Bacterial cells and yeast

Bacterial cells

Structure of a salmonella bacterium cell

A bacterium is a single-celled organism. A bacterial cell has a different structure to an animal or plant cell. It has cytoplasm, a membrane and a surrounding cell wall, but the genetic material in a bacterial cell is not in a distinct nucleus.

Yeast

Yeast is a single-celled organism. Like bacterial cells, yeast cells have cytoplasm and a membrane surrounded by a cell wall. But unlike bacterial cells, yeast cells have a nucleus.

Cells may be specialised for a particular function. Their structure will allow them to carry this function out. Here are some examples:

Examples of the functions of cells

CellFunctionAdaption

Leaf cell

Absorbs light energy for photosynthesis Packed with chloroplasts. Regular shaped, closely packed cells form a continuous layer for efficient absorption of sunlight.

Root hair cell

Absorbs water and mineral ions from the soil Long 'finger-like' process with very thin wall, which gives a large surface area.

Sperm cell

Fertilises an egg cell - female gamete The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg.

Red blood cells

Contains haemoglobin to carry oxygen to the cells. Thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus, so the whole cell is full of haemoglobin.

You are likely to be given information, perhaps in a diagram, to help you to explain the adaptations of a particular cell type to its function.