Eukaryotic Cells and Organelles for OCR As-Level Biology Unit 1.

Eukaryotic Cells and Organelles 

For Unit 1 of OCR AS-Level Biology 

Eukaryotic cells are found in Eukaryotes. Both plants and animals are eukaryotes with eukaryotic cells.

Eukaryotic cells are a bit more complicated than prokaryotic cells and contain a lot of different organelles with different functions listed below:

Plasma Membrane:

Found in both plant and animal cells the membrane is made of mainly lipids and proteins in a phospholipid bilayer. It regulates the movement of substances into and out of the cell. It also has receptor molecules which are complimentary to a specific cell signalling molecule and trigger a change in the cell.

Cell Wall:

Found only around plant cells it provides the cell with a rigid structure for support made of mainly cellulose. 

Nucleus:

Found in both plant and animal cells, the nucleus in a eukaryotic cell is said to be a closed nucleus. The nucleus contains the nucleolus and chromatins wrapped by a nuclear membrane to separate it from the cytoplasm. The nucleus contains the DNA which controls the cell activities inside the chromatins. The nucleolus produces Ribosomes.

Lysosome:

Found in only animal cells the lysosome is a round organelle surrounded in a membrane it contains digestive enzymes which are kept separate from the cytoplasm by the membrane. There are lots of lysosomes in white blood cells as they are used to break down or digest foreign bodies. They are also found in other animal cells as they can break down worn out components of the cell.

Ribosomes:

Are very small organelles found in both animal and plant cell that make proteins under the instruction from the nucleolus. They can be either floating in the cytoplasm or attached to the endoplasmic reticulum to make rough endoplasmic reticulum.

Rough…