Topic 1.6: Cell Division

Question 1

Define cell cycle

Answer 1

an ordered set of events which culminates in the division of a cell into two daughter cells

Question 2

What is an ordered set of events which culminates in the division of a cell into two daughter cells?

Answer 2

cell cycle

Question 3

Define interphase

Answer 3

The stage in the development of a cell between two successive divisions

Question 4

What is The stage in the development of a cell between two successive divisions?

Answer 4

interphase

Question 5

What are the 3 stages of interphase?

Answer 5

G1, S, G2

Question 6

What happens during G1 of interphase?

Answer 6

First intermediate gap stage in which the cell grows and prepares for DNA replication

Question 7

What happens during S of interphase?

Answer 7

Synthesis stage in which DNA is replicated

Question 8

What happens during G2 of interphase?

Answer 8

Second intermediate gap stage in which the cell finishes growing and prepares for cell division

Question 9

What stage of interphase is the First intermediate gap stage in which the cell grows and prepares for DNA replication?

Answer 9

G1

Question 10

What stage of interphase is the Synthesis stage in which DNA is replicated?

Answer 10

S

Question 11

What stage of interphase is the Second intermediate gap stage in which the cell finishes growing and prepares for cell division
?

Answer 11

G2

Question 12

Define M phase

Answer 12

The period of the cell cycle in which the cell and contents divide to create two genetically identical daughter cells

Question 13

What is The period of the cell cycle in which the cell and contents divide to create two genetically identical daughter cells?

Answer 13

M phase

Question 14

What are the two stages of M phase?

Answer 14

mitosis and cytokinesis

Question 15

What happens during mitosis?

Answer 15

Nuclear division, whereby DNA (as condensed chromosomes) is separated into two identical nuclei

Question 16

What happens during cytokinesis of M phase?

Answer 16

Cytoplasmic division, whereby cellular contents are segregated and the cell splits into two

Question 17

What stage of M phase does Nuclear division, whereby DNA (as condensed chromosomes) is separated into two identical nuclei?

Answer 17

mitosis

Question 18

What stage of M phase does Cytoplasmic division, whereby cellular contents are segregated and the cell splits into two?

Answer 18

cytokinesis

Question 19

What happens during interphase of mitosis? (4)

Answer 19

DNA is present as uncondensed chromatin (not visible under microscope)
DNA is contained within a clearly defined nucleus
Centrosomes and other organelles have been duplicated
Cell is enlarged in preparation for division

Question 20

What happens during prophase of mitosis? (4)

Answer 20

DNA supercoils and chromosomes condense (becoming visible under microscope)
Chromosomes are comprised of genetically identical sister chromatids (joined at a centromere)
Paired centrosomes move to the opposite poles of the cell and form microtubule spindle fibres
The nuclear membrane breaks down and the nucleus dissolves

Question 21

What happens during metaphase of mitosis? (3)

Answer 21

Microtubule spindle fibres from both centrosomes connect to the centromere of each chromosome
Microtubule depolymerisation causes spindle fibres to shorten in length and contract
This causes chromosomes to align along the centre of the cell (equatorial plane or metaphase plate)

Question 22

What happens during anaphase of mitosis? (3)

Answer 22

Continued contraction of the spindle fibres causes genetically identical sister chromatids to separate
Once the chromatids separate, they are each considered an individual chromosome in their own right
The genetically identical chromosomes move to the opposite poles of the cell

Question 23

What happens during telophase of mitosis? (4)

Answer 23

Once the two chromosome sets arrive at the poles, spindle fibres dissolve
Chromosomes decondense (no longer visible under light microscope)
Nuclear membranes reform around each chromosome set
Cytokinesis occurs concurrently, splitting the cell into two

Question 24

During what stage of mitosis is DNA is present as uncondensed chromatin (not visible under microscope)?

Answer 24

interphase

Question 25

During what stage of mitosis is DNA is contained within a clearly defined nucleus?

Answer 25

interphase

Question 26

During what stage of mitosis is Centrosomes and other organelles have been duplicated?

Answer 26

interphase

Question 27

During what stage of mitosis is Cell is enlarged in preparation for division?

Answer 27

interphase

Question 28

During what stage of mitosis is DNA supercoils and chromosomes condense (becoming visible under microscope)?

Answer 28

prophase

Question 29

During what stage of mitosis is Chromosomes are comprised of genetically identical sister chromatids (joined at a centromere)?

Answer 29

prophase

Question 30

During what stage of mitosis is Paired centrosomes move to the opposite poles of the cell and form microtubule spindle fibres?

Answer 30

prophase

Question 31

During what stage of mitosis is The nuclear membrane breaks down and the nucleus dissolves?

Answer 31

prophase

Question 32

During what stage of mitosis is Microtubule spindle fibres from both centrosomes connect to the centromere of each chromosome?

Answer 32

metaphase

Question 33

During what stage of mitosis is Microtubule depolymerisation causes spindle fibres to shorten in length and contract?

