Functions of organelles

Description + Function of Cell-surface membrane

Description + Function of Cell-surface membrane

Description:

Found on the surface of animal cells and just inside the cell wall of other cells. Mainly made up of lipids and proteins.

Function:

Regulates the movement of substances into and out of the cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.

Description + Function of Nucleus

Description:

A large organelle surrounded by a nuclear envelope (double membrane), which contains many pores. The nucleus contains chromosomes and one or more structure(s) called a nucleolus.

Function:

The nucleus controls the cell’s activities. DNA contains instructions to make proteins. The pores allow substances (e.g. messenger RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.

Description + Function of Mitochondrion

Description:

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.

Function:

The site of aerobic respiration. Aerobic respiration produces ATP - a common energy source in a cell. Mitochondria are found in large numbers in cells that are very active and require a lot of energy.

Description + Function of Chloroplast

Description:

A small, flattened structure found in plant cells and algal cells. It is surrounded by a double membrane, and also has membranes inside called thylakoid membranes. These membranes are stacked up in some parts of the chloroplasts to form grana. Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.

Function:

The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts).

Description + Function of Golgi apparatus

Description:

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

Function:

It processes and packages new lipids and proteins. It also makes lysosomes.

Description + Function of Golgi vesicle

Description:

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

Function:

Stores lipids and proteins made by the Golgi apparatus and transports them out of the cell (via the cell-surface membrane).

Description + Function of Lysosome

Description:

A round organelle surrounded by a membrane, with no clear internal structure.

Function:

Contains hydrolytic enzymes. These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading ells or to break down worn out components of the cell.

Description + Function of Ribosome

Description:

A very small organelle that floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. It is made up of proteins and RNA. It is not surrounded by a membrane.

Function:

The site where proteins are made.

Description + Function of Rough endoplasmic reticulum (RER)

Description:

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

Function:

Folds and processes proteins that have been made at the ribosomes.

Description + Function of Smooth endoplasmic reticulum (SER)

Description:

Similar to rough endoplasmic reticulum, but with no ribosomes.

Function:

Synthesises and processes lipids.

Description + Function of Cell wall

Description:

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.

Function:

Supports cells and prevent them from changing shape.

Description + Function of Cell vacuole

Description:

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.

Function:

Helps to maintain pressure inside the cell and keep the cell rigid.