Cell Replication

Question 1

Function of mitosis

Answer 1

Growth, repair of tissue

Asexual reproduction

Question 2

Interphase mitosis

Answer 2

Engaged in metabolic activity in prep for mitosis

Chromatin replicated

Question 3

Prophase mitosis

Answer 3

Chromatin condenses
Nuclear envelope disintegrates
Centrioles move to opposite poles of cell, extend fibres

Question 4

Metaphase mitosis

Answer 4

Spindle fibres align chromosome along equator

Ensure that during anaphase, each new nucleus receives 1 copy of each chromosome

Question 5

Anaphase mitosis

Answer 5

Paired chromatids pulled to opposite poles of cell after being separated at centromeres

Question 6

Telophase mitosis

Answer 6

Chromatids arrive at opposite poles of cell

Chromosomes get longer and thinner

Question 7

Cytokinesis mitosis

Answer 7

Actin fibre ring around cell centre contracts, pinching cell into 2 daughter cells

Question 8

Binary fission

Answer 8

Circular DNA replicated, both copies attach to cell membrane
Plasmids replicate, cell membrane grows between 2 DNA molecules, pinches, divides cytoplasm
New cell wall forms between 2 DNA molecules
Plasmid numbers in daughter cells vary

Question 9

Differences in mitosis in eukaryotes and prokaryotes

Answer 9

No nuclear envelope

1 chromosome

Question 10

Virus replication

Answer 10

Not living, cannot undergo cell division
Attach to host cell via attachment proteins
Inject nucleic acid (RNA DNA)
Host cell produces viral components
Assembled into new viruses
New viruses burst out of cell

Question 11

Describe how the mass of the cell changes during mitosis

Answer 11

Intense chemical activity in interphase
Chromatin replication, protein production increases cell mass
Cell undergoes mitosis, cell mass halves

Question 12

Causes of cancer

Answer 12

Mutations in DNA, affects regulation of division bad cell cycle
Divide at higher rate, proliferate
Uncontrolled abnormal mitosis, escape normal mitotic controls

Question 13

Tumours

Answer 13

Mass of cancer cells, grows, releases proteins into body to attract blood vessel growth to supply it with steady oxygen, glucose supply

Question 14

Malignant and benign

Answer 14

Grow more rapidly, life threatening

Grow more slowly, less life threatening

Question 15

Metastasis

Answer 15

Cancer cells break away from tumour travel through bloodstream to different parts of body
Start new tumours elsewhere

Question 16

Treating cancer

Answer 16

Chemo, kills dividing cells, block part of cell cycle

Prevents DNA replication, inhibits metaphase, interrupts spindle formation

Question 17

Effectiveness of chemo on cells

Answer 17

Affects cell cycle of all cells, more effective against rapidly dividing cells
Cancer cells damaged to a greater degree, fast dividing cells are vulnerable to damage, hair

Question 18

Mitotic index

Answer 18

Measure of proliferation status of a cell population
Elevated during processes that promote division, growth, repair
Prognostic tool for predicting response of cancer cells to chemo

Cell in mitosis
—

Question 19

Interphase meiosis

Answer 19

Chromatin replicated into

Question 20

Prophase I meiosis

Answer 20

Chromatin condenses into chromosomes
Nuclear envelope breaks down
Recombination

Question 21

Metaphase I meiosis

Answer 21

Homologous chromosome pairs move to equator of cell

Question 22

Anaphase I meiosis

Answer 22

Chromosomes move to opposite sides of cell

Question 23

Telophase, cytokinesis I meiosis

Answer 23

Chromosomes gather at poles of cell

Cytoplasm divides

Question 24

Prophase II meiosis

Answer 24

2 daughter haploid cells

New spindle fibres form around chromosomes

Question 25

Metaphase II meiosis

Answer 25

Chromosomes line up at equator

Question 26

Anaphase II meiosis

Answer 26

Centromeres divide

Chromatids move to opposite poles of the cells and pulled apart

Question 27

Telophase and cytokinesis II meiosis

Answer 27

Nuclear envelope forms around each set of chromosomes
Cytoplasm divides
4 grand daughter cells

Question 28

How meiosis increases variation

Answer 28

Independent segregation
Recombination
Random fertilisation of 2 haploid gametes

Question 29

Independent segregation

Answer 29

Random assortment of maternal and paternal genes in meiosis I, II in metaphase

Question 30

Recombination

Answer 30

Crossing over to form recombination chromosome

Question 31

Random fertilisation of 2 haploid gametes

Answer 31

Homologous pairs, maternal, paternal chromosomes in homologous pairs have same genes at the same loci, diff alleles

Question 32

Lytic cycle

Answer 32

Attachment 
Entry of phage DNA, degradation of host DNA
Synthesis of viral genomes and proteins
Self assembly
Release

Question 33

Attachments

Answer 33

Tail fibres bind to specific surface proteins on cell that acts as receptors

Question 34

Entry of phage DNA, degradation of host DNA

Answer 34

Sheath of tail contracts, inject phage DNA into cell, leaving empty capsid outside.
Cell DNA hydrolysed

Question 35

Synthesis of viral genomes and proteins

Answer 35

Phage DNA directs production of phage proteins and copies of the phage genome by host and viral enzymes, with components from cell

Question 36

Self assembly

Answer 36

3 separate sets of proteins self assemble to form phage

Phage genome packaged inside caspids as head forms

Question 37

Release

Answer 37

Phage directs production of enzyme that damages bacterial cell wall, allow fluid to enter
Cell swell, lyses, release, phages