An introduction to bacteria They Are Everywhere An introduction to bacteria

Prokaryotes Prokaryote: Single-celled organism that lacks a true nucleus (also called bacteria) DNA is not surrounded by a nuclear membrane, have no membrane bound organelles. Cover almost every cm2 of earth!

Size Matters Prokaryotes = 1-5 micrometers Eukaryotes = 10-100 micrometers Vs. Prokaryotic cells are much smaller than eukaryotic cells.

One to Two *Until recently all prokaryotes were one kingdom, Monera Monera is now split into 2 kingdoms: Eubacteria, Archaebacteria Now three domains Eubacteria/Bacteria Archaea Eukaryota/Eukarya

A hot springs in Yellowstone National park! Archaebacteria! A hot springs in Yellowstone National park!

Archaea Lack peptidoglycan walls and have different membrane lipids than Eubacteria DNA sequences are closer to Eukaryotes than Bacteria

Extremophiles – ‘phileo’ in Greek means love Live in extreme environments!

Halophilic: salt loving

Thermophilic: heat loving

Methanogens – produce methane gas Live in the gut of mammals, sewage disposal plants and swamps

Eubacteria Largest of prokaryote groups *Have cell walls that contain peptidoglycan (carbohydrate) Find everywhere on earth.

Ribosome Flagella Pili Cell wall Cell membrane DNA Plasmid Cytoplasm

plays role during conjugation Capsule – Protects against drying out, chemicals and host’s white blood cells. Plasmid – piece of DNA , plays role during conjugation Pili - Help with conjugation – transferring of genetic material p.558, Stick to host’s cells Flagella: Movement Ribosomes- Making proteins Cell wall - Protects, gives cell shape Eubacteria–has peptidoglycan Cytoplasm - Contains DNA, Proteins and plasmid DNA - Carries the genetic material Cell membrane – Regulates the movement of materials in and out of the cell

Shapes Three Shapes Bacili (rod-shaped) 3) Spirilla (spiral or corkscrew) 2) Cocci (spherical)

“Strep” throat

Form clumps like grapes Shapes S S S Streptococci Streptobacilla Streptospirilla Form chains S S Staphylococci Staphylobacilla Staphylospirilla Form clumps like grapes

Cell Walls Two Types: Gram-Positive Gram-Negative Thick peptidoglycan walls Turn dark purple when stained Gram-Negative Much thinner walls inside an outer lipid layer Appear pink or light red

Energy

Heterotrophs Parasitic – Cause diseases (pathogens) Saprophytic – Feed on dead tissues - Decomposers

Autotrophs Photoautotrophs: Chemoautotrophs: Use light energy to convert CO2 and H2O to food (like plants) Ex: cyanobacteria Chemoautotrophs: Use chemical energy to convert CO2 and H2O to food

Releasing Energy Obligate Aerobes: Obligate Anaerobes: Require constant supply of oxygen Obligate Anaerobes: Do not require oxygen . . . It kills them Facultative Anaerobes: Do not require oxygen, but can live with it Ex: E. coli

*Growth and Reproduction Some bacteria can divide every 20 minutes If there was unlimited resources 1 bacteria could grow into a mass 4000 times the mass of earth in just 48 hours!!!

Reproduction Binary fission

1) Binary Fission Binary Fission: Asexual reproduction where organism replicates DNA and divides in half Produces two identical daughter cells

2) Conjugation Conjugation: (“Sexual” reproduction) A type of sexual reproduction where organism exchange genetic information

3. Forming Endospores Help survive unfavorable conditions. Anthrax spores

Some are BAD and make us ill

Streptococcus Strep throat Pneumonia

Affects nervous system Tetanus (lock jaw) Affects nervous system E. coli Some in our intestines … others are pathogens that can cause kidney failure

Can be bad … but can be good Bacteria Can be bad … but can be good intestines Feel better with?? decomposers antibiotics

Decomposers Break down things into simpler materials and release into the soil *Help breakdown sewage treatment water

Nitrogen Fixers Converting nitrogen gas into a form plants can use (nitrates – NO3) Allows nitrogen to cycle through biosphere For example Rhizobium living in the roots of legumes Such as soybean plants.

Other Uses E. coli in our intestines Oil digestion/ Make vitamins that we cannot make Oil digestion/ Clean up of pollutants (Bioremediation)

Bacteria Are living: Made up of cells Have DNA Grow and develop Use energy Homeostasis Reproduction Show organization – Flagella, pili, plasmid. Adapt/Evolve – Antibiotic resistance Respond to stimuli - Endospores