Division and Differentiation in Human Cells

What are somatic cells?

Any cell in the body other than cells involved in reproduction.

How many pairs of chromosomes do somatic cells have?

23

Are somatic cells diploid or haploid?

Diploid

What type of chromosomes do somatic cells have?

homologous

Type of cell division(s) in somatic cells that maintain the chromosome number

Mitosis

What are germline cells?

Gametes and the stem cells that divide to form gametes.

Two examples of gametes

Sperm and ova

Type of cell division carried out by germline cells to produce gametes

Meiosis

What type of division(s) do germline stem cells go through

mitosis and meiosis

How many single chromosomes does a cell with the diploid chromosome number have?

46

How many single chromosomes does a cell with the haploid chromosome number have?

23

How many divisions does the nucleus undergo in meiosis

2

State the stages of meiosis

• homologous chromosomes are separated

• Chromatids are separated

Explain how differentiation of tissue stem cells leads to the production of specialised cells such as red blood cells.

Switches on specific genes

Process by which an unspecialised cell develops a specialised function by expressing genes to produce proteins characteristic of that cell type.

Differentiation

Examples of how stem cells are used to repair damaged or diseased organs or tissues

Corneal transplants and regeneration of damaged skin

Reason why stem cells are used as model cells

To study how diseases develop or for drug testing.

Types of stem cells

• Embryonic

• Tissue

What does pluripotent mean?

Can differentiate into all the types of cell that make up an individual.

Are embryonic stem cells pluripotent or multipotent?

pluripotent

Why are embryonic stem cells pluripotent?

All the genes in embryonic stem cells can be switched on.

What are tissue stem cells are involved in

The growth, repair and renewal of cells found in that tissue.

Are tissue stem cells pluripotent or multipotent?

Multipotent

Why are tissue stem cells multipotent?

They can differentiate into all the types of cell found in a particular tissue type.

What types of cells can blood stem cells located in bone marrow make?

• Red blood cells

• Platelets

• lymphocytes

• phagocytes

What does tissue repair require?

The renewal of cells that have died.