BACTERIA

What is Bacteria? BACTERIUM: (singular)

Bacteria are Prokaryotes  Prokaryotes were the initial inhabitants of Earth and today are found almost everywhere  Have no _______________________nor membrane enclosed _______________  Inside the cell is one large circular strand of ____ or ____

PROKARYOTES Prokaryotes exist in 2 kingdoms:

Bacteria In General:  Are the _______ most ____________ living organisms on Earth  All share basic structures but are diverse in cell ____ and ________________ patterns  Affect humans in various ways: cause _______, spoil foods, can be resistant to ____________  Fix nitrogen for plants, decompose organic matter, manage hazardous waste, aid animal digestion, help create dairy products

Bacteria!

General Structure of Bacteria:

Further Investigation...

Archaebacteria:  ____________ of all life forms  Hypothesized that all life kingdoms descended from ancestors of this group!  Organisms in this taxon possess:

Archaebacteria  Found in extremely _____________ environments  Over half the ______ in archaebacteria differ from those of eubacteria  Different ___________ classify them into different kingdoms  Contain specific chemical make-up of cell walls different from Eubacteria

3 Main Orders of Archaebacteria: METHANOGENS -

3 Main Orders of Archaebacteria: HALOPHILES -

3 Main Orders of Archaebacteria: EXTREME THERMOPHILES - -develop at temperatures between 45-80°C, but some need hotter temperatures! -first found living in the hot springs of Yellowstone National Park

In Fact....  Many other organisms are found in the hot springs of Yellowstone National Park and those microorganisms are responsible for the vibrant colors of the springs.  Because thermophiles are ancient, and because they prefer the steamy conditions that were typical of the early times on Earth, many scientists think they could help us understand _____________.

Eubacteria  Most successful of _________________  Categorized according to their mRNA into phylogentic groups: GRAM-POSITIVE, spirochaetes, chlamydias, cyanobacteria proteobacteria

Eubacteria  Organisms belonging to this taxon possess:

Basic Bacteria Structure:  Both archaebacteria and eubacteria are classified according to:

1. Cell Shape Bacteria cell shapes come in 3 basic forms: 1. Round – 2. Rod – 3. Spiral -

1. Cell Shape  Cocci that live as _________ cells = monococci.  Cocci live in ______ = diplococci  Cocci live in _______ chains = steptochocci.  Cocci live in ____________ clusters = staphlococci

1. Cell Shape  Mono =  Di or diplo =  Strepto =  Staphyto =

1. Cell Shape  Bacilli also exists as single, pairs or chains or random attachments  Spiral bacteria exist only as single cells

2. Gram Stain  Gram staining is a differential staining procedure that allows the categorization of bacteria into 2 groups based on their  2 groups: OR

2. Gram Stain GRAM POSITIVE -Cell walls stain a ________ colour (they retain the stain) -Gram positive bacteria have a different cell wall structure than gram – negative bacteria and the stain shows this - Gram positive bacteria are quite common and usually not as pathogenic (cause disease in a host organism)

2. Gram Stain GRAM NEGATIVE -Cell walls stain ______ (unable to retain the stain) -usually more ________; bacteria that cause typhoid, gonorrhoea, meningitis and pneumonia

3. Nutrition  All cells need energy and a source of carbon for cellular respiration. major energy source light= Inorganic compounds = Photoautotrophs photoheterotrophs chemoautotrophs chemoheterotrophs

3. Nutrition Photoautotrophs: -can _____________ their own organic compounds from sunlight -Cyanobacteria (a.k.a. Blue green algae) -forms blooms in polluted water due to nitrate and phosphate run-off into the water -use up oxygen in lakes/ponds/water source

3. Nutrition Chemoautotrophs: -obtain energy by ____________________ bonds in inorganic compounds such as hydrogen sulphide and ammonia

3. Nutrition Chemoheterotrophs: -live everywhere -some are _____________ and live off _________ -some are ________ and consume decomposing hosts

4. Respiration  All living things must carry out ______________to receive energy for life’s functions  Bacteria differ in whether or not they ___________  Bacterial respiration falls into 2 basic categories: 1. Aerobes -cellular respiration ______________ to produce energy from food that is broken down -_______________________absolutely need oxygen for survival

4. Respiration 2. Anaerobes -bacteria that carry out cellular respiration in an ______________________________ -if the presence of oxygen kills these organisms, they are called ____________________

4. Respiration Example: obligate anaerobe = soil bacterium called Clostridium botulinum that produces toxins that can cause an extreme form of food poisoning called botulism 3. __________________ can survive in either environment

Bacterial Reproduction Depending on environmental conditions, bacteria can reproduce in a variety of manners:

Under Favourable Conditions:  All bacteria use _______________(asexual reproduction) under ideal conditions  Produce ___________ copies of themselves: parent cell divides into 2 identical offspring  Can divide every ________ minutes  In 12 hours there is 10 to 100 million bacteria!  Genetic _________________ occur which increase their diversity and ability to survive  Due to fast reproduction rate bacteria mutate often – ____________  If the mutation is favourable then it spreads through the population quickly

Binary Fission

Under Unfavourable Conditions  Will reproduce using _____________ if conditions begin to fail (lack of food, heat, dessication –drying out- or space)  2 bacteria cells connect to each other by long protein bridges called a _______ between them  1 cell transfers a copy of their ___ (smaller ring of DNA with fewer genes than chromosomes) to the other cell  The bacteria that received this plasmid now has a different genetic make up and this thereby ____________their chances of survival  Example: bacteria become resistant to antibiotics

Conjugation

Under Extreme Conditions:  Bacteria form structures called spores – one such is called an _____________________  Many gram positive bacteria form these spores  Endospore:  This enables them to remain _______ for long periods (months) until conditions are once again favourable  So, endospores do not metabolize or reproduce but simply ______ until conditions become favourable

Endospores

 Example of Clostridium bacteria with characteristic drumstick-shaped endospore- producing cells.  The dark rod-shaped cells are vegetative cells.  The clear ovals are endospores, and the objects consisting of both dark rod and clear oval are vegetative cells producing endospores. 