What is cancer?

Cancer is a disease caused by uncontrolled cell division.

What causes cancer cells to divide uncontrollably?

Mutations in genes that control the cell cycle

What is a tumour?

A mass of cells formed by uncontrolled cell division.

What is a benign tumour?

A tumour that stays in one place and does not spread.

What is a malignant tumour?

A tumour that can invade other tissues and spread around the body.

What is a stem cell?

An unspecialised cell that can divide and develop into different cell types.

What is active transport?

The movement of substances from a low concentration to a high concentration using energy.

Does active transport move substances against the concentration gradient?

Yes.

Give one example of active transport in plants.

Mineral ions moving into root hair cells

What is osmosis?

The movement of water molecules through a partially permeable membrane from high water concentration to low water concentration.

What happens to a potato in distilled water?

It gains mass because water enters by osmosis.

What happens to a potato in a concentrated sugar solution?

It loses mass because water leaves by osmosis.

What variable is usually measured in the potato osmosis practical?

Change in mass.

Why are potato pieces kept the same size?

To make the test fair.

What is a microscope used for?

To observe small objects that cannot be seen clearly with the naked eye.

What is the magnification equation?

Magnification = Image size ÷ Real size

What unit is often used for cell size?

Micrometres (µm).

What is a specialised cell?

A cell adapted to carry out a specific function.

How is a sperm cell specialised?

It has a tail for movement and many mitochondria for energy.

How is a root hair cell specialised?

It has a large surface area to absorb water and minerals.

What is a eukaryotic cell?

A cell that contains a nucleus and membrane-bound organelles.

Give two examples of eukaryotes.

Animal cells and plant cells.

What is a prokaryotic cell?

A cell that does not contain a nucleus.

Give one example of a prokaryote

Bacteria.