Eukaryotic cell

The word 'Eukaryotic' means 'true nucleus' and eukaryotic cells have . Eukaryotic cells only contain organelles that are distinctly membrane-bound such as nuclei, mitochondria and chloroplasts (plants only). Animals, Plants, Fungi and Protoctista are all eukaryotes; bacteria are prokaryotes. In comparison, eukaryotic cells are larger than prokaryotic cells with a diameters ranging from 10-100 μm. Organisms with eukaryotic cells are referred to as eukaryotes. There are two types of eukaryotic cells; animal and plant cells, which are distinguishable in terms of their ultrastrctures.

Ultrastructure

To be classed as a eukaryotic cell, the cell must contain a nucleus, with genetic material, surrounded by a double membrane (or envelope) and organelles (structures) in the cytosol, each surrounded by one or two membranes also. The organelles include; the nucleus which contains the main genome and is the site of  DNA synthesis and RNA synthesis, the endoplasmic reticulum which is the site of synthesis for most lipids and proteins and is responsible for the distributution of these molecules to many organelles and to the plasma membrane, the Golgi apparatus is responsible for the modification, sorting and packaging of proteins and lipids for either secretion or delivery, lysosomes which are used for intracellular degradation, endosomes which are responsible for endocytosed material, mitochondria which are required for oxidative phosphorylation and peroxisomes which are responsible for the oxidation of toxic molecules. In plant cells, an addition number of organelles are present such as chroloplasts which are essential photosynthesis instead of mitochondria but also do not contain organelles such as peroxisomes.