Cell Division and Cell Death

Question 1

Steps of cell proliferation (division)

Answer 1

DNA replication, DNA segregation, cytokinesis

Question 2

Cell proliferation is essential for…

Answer 2

Reproduction, embryogenesis, tissue (growth, regeneration, and repair)

Question 3

Cell cycle steps

Answer 3

G1 phase, s phase, G2 phase, mitosis

Question 4

G1 phase

Answer 4

Cell increases in size, maintains single copy of chromosomes, highly variable duration, ends with G1 to S transition where commitment is made to DNA replication and cell division

Question 5

S phase

Answer 5

DNA replication occurs, 2 sister chromatids formed from each chromosome

Question 6

G2 phase

Answer 6

Preparation for mitosis (assembly of structures that move chromaids to opposite sides of the dividing cells)

Question 7

G0 phase

Answer 7

Resting phase of the cell cycle

Question 8

Kinases

Answer 8

Proteins that phosphorylate other proteins

Question 9

Function of CDKs

Answer 9

Specific forgets which are activated or inactivated, regulate cell cycle

Question 10

Cyclins

Answer 10

Synthesised and destroyed at different points in the cell cycle, presence or absence regulates CDKs, concentrations peak at different points in the cell cycle

Question 11

Retinoblastoma protein

Answer 11

Inhibits progression through the cell cycle by preventing progression from G1 to S

Question 12

Cell cycle checkpoints

Answer 12

G1 (DNA damage, unfavorable conditions), S (DNA damage, incomplete replication), G2 (DNA damage, un-duplicated chromosomes), M (chromosome unattached to spindle)

Question 13

Regulation of cell cycle

Answer 13

Cell damage triggers production of p21, binds to CDK2, prevents cycling binding, cell cycle pauses.
If repaired, p21 breaks down, if not apoptosis occurs

Question 14

Oncogenes

Answer 14

Positive regulators of cell division, become overactive or more highly expressed, can drive unregulated cel division, includes growth factors, their receptors, and other factors that stimulate cell division

Question 15

Tumor suppressors

Answer 15

Negative regulators of cell division, inactive in cancer cells

Question 16

5 stages of mitosis

Answer 16

Prophase, prometaphase, metaphase, anaphase, telophase

Question 17

Prophase

Answer 17

Chromatin condenses into chromosomes, centrosomes move to opposite poles, mitodic spindles start to form

Question 18

Prometaphase

Answer 18

Nuclear envelope breaks down, spindle formation and attachment to chromosomes is completed

Question 19

Metaphase

Answer 19

Centromeres align of the cell’s equator, chromosomes align on the metaphase plate

Question 20

Anaphase

Answer 20

Chromatids separate, regulated by m-phase CDK, activates anaphase-promoting complex (APC)

Question 21

Polar microtubules

Answer 21

Run from one pole to the other, connect centrosomes, stabilise structures

Question 22

Kinetochore microtubules

Answer 22

Attach kinetochores to the spindle

Question 23

Telophase

Answer 23

Spindle disappears, nuclear envelope forms around each set of daughter chromosomes, chromatin de-condenses

Question 24

Cylokenesis

Answer 24

Cell membrane furrows, driven by actin-myosin driven contraction, forms contractile ring, cell splits

Question 25

Necrosis

Answer 25

Cell death caused by damaging agents by cell swelling, lysis, and loss of membrane integrity

Question 26

Apoptosis

Answer 26

Cell becomes detached from neighbours, decreases in size, chromain condenses and is digested into fragments, cells form blebs that break up into apoptotic bodies, these are engulfed by neighbouring cells

Question 27

Apoptosis regulators

Answer 27

Hormones, growth factors, toxins, viral infection, DNA damage

Question 28

capases (proteases)

Answer 28

Cleave specific targets after an aspartic acid residue, present in cytoplasm and mitochondria, inhibited by IAP proteins, mediated by mediator capases

Question 29

Executor capases

Answer 29

Activated by cleavage by initiator capases, hydrolyse proteins of (nuclear envelope, nucleosomes, cytoskeleton, and cell membrane)

Question 30

Bcl-2

Answer 30

Inhibits apoptosis by preventing opening of membrane pores