Chapter 11

Question 1

What four events must occur for cell division

Answer 1

Reproductive Signal: initiate cell division
Replication: DNA replication and cell growth
Segregation: Distribute DNA into two cells
Cytokinesis: Separation of the new cells

Question 2

What reproduction do prokaryotes use

Answer 2

binary fission

Question 3

How are prokaryotes DNA usually found
How are eukaryotes DNA found

Answer 3

Pro: circular
Euk: linear

Question 4

What two external factors initiate cell division

Answer 4

nutrient concentration
environmental conditions

Question 5

What are interphases three subphases

Answer 5

G1: between mitosis and S phase
S phase: DNA replicates
G2: after S and before mitosis

Question 6

Sister Chromatids definition

Answer 6

two identical molecules of DNA double helix that make up a chromosome

Question 7

Why is DNA packaged tightly

Answer 7

So they do not separate and get tangled (spools of thread)

Question 8

Sister chromatids are held together by what

Answer 8

COHESIN

Question 9

Removal of what will have mitosis move forward

Answer 9

COHESIN

Question 10

What are microtubules made out of?

Answer 10

two centrioles
microtubule organizing centers
spindle radiates outward

Question 11

Mitosis is ________, but 5 stages have been named to characterize the process

Answer 11

continuous

Question 12

What are the 5 stages in mitosis

Answer 12

prophase, prometaphase, metaphase, anaphase, telophase

Question 13

What happens during prophase

Answer 13

chromosomes compact/coil becoming visible (packaging)
microtubules form between the centrosomes to make the spindle
kinetochores develop in the centromere regions

Question 14

What happens during prometaphase

Answer 14

nuclear envelop breaks down
chromosomes attach to the kinetochore microtubules (extend from centrosomes to attach to chromosomes)

Question 15

What happens during metaphase

Answer 15

chromosomes lined up at the middle of the cell (NOT PAIRED)

Question 16

What happens during anaphase

Answer 16

sister chromatids separate and move to opposite ends of the spindle–referred to as “daughter” chromosomes

Question 17

What causes the moval of chromosomes toward their sides

Answer 17

microtubules shortening

Question 18

What happens during telophase

Answer 18

chromosomes finish moving and uncoil
spindle breaks down
the nuclear envelope is reformed

Question 19

What motor proteins are the cause of the contraction of the ring

Answer 19

actin and myosin (in cytokinesis)

Question 20

In cytokinesis, other organelles segregate _______; no special mechanism

Answer 20

randomly

Question 21

What is the cause for plant cells to divide

Answer 21

New cell wall fuzing

Question 22

Somatic cell definition

Answer 22

body cells not specialized for reproduction

Question 23

Germ cell definition

Answer 23

make the gametes (haploid cells)

Question 24

How do homologous pairs differ from one another

Answer 24

they have different allels

Question 25

What is another word for tetrad

Answer 25

bivalent (4 chromatids)

Question 26

Chromosome homologs are held together at ________ that forms between non-sister chromatids

Answer 26

chiasmata (crossing over)

Question 27

The number of chromosomes at the equatorial plate in ________ is ____ the number of those in mitosis

Answer 27

Meiosis II, half

Question 28

Where does independent assortment occur in meiosis

Answer 28

anaphase I (random segregation of homologous pairs)

Question 29

What are polar bodies?

Answer 29

They are female gametes that do not turn into functional products/eggs

Question 30

In mitosis what is the only stage in which there is not 46 chromosomes

Answer 30

anaphase

Question 31

What are the main differences between mitosis and meiosis?

Answer 31

Mitosis: one somatic division, cytokinesis at the end of telophase, 2 cells produced, genetic clones Meiosis: two cell divisions, cytokinesis at end of telophase I and II, 4 haploid cells produced, genetic recombination and diversity, chromatids do not separate during anaphase I

Question 32

Crossing over definition and when does it occur

Answer 32

homologs cross over to exchange genetic material prophase I

Question 33

Independent assortment definition and when does it occur

Answer 33

homologs randomly line up during anaphase I

Question 34

What are growth factors?

Answer 34

external chemical signals that stimulate cells to divide

Question 35

Experiment: A cell in S phase contains an activator of DNA replication. A cell in S phase is combined with a cell in G1 phase. What are the results and conclusion?

Answer 35

The fuzed cell has two nuclei. The S phase cell produces a substance that diffuses to the G1 nucleus and activates DNA replication

Question 36

Are CDKs always present in the cells

Answer 36

yes

Question 37

A kinase is an enzyme that catalyzes _____________. Cdks are activated by binding to _______.

Answer 37

phosphorylation, cyclins (goes up and down in concentration during the cell cycle)

Question 38

What are the two outcomes when a checkpoint is activated

Answer 38

repair or cell death

Question 39

DNA damage activates protein kinases that ___________ p53.

Answer 39

phorphorylates

Question 40

phosphorylated p53 acts as a ____________ that turns on genes that inhibit the cell cycle

Answer 40

transcription factor

Question 41

___________ the cell cycle gives the cell time to repair the damaged DNA

Answer 41

inhibiting

Question 42

When fixed p53 is ________ and processes move _____

Answer 42

shut down, on

Question 43

p53 is only activated when _____

Answer 43

phosphorylated

Question 44

Definition of oncogene and proto-oncogene

Answer 44

oncogene: mutated form of a gene that promotes cancer proto-oncogene: the unaltered verision of an oncogene

Question 45

oncogenes play a role in ______ cancer. Cancer ___ usually caused by _____, but by chemical agents instead

Answer 45

human, not, viruses

Question 46

Definition of tumor suppressor

Answer 46

proteins whose normal activities inhibit cell division

Question 47

Necrosis causes cells to swell and burst. This leads to _______ because cell contents are released to the extracellular environment

Answer 47

inflamation

Question 48

Events of apoptosis:

Answer 48

cells are cut up, form blebs, surrounding cells eat the dead cells (this limits inflammation)

Question 49

What are caspases

Answer 49

proteolytic (protein breakdown) enzymes, their role in controlling cell death and inflammation

Question 50

The removal of growth factors equals

Answer 50

cell death

Question 51

Mutational activated RAS is an example of

Answer 51

an oncogene

Question 52

A cell dies in apoptosis because

Answer 52

it is programmed to die

Question 53

A mutation acquired by a bacterium will very likely be inherited by all daughter cells

Answer 53

true

Question 54

What DNA sequences are most alike

Answer 54

a pair of sister chromatids

Question 55

A skin cell in G2 of interphase has _______ as much DNA as it had in G1

Answer 55

twice

Question 56

What would happen during cell division if the cell was deficient in actin?

Answer 56

the cell would not divide

Question 57

Synapsis occurs during

Answer 57

prophase I of meiosis