Microbiology – Alcamo Lecture: Bacterial Structures -Not all bacteria have all structures

Shapes of Bacteria _______ Different Shapes:

Bacilli _______ shaped Most occur singly, but some form long chains called _____________ Examples: –__________ _________ –__________

Cocci Usually ______ shaped but can be oval Diplococci – cocci that remain in _____ –Examples – Gonorrhea, Menengitis Streptococci – cocci in __________ –Examples - Strep throat, Tooth decay Staphylococcus – irregular __________ __________ of cells –Examples – Food poisoning, staph skin infections

Spiral Bacteria __________ – curved rods - look like a comma –Example - Cholera __________ – corkscrew shape with flagella –Example – Rat Bite fever __________ – corkscrew shape but no flagella –Example - syphilis

Flagella Used by some bacteria to achieve _________ Made of long rigid strands of protein called __________ Protein strands are permanently ________ Permits the flagellum to rotate and ________ the bacterium forward

Flagella Complicated structure: Filament attached to hook-like shaft which is inserted through cell wall and attached to cell membrane

Flagella _______trichou s

Axial Filament Only ____________ One flagella attached at both ends of flexible spiral MO Motion effected by cell spinning around filament

Pili Look like short flagella but have nothing to do with _________ Very tiny protein “Hairs” that enable MO to ________ to surfaces - like “Velcro”

Pili Pili aid in transfer of ___________ __________ between bacteria Pili anchor bacteria to surfaces like _________ ________ Can __________ MO’s disease effect Example - gonorrhea

Capsule Some bacteria secrete a layer of _____________ and ___________ that stick to its surface Sticky and gelatinous Serves as a buffer between the bacteria and its environment –Protects bacteria against ______________ –Protects bacteria against host’s _________ _____________

White Blood Cell

Glycocalyx Some bacteria produce a _______ _______ Complex _____, made inside cell wall secreted as liquid, polymerizes to jelly like substance _________ – S. mutans attaches itself to teeth by using the sugar a person eats – creates an acid that breaks down tooth enamel

Cell Wall All bacteria have a cell wall except mycoplasmas Semi-rigid structure, _________, gives _________ Amount of chemical “_____________” determines characteristics of cell wall If a lot: Thick, G+ stain reaction, sensitive to penicillin and lysozyme in tears, saliva, mucous

If small: thinner, G- stain reaction, not sensitive to penicillin or lysozyme If MO is pathogenic, disease more difficult to cure

Cell Membrane Boundary layer of the cell ________ of cell wall Contains _________, controls _________ ________ in and out of the cell Triple layer structure, 60% proteins, 38% lipids (phospholipid bilayer), 2% sugars Antimicrobials (detergents, alcohol, some antibiotics) __________ cell membrane

cell membrane animation

Cytoplasm Gelatinous mass of ________ carbohydrates ________ nucleic acids ________ ions ________

Important Structures in Cytoplasm Ribosomes – ________ __________ Inclusion Bodies – globules of starch or lipids – ________ _________ Bacterial Chromosome – closed loop of DNA ________ a membrane or proteins (nucleoid region) Plasmids – smaller, separate _________ __ ______ – few genes but do give bacteria drug resistance (R genes)

Endospores Some Gram + bacteria produce highly resistant structures - ___________ –Bacteria grow, mature and reproduce as _____________ cells –Then the bacterial chromosome replicates and the cell membrane grows in to _______ ______ a developing spore –Next, thick layers of peptidoglycan form to _________ the cell –Finally, the cell wall of the vegetative cell disintegrates and the spore is __________

Endospores Very resistant to poor environmental conditions: –________ _____________– boiling water –____________ – 70% alcohol –Spores have even been recovered alive from an Egyptian mummy’s intestines Examples of spore formers – anthrax, botulism, tetanus

“__________” is spore formation - DNA + some cytoplasm wrapped in spore case formed by cell membrane “__________” occurs when good environmental conditions return – vegetative cell

Kingdom Classification

Archaeobacteria Have existed on earth longer than any other living organism They are different from eubacteria: –No ______________ in cell wall –Different _________ in cell membrane –Different ribosomal ________ –Now archaeobacteria and eubacteria are classified as different kingdoms

Archaeobacteria 3 Types: –_______________ – rods that live in anaerobic conditions and produce methane gas – common in marshes and the guts of cows and humans –________________ – resistance to acid and high temperatures – live in hot springs and ocean vents –___________ ____________– thrive in high salt environments (Great Salt Lake)