Cell Differentiation and Organisation in Multicellular Organisms

What allowed the evolution of cell specialisation?

The evolution of multicellular organisms.

What happens after fertilisation in multicellular organisms?

Repeated cell divisions produce genetically identical, unspecialised cells.

What is cell differentiation?

The process by which unspecialised cells develop into specialised cells and tissues.

Why are differentiated cells specialised?

They are adapted to carry out one specific role.

Do all cells have the same genetic makeup?

Yes, all cells contain the same genes.

How does differentiation occur if all cells have the same genes?

Some genes are switched on (expressed) while others are switched off.

What happens when specific genes are expressed?

Only specific proteins or gene products are produced.

What role does mitosis play in development?

It produces two daughter cells with identical DNA.

How do signalling chemicals affect differentiation?

They form gradients that indicate a cell’s position in the embryo and determine its differentiation pathway.

What happens once cells are fully differentiated?

They form specialised tissues and organs.

What is a tissue?

A group of differentiated cells with a similar function.

What is an organ?

A structure made of several different tissues working together.

What is an organ system?

Several organs working together.

Name examples of specialised tissues.

Epithelial tissue, muscle tissue, connective tissue, nervous tissue, transport tissue in plants.