Biology AQA additional science - CELLS

Animal and Plant cells both have:

Nucleus - Contains genetic material, controlling the activities of the cell.

Cytoplasm - This is where the majority of chemical processes take which are controlled

by enzymes.

Cell Membrane - This contols the substances that move in and out of the cell.

Mitochondria - The majority of energy is released here through respiration.

Ribosomes - This is where protein synthesis* takes place.

Only plant cells have:

Cell Wall - The cell wall strengthens the cell.

Chloroplasts - These contain chlorophyll which absorb light energy used in

photosynthesis.

Permanent Vacuole - This is filled with sap to keep the cell turgid

A specialised cell is where the structure of the cell is adapted to the function it must carry out; here are four common specialised cells:

A leaf cell:

This cell is packed full of chloroplasts so it can absorb plenty of light energy for photosynthesis. The cell has a regular shape and is closely packed together with other leaf cells to absorb light energy efficiently.

A sperm cell:

A sperm cell's function is to fertilize an egg cell (female gamete). The cell has three main parts: the tail which is used to move the sperm cell to reach the egg cell, the middle section which is packed full of mitochondria for energy and the head which contains all genetic information as well as an enzyme to help penetrate the egg cell itself.

A red blood cell:

This cell is adapted to contain haemoglobin to carry oxygen to the cells. The reason it is specialised is because it has no nucleus so it can carry as much hamoglobin as possible. It also has a thin cell membrane to let oxygen diffuse more easily and finally it's shape increases the surface area to allow oxygen to be absorbed mor efficiently.

A root hair cell:

The function of a root hair cell is to absorb water and mineral ions from the soil. What makes the cell specialized is that it has adapted a long 'finger like' shape with a very thin cell wall, therefor giving it more surface area allowing more water and mineral ions to be absorbed.