Cell Division

Question 1

Cell continuity

Answer 1

All cells come from pre-existing cells

Question 2

Chromosomes

Answer 2

Structures within the Nucleus, made of DNA & Protein. People have 46 of them

Question 3

Gene

Answer 3

Short section of DNA. Humans have 20-30,000 genes

Question 4

Genome

Answer 4

All genes in an organism

Question 5

Haploid

Answer 5

Has one set of chromosomes Ie has only one of each type of chromosome in the nucleus. E.g human Sperm = 23 Egg = 23

Question 6

Diploid Cell

Answer 6

Two sets of chromosomes. I.e It has two of each type of chromosome in the nucleus. 2n = Diploid
Body cells are always diploid

Question 7

Cell cycle structure

Answer 7

Interphase is big piece of diagram
Cell is smaller piece
- Cytokinesis
- Mitosis

Question 8

Interphase

Answer 8

Longest phase, 90% of cells life, chromatin, everything duplicated

Question 9

Mitosis

Answer 9

PART of cell division, division of NUCLEUS.

Question 10

Prophase

Answer 10

At the end of the interphase chromosomes contract and become more visible. Each chromosome is in a duplicated strand. Spindle fibres appear in cytoplasm at poles. Nuclear membrane breaks down

Question 11

Metaphase

Answer 11

Nuclear membrane broke down. Chromosomes line up across the cells equator. Spindle fibres attach to chromosomes. Each chromosome has 2 fibres attached (1 for each side)

Question 12

Anaphase

Answer 12

Spindle fibres contract. Chromosomes pulled apart. Each strand is pulled to the opposite end of the cell. Hence an identical set of genes pulled to each end of the cell

Question 13

Telophase

Answer 13

Nuclear membrane forms around each of the 2 sets of chromosomes. Chromosomes elongate back to chromatin within nuclei. Mitosis is done. Then cytokinesis commences

Question 14

Function of mitosis
In unicellular organisms

Answer 14

Asexual reproduction

Question 15

Function of mitosis in multicellular organisms

Answer 15

Produces more/new cells to allow us to grow.

Question 16

Cancer

Answer 16

Group of disorders in which certain cells lose their ability to control both the rate of mitosis and number of times it takes place.

Question 17

Benign tumour

Answer 17

Not life threatening

Question 18

Malignant tumour

Answer 18

Uncontrolled multiplication of abnormal cells. Other word for cancer. Movement of these cells is metastasis

Question 19

Causes of cancer

Answer 19

Carcinogens (cancer causing agents)
E.g ultraviolet radiation, chemicals in cigarettes, x-rays
Genetic mutations

Question 20

Meiosis

Answer 20

Form of nuclear division in which the daughter nuclei contains half the chromosome number of parent nuclei

Question 21

Functions of meiosis

Answer 21

• Produces haploid sex cells (sperm, egg)
• Allows for sexual reproduction without increasing the chromosome number in the offspring
• Allows for new combinations of genes. Therefore variation in offspring

Question 22

Cytokinesis

Answer 22

When the actual cell splits in two

Question 23

Cytokinesis in animal cells

Answer 23

The deepened cleavage furrow. Then the cell splits in two

Question 24

Cytokinesis in plant cells

Answer 24

• Vesicles - bags of cellulose
• Cell plate forms new cells walls to separate the cell into two
  (In between is the middle lomella)