Microorganisms (Microbes) Bacteria Viruses Protists Fungi
Bacteria Introduction
Killer in London Recap (1:41)
Prokaryote Review Microscopic. Can only be seen with very powerful electron microscopes Single-celled (unicellular) But carry out ALL the characteristics of life. This means bacteria are LIVING!!! Lacks nucleus No membrane-bound organelles Less complicated than eukaryotes
Classifying Prokaryotes: Kingdoms At the base of the tree of life are two kingdoms of prokaryotes: Archaebacteria & Eubacteria
Kingdom Archaebacteria Methanogens Halophiles Thermoacidophiles
Kingdom Archaebacteria Methanogens Halophiles Environments with high concentrations of saltwater like Utah’s Great Salt Lake Oxygen free environments like animal intestines Thermoacidophiles Environments of hot, acidic waters where temperatures can reach the boiling point of water like Sulphur Springs
Kingdom Eubacteria Larger of the two kingdoms Wide range of organisms with diverse lifestyles Live almost anywhere: land, water, in and on animals Cyanobacteria common in ponds, streams, and moist areas of land.
General Bacteria Structures Cell Wall (Peptidoglycan) Cell membrane Ribosome DNA Flagella
Fundamental difference between Archaebacteria and Eubacteria is the carbohydrate that makes up their cell wall Eubacteria ~ cell wall made up of peptidoglycan Archaebacteria ~ cell wall made up of glycan polymers NOTICE: No membrane-bound organelles or nucleus, small ribosomes & and a single-circular strand of DNA
General Characteristics of Bacteria
1) Cell Shapes Spheres: cocci (-us) Rods: bacilli (-us) Spiral: spirilla (-um)
2) Cell Arrangements Pairs: Diplo- Cluster: Staphylo- Chain: Strepto-
Name These Bacteria Shapes
Name this bacterium streptococcus
1) Heterotrophs: decomposers or parasites 3) Metabolism Two categories based on how they obtain energy… 1) Heterotrophs: decomposers or parasites
photosynthetic or chemoautotrophic 3) Metabolism Two categories based on how they obtain energy… 2) Autotrophs: photosynthetic or chemoautotrophic
3) Metabolism Three additional categories based on their oxygen requirements Obligate aerobes: require oxygen Obligate anaerobes: no oxygen; produce energy from glycolysis or fermentation Facultative anaerobes: can survive with or without oxygen
4) Growth & Reproduction Some bacteria grow and divide every 20 minutes (exponential growth) Populations are controlled by availability of food, space and waste produced 2 types of reproduction: Binary Fission Conjugation
1. Binary Fission Asexual form of reproduction as genetic info is not exchanged
2. Conjugation
Conjugation: Sexual form of reproduction During conjugation, a hollow bridge forms between two bacterial cells Genes move from 1 cell to another Increases genetic variation
2. Conjugation
Questions??
CONCEPT REVIEW: True or False Members of Archaea live in extreme environments. TRUE
CONCEPT REVIEW: True or False Members of Kingdom Eubacteria are ecologically diverse. TRUE
CONCEPT REVIEW: True or False The cell walls of Eubacteria contain peptidoglycan, while those of Archaea do not. TRUE
Which micrograph shows bacillus bacteria? CONCEPT REVIEW: Which micrograph shows bacillus bacteria? A B C
Which of the following does not belong with the others? These are metabolisms based on oxygen requirements Obligate Aerobes Obligate Anaerobes Chemo autotrophs Facultative Anaerobes
CONCEPT REVIEW: Multiple Choice Bacteria reproduce asexually by binary fission spores conjugation fixation
Turn to a Partner Tell your partner the three parts to conjugation. Take turns
Notes: Bacteria,cont. 9 Fun Facts
Turn to a Partner Discuss with a partner why bacteria are considered to be “living.” HINT: Use the characteristics of life
Endospore When growth conditions become unfavorable, many bacteria form structures called spores Spores can remain dormant for months or years until conditions improve. When conditions improve, the bacteria can start to grow again Makes it possible for bacteria to survive harsh conditions like extreme heat or dryness, or lack of nutrients which might otherwise kill them
Not All Bacteria Are Bad!!!
Ecological Importance
Bacteria are vital to maintaining the living world and have very important jobs Decomposers: Break down and recycle nutrients Nitrogen-fixers: break down nitrogen gas from the atmosphere and turn it into a form of nitrogen that plants can use Producers: remember cyanobacteria??
Human Importance
Bacteria used in production of many foods (Swiss cheese, pickles, yogurt) Some bacteria are used to clean up oil spills Bacteria called E. coli is found in the human large intestine and aids in digestion
Not All Bacteria Are Good!!!
Bacteria are everywhere in nature, but only a few cause disease Disease causing agents are referred to as pathogens
Bacteria cause disease in 2 general ways: Break down cells & tissue: staph infection Release toxins that travel throughout the body: Strept throat
Diseases Staph infection Strep throat Scarlet fever
Controlling Bacteria Vaccines Antibiotics Sterilization Disinfectants Food Processing & Storage
Antibiotics Staphylococcus aureus & penicillium mold How some bacteria “resist” antibiotics
Controlling Bacteria Vaccines are used to prevent infection: introduction of mild form to boost immunity. Examples include meningitis, Diphtheria, Tetanus Antibiotics are used after infection to kill bacteria. Examples are penicillin, amoxicillin, Neosporin (ointment)
Controlling Bacteria Sterilization: heating medical/dental instruments to a temperature high enough to kill bacteria and their endospores Disinfectants are used on surfaces to kill specific strains of bacteria. Examples are Lysol, bleach
Controlling Bacteria Antiseptics are used on living tissue to kill or reduce the populations of bacteria. Examples are mouthwash, rubbing alcohol and hydrogen peroxide Food Processing & Storage: Refrigerating foods to slow reproduction, heating foods to proper temperature
Bacteria Lab
Dinosaur plague video 15min http://video.pbs.org/video/1893797003
How do bacteria make people sick? Pneumonia bacteria experiments by Fredrick Griffith Oswald Avery – DNA