the cell cycle

Question 1

difference between mitosis and meiosis

Answer 1

mitosis produces two identical daughter cells with same number of chromosomes as parent cell

meiosis produces 4 daughter cells with half number of chromosomes of parent cell

Question 2

what is interphase

Answer 2

the phase preceding mitosis where cell is not dividing
high level of cellular activity
DNA replication occurs, two pieces of DNA remain joined at centromere

Question 3

what are the 4 stages of mitosis

Answer 3

prophase
metaphase
anaphase
telophase/ cytokinesis

Question 4

describe prophase

Answer 4

chromosomes become visible as thin threads
centrioles move to opposite poles of cell, spindle fibres develop
nucleolus disappears, nuclear envelope breaks down- freeing chromosomes
chromosomes drawn to equator, spindle fibres attach

Question 5

describe metaphase

Answer 5

chromosomes made up of two chromatids joined by a centromere
chromosomes pulled along spindle apparatus, arrange across equator

Question 6

Anaphase

Answer 6

centromeres divide in 2, spindle fibres pull chromatids apart to opposite poles
energy provided by mitochondria gathered around spindle fibres

Question 7

telophase and cytokinesis

Answer 7

chromosomes reach respective poles and disappear, leaving widely spread chromatin
spindle fibres disintegrate
nuclear envelope and nucleolus reform
cytoplasm divides in cytokinesis

Question 8

how do viruses replicate?

Answer 8

attach to host cell through attachment proteins
inject nucleic acid into host cell, providing instructions for cells metabolic processes to start producing viral components
components assembled into new virus

Question 9

why is mitosis important

Answer 9

growth of cells
repair
reproduction

Question 10

three stages of the cell cycle

Answer 10

interphase/ resting phase
nuclear division
cytokinesis

Question 11

define cancer

Answer 11

a group of diseases caused by a growth disorder of cells
result of damage to genes which regulate mitosis and the cell cycle
results in uncontrolled growth and division of cells
tumour develops and expands in size

Question 12

what are the 2 types of tumour

Answer 12

malignant- grow rapidly, less compact and more likely to be life threatening
benign- slower growth, more compact ad less likely to be life threatening

Question 13

how does chemotherapy disrupt the cell cycle

Answer 13

preventing DNA from replicating
inhibiting metaphase by interfering with spindle formation

Question 14

problems with chemotherapy

Answer 14

also damage healthy cells
but cause more damage to rapidly dividing cells so more effective against cancerous cells
however rapidly dividing healthy cells such as hair are vulnerable t damage