Cells

The Discovery of Cells Robert Hooke, and English scientist, discovered and named cells in 1665. He looked at thin slices of cork through a light microscope.

Cell Theory Cells are the smallest unit of living organisms All living organisms are composed of one or more cells Cells arise from existing cells

Prokaryotic Cells Very simple Always unicellular No membrane-bound nucleus (That means there is not a membrane around the DNA) No membrane-bound organelles Bacteria, cyanobacteria (blue-green algae)

Eukaryotic Cells Complex Cell Structure Membrane-bound nucleus Membrane-bound Organelles Plants & animals

Animal Cell

Plant Cell

Inside the cells are organelles

Organelles Found In BOTH plant and animal cells:

Nucleus Surrounded by a double membrane called the nuclear membrane Contains DNA Controls cell functions

Nucleus

Nucleus

Nucleolus Located in the nucleus Synthesizes ribosomes

Nucleolus

Nucleolus

Ribosomes Protein Synthesis Made of protein and RNA

Ribosomes

Ribosomes

Endoplasmic Reticulum Membrane where chemical reactions take place. Rough ER – covered with ribosomes. Site of protein synthesis. Located next to the nucleus. Smooth ER – not covered with ribosomes. Site of lipid synthesis and carbohydrate metabolism.

Rough Endoplasmic Reticulum

Rough ER

Smooth Endoplasmic Reticulum

Mitochondria Converts stored energy (ATP) into cellular energy Has it’s own DNA

Mitochondria

Mitochondria

Golgi Apparatus Stores macromolecules until they are needed by the cell.

Golgi Apparatus (AKA Golgi Complex, Golgi Bodies)

Golgi Apparatus

Cytoskeleton Network of protein fibers Helps give the cell structure. Involved in transport of organelles around the cell

Cytoskeleton

Cytoskeleton

Cell membrane Double layer of phospholipids Controls what enters and leaves the cell

Cell Membrane Also called plasma membrane Controls what enters and leaves the cell Made of a phospholipid bilayer Hydrophilic heads face out Hydrophobic tails face in

Cell membrane

Organelles Found ONLY In plant cells:

Chloroplast Site of photosynthesis

Chloroplasts

Cell Wall Gives the cell structure and support

Central Vacuole Often the largest structure in a plant cell Contains water and organics Helps keep the cell rigid (maintains turgor pressure)

Central Vacuole

Organelles Found ONLY In animal cells:

Centrioles Involved in cell division

Centrioles

Lysosomes Contains digestive enzymes.

Structures used by unicellular organisms for movement:

Cilia

Lung Tissue

Flagella

RIBOSOME ROUGH ENDOPLASMIC RETICULUM NUCLEOLUS NUCLEUS MITOCHONDRIA GOLGI APPARATUS SMOOTH ENDOPLASMIC RETICULUM