Cells Cells
Dec 28, 2015
CellsCells
The Discovery of CellsThe 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 TheoryCell Theory
Cells are the smallest unit of living organismsCells are the smallest unit of living organisms All living organisms are composed of one or All living organisms are composed of one or
more cellsmore cells Cells arise from existing cellsCells arise from existing cells
Prokaryotic CellsProkaryotic Cells
Very simpleVery simple Always unicellularAlways unicellular No membrane-bound nucleus (That means No membrane-bound nucleus (That means
there is not a membrane around the DNA)there is not a membrane around the DNA) No membrane-bound organellesNo membrane-bound organelles
Bacteria, cyanobacteria (blue-green algae)Bacteria, cyanobacteria (blue-green algae)
Eukaryotic CellsEukaryotic Cells
Complex Cell StructureComplex Cell Structure Membrane-bound nucleusMembrane-bound nucleus Membrane-bound OrganellesMembrane-bound Organelles
Plants & animalsPlants & 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 WallGives 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
NUCLEUSNUCLEOLUSROUGH ENDOPLASMIC RETICULUM
GOLGI APPARATUS
SMOOTH ENDOPLASMIC RETICULUM
MITOCHONDRIARIBOSOME