structure

Question 1

types of glycans making up cell wall and how they form it together with peptides

Answer 1

N-acetylglucosamine and N-acetylmuramic acid form sugar backbone and ensyme transpeptidase links backbones together.

Peptide chain that cross links glycan backbone

Question 2

things found in the cytoplasm

Answer 2

Ribosomes, plasmis, genetic material, enzymes, ions, and granules

Question 3

types of granules in cytoplasm

Answer 3

• made of polysaccharides, lipids, polyphosphates
  gram positive bacteria have high glycogen stores
• metachromatic/volutin granules made up of polyphosphates, RNA and proteins used as a source of P for the cell

Question 4

species that metachromatic granules

Answer 4

Corynebacterium species, Yersinia pestis, Mycobacterium species

Question 5

mention an inhibtor of cell wall synthesis

Answer 5

Beta Lactam antibiotics

Question 6

types of thecoic acids

Answer 6

-ribitol thecoic acids 5 carbon and associated with the cell wall
-glycerol thecoic acids 3 carbon associated with tthe inner aspect of the cell membrane

Question 7

what are Thecoic acids

Answer 7

-TA are water soluble anionic polymers of polyol phosphates covalently linked to peptidoglycan

Question 8

function of thecoic acids

Answer 8

-stabilize the cell wall
- distinguish bacterial serotypes
- maintain association between cell wall and membrane
- adherance to surfaces; other bacteria or receptors
- stimulate WBC and macrophages to release cytokines ( initiates innate responses similar to endotoxin) VIRULENCE

Question 9

what is present in gram positive cell walls apart from TA?

Answer 9

Antigens; polysaccharide (lancefield) or protein (griffith)

Question 10

gram negative outer membrane functions

Answer 10

• protects peptidoglycan from affects of lysozyme and ingress of antibiotics- has beta lactamase enzyme to render antibiotics ineffective
• many LPS

Question 11

structure of LPS and their uses if any

Answer 11

Lipid A- immunogenic component, essential for bacterial viability, activates b cells, and induces macrophages, dendtriic celss etc… induces fever and shock

Core polysaccharide
Surface exposed carbohydrate O antigen- antibody attachment site, distinguishes serotypes

Question 12

explain acid fast bacterial cell wall structure

Answer 12

• modification of gram positive cell wall.
• peptidoglycan layer attached to arabinogalactan, attached to mycolic acid

Question 13

bacterial cells with acid fast cell wall and type of mycolic acid they have

Answer 13

Corynebacterium species- 30 carbon
Nocardia species- 50 carbon
Mycobacteria- 90 carbon

Question 14

function of mycolic acid in mycobacteria

Answer 14

Virulence, cell membrane cytotoxicity, inhibition of polymorphonuclear cell migration

Question 15

what are plasmids

Answer 15

smaller circular extrachromosomal DNA
not essential for survival but confer resistance to 1 or more antibiotics

Question 16

stain used to show the presence of metachromatic granules

Answer 16

albert’s stain

Question 17

capsule: how can it be seen and what is it made up of

Answer 17

via light microscope
organized polysaccharide network in most but found as a polypeptide in Bacillus species

Question 18

function of capsule

Answer 18

important for survival within host
MAJOR VIRULENCE FACTOR :
-antiphagocytic
- resistance to bactericidal action of complement and serum antibodies
- adherance to bacterial cells and mucosal surfaces

• protects cell from dessication and toxic materials

Question 19

examples of encapsulated bacteria

Answer 19

Streptococcus pneumoniae
Haemophilus influenzae
Neisseria menengitidis
Neisseria gonorrhoeae
Streptococcus pyogenes

Question 20

slime layer structure and function

Answer 20

loose polysaccharides
allow adherane to cell surface na dforeign materials

Question 21

mention 4 type sof complement pathways

Answer 21

Classic, alternative Lectin to form the Common pathway

Question 22

Explain classic pathway

Answer 22

initiated by immune complexes that activating C1q
antibody binds to antigen on pathogen and changes shape to expose its complement binding sites. Complement C1 binds and sets off reaction cascade which is an amplifying process

Question 23

Explain the Lectin pathway

Answer 23

Mannose binding lectin (plasma protein) binds to mannose resideus on microbial cells and sets off reaction cascade leading to C3b production

Question 24

Explain Alternative pathway

Answer 24

initiated by binding of spontaneously generated C3b proteins to target cells. Triggers reaction cascade with autocatalytic effect (more breakdonw of C3 proteins)

Question 25

about complement proteins

Answer 25

grou p of 30 or more globulins that contribute to innate and adaptive immunity. synthesized by the liver and circulate in the blood in inactive form.

Question 26

what are the 4 end results of the complement system

Answer 26

• Inflammation
• Chemotaxis or Immune Clearance
• Opsonization or Phagocytosis
• Cytolysis or destruction of membranes

Question 27

what takes place once common pathway is achieved

Answer 27

Membrane attack complex is formed —> damage of cell membrane and lysis of target cell

Question 28

function of flagella

Answer 28

-cellular motility- escape from defense mechanisms
-flagellar antigens (H) are used in identification
-

Question 28

structure of flagellum

Answer 28

Basal body, Hook and filament
helically coiled protein subunits driven by ATP

Question 29

difference between flagella of gram + and -

Answer 29

+ has 2 rings in basal body and - has 4 rings in basal body

Question 30

types of flagella (5 types) and meaning

Answer 30

Monotrichous- single at 1 pole
Lophotrichous- 2 or more at one pole
Peritrichous- all over
Amphitrichous- 1 at each pole
Amphilophotrichous- tuft of flagella at each pole

Question 31

example of monotrichous bacteria

Answer 31

Vibrio metchnikovii

Question 32

example of lophotrichous bacteria

Answer 32

Spirillum serpens

Question 33

example of peritrichous bacteria

Answer 33

Proteus vulgaris

Question 34

about fimbrae (6)

Answer 34

• found in both gram + and -
• non flagellar hairline appendages
• short and thin
• found in large numbers
• formed from bacterial chromosome
  -adhesion of bacterial cell to cell an mucous membrane

Question 35

about pili (5)

Answer 35

• only in gram negative
• transfer of DNA/nuclear material in conjugation
• long and thick
• small numbers
• made from plasmid

Question 36

bacteria that can from endospores

Answer 36

Aerobic endospore forming gram positive rods- Bacillus species
anaerobic endospore forming gram positive rods- Clostridium species

Question 37

what is an endospore and why does it form

Answer 37

spherical or oval dormant structure
forms in response to nutritional deprivation
allows for resistance against harsh environments

Question 38

Explain the sporulation process

Answer 38

1.replication of genetic material in mother cell
2. septum forms between copies
3. forespore is engulfed by the membrane of the mother cell.
4. Calcium rushes into endospore componenets and all water is expelled.
5. Coat and Cortex synthesis
6. Spore maturation and mother cell lysis

Question 39

what is the core of an endospore made of

Answer 39

copy of DNA and cytoplasmic contents, surrounded by 2 membranes and peptidoglycan.. Made of calicum ionstightly cross linking the peptidoglycan layer

Question 40

what is the cortex of the endospore

Answer 40

thin inner layer of tightly cross linked peptidoglycan. surrounded by keratin protein coat.

Question 41

layers of en endospore

Answer 41

core, inner membrane, spore wall/ germ cell wall, cortex, outer membrane, protein coat and exosporium