module 2 - 6.1 the cell cycle

Question 1

what is the cell cycle?

Answer 1

series of events that take place in a cell, causes it to divide into 2 DAUGHTER CELLS that are GENETICALLY DENTICAL

Question 2

what events occur in the cell cycle?

Answer 2

• replication of DNA
• duplication of some organelles
• partitioning of the cytoplasm and other components

Question 3

what is mitosis?

Answer 3

nuclear division (nuclei dividing)

Question 4

what are the 2 phases that eukaryotic cells have in the cell cycle?

Answer 4

• interphase
• mitotic phase (mitosis AND cytokinesis)

Question 5

why cant prokaryotic cells do mitosis?

Answer 5

they do not have a nucleus

Question 6

what do prokaryotic cells go through instead of mitosis?

Answer 6

binary fission (2 cells splitting)

Question 7

what does the cell cycle allow the cell to do?

Answer 7

• zygote becomes an adult organism
• allows growth and repair of tissues
• allows asexual reproduction in animals and fungi

Question 8

what is a zygote?

Answer 8

when we were 1 cell (when egg becomes fertilised)

Question 9

where does a cell spend most of its time?

Answer 9

interphase

Question 10

what is interphase?

Answer 10

• when a cell grows
• when it carries outs its metabolic functions
• end of interphase prepares for cell division (mitotic phase)

Question 11

what is the mitotic phase?

Answer 11

the cell division phase to produce 2 genetically identical daughter cells
- divided first by mitosis, then cytokinesis

Question 12

when is the G0 phase?

Answer 12

when the cell stops its own cell cycle
- can be temporary or permanent

Question 13

what happens during the G1 phase?

Answer 13

cellular contents, apart from chromosomes, are synthesised/ duplicated

Question 14

what happens during the S phase?

Answer 14

each of the chromosomes (DNA) is duplicated in nucleus

Question 15

what happens during the G2 phase?

Answer 15

• cell checks the duplicated chromosomes for error, making any repairs that are needed
• energy stores are increased

Question 16

what is the order of phases in the cell cycle?

Answer 16

. G2
/ \
S MITOSIS & CYTOKINESIS
\ /
. G1
(G0)

Question 17

when do cells only enter the mitotic phase?

Answer 17

if:
- it has grown to correct size
- DNA replication is error free
- the chromosomes are in the right place in the cell

Question 18

what ensures the fidelity of cell division?

Answer 18

checkpoints are employed to check eat stage of the cell cycle has happened correctly

Question 19

what are the 3 checkpoints?

Answer 19

• G1 checkpoint
• G2 checkpoint
• spindle assembly checkpoint

Question 20

what does fidelity mean?

Answer 20

the accuracy of copying something

Question 21

what are 5 events that can happen during interphase?

Answer 21

• DNA is replicated and checked for errors in the nucleus
• protein synthesis occurs in cytoplasm
• chloroplasts grow and divide in plant and algal cell cytoplasm
• mitochondria grow and divide
• normal metabolic processes of cells occur

Question 22

what are the 3 reasons why the cell might enter G0?

Answer 22

• differentiation
• DNA may be damaged
• age

Question 23

why can differentiation make a cell enter G0?

Answer 23

cells that become specialised may no longer be able to carry out its function
- can re enter cell cycle

Question 24

why can the DNA maybe being damaged make a cell enter G0?

Answer 24

cell may not be able to divide and so it enters a period of permanent cell arrest (G0)

Question 25

why can age make a cell enter G0?

Answer 25

as you age the number of senescent cells in your body increases which can lead to many age related diseases

Question 26

what does it mean if a cell is senescent?

Answer 26

slowly sit until they die

Question 27

what is apoptosis?

Answer 27

cell death

Question 28

where does G1 checkpoint occur?

Answer 28

end of G1 phase

Question 29

what are the requirements that need to be met by G1 checkpoint?

Answer 29

cell size, nutrients, growth factors, DNA damage

Question 30

what happens if the requirements by G1 have been met?

Answer 30

begins DNA replication

Question 31

what happens if the requirements by G1 have not been met?

Answer 31

enters G0

Question 32

where does G2 checkpoint occur?

Answer 32

end of G2 phase

Question 33

what are the requirements that need to be met by G2 checkpoint?

Answer 33

cell size, DNA replication, DNA damage

Question 34

what happens if the requirements for G2 have been met?

Answer 34

cell initiates molecular processes that signal beginning of mitosis

Question 35

what happens if the requirements for G2 have not been met?

Answer 35

enters G0 if attempt to repair at checkpoint fails

Question 36

where does spindle assembly checkpoint occur?

Answer 36

metaphase

Question 37

what are the requirements needed to be met by spindle assembly checkpoint?

Answer 37

point in mitosis where all spindle fibres should be attached to chromosomes and have been aligned

Question 38

what happens if the requirements for spindle assembly checkpoint have been met?

Answer 38

mitosis occurs

Question 39

what happens if the requirements for spindle assembly checkpoint have not been met?

Answer 39

• enters G0
• mitosis cannot proceed unless passed