14.4

Question 1

control of the eukaryotic cell cycle

Answer 1

basic control mechanisms are conserved
1. cell cycle has 2 irreversible points
2. cell cycle can be put on hold at checkpoints

Question 2

cell cycle has 2 irreversible points

Answer 2

replication of genetic material
seperation of sister chromatids

Question 3

cell cycle can be put on hold at checkpoints

Answer 3

process can be halted if errors are detected
allows cell to respond to internal and external signals

Question 4

3 major cell cycle checkpoints

Answer 4

G1/S= nutreins. cell size, growth factors
G2/M= replication complete, DNA damage
M= spindle checkpoint= chromsomes alligned

Question 5

cell cycle control in multicellular eukaryotes

Answer 5

-central control mechansism same as single-cell eukaryotes
-key difference: cells dont reproduce until told
growth factor signal is recognized by receptor protien
activated receptor leads to express of proteins that cause cell to move past the G1/S checkpoint
multicellular organisms depend on maintenace of cell number and organization many different types of cells
failure to maintain cell number and organization create major problems for multiceulluar organisms

Question 6

failure of animal cell cycle control leads to cancer

Answer 6

cancer involves uncontrolled cell proliferation and metastasis
when mutated, 2 kinds of genes can pertrub cell cycle contrl
1. proto-oncogenes
2. tumor suppressor genes

Question 7

proto-oncogenes

Answer 7

1. normal genes that become oncogenes when mutated
2. oncogene may be overexpressed or stuck in “on state (created push)
3. gain of function mutation: only one copy needs to be mutated

Question 8

tumor-suppressor genes

Answer 8

1. normal genes that code for proteins that detect problems/ stop cycle
2. loss of safety net when inactivated or delted
3. loss of function mutation: both copy needs to be mutated