lecture 2 - intro to bacteria - PoD

Bacteria structure (5)

capsule

peptidoglycan cell wall

plasma membrane

no membrane bound organelles (but simple ones like ribosomes )

single circular DNA

cytoplasmic membrane of bacterial cell characteristics (3)

very thin

elastic

semi permeable

bacteria cell wall characteristics

rigid
gives strength and shape

outer membrane of bacteria

only found in gram negatives

light microscopy of bacteria

- gram negative stain

- gram positive stain

- gram negative = red (THINK RED IS ANGRY AND ANGRY IS NEGATIVE)

- gram positive = purple (PP = POSITIVE PURPLE)

name the shapes of bacteria (3)

cocci

bacilli

spiral/corkscrew (spirochete)

what is the bacterial cytoplasmic membrane made of

phospholipids and protein

functions of proteins in bacterial cytoplasmic membrane (2)

transport systems for specific nutrients and ions
act as enzymes involved in processes such as energy generation, cell wall synthesis and DNA replication

what is the bacterial cell wall made of?

peptidoglycan

Why is peptidoglycan important?

some antibiotics interfere with peptidoglycan of cell wall

what is the gram negative bacterial outer membrane made of?

lipopolysaccharide (LPS)

what is the function of lipopolysaccharide

protects peptidoglycan from bile salts and lysozymes

blocks many antibiotics from getting into cell

bacterial capsule structure

polysaccharide layer outside cell wall

bacterial capsule function

role of adherence in some bacteria

biofilm construction

flagella structure

composed of filament, hook, and basal body

flagella function

motility

types of flagella

monotrichous (one flagella at one point)

amphitrichous (2 flagella, one each side)

lophotrichous (multiple flagella at one point)

peritrichous (flagella all over)

Structure of fimbriae

similar to flagella, look like spikes on bacterial cell

function of fimbriae

adherence to cells

what are plasmids

small rings of DNA found in bacterial cells

how to bacterial cells replicate?

binary fission

how does genetic variation arise in bacterial cells (2)

transfer of plasmids
spontaneous mutation

what are bacteriophages

type of virus that infects bacteria

How do bacteriophages work? (4)

bacteriophage attaches to susceptible bacteria

injects own DNA

bacteriophage hijacks bacterium cellular machinery to form viral components intstead of bacteria

new bacteriophages assemble and burst out of bacterial cell (lysis)

bacteriophage structure (5)

- head (contains DNA and protein)

- collar

- tail (protein only)

- tail fibers

- end plate

bacterial ribosome structure

composed of RNA and associated proteins

function of bacterial ribosomes

synthesise proteins used for a variety of purposes within the cell

bacterial ribosome subunits

70S ribosomes (30S + 50S)

bacterial spores

Bacteria capable of producing a protective coating that allows them to withstand very harsh environments, and shed the coating when conditions become more favorable.

what colour do non-sporulating cells stain?

dark blue

how are singular bacteria detected and cultured?

gram stain light microscopy

how are bacterial colonies detected and cultured?

agar plates

how are bacteria classified?

phenotypically (shape, stain, growth requirements, serology, mass spec)

genotypical (DNA)

staphylococcus aureus - which part is the genus and which part is the species

genus - staphylococcus

species - aureus