1. Prokaryotic Vs. Eukaryotic
Section 4.3

2. Learning Objectives
Compare & contrast the structure of prokaryotic cells & eukaryotic cells
Describe the functions of prokaryotic organelles
Explain how internal membranes increase efficiency of cell processes & allow eukaryotes to be larger than prokaryotes

3. 2 Types of Cells
Prokaryotic cell = cell that lacks a nucleus & membrane-bound organelles
Ex. Bacteria & Archaea
Eukaryotic cell = cell with a nucleus & membrane-bound organelles
Ex. Plant cell & animal cell

4. Prokaryotes Single-celled organisms
Cells have no nucleus or membrane-bound organelles
Includes all bacteria & archaea
Smallest organisms
Live almost everywhere on Earth

5. Eukaryotes
Can be free-living unicellular organisms or multi-cellular organisms
Includes all protists, fungi, plants, & animals
Cells have a nucleus & membrane-bound organelles
Cells are usually larger than prokaryotic cells

6. Review… Remember that all cells have: Plasma membrane DNA Ribosomes
Cytoplasm
Cytoskeleton

7. Structure of Prokaryotic Cells

8. Have the 5 things found in all cells
But the DNA in prokaryotes is usually just one circular chromosome
Some cells have a piece of extra DNA called a plasmid
Plasmid – extra small circle of DNA that contain a few specific genes
Can provide resistance to antibiotics (medicines)

9. Nucleoid – area of cytoplasm where DNA is found
Cell wall – layer surrounding the plasma membrane, reinforces cell shape
In bacteria it is made of peptidoglycan
In archaea it is made of proteins
Capsule – sticky outer coating that helps the cell attach to surfaces
Also offers protection from toxins & predators

10. Flagella – long, tail-like structures used for movement
Works like a propeller on a boat
Pili, Cilia, & Fimbriae – short protein filaments that help the cell grab & move along surfaces
A specific kind (sex pili) help bacteria catch another bacteria & transfer plasmids during “mating”

12. Oldest Evidence of Life on Earth Are Prokaryotic Biofilms
Biofilm = community living arrangement where many individuals live together in a shared mass of slime
Can include more than one species
Often a type of symbiosis with each species benefiting somehow from the community

14. Membrane-Bound Organelles Allow For Larger Cells
Eukaryotic cells have membrane-bound organelles
Prokaryotic cells do not
Membranes create separate “rooms”
Allows the cells to be more efficient
Different reactions can occur simultaneously (at the same time)
Allows the cell to grow larger

16. Membrane-bound organelles have internal environments different from the rest of the cell
Optimizes reaction rate
Allows cells to store energy
One reaction does not affect the entire cell
Ex. The enzymes in lysosomes destroy only what is in the organelle with them, not the entire cell