Module 2:Cell Division

Question 1

How many stages are involved in the cell cycle?
What are they called?

Answer 1

3
interphase
mitosis(nuclear division)
cytokinesis(cell division)

Question 2

How would you describe the cells produced from mitosis?

What can the cells be used for?

Do cells produced by mitosis give rise to genetic variation?

Answer 2

two genetically identical diploid daughter cells

for growth and asexual reproduction of cells

no

Question 3

What happens during interphase and how many stages are there?

Answer 3

the cell grows , replicates its organelles and prepares to divide
three stages

Question 4

What is the first stage and checkpoint within interphase?

Answer 4

G1-the cell grows and organelles replicate
G1 checkpoint-if cell meets requirements it is triggered to begin DNA replication , if not it enters the G0 phase (cell leaves the cycle)

Question 5

What is the second phase within interphase?

Answer 5

S phase- DNA (chromosomes) are replicated

Question 6

What is the last stage and other checkpoint within interphase?

Answer 6

G2-cell continues to grow , energy stores increase and DNA checked for errors
G2 checkpoint-checks cell size and checks DNA for errors

Question 7

What are the 4 stages of mitosis?

Answer 7

prophase , metaphase , anaphase , telophase

Question 8

What happens during prophase?

Answer 8

nuclear envelope broken down
chromosomes condense
centrioles more to opp poles of the cell for spindle fibre formation

Question 9

What happens during metaphase?

Answer 9

chromosomes line up along metaphase plate in the centre of the cell and attach to spindle fibres via centromeres

Question 10

What happens during anaphase?

Answer 10

sister chromatids are separated at their centromere and spindle fibres pull them to opp ends of the cell

Question 11

What happens during telophase?

Answer 11

chromatids arrive at poles
new nuclear envelope formed
chromatids condense and join up to become homologous pairs again

Question 12

What happens during cytokinesis?

Answer 12

cytoplasm and cell membrane divide to produce 2 daughter cells

Question 13

What is an allele ?
What is a homologous pair?

Answer 13

allele-a different version of the same gene
homologous pair-matching set of chromosomes

Question 14

How would you describe the cells produced by meiosis?
How many times does division occur within one cycle?

Answer 14

four genetically non identical haploid gametes
2 times

Question 15

Does meiosis give rise to genetic variation , if so how?

Answer 15

yes
through crossing over of chromatids
through independent assortment of chromosomes

Question 16

What happens during prophase 1 ?
6 points

Answer 16

chromosomes condense
homologous chromosomes form bivalents
crossing over takes place
nuclear envelope disintegrates
spindle fibres form
replication occurs

Question 17

What is a bivalent?

Answer 17

made up of a pair of homologous chromosomes , has 2 chromosomes and four chromatids

Question 18

What happens during metaphase 1 ?

Answer 18

homologous chromosomes arrange at metaphase plate and independent assortment occurs

Question 19

What happens during anaphase 1?

Answer 19

spindle fibres attach to centromeres and chromosomes are pulled to either poles of the cell

Question 20

What happens during telophase 1 ?

Answer 20

nuclear envelope reforms
cytokinesis occurs to produce 2 haploid cells

Question 21

What happens during prophase 2?

Answer 21

chromosomes recoil and condense
nuclear envelope disintegrates again

Question 22

What happens during metaphase 2 ?

Answer 22

individual chromosomes assemble at the metaphase plate and independent assortment occurs

Question 23

What happens during anaphase 2 ?

Answer 23

spindle fibres attach to centromeres and contract , separating sister chromatids and pulling them to either poles of the cell

Question 24

What happens during telophase 2 ?

Answer 24

nucleolus becomes visible
nuclear envelope reforms
cytokinesis occurs producing four unique haploid cells

Question 25

Whats the main difference between meiosis 1 and 2?

Answer 25

1-whole chromosomes are pulled apart from their homologous pairs
2-sister chromatids are pulled apart