Topic 1 - Cell Biology - Cell Differentation and Specialisation

What is cell differentiation?

The process by which a cell changes to become specialised for its job.

What do cells develop as they differentiate to carry out specific functions?

Different subcellular structures (and turn into different types of cells).

When is the ability to differentiate lost in most animal cells?

At an early stage, after they become specialised.

Do plant cells ever lose the ability to differentiate?

Lots of plant cells never lose the ability to differentiate.

What are cells that differentiate in mature animals mainly used for?

Repairing and replacing cells, such as skin or blood cells.

What are stem cells?

Undifferentiated cells that can divide to produce more cells that can differentiate.

What is the function of a sperm cell?

To get the male DNA to the female DNA.

How is a sperm cell adapted for reproduction?

1. Long tail and streamlined head to swim. 2. Lots of mitochondria for energy. 3. Enzymes in head to digest egg cell membrane.

What is the function of a nerve cell?

To carry electrical signals from one part of the body to another.

How is a nerve cell adapted for rapid signalling?

1. Long to cover more distance. 2. Branched connections at ends to connect to other nerve cells and form a network.

What is the function of a muscle cell?

To contract quickly.

How is a muscle cell adapted for contraction?

1. Long so they have space to contract. 2. Contains lots of mitochondria to generate energy for contraction.

What is the function of root hair cells?

Cells on the surface of plant roots specialised for absorbing water and mineral ions from the soil.

How are root hair cells adapted for absorbing water and minerals?

Grow into long "hairs" that stick out into the soil, giving the plant a big surface area.

What is the function of phloem and xylem cells?

Form tubes which transport substances such as food and water around plants.

How are phloem and xylem cells structurally adapted to form tubes?

They are long cells joined end to end.

Why are xylem cells hollow in the centre?

So substances can flow through.

Why do phloem cells have very few subcellular structures?

So substances can flow through.

Explain why root hair cells do not contain chloroplasts.

They grow underground, do not receive light, and do not perform photosynthesis.

Why don't all specialised cells contain the same subcellular structures?

It depends on their function; cells don't contain structures they have no use for.