Outline the functions of the main cell components

Cell membrane: The cell membrane surrounds the cytoplasm of a cell and its job is to protect the inside of a cell by only allowing certain substances into the cell and keeping other substances out. It also helps to support the cell and maintains its shape. Nucleus: This is the biggest part of the cell and is the part of the cell which acts like the brain. It is not always in the middle of the cell but will be placed within the cytoplasm. In some cases a cell may have many nuclei and these are called multinucleate and are usually in muscle cells. In red blood cells, the nucleus is lost during development and is the only cell that is able to survive without a nucleus.

The nucleus includes DNA. Cytoplasm: The cytoplasm of a cell is the material in the inside of the cell which is semi-fluid and is able to flow slowly and all chemical reactions within cells are carried out in there. Complex sugars including glycogen and melanin which is the pigment responsible for skin and hair colour are in the cytoplasm. These chemicals are the basic living materials that a cell needs. Organelles are the various components of a cell with a specific structure and function and are linked to miniature organs. These include:

Mitochondria: These are small components within cells that perform different important functions in order to keep the body healthy. They make the energy that cells need to do to work correctly. An example of this is brain cells which need a large amount of energy in order to communicate with other parts of the body that may be further away. Every cell in the body has approximately 1000 of mitochondria and each one has a double layered membrane which is similar to the cell membrane but has several folds which produces a series of “shelves” which are called cristae. Endoplasmic reticulum(ER): There are two types of ER which are called rough and smooth. Endo translates to “within” and reticulum is a term for network, therefore ER is a branching network inside of a cell. Both the smooth and rough ER have the same types of membranes but they both have different shapes and functions.

Rough ER has ribosomes attached (black bodies) and its function is manufacturing cell proteins and is a storage area. Smooth ER does not have ribosomes attached and is involved in metabolising lipids and fats. Golgi apparatus: This looks like a series of flattened fluid-filled sacs and is found in most cells. The single membrane is similar to cell membrane as they both have two layers. There are a lot of fluid filled globules/bags that are by the main sack which are called vesicles. The function of the Golgi apparatus is packaging proteins for delivery outside of the cell. It also produces lysosomes. Lysosomes: These are known as the digestive enzymes. These are found in the cytoplasm of a cell and are also produced by the Golgi apparatus. Inside lysosomes are enzymes that are capable of digesting all major chemical components in living cells and are often called suicide bags. They travel through the cell and are able to destroy old or damaged organelles and in some cases destroy cells. Another function of lysosomes are to destroy any bacteria that shouldn’t be inside the cell.