Bacterial Evolution  First living cells were prokaryotes Single celled, NO NUCLEUS  Change in Earths atmosphere 1 st living organism Archeobacteria (chemosynthetic) 3.8 BYA 4.5 BYA Earth formed 2 BYA Eukaryotic cell Complex cells Life forms diversify

Classification  Kingdom Eubacteria Normal bacteria Found everywhere Cell wall of peptidocylcan EX: E. coli  Kingdom Archaebacteria Extremophiles Live in extreme conditions Cell wall lacks peptidoglycan DNA similar to eukaryotes EX: Methanogens

Variety & Diversity in Both Domains Still Successful on Earth after 3.5 Billion Years!

How do bacteria get energy and grow??  Energy: Heterotrophs: eat for energy Autotrophs: photosynthesis/chemisynthesis Photoheterotrophs: eat for energy and photosynthesis Autotrophic Cyanobacteria… >3.5 BYA Oldest know fossils! O 2 in the air

Bacteria Identification  3 methods to identify a bacteria: Shape Cell wall movement Petri dish with bacterial growth

Shape  Bacilli: rod-like  Spirilla: spiral-like  Cocci: sphere-like  Diplo—pair  Strepto—chain  Staphlo—clump

Name…based on shape Streptococcus Staphlococcus

Movement  Do they move? Yes/no  How do they move? Snake or spiral Glide in ooze Flagella or cilia

Cell Walls 2 different cell walls in bacteria –distinguish with GRAM STAINING  Gram-positive Violet color Simple cell wall Positive = good bacteria  Gram-negative Pink color Complex cell wall Negative = bad bacteria, more resistant to antibiotics Lactobacillus Salmonella

Bacterial DNA  Have circular DNA  Plasmids: small circular DNA fragments with additional genes—can provide resistance

Bacterial Diversity  Antibiotic Resistance (passed via plasmids) Transformation during time of stress Bacteria will uptake any plasmid in environment  Resistance can also arise from spontaneous mutations Some will survive exposure to antibiotics some will not o Bacteria can share DNA via conjugation (sexual reproduction)

Cellular Energy— Photosynthesis  Autotrophic bacteria can carry out photosynthesis using the sun’s energy to make sugars LIGHT 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 CHLOROPHYLL

Cellular Energy— Respiration  Heterotrophic bacteria carry out cellular respiration to get energy from organic compounds C 6 H 12 O 6 + 6O > 6H 2 O + 6CO 2 Or C 6 H 12 O > 6H 2 O + 6CO 2

Cellular Respiration  Obligate Aerobes: require O2 EX: tuberculosis, lives in the lungs  Obligate Anaerobes: lives in absence of O2 EX: botulism in canned foods

Cellular Respiration  Facultative Anaerobes: live w/o O2, but won’t be killed in presence EX: E. coli, lives anaerobically in intestines and aerobically in sewage

Roles of Bacteria  Symbiotic Relationships Probiotic Bacteria—keep the bad bacteria in our bodies in check E. coli—in intestines aids in digestion Lactobacillus—small intestine Lactobacillus

Roles of Bacteria  Nature’s Recycling Machines Decomposers Nitrogen fixation— from N2 (nitrogen gas) to a form plants use Oil eating bacteria Break down raw sewage

Roles of Bacteria  Many fermented foods are produced with the help of bacteria: Cheese Buttermilk Yogurt Sour cream Vinegar Pickles Sourdough bread

Pathogen—Disease causing agent  Bacteria cause diseases in 2 ways Damaging cells Releasing toxins (poisons) Acne Propionibacterium acne

Bacterial Diseases  Streptococcus (strep throat) Transmission: direct contact with bodily fluids Symptoms: fever, white patches on tonsils

Bacterial Diseases  Diphtheria Transmission: sneezing, coughing Symptoms: sore throat, fever, swollen glands Bull Neck— swollen neck Cutaneous Diphtheria

Bacterial Diseases  Anthrax Transmission: inhalation of spores, through the skin Symptoms: fever, severe difficulty breathing, death Cutaneous Anthrax Inhalation Anthrax

Bacterial Diseases  Tuberculosis Transmission: inhalation Symptoms: fever, difficulty breathing

Bacterial Diseases  Botulism Transmission: contaminated food Symptoms: blurred vision, difficulty swallowing, muscle weakness/paralysis

Bacterial Diseases  Staphylococcus (staph infections) Transmission: direct contact Symptoms: red scaly sores, can spread to blood

Bacterial DiseasesDiseaseTransmissionSymptoms Streptococcus infections Direct contact with saliva or nasal discharge Fever, white patches on tonsils Diphtheria Sneezing or coughing Sore throat, fever, swollen glands Anthrax Inhalation of spores Fever, severe difficulty in breathing TuberculosisInhalation Fever, difficulty in breathing Botulism Contaminated food Blurred vision, difficulty in swallowing, muscle weakness

Control of Bacteria  Antibiotics: medicines that stop bacteria growth by destroying cell wall  Sterilization: heat or disinfect  Cooking food all the way  Refrigeration: slows it down…does not kill it

Pasteurization  Pasteurization is a process of heating a food to a high temperature  This process slows/kills microbial growth in food  Created by Louis Pasteur