cell cycle

Question 1

Interphase

Answer 1

cell grows and copies its chromosomes; 90% of cell cycle

Question 2

G1 phase

Answer 2

about 5-6 hours; mRNA and proteins required for DNA synthesis; some organelle replication

Question 3

S phase

Answer 3

10-12 hours; sister chromatids form but are not visible yet

Question 4

G2 phase

Answer 4

4-6 hours; final checkpoint before mitosis; some organelle replication

Question 5

centrosome

Answer 5

spindle microtubules are assembled here for cell cycle

Question 6

centrioles

Answer 6

pair are found in animal centrosome but are not essential; not in plants

Question 7

aster

Answer 7

radial array of short microtubules extends from each centrosome

Question 8

kinetochore microtubules

Answer 8

during prometaphase some spindle microtubules attach to kinetochores of sister chromatids

Question 9

prophase

Answer 9

first phase of mitosis; sister chromatids are visible

Question 10

prometaphase

Answer 10

second mitosis stage; nuclear envelope fragments; sister chromatids attach to kinetochore microtubules

Question 11

metaphase

Answer 11

third mitosis stage; sister chromatids line up at metaphase plate

Question 12

anaphase

Answer 12

fourth mitosis stage; sister chromatids separate into chromosomes

Question 13

telophase

Answer 13

fifth mitosis stage; nuclear envelope forms and mitosis is complete

Question 14

cytokinesis

Answer 14

animal cells-formation of a cleavage furrow; plant cells-formation of cell plate

Question 15

binary fission

Answer 15

reproduction by prokaryotes (bacteria and archaea)

Question 16

dinoflagellate mitosis

Answer 16

unicellular protists nuclear envelope remains intact and chromosomes attach to nuclear envelope; microtubules pass through nucleus inside cytoplasmic tunnels

Question 17

diatoms

Answer 17

unicellular protists also nuclear envelope remains intact; microtubules form a spindle within the nucleus

Question 18

cyclin dependent kinases

Answer 18

the presence of cyclin and its kinase promotes the passage of different checkpoints

Question 19

G2 checkpoint

Answer 19

maturation promoting factor (MPF) rises during S and G2 phase and is present to degrade the nuclear lamina in prometaphase

Question 20

cell division regulators

Answer 20

density dependent inhibition and anchorage dependence