Answer 33

metaphase

Question 34

During what stage of mitosis is This causes chromosomes to align along the centre of the cell (equatorial plane or metaphase plate)?

Answer 34

metaphase

Question 35

During what stage of mitosis is Continued contraction of the spindle fibres causes genetically identical sister chromatids to separate?

Answer 35

anaphase

Question 36

During what stage of mitosis is Once the chromatids separate, they are each considered an individual chromosome in their own right?

Answer 36

anaphase

Question 37

During what stage of mitosis is The genetically identical chromosomes move to the opposite poles of the cell?

Answer 37

anaphase

Question 38

During what stage of mitosis is Once the two chromosome sets arrive at the poles, spindle fibres dissolve?

Answer 38

telophase

Question 39

During what stage of mitosis is Chromosomes decondense (no longer visible under light microscope)?

Answer 39

telophase

Question 40

During what stage of mitosis is Nuclear membranes reform around each chromosome set?

Answer 40

telophase

Question 41

What is the first step to cytokinesis in animal cells?

Answer 41

After anaphase, microtubule filaments form a concentric ring around the centre of the cell

Question 42

After the After anaphase, microtubule filaments form a concentric ring around the centre of the cell what is the next step to cytokinesis in animal cells?

Answer 42

The microfilaments constrict to form a cleavage furrow, which deepens from the periphery towards the centre

Question 43

After The microfilaments constrict to form a cleavage furrow, which deepens from the periphery towards the centre what is the next step to cytokinesis in animal cells?

Answer 43

When the furrow meets in the centre, the cell becomes completely pinched off and two cells are formed

Question 44

After When the furrow meets in the centre, the cell becomes completely pinched off and two cells are formed what is the last step to cytokinesis in animal cells?

Answer 44

Because this separation occurs from the outside and moves towards the centre, it is described as centripetal

Question 45

What is the first step to cytokinesis in plant cells?

Answer 45

After anaphase, carbohydrate-rich vesicles form in a row at the centre of the cell (equatorial plane)

Question 46

After the After anaphase, carbohydrate-rich vesicles form in a row at the centre of the cell (equatorial plane) what is the next step to cytokinesis in plant cells?

Answer 46

The vesicles fuse together and an early cell plate begins to form within the middle of the cell

Question 47

After The vesicles fuse together and an early cell plate begins to form within the middle of the cell what is the next step to cytokinesis in plant cells?

Answer 47

The cell plate extends outwards and fuses with the cell wall, dividing th cell into two distinct daughter cells

Question 48

After The cell plate extends outwards and fuses with the cell wall, dividing th cell into two distinct daughter cells what is the last step to cytokinesis in plant cells?

Answer 48

Because this separation originates in the centre and moves laterally, it is described as centrifugal

Question 49

What are cyclins?

Answer 49

a family of regulatory proteins that control the progression of the cell cycle

Question 50

What are a family of regulatory proteins that control the progression of the cell cycle?

Answer 50

cyclins

Question 51

How do cyclins work?

Answer 51

Cyclins activate cyclin dependent kinases (CDKs), which control cell cycle processes through phosphorylation

Question 52

Define tumors

Answer 52

are abnormal cell growths resulting from uncontrolled cell division and can occur in any tissue or organ

Question 53

Define cancers

Answer 53

Diseases caused by the growth of tumours

Question 54

What are abnormal cell growths resulting from uncontrolled cell division and can occur in any tissue or organ?

Answer 54

tumors

Question 55

What are Diseases caused by the growth of tumours called?

Answer 55

cancers

Question 56

Define mutagen

Answer 56

an agent that changes the genetic material of an organism (either acts on the DNA or the replicative machinery)

Question 57

What is an agent that changes the genetic material of an organism (either acts on the DNA or the replicative machinery)?

Answer 57

mutagen

Question 58

Define carcinogens

Answer 58

Mutagens that lead to the formation of cancer

Question 59

What are Mutagens that lead to the formation of cancer called?

Answer 59

carcinogens

Question 60

Define oncogene

Answer 60

a gene that has the potential to cause cancer

Question 61

What is a gene that has the potential to cause cancer?

Answer 61

oncogene

Question 62

What are the two classes of genes that mutations happen to that cause cancers?

Answer 62

proto-oncogenes and tumour suppressor genes

Question 63

What do proto-oncogenes code for?

Answer 63

code for proteins that stimulate the cell cycle and promote cell growth and proliferation

Question 64

What do tumor suppressor genes code for?

Answer 64

code for proteins that repress cell cycle progression and promote apoptosis

Question 65

What types of genes code for proteins that stimulate the cell cycle and promote cell growth and proliferation?

Answer 65

proto-oncogenes

Question 66

What types of genes code for proteins that repress cell cycle progression and promote apoptosis?

Answer 66

tumor suppressor genes

Question 67

Define metastasis

Answer 67

the spread of cancer from one location (primary tumour) to another, forming a secondary tumour

Question 68

What is the spread of cancer from one location (primary tumour) to another, forming a secondary tumour?

Answer 68

metastasis