Chapter 12

Question 1

What is the purpose of mitosis in multicellular orgnaisms?

Answer 1

• Development from zygote

- Growth and repair

Question 2

Genome

Answer 2

All the DNA in a cell

Question 3

Why is DNA coiled into chromosomes?

Answer 3

To condense so that each cell receives that accurate amount of genetic information

Question 4

What does 1 chromosome consist of?

Answer 4

1 long coiled strand of DNA and protein

Question 5

Centromere

Answer 5

Narrow waist between replicated chromosome where chromatids are attached

Question 6

In which phase does the centriole replicate?

Answer 6

G2

Question 7

What is the centrosome?

Answer 7

Microtubule organizing center

Question 8

What forms from centrosomes?

Answer 8

Spindle microtubules and aster

Question 9

How do microtubules shorten during anaphase?

Answer 9

Depolymerizing at the kinetochore

Question 10

What do the microtubules that don’t connect to kinetochores do?

Answer 10

Overlap each other and elongate cell

Question 11

What is the process that seperates animal cells?

Answer 11

Cleavage

Question 12

What forms during cleavage?

Answer 12

Cleavage furrow

Question 13

How do plant cells perform cytokinesis?

Answer 13

Cell plate forms from vesicles from golgi apparatus

Question 14

How does a cleavage furrow split cell?

Answer 14

Actin microfilaments interact with myosin proteins to form ring and contract

Question 15

Explain the steps of binary fission

Answer 15

Chromosomes replicates beginning at origin of replication and the two chromatin move to each side. Origins push to elongate and form new cells

Question 16

If DNA is the same in every somatic cell, how do some cells divide quicker?

Answer 16

Through checkpoints

Question 17

What is the cell cycle driven by?

Answer 17

Specific chemical signals present in cytoplasm

Question 18

What is the most important checkpoint?

Answer 18

G1 checkpoint

Question 19

What happens if cell at G1 checkpoint does not receive signal to go ahead?

Answer 19

It will enter G0, nondividing phase

Question 20

What are cyclin-dependent kinases?

Answer 20

Regulatory protein that needs to be activated by cyclin to work

Question 21

What is a cyclin?

Answer 21

Regulatory protein that activates Cdk to form complex that triggers cells passage past certain checkpoint

Question 22

What is MPF?

Answer 22

Cyclin-dependent kinase and cyclin complex that triggers cell’s passage past G2 checkpoint into M phase

Question 23

What happens to the cyclin of MPF after the M phase is over?

Answer 23

It is destroyed

Question 24

How does the cyclin and MPF concentration change during the cell cycle?

Answer 24

Cyclin gradually increases and increases at point between G2 and interphase; MPF only appears during that point

Question 25

What happens if not all kinetochores are connected to a microtubule?

Answer 25

Kinetochores send out internal signal to delay anaphase

Question 26

What are the three external signals?

Answer 26

- Growth factors - Density-dependent inhibition - Anchorage dependence

Question 27

What are growth factors

Answer 27

Proteins released that stimulate other cells to divide

Question 28

What is density-dependent inhibition?

Answer 28

If area is too crowded, surrounding cells use receptor proteins to signal cell to stop dividing

Question 29

What is anchorage dependence?

Answer 29

Most animal cells need to be attached to a surface before division (another cell or in culture)

Question 30

How do cancer cells disregard growth factors?

Answer 30

- Make own growth factor - Convey signal without presence of the receptor - Have abnormal cell cycle control system

Question 31

What is transformation?

Answer 31

Process that converts normal cell to cancerous cell

Question 32

What is a benign tumor?

Answer 32

When cancerous cells remain at original site

Question 33

What is a malignant tumor?

Answer 33

When cancerous cells invade surrounding tissues

Question 34

What is the process of metastasize?

Answer 34

When malignant tumors transport cancer cells to other parts of body and form secondary tumors