functions of organelles

cell surface membrane

- the membrane found on the surface of animal cells and just inside the cell wall of other cells. made up of lipids and protein.

nucleus

- a large organelle surrounded by a nuclear envelope, which contains many pores. the nucleus contains chromosomes called a nucleolus.

mitochondrion

- they're usually oval shaped. they have a double membrane - the inner one is folded to form structures called cristae. inside is the matrix, which contains enzymes involved in respiration.

chloroplast

- a small, flattened structure found in plant and algal cells, surrounded by a double membrane, containing thylakoid membranes. these are stacked to form grana and linked by lamellae (thin, flat pieces of membrane).

golgi apparatus

- a group of fluid-filled membrane-bound flattened sacs. vesicles are often seen at the edges of the sacs.

golgi vesicles

- a small fluid-filled sac in the cytoplasm, surrounded by a membrane and produced by the golgi apparatus.

lysosome

- a round organelle surrounded by a membrane, with no clear internal structure. it's a type of golgi vesicle.

ribosome

- a very small organelle which floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. it's made up of proteins and rna. it's not surrounded by a membrane.

rough endoplasmic reticulum

a system of membranes enclosing a fluid-filled space. the surface is covered with ribosomes.

smooth endoplasmic reticulum

similar to rough endoplasmic reticulum, but with no ribosomes.

cell wall

- a rigid structure that surrounds cells in plants, algae and fungi. in plants and algae it's made mainly of the carbohydrate cellulose. in fungi, it's made of chitin.

cell vacuole (plants)

- a membrane-bound organelle found in the cytoplasm. it contains cell sap - a weak solution of sugar and salts. the surrounding membrane is called the tonoplast.