1. Biology of Prokaryotes

2. Two Basic Types of Cells
Prokaryotes
Lack a nucleus and membrane-bound organelles
Have a nucleoid instead of a nucleus
Examples are all bacteria and cyanobacteria

3. Two Basic Types of Cells
Eukaryote Cells
Contains a nucleus
Has membrane-bound organelles
Examples are plant cells, protists, fungi, and animal cells

4. Domain: Bacteria
Domain bacteria is divided into two separate kingdoms:
Eubacteria
Archaebacteria

5. Eubacteria Larger of the two kingdoms Live almost anywhere
Contain peptidoglycan in their cell walls
Example: E. coli

6. Archaebacteria
Archaebacteria main differences is their chemical make-up
Lack petidoglycan and also have membrane lipids
Live in extremely harsh conditions
DNA sequence are more like eukaryotes than eubacteria
Methanogens: archaebacteria that live in oxygen-free environments

7. Structure and Function
Major Structures in Prokaryote cells are:
Cell Wall
Cell Membrane
Cytoplasm
Ribosomes
Sometimes a capsule, pili, endospores, and flagella

8. Cell Wall Most Prokaryotes have cell walls
Bacteria cell walls contain peptidoglycan
Protein carbohydrate compound
Archaeal cell walls do not contain peptidoglycan but contain pseudomurein, a compound made up of unusual lipids and amino acids

9. Cell Wall

10. Cell Membrane and Cytoplasm
Bacterial and Archaeal cell membranes are lipid bilayers but the types of lipids differ between the two.
The cytoplasm in both contain:
Ribosomes
DNA
Small organic and inorganic molecules
Ions

11. DNA
Prokaryotic DNA is a single closed loop of double-stranded DNA attached to the cell membrane
Some prokaryotes also have plasmids.
Small circular, self-replicating double- stranded DNA

12. Capsules and Pili
Many bacteria have an outer capsule made up of polysaccharides that protects the cell against drying, pathogens, or harsh chemicals
Pili are short, hairlike proteins on the surface of some bacteria
Use these to connect to each other and to surfaces such as a host cell

13. Endospores
Some Gram Positive bacteria can form a thick-coated resistant structure called an endospore .

15. Prokaryotic Movement
Many prokaryotes have long flagella to help them move towards food sources or away from danger

17. Bacteria Shapes 3 shapes of bacteria cells: 1) Bacillus
Rod-shaped bacteria
2) Coccus
Round or circular-shaped bacteria
3) Spirilla
Spiral-shaped bacteria

18. Bacteria Shapes

19. Strepto vs. Staphylo Strepto: bacteria cells are aligned in chains
Staphylo: bacteria cells are aligned in clusters

20. Gram Staining 2 types of Eubacteria cell walls
Gram staining is used to tell them apart
Gram stain consists of two dyes:
One violet (the primary stain)
One red (the counterstain)

21. Gram Staining Process
1) Violet stain is applied to the bacteria culture first.
This stains the peptidoglycan walls
2) Alcohol wash
3) The red counter stain is applied second

22. Gram Stain Results
Gram Staining results in either a gram- positive or gram-negative bacteria
Gram-Positive Bacteria
Have thick peptidoglycan walls that retain the dark color of the violet stain
Gram-Negative Bacteria
Much thinner cell walls
Alcohol dissolves the lipid and removes the dye from the walls
The counterstain then makes these bacteria appear pink or bright red

24. Nutrition and Metabolism
Prokaryotes obtain nutrients from non- living organisms or by utilizing the products or bodies of living organisms
Heterotrophs-obtain carbon from other organisms
Autotrophs-obtain carbon from CO2
Chemotrophs-get energy from chemicals in the environment

25. Metabolic Diversity Chemoheterotrophs Photoheterotrophs
Photoautotrophs
Chemoautotrophs

26. Prokaryotic Habitats Different species live in different environments
Temperature requirements range from degrees celsius
Most grow best at a neutral pH, 7.

27. Reproduction and Recombination
Reproduction of bacteria is done by binary fission (asexual reproduction)
Bacteria cell doubles in size, replicates its DNA, and divides in half producing two identical “daughter” cells
MITOSIS!!!!

28. Reproduction and Recombination
Genetic Recombination occurs in 3 ways:
Transformation: Taking in DNA from the outside environment
Conjugation: exchanging DNA with other bacteria via pili
Transduction: transmission of bacterial DNA via viruses

29. Releasing Energy
Like all other organisms, bacteria need a steady supply of energy.
This supply is done by either cellular respiration or fermentation
Organisms that require a constant supply of oxygen in order to live are called obligate aerobes
Bacteria that do not require oxygen and may be killed by it are called obligate anaerobes
Bacteria that can survive with or without oxygen are known as facultative anaerobes
Have the ability to switch from CR to Fermentation. This allows them to live almost everywhere!

30. Importance of Bacteria
Bacteria are vital to maintaining the living world
Some bacteria are decomposers that help break down dead organic matter in the ecosystem
Others help in the process of nitrogen fixation (process of converting nitrogen gas into a form plants can use)
Lastly, humans have specific uses for bacteria
Production of food and beverages
Some bacteria can digest petroleum, making them useful in oil spills
Some bacteria live in our stomaches to help break down foods and make a number of vitamins our body could not produce by itself

31. Bacteria and Health
Human diseases may result from endotoxins or exotoxins produced by bacteria or from the destruction of body tissues

32. Bacteria and Health Endotoxins
Toxin that occurs in the outer membrane of Gram negative bacteria and that is released when the bacterial cells break apart
Exotoxin
Potent, extracellular toxin secreted by some gram positive bacteria

33. Antibiotics and Antibiotic Resistance
Mutation in the DNA of bacteria may cause a resistance to an antibiotic
Cells with mutant gene have selective advantage when antibiotic is present
Mutant cells take over population when normal cells die

34. Food Hygiene Preventative Measures:
Wash all fruits and vegetables before eating them
Selecting, storing, cooking and handling food properly
Frequently wash hand and utensils in hot, soapy water