Quiz 3 (part of Exam 3)

Question 1

mycobacterium cell wall?

mycolic acid

tuberculosis

Answer 1

tuberculosis

gram positive cell wall (stratified)
also has mycolic acid (providing waxy nature to cell wall) a virulence factor *help escape**

Question 2

Gram positive cell wall properties

bridge composition uniqueness

Answer 2

stratified.
thick cell wall
typical: backbone, tail, bridge

permits free passage of substance (sugar ion, amino acid, etc)

• third amino acid is always L-lysine
• wide variation of bridge amino acid (thus indirect bridge)
• teichoic acid (TA)

Question 3

Teichoic acid

-how does it contribute to negative charge around cell surface?

functions?

2 type of TA:

• lipoteichoic acid
• wall teichoic acid

antigenic specificity

Answer 3

phosphate group of TA give neg charge around cell surface.

attached to NAM (to which the tail is also attached)

this attracts positive charge, thus
fx: regulate + charge ion movement into/out of cell.

fx2: furnish attach site for many bacteriophage (virus that attack bacteria) (first step for virus is attachment)

fx3: serve as PAMP (pathogen associated molecular pattern) ID barcode. recognized as non self.
antigenic specificity. alert our defense cell.

-lipoteichoic acid
span thick peptidoglycan layer.
fx: attach to plasma membrane lipid

-wall teichoic acid
confine to the petidoglycan layer
embedded in the cell wall

Question 4

PAMP and PRR

MAMP?

Answer 4

PRR: pathogen recognition receptor on our body defense cell

PAMP: pathogen associated molecular pattern. on bacteria cell surface.

PRR (bar scanner) exist on our defense cell. it recognize PAMP (bar code).

either trigger phagocytosis or other mechinism.

example of PAMP: teichoic acid, capsule component such as poly D glutamic acid, D amino acid)

MAMP: microbial associated molecular pattern (another type of molecular pattern as oppose to PAMP)

however, it is nonpathogen (part of our normal microflora that has it)

Question 5

Gram negative

cell wall structure

Answer 5

thin cell wall (compared to gram pos)

has periplasm/periplasmic space (this is where the cell wall resides)
has outer membrane (unique to gram neg)

compared to gram +
third amino acid is not L (unlike gram +)
third amino acid is D

LACKS teichoic acid

has direct cross bridge

Question 6

periplasmic space

Answer 6

unique to gram neg cell wall

cell wall resides within periplasmic space

outermembrane
periplasmic space (cell wall here)
plasma membrane

Question 7

gram + vs gram -

bridge connection

location of peptididoglycan

Answer 7

gram +: indirect bridge

gram -: direct cross bridge

gram + always has L lysine as third
gram- has D acid

location of peptidoglycan:
gram +: outer

gram -: under outermembrane
part of periplasmic space above plasma membrane.