A Tour of the Cell

Cellular Control Center

NucleusIn eukaryotes the nucleus contains most of the cell’s DNA; the instructions for making important cellular molecules.

Animal Plant

Nuclear Envelope The nucleus is surrounded by a two-layer

membrane called the nuclear envelope.

Nucleolus The nucleolus is a dense region in the nucleus

where ribosomes are assembled.

Support, Storage, and Clean-up

Cytoskeleton The cytoskeleton is a network of proteins that

helps the cell maintain shape and transport materials around the cell.

Centrioles Centrioles cytoskeleton structures found in

animal cells that help organize chromosomes during cell division.

Vacuoles and Vesicles

Vesicles store and move materials between cell organelles, and to the cell surface.

Plant cells store materials (water, salts, and proteins) in saclike structures called as vacuoles.

Vesicle

Vacuole

Moving CargoVesicles are transported around the cell by attaching to the cytoskeleton.

Lysosome Lysosomes are small

organelles filled with digestive enzymes that break down worn-out or damaged organelles.

Building Proteins

Ribosomes One of the most important jobs of the cell is

making proteins. Ribosomes are the protein making machinery.

Endoplasmic Reticulum The endoplasmic reticulum is folded membrane

system with a large surface area.

Rough Endoplasmic Reticulum The rough endoplasmic reticulum assists in

protein formation.

Smooth Endoplasmic Reticulum The smooth endoplasmic reticulum aids in the

formation of complex lipids (e.g. membranes and hormones).

Golgi The Golgi modifies, sorts, and packages proteins

and lipids for storage or transport out of the cell.

Protein Synthesis

Cellular Energy

Chloroplasts

Chloroplasts use the energy from sunlight to make energy-rich food molecules (sugar) in a process known as photosynthesis.

Mitochondria

Mitochondria use energy from food to make high-energy compounds (ATP) that the cell uses to power cellular processes.

Cellular Boundaries

Plasma MembraneThe plasma membrane is a thin flexible barrier that regulates what enters and leaves the cell.

Cell WallPlants, bacteria, fungi, and algae have a tough cell wall made out of cellulose.