Cell Structure & Transport

Cytoplasm - A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.

Nucleus - Contains genetic material, including DNA which controls the cell's activities.

Cell Membrane - Its structures is permeable to some substances but not others. Therefore it controls the movement of substances in and out of the cell.

Mitochondria - Organelles that contain the enzymes for respiration, and wheremost energy is released in respiration.

Ribosomes - Tiny structures where protein synthesis occurs.

Chloroplast - Organelles that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.

Cell Wall - Made from cellulose fibres and strengthens the cell and supports the plant.

Permanent Vacuole - Filled with cell sap.

The head of the sperm contains the genetic material for fertilisation.

The middle piece is packed with mitochondria to release energy needed to swim and fertilise the egg.

The tail enables the sperm to swim.

The nerve cell is extended, so nerves can run to and from different parts of the body. The cell has extensions and branches, so that it can communicate with other nerve cells, muscles and glands.                                                                                                               

Muscle cells contain filaments of protein that slide over each other to cause muscle contraction. They contain many well-developed mitochondria to provide the energy for muscle contraction. In skeletal muscle, the cells merge so that the muscle fibres contract in unison.

 The root hair cell has a large surface area to provide contact with soil water. It has thin walls so as not to restrict the movement of water.

 There are no top and bottom walls between xylem cells, so there is a continuous column of water running through them. Their walls become thickened and woody. They therefore support the plant.

Dissolved sugars and amino acids can be transported both up and down the stem. Companion cells provide energy required to transport substances in the phloem.