Cells and their Organelles

The Animal Cell

Nucleus

• The largest organelle
• Enclosed by nuclear membrane
• Nuclear membrane has small channels known as the nuclear pores
• Functions: 
• Contains genetic material (DNA)
• Controls cell activity
• Important for cell division

Endoplasmic Reticulum (ER) 

• Rough ER
• for protein secretion
• synthesis of proteins which are to be secreted out of the cell or to be inserted into the cell membrane.
• Smooth ER
• makes non-protein substances such as fats, lipids, steroids which are either secreted (to prevent cell damage) or used by the cell.
• Exists in stomach cells.

Ribosomes

• Bound ribosomes or Free ribosomes.
• Smallest organelle
• It has 2 sub unites
• Involved in protein synthesis
• Free ribosomes synthesize proteins found in protoplasm.

Golgi Body/ Apparatus:

• Consists of membrane-enclosed stacks
• Surrounded by Golgi Vesicles
• Vesicles from ER fuse with the Golgi Apparatus
• Functions:
• Stores and modifies contents
• Packages these substances for secretion

Mitochondrion

• Enclosed by an inner membrane (highly folded) and outer membrane
• It is the site of aerobic respiration 
• Synthesis of ATP (adenosine tri-phosphate)
• Needed for movement
• Found in sperm cells