Cell division and development

Question 1

What is mitosis?

Answer 1

Mitosis is a process where a single cell divides into two identical daughter cells (cell division).

Question 2

Why is mitosis important?

Answer 2

The major purpose of mitosis is for growth and to replace worn out cells. Mitosis plays an important part in the life cycle of most living things, though to varying extents. In unicellular organisms such as bacteria, mitosis is a type of asexual reproduction, making identical copies of a single cell. In multicellular organisms, mitosis produces more cells for growth and repair. The importance of mitosis for the individual is influenced by whether it is single-celled or multicellular organism.

Question 3

Chromosomes

Answer 3

Contains genetic information
The nucleus of a cell contains chromosomes
Chromosomes are coiled up lengths of DNA molecules
Each chromosome carries a large number of genes
Different genes control the development of different characteristics, e.g. hair colour
Body cells normally have two copies of each chromosome
There are 23 pairs of chromosomes in a human cell.

Question 4

DNA

Answer 4

DNA is the chemical that all of the genetic material in a cell is made up from
It contains all the instructions to put an organism together and make it work
A DNA molecule is made up of two strands of DNA coiled together. They make a double helix (a double-stranded spiral)
A DNA strand is a polymer. A polymer is something made up of lots of smaller pieces joined together
DNA is found in the nucleus of animal and plant cells
It’s found in really long structures called chromosomes

Question 5

Genes

Answer 5

A gene is a small section of DNA found on a chromosome