Cell Division

Question 1

Cell continuity

Answer 1

Means that all cells develop from pre-existing cells

Question 2

Chromatin

Answer 2

Chromosomes that are not dividing ( during interphase)

Question 3

Chromosomes

Answer 3

Threads of DNA and protein that become visible in the nucleus at cell division

Question 4

Haploid cell

Answer 4

One set of chromosomes

Question 5

Diploid cell

Answer 5

Two sets of chromosomes

Question 6

What are body cells also called

Answer 6

Somatic cells

Question 7

What human cells contain 23 chromosomes

Answer 7

Sperm and egg cells

Question 8

What does the cell cycle contain

Answer 8

90% Interphase mitosis 10%

Question 9

Interphase

Answer 9

Phase in the cell cycle when the cell is not dividing

Question 10

What is interphase used for

Answer 10

Processes like respiration,photosynthesis and protein synthesis

Question 11

Mitosis

Answer 11

A form of nuclear division which one nucleus divises to form two nuclei, each with identical gene in somatic cells (body cell)

Question 12

What is Mitosis used for

Answer 12

Multicellular growth and repair
Unicellular - reproduction

Question 13

What are the stages of mitosis

Answer 13

Prophase
Metaphase
Anaphase
Telophase

Question 14

Describe prophase

Answer 14

Chromatin contract and chromosomes become visible.
Nucleolus disappears and spindle fibres appear in the cytoplasm.
The nuclear membrane starts to break down

Question 15

Describe Metaphase

Answer 15

The nuclear membrane disappears completely.
A spindle fibre from each pole attaches to the centrometers of all the chromosomes. Chromosomes line up across the middle of the cell

Question 16

Describe Anaphase

Answer 16

Spindle fibres contract and pull chromosomes to opposite poles of the cells

Question 17

Describe Telophase in plant cells

Answer 17

Chromosomes lengthened and turn into chromatin. Spindle fibres breakdown and the nucleoli reform
Cytokineses from immediately after mitosis.
In Plants, cleavage cannot occur due to cell walls, a cell plate forms, the region between the cell walls is called the middle lamella

Question 18

Describe Telophase in Animals

Answer 18

Chromosomes lengthened and turn into. Spindle fibres breakdown and the nucleoli reform
Cytokineses from immediately after mitosis.
A cleavage furrow forms

Question 19

What is cancer

Answer 19

When cells lose their ability to control both the rate of mitosis and the number of times mitosis takes place

Question 20

What are tumours

Answer 20

Masses of cancerous cells

Question 21

What are benign tumours

Answer 21

Benign tumours do not spread to other tissue

Question 22

Malignant tumours

Answer 22

Malignant tumours spread and are life threatening

Question 23

What is cancer caused by (with examples)

Answer 23

Cancer is caused by carcinogens
( radiation, cigarette smoke)

Question 24

Examples of Cancer treatment

Answer 24

Surgery to remove tumours , radiation to kill cancer cells, chemotherapy (stops cell division)

Question 25

What is Meiosis

Answer 25

Nuclear division which the daughter nuclei contain half the chromosome number of their parent nucleus

Question 26

Functions of Meiosis

Answer 26

Allows for sexual reproduction while maintaining the chromosome number. Allows for variation among organisms

Question 27

Differences between Mitosis and Meiosis

Answer 27

**Mitosis** Chromosome number maintained 1 parent 2 daughter cells Daughter cells identical to parent **Meiosis** Chromosome number halted 1Parent 4 daughter cells Gametes different to parent genes