growth factors

Answer 22

proteins secreted by cells stimulating other cells to divide

required for division, division stops when no more growth factor

Question 23

cell cycle control system

Answer 23

cyclical operating set of molecules that triggers and coordinates key events in the cell cycle
if a growth factor is not released at three major checkpoints, the cell cycle will stop

Question 24

cyclins

Answer 24

a group of proteins regulating cell cycle by binding to Cdks

Question 25

cyclin-dependent kinases (Cdk)

Answer 25

always present in cell, activated when bound to cyclins

Question 26

when does cancer occur?

Answer 26

occurs when cells do not respond normally to the cell cycle control system

Question 27

what makes cancer dangerous?

Answer 27

uncontrollable division | can invade other body tissues

Question 28

why doesn't every abnormal cell turn into a tumor or cancer?

Answer 28

immune system does destroy malformed cells however, some evade destruction

Question 29

benign tumors

Answer 29

abnormal cells remain at original site, take up space, easily removed

Question 30

malignant tumors

Answer 30

abnormal cells spread to other tissues and parts of the body, displace tissues, interrupt organ function, signal blood vessels to grow into it

Question 31

metastasis

Answer 31

spread of cancer via circulatory

Question 32

major categories of cancer

Answer 32

carcinomas sarcomas leukemias/lymphomas

Question 33

carcinomas

Answer 33

originate in coverings of the body (skin)

Question 34

sarcomas

Answer 34

originate in tissues that support the body (bone)

Question 35

leukemias/lymphomas

Answer 35

originate in blood-forming tissue

Question 36

abilities of stem cells

Answer 36

can divide and renew themselves for long periods of time remain undifferentiated in form develop into a variety of specialized cell types