Cell cycle

Question 1

Anucleate Cells

Answer 1

• have no nucleus
• skin cells
• 3 lens fibers
• RBCs

Question 2

Nuclear envelope

Answer 2

• outer part of nucleus
• 50% pores
• connected to ER

Question 3

Nucleoplasmin

Answer 3

• pentamers
• first chaperone protein discovered
• nucleosome assembly
• genome stability
• transcription regulation

enters nuceus via ATP dependent receptors on nuclear pores

Question 4

Lamin

Answer 4

• intermediate filament only found in nucleus
• A, B, and C types
• interconnects chromatin to form nuclear skeleton

Question 5

Lamin B

Answer 5

• phosphorylated by MPF
• associated with dissolution of nucleus in prophase M

Question 6

Get cells to stall at G1

Answer 6

• Amino Acid deprivation
• Serum deprivation
• protein synthesis inhibition

Question 7

get cells to stall at M

Answer 7

microtubule inhibitors

Question 8

get cells to stall at S

Answer 8

DNA synthesis inhibitors

Question 9

Cyclins and CDK

Answer 9

• bind together to activate
• initiates mitosis
• phosphorylates proteins for DNA synthesis
• controls metaphase-anaphase transition

Question 10

Cyclin D

Answer 10

• forms CDK4/6
• regulates mitosis, less functional in cancer
• promotes G1 ==> S

Question 11

Early Response / Late response genes

Answer 11

• early response genes promote protein synthesis of proteins that promote cell division and differentiation, activate late response genes
• late response genes wil promote protein synthesis of proteins that aid in DNA synthesis and repair

Question 12

G1 checkpoint

Answer 12

• checks if ready for DNA synthesis
• checks external factors
• checks if cell is big enough
• checks resources for cell division
• pardee point either committs to S or reverts to G0
• p53

Question 13

S phase

Answer 13

• occurs solely in nucleus
• DNA unwound and replicated identically (sister chromatids)
• 2 chromatids on 1 centromere (x like structure)

Question 14

Replicons

Answer 14

in charge of the S phase

Question 15

Replication in low CDK state

Answer 15

1. ORC (origin recognition complex) is on DNA
2. Cdc6 and Cdt1 (ATP binding proteins) attach to ORC
3. Cdc6 and Cdt1 bind MCM helicase to ORC
4. MCM helicase unwinds the DNA for replication

Question 16

Replication in high CDK state

Answer 16

1.ORC (origin recognition complex) is on DNA
2.Cdc6 and Cdt1 (ATP binding proteins) attach to ORC
3.ORC detaches from DNA
4.Cdc45, GINS, and dpbll bind to MCM and activate it
5.DNA polymerase is loaded to make identical copy

Question 17

G2 phase

Answer 17

• new organelles synthesized
• microtubules and proteins are synthesized
• checks for errors in DNA synthesis
• early organization of cytoskeleton
• chromosome condensing
• MPFB triggers transition to M phase

Question 18

M phase

Answer 18

• most dramatic but shortest
• terget for chemotherapy
• ER forms new nuclear envelope
  1. prophase
  2. metaphase
  3. anaphase
  4. telophase

Question 19

prophase

Answer 19

• first step
• chromosomes condense and are visible on microscope
• mitotic spindle of microtubules forms
• lamin B dissolves nuclear envelope

Question 20

metaphase

Answer 20

• second step
• chromosomes line up in the middle of the cell (metaphase plate)

Question 21

anaphase

Answer 21

• 3rd step
• spindle pulls chromosomes to either end of the cell
• CDK activity decreases

Question 22

telophase

Answer 22

• last step
• 2 new cells are formed
• chromosomes decondense
• nuclear envelope reforms around chromosomes from ER

Question 23

P53

Answer 23

• Tumor suppressor gene
• mutated P53 found in 50% of all cancers
• ATM-R stablizes P53
• activates P21, stopping S phase
• determines if cell can keep dividing or apoptose