Biology Unit 3- chapter 12

Question 1

what is bacterial cell division called?

Answer 1

Binary fission

Question 2

does binary fission work

Answer 2

replicate and separate genomes within the cell then divide. ends with two identical cells that are identical to each other and the beginning cell

Question 3

what are the two forms of cell division in Eukaryotes?

Answer 3

mitosis and meiosis

Question 4

what do you end with after mitosis?

Answer 4

two diploid cells identical to to each other and the beginning cell

Question 5

what do you end with after meiosis?

Answer 5

four haploid cells- 1/2 of original DNA in each cell

Question 6

what is meiosis used for

Answer 6

sex cells- gametes- sperm and egg

Question 7

what are the phases of the Eukaryotic cell cycle in order?

Answer 7

G1, S, G2, and M

Question 8

what is G1 in the cell cycle?

Answer 8

longest phase, cells are most active metabolically

Question 9

what is S in the cell cycle?

Answer 9

when DNA synthesis takes place

Question 10

what is G2 in the cell cycle?

Answer 10

cell prepares for DNA division

Question 11

what is M in the cell cycle?

Answer 11

cell division- nuclear division and cytokinesis

Question 12

what is interphase?

Answer 12

anything besides mitosis

Question 13

what was the research done on if the M-phase was controlled by the cytoplasm or the nucleus?

Answer 13

they injected cytoplasm from the M-phase cell and a regular cell into one frog oocyte, then same with nucleus

Question 14

what is the conclusion from the research of the M-phase

Answer 14

the M-phase cytoplasm contains a regulatory molecule that induces M phase in interphase cells.

Question 15

what is the molecule called that induces M-phase

Answer 15

M-phase promoting factor (MPF)

Question 16

what are the two parts of the MPF

Answer 16

cyclin (regulator) and CDK (kinase that catalyzes phosphorylation)

Question 17

what happens to the levels of Cyclin and Cdk during the cell cycle?

Answer 17

Cdk stays constant, but Cyclin peaks right before the transition from G2 into M-phase

Question 18

what is Cdk regulated by?

Answer 18

phosphates and Cyclin

Question 19

how is Cdk regulated by phosphate?

Answer 19

one phosphate has to be in the correct orientation for Cdk to be active. phosphate bonded to active site not inhibiting site.

Question 20

what is MPF specifically made of?

Answer 20

Cyclin B and Cdk 1

Question 21

what are cell cycle checkpoints?

Answer 21

they are where decisions whether or not to proceed through the cell are made

Question 22

how many checkpoints are there in the cell cycle?

Answer 22

three

Question 23

what are the three checkpoints in the cell cycle?

Answer 23

G1, G2, M-phase

Question 24

what do cells need to pass the G1 checkpoint?

Answer 24

1. adequate cell size
2. sufficient nutrients
3. social signals are present
4. undamaged DNA

Question 25

what do cells need to pass the G2 checkpoint?

Answer 25

1. chromosomes have successfully replicated 2. DNA is undamaged 3. activated MPF is present

Question 26

what do cells need to pass the M-phase checkpoint?

Answer 26

1. chromosomes have attached to spindle apparatus 2. chromosomes have properly segregated and MPF is absent

Question 27

What happens if cells do not pass the checkpoints?

Answer 27

1. the cell stalls and attempts to fix it 2. the cell dies

Question 28

How do the checkpoints work?

Answer 28

they work by regulating the activity of the appropriate cdk (phosphorylation, production of cyclin)

Question 29

what are two examples of social signals?

Answer 29

growth factors and mitogens

Question 30

why is mitogen needed?

Answer 30

activation needed to drive the cell cycle

Question 31

why is the growth factor needed?

Answer 31

activation needed for nutrient uptake and utilization

Question 32

what is Rb?

Answer 32

S-phase inhibitor, most common mitogen signalling pathways that activate G1 cyclin/cdk inhibit Rb

Question 33

what is E2F?

Answer 33

inactivator of Rb

Question 34

what happened in the mitogen signaling at the G1 checkpoint and the S phase transition? 6 steps

Answer 34

1. mitogens arrive from other cells 2. mitogens cause increase in cyclin and E2F concentrations 3. Cyclin binds to Cdk; Cdk is phosphorylated. Rb inactivates E2F by binding to it. 4. inactivating phosphate is removed and active Cdk phosphorylated Rb 5. Phosphorylated Rb releases E2F 6. E2F triggers production of S-phase protein

Question 35

what is the p21 gene?

Answer 35

Cdk inhibitor - inhibits the cell cycle through cyclin kinase pathway

Question 36

what are benign tumor cells?

Answer 36

they continue to divide by are not invasive they do not spread outside of the tumor

Question 37

what are malignant tumor cells?

Answer 37

they divide and spread to adjacent tissues and to distant tissues through lymphatic vessels and blood vessels

Question 38

what are proto-onogenes?

Answer 38

cause genes to activate and grow them are not suppose to

Question 39

what are tumor suppressor genes?

Answer 39

genes whose normal function is to stop cel cycle progression

Question 40

how does cancer happen?

Answer 40

cells lose the ability to regulate their cell cycle

Question 41

chromosome definition

Answer 41

A structure containing genetic information in the form of genes

Question 42

chromatin definition

Answer 42

the material that makes up eukaryotic chromosomes; consists of a DNA molecule complexed with histone proteins

Question 43

Chromatid

Answer 43

one double stranded DNA copy of a replicated chromosome with its associated proteins

Question 44

sister chromatids

Answer 44

the two attached, double stranded DNA copies of a replicated chromosome

Question 45

centromere

Answer 45

a specialized region of a chromosome where sister chromatids are most closely joined to each other

Question 46

kinetochores

Answer 46

the structure on sister chromatids where microtubules attach

Question 47

microtubule- organizing center

Answer 47

any structure that organizes microtubules

Question 48

centrosome

Answer 48

the microtubule- organizing center in animals and certain plants and fungi

Question 49

centrioles

Answer 49

cylindrical structures consisting of microtubules triplets, located inside animal centrosomes