Animal Cell Structure

The nuleus is a large organelle surrounded by a nuclear envelope (double membrane). The nuclear envelope causes there to many nuclear pores around the nucleus. Also the nucleus contains chromatin made from proteins and DNA. Often there is a structure called the nucleolus inside the nucleus. The nucleus contains instructions for making proteins and it makes RNA and ribosomes.

The microvilli are folds in the plasma membrane. They are found on cells that are involvd with processes like absorbtion because they increase surface area.

A mitrochondrian is usually oval shape. They have a double membane the inner membrane is folded to form structures called cristae. Inside the mitrochondria is the matrix which contains enzymes involved in respriration. The mitrochondria are the site of aerobic respiration. They are found in large numbers in cells that are very active and require lots of energy.

Lysosomes are round organelles which are surrounded by a single memebrane.They hae no clear internal structure but they contain digestive enzymes which are kept seperate from the cytoplasm. A specialised lysosomes are those found in the head of  sperm to digest the egg.

Ribosome are very small organelles that float free in the cytoplasm or is attached to the rough endoplasmic reticulum. They are the site in which proteins are made. Ribosome are not surrounded by a membrane.

There are two types of endoplasmic reticulum these are smooth endoplasmic reticulum and rough endoplasmic reticulum. Both types are in close association with nuclear membrane.

Smooth Endoplasmic Reticulum are a system of membranes enclosing a fluid filled space. The smooth endoplasmic reticulum synthesises and processes lipids.

Rough Endoplasmic Reticulum is a system of membranes enclosing a fluid filled space covered in ribosomes. The Rough Endoplasmic Reticulum folds and processes proteins that have been made at the ribosomes.

Golgi Apparatus is a group of fluid filled dlatened sacs. They process and package new lipids and proteins. They also make libsosomes.