Differentiation

What is fertilisation in multicellular organisms?

The fusion of a male and female gamete to produce a zygote.

What happens after fertilisation in multicellular organisms?

The zygote divides repeatedly to form an embryo with many genetically identical cells.

What are the initial characteristics of cells in an embryo?

Initially, all cells are unspecialised.

What is cell differentiation?

The process that leads to the formation of specialised cells and tissues.

How do cells become specialised?

Cells develop to become specialised, each adapted to carry out one specific role.

What happens to genes during cell differentiation?

Certain genes are 'switched on' or expressed, while others are not.

What does it mean when certain genes are expressed in differentiated cells?

Only specific types of proteins or gene products are produced.

What do gradients of signalling chemicals indicate in an embryo?

A cell's position in the embryo and the pathway of differentiation it follows.

What makes up multi-cellular organisms after differentiation?

Many specialised cells form specialised tissues and organs.

What is the relationship between muscle cells, muscle tissue, and organs?

Muscle cell —> muscle tissue —> organ —> organ system

What can tissues be made of?

One type of cell

How are organs composed in multicellular organisms?

Organs are made of several different types of tissues working together.

What are organ systems made of?

Several different organs working together.

Examples (eye)

Retinal tissue in the retina of the eye.

Example (skeletal muscle)

Striated muscle tissues.

Example: ST

Skin tissue.

Example (plants)

Transport tissue is responsible for water and sugar transport.