Mitosis

Question 1

Define mitosis

Answer 1

type of nuclear division where the daughter cells have the same number of chromosomes as the parent cell

Question 2

Describe the difference between meiosis and mitosis

Answer 2

Meiosis= 4 daughter cells which are haploids ( half the number of chromosomes as the parents cell)
Mitosis= 2 daughter cells which are diploids( the same number of chromosomes as the parents cell)

Question 3

What precedes mitosis?

Answer 3

interphase

G1= the cell grows
Synthesis= the DNA  and chromosomes replicate organelles replicates
G2= cell prepares for cell division

Question 4

Name the stages of mitosis

Answer 4

Prophase
Metaphase
Anaphase
Telophase

Question 5

Describe what occurs in Prophase

Answer 5

Chromosomes become visible
Centriole move to the poles of the cells (not in plants)
Spindle fibres develop from centriole
Nuclear envelope breaks down and nucleolus disappears

Question 6

Describe what occurs in Metaphase

Answer 6

Chromosomes= 2 chromatids
chromatids joined by centromere
microtubule from poles attach to centromere
Chromosomes pulled along spindle apparatus and are arranged along the equator

Question 7

Describe what occurs in Anaphase

Answer 7

Centromere divided in two
Spindle fibres pulls chromatids apart chromatids move to opposite poles and are called chromosomes
energy provided by mitochondria which gather around spindle fibres

Question 8

What happens if the spindle is destroyed and which part of mitosis does this affect?

Answer 8

Anaphase

the chromosomes stay at the equator and are unable to move to the pole

Question 9

Describe what occurs in Telophase

Answer 9

chromosomes reach respective poles become longer and thinner before disappearing leaving only chromatin
Spindle disintegrates
Nuclear envelope and nucleolus reform
Cytokinesis

Question 10

How do cells divide in prokaryotic cells ?

Answer 10

Binary fission

Question 11

Describe binary fission

Answer 11

Circular DNA replicates and attaches to the cell membrane

Plasmids replicate,cell membrane grows and pinch occurs between DNA so the cytoplasm splits

new cell wall forms between DNA so the daughter cells have a single copy of circular DNA but varied number of plasmids

Question 12

How do viruses replicate?

Answer 12

they are non living so cannot divide on their own. Instead they use the cell mechanism of the host cell,

Question 13

Describe how viruses replicate

Answer 13

Attach to host cells with attachment proteins
Inject own nucleic acid into host cell
genetic material instructs host cells metabolic process to produce viral components which assemble into new viruses

Question 14

Why is mitosis important?

Answer 14

For growth, repair and reproduction