All cells arise from other cells

Question 1

Mitosis

Answer 1

The division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell

Question 2

What happens during prophase

Answer 2

Chromatin shortens to form chromosomes
Nucleolus and nuclear envelope disappears
centrioles go to the opposite ends of the poles of the cell and spindle fibres are produced by centrioles

Question 3

What happens during metaphase

Answer 3

Spindle fibres attach to centromeres
Centromeres line up on the equator of the cell

Question 4

What happens during anaphase

Answer 4

Chromosomes pulled apart at the centromere by spindle fibres
Chromosomes move to the poles of the cell

Question 5

Telophase

Answer 5

Chromosomes detach from the spindle fibres
spindle fibres disappear
Chromosomes uncoil and become chromatin
Nucleolus and nuclear envelope reappear

Question 6

Cytokinesis

Answer 6

Division of the cytoplasm

Question 7

What are the 3 stages of the cell cycle

Answer 7

Interphase, mitosis, cytokinesis

Question 8

Cancer and the control of mitosis

Answer 8

• cancer is the result of damage to the genes
• leading to uncontrolled cell division
• tumours are most commonly found in the lungs, breast and ovaries.
• They are cancerous if they change from benign to malignant

Question 9

What is mitosis important for

Answer 9

Growth and repair

Question 10

Treatment of cancer

Answer 10

-Involves killing dividing cells by blocking a part of the cell cycle
- chemotherapy usually disrupts the cell cycle by preventing DNA replicating and inhibiting the metaphase stage of mitosis by interfering with spindle formation

Question 11

What are the 4 stages of mitosis

Answer 11

Prophase, metaphase, anaphase, telophase

Question 12

Describe binary fission in bacteria

Answer 12

-Replication of DNA
-Replication of plasmids
-Division of cytoplasm

Question 13

Suggest and explain how 2 environmental variables could be changed to increase the growth rate of bacteria.

Answer 13

-Increase temperature
-increase enzyme activity
-Increase oxygen concentration
-Increase respiration

Question 14

Name the fixed position occupied by a gene on a DNA molecule

Answer 14

Locus

Question 15

replication of viruses

Answer 15

viruses are non-living and replicate by attaching to host cells by attachment proteins and injecting nucleic acid into the cell.
This provides the instructions to produce the viral protein