MIMM211 real shit

what are the features of the bacterial envelope? how is it different for gram negative, gram positive and mycoplasma?

• gram negative → cytoplasmic membrane, cell wall (thin), outer membrane

• gram positive → cytoplasmic membrane, cell wall (thick)

• mycoplasma → cytoplasmic membrane

what does the periplasmic space include? for gram negative? gram positive?

• gram negative → space between outer membrane and cytoplasmic membrane (includes cell wall)

• gram positive → space between cytoplasmic membrane and cell wall

• enzyme rich

what are the functions of the cytoplasmic membrane?

• contain cytoplasm

• selective transport

what is the cytoplasmic membrane composed of? what model describes its structure?

• phospholipid bilayer

• ~50% protein

• fluid mosaic model → proteins suspended in thin layer of oil

what are phospholipids composed of?

• polar head → phosphate (-), glycerol, R group

• non-polar fatty acid tails

what types of proteins are found in the cytoplasmic membrane?

• transmembrane → transporters

• peripheral → on the surface

what is the function of the cell wall?

• cell structure and rigidity

• prevents swelling and bursting from osmotic pressure

what is the cell wall made of?

peptidoglycan

• glycans → long polysaccharides (alternating NAG/NAM)

• peptides → cross linking NAM units of glycans

how does the peptide cross linking of peptidoglycans differ between gram negatives and positives?

• gram negative → direct bonding of peptides

• gram positive → glycine peptide interbridge between peptide chains

how does penicillin function?

prevents cell wall synthesis

what do gram-positive cells contain in their cell wall to solidify its structure?

• teichoic acid

how is the cell wall anchored in gram-negative cells? what about gram-positives?

• gram negative → lipoproteins → connect cell wall to outer membrane

• gram positive → lipoteichoic acid → connect cell wall too cytoplasmic membrane

what are the functions of the outer membrane?

• protection

• selective transport

what is the outer membrane composed of?

• inner → phospholipids

• outer → lipopolysaccharides (LPS)

what is the structure of LPS?

• O side chain

• core polysaccharide

• fatty acids

what are some structures that occur outside of the cell envelope?

• capsule

• slime layer

• s-layer

what is the main function of structures outside of the cell envelope?

protection

• from phagocytes and protozoa

• environmental changes

• bacteriophage

what are capsules made of? what is its structure?

• polysaccharides

• thick/well organized → visible by microscopy

what are slime layers made of? what is its structure?

• polysaccharides, glycoproteins, glycolipids

• thin/less organized → not easily visible by microscopy

what are s layers made of? what is its structure?

• proteins and glycoproteins

• highly organized → visible by microscopy

what are some surface appendages of bacteria?

• flagella

• pili

what is the function of flagella? what are they made of?

• movement

• protein → flagellin

what is the function of pili?

• adhesion

• sex pili for mating

what are the possible arrangements for flagella?

• monotrichous→ 1

• amphitrichous → 1 at each pole

• lophotrichous → 2 or more at one/both poles

• petrichous→ all over

what happens if flagella rotate clockwise vs counterclockwise?

• counterclockwise→ forward

• clockwise → tumble

what are the different types of bacterial movement?

• chemotaxis

• aerotaxis

• phototaxis

• magnetotaxis

what are some components of the cytoplasm?

• nucleoid region

• ribosomes

• inclusion bodies

• cytoskeleton

what are some inclusion bodies and their functions?

• storage granules → nutrient reserves

• gas vacuoles → helps bacteria float

• magnetosomes → magnetotaxis

what is the most resistant bacterial structure?

endospores

• can survive millions of years in harsh conditions

what is the process of sporulation?

• cell divide into unequal parts

• large part engulfs small part (forespore)

• forespore matures into an endospore

what happens to a forespore as it becomes an endospore?

• gains a thick wall

• dehydrates

• vegatative cell is lysed

what are the components of an endospores wall?

• inner cortex → peptidoglycan

• spore coat → keratin like proteins

• exosporium → proteins, polysaccharides, lipids

what is the name of the process by which endospores become vegetative cells?

germination

what is the process of germination?

• permeability of the wall changes and water enters

• endospore swells and coat ruptures

• germ tube grows out

what are the types of cell division?

• binary fission

• budding

• others: fragmentation, exospore formation