Animal Cell (Eukaryote)

Mitochondria

• Inner membrane is folded to form finger-like projections called cristae.
• The mitochondria are the site of the later stages of aerobic respiration

Nucleus

• Enclosed by an envelope made up of 2 membranes perforated by pores
• Contains chromosomes and a nucleolus
• The DNA in chromosomes contains genes that control protein synthesis

Nucleolus

• A dense body within the nucleus where ribosomes are made

Rough Endoplasmic Reticulum (rER)

• A system interconnected, membrane-bound, flattened sacs
• Ribosomes are attached to the outer surface
• Proteins made by these ribosomes are transported through the ER to other parts of the cell

Ribosomes

• Made of RNA and protein
• Are found free in the cytoplasm or attached to endoplasmic reticulum
• The site of protein synthesis

Cell Surface Membrane

• Phospholipid bilayer containing proteins and other molecules forming a partially permeable barrier

Smooth Endoplasmic Reticulum (sER)

• Similar to rER but with no ribosomes attached
• Makes lipids and steroids, e.g. reproductive hormones

Golgi Apparatus

• Stacks of flattened, membrane-bound sacs formed by fusion of vesicles from the ER
• Modifies proteins and packages them in vesicles for transport

Lysosomes

• Spherical sacs containing digestive enzymes and bound by a single membrane
• Involved in the breakdown of unwanted structures within the cell
• Involved in destruction of whole cells when old cells are to be replaced or during development

Centrioles

• Hollow cylinders made up of a ring of 9 protein microtubules
• Involved in the formation of the spindle during nuclear division and in transport within the cell cytoplasm