Cell Organelles  What is an organelle?  An organelle is a tiny body inside a cell that performs a specialized cell function.  Just like the organs in your body, the organelles in cells perform a variety of functions.  Eukaryotic cells can be divided into two different groups.  Animal Cells  Plant Cells  Some organelles are in both types of cells, but others are only in one or the other.

Plant Cell

Animal Cell

Cell Membrane  Location: Surrounds the cell  Structure: The cell membrane is a phospholipid bilayer with proteins and other molecules embedded in the membrane  Function: Separates the insides of the cell, called the cytoplasm, from the outside. Also, regulates what enters and exits a cell.  Found in: All cells Bacterium (colored SEM; magnification 8800x)

Cytoskeleton  Location: Extends throughout the cytoplasm  Structure: Protein tubes and chains  Function: Provides support for the cell, much like a human skeleton, provides pathways for vesicles and other molecules to move through the cell, anchors cell organelles in place, aids in cell division and movement.  Found in: All cells.

Ribosomes  Location: Mostly found attached to the rough endoplasmic reticulum, but sometimes found in the cytoplasm.  Structure: Made of proteins and rRNA.  Function: Translates the genetic instructions in RNA into proteins that the cell can use.  Found in: All Cells

Nucleus  Location: Usually in the center of the cell.  Structure: Membrane bound compartment that has pores for molecules to enter and exit.  Function: Stores and protects DNA.  Found in: All eukaryotic cells.

Rough Endoplasmic Reticulum  Location: Close to the nucleus, sometimes attached to the nucleus.  Structure: System of membranes that separate an area from the rest of the cytoplasm. Has ribosomes attached.  Function: Helps prepare and transport the proteins that are made by the attached ribosomes.  Found in: All eukaryotic cells. Rough ER

Smooth Endoplasmic Reticulum Smooth ER  Location: Close to the nucleus, attached to the rough ER.  Structure: System of membranes that separate an area from the rest of the cytoplasm. Does not have ribosomes attached.  Function: Makes lipids and other molecules and breaks down toxic substances.  Found in: All eukaryotic cells.

Vesicle  Location: Located throughout the cytoplasm.  Structure: Small membrane-bound sacs.  Function: Transports proteins and other molecules around the cell.  Found in: All eukaryotic cells.

Golgi Apparatus  Location: One per cell, found in the cytoplasm.  Structure: Series of flattened membrane sacs, like flattened vesicles.  Function: Serve as the packaging and distribution center of the cell. Enzymes inside modify the proteins that come from the ER. Molecules are packaged in vesicles for transport out of the cell.  Found in: All eukaryotic cells.

Lysosome  Location: Located throughout the cytoplasm.  Structure: Small, membrane-bound sac that contains digestive enzymes.  Function: Digest and recycle the cell’s used components by breaking down proteins, nucleic acids, lipids and carbohydrates.  Found in: Animal cells only.

Mitochondria  Location: Found in the cytoplasm, a cell can have one or many, depending on the cell function  Structure: Double membrane-bound, with the inner membrane folded in to increase surface area.  Function: Uses the energy from glucose and other molecules to make ATP that powers all the cell functions.  Found in: All eukaryotic cells.

Cell Wall  Location: On the outside of the cell membrane, completely surrounding the cell.  Structure: Made of carbohydrates, including cellulose, and proteins.  Function: Supports and maintains the structure of the cell, protects the cell from damage and connects it to adjacent cells.  Found in: Plant cells.

Chloroplast  Location: Located in the cytoplasm of the cell.  Structure: Double membrane with stacks of flattened membrane sacs inside called grana.  Function: Uses the energy from sunlight to convert water and carbon dioxide into glucose in a process called photosynthesis.  Found in: Plant cells only.

Central Vacuole  Location: Often in the center of the cell.  Structure: Large membrane-bound sac that takes up most of the cell.  Function: Stores water and may contain other substances, makes the cell rigid when full, which allows plants to stand upright.  Found in: Plant cells.

Cilia  Location:  Structure:  Function:  Found in:

Flagella  Location:  Structure:  Function:  Found in: