bcm38

Question 1

what are the components of a gram positive bacterias cell wall

Answer 1

cytoplasmic memebrane 8nm

peptidoglycan and techoic acid layer 10-80nm 90% of membrane (thick)

Question 2

why is gram positive bacteria more suseptible to antibiotics?

Answer 2

no outter membrane

Question 3

give 5 facts about gram positive bacterial cell

Answer 3

1. retains crystal violet dye - stains purple
2. produces exotoxins - released from cell
3. some have proteins in cell wall.
4. no lipid in cell wall
5. no polysaccharide in cell wall

Question 4

where is techoic acid found

Answer 4

gram positive bacteria
wall techoic acid - found with peptidoglycan
lipotechoic acid - found between cytoplasmic membrane and wall

Question 5

give examples of bacterias containing techoic acid

Answer 5

streptococcus
bacillus
clostridium
stephylococcus

Question 6

what does techoic acid bond to?

Answer 6

covalently linked to NAM or teminal D alanine

Question 7

what is techoic acids function

Answer 7

provides rigidity

assist regulation of cell growth by limiting autolysin action

Question 8

give an example of a gram negative bacteria``

Answer 8

e.coli

Question 9

what are the components of the gram negative bacterial cell wall

Answer 9

outer membrane 8nm
periplasm
peptidoglycan later 2-3nm
cytoplasmic membrane 8nm

Question 10

describe the gram negative cell wall

Answer 10

protein and polysaccharide in cell wall

no techoic acid

Question 11

what stain can gram pos retain

Answer 11

crystal violet

Question 12

what stain can gram neg retain

Answer 12

decolourised to accept saffrin - red stain

Question 13

what does the outter membrane of the gram neg bacteria secrete

Answer 13

lps
lipopolysaccharide endotoxins
which elicit a strong immune response.

Question 14

give examples of gram negative bacteria which elicit a strong immune response and why

Answer 14

salmonella - food poisening caused by lps
shingella - lps variations stop recognition cause dysentry
meningitus - lps so prevelent is causes leaky rbcs

Question 15

describe the basic structure of peptidogylcan

Answer 15

form mesh like layer
alternating residues of N- acetyl glucosamine and N- acetylmuric acid
NAG and NAM
C2 is N acetyl grou0p NHCOCH3

Question 16

What is attatched to NAM

Answer 16

a peptide chain of 3-5 amino acids at c3

OCHCH3CO-> L-alanine -> D glutamine -> m-diamino pimellic acid (gramneg) /L-Lysine (grampos) -> D alanine->d-alanine

Question 17

how does lysines structure differ from m diamino pimellic acid

Answer 17

where lysine has a h group diaminopimelic acid has a coo

Question 18

what does dap bind to in gram neg

Answer 18

covelently bonds to d ala in next nam via transpeptidase

Question 19

how does peptidoglycan have such a strong structure

Answer 19

it is extensively cross linked by transpeptidase enzyme

molecular mesh of glucan strands

Question 20

how are gram negative peptidoglycan molecules joined

Answer 20

directly covalently bonded to each other

Question 21

how are gram positive peptidogylcan molecules joined

Answer 21

crosslinked by pentapeptide bridge

Question 22

what does penicilin do

Answer 22

inhibits transpeptidase

Question 23

what is ampiccilin

Answer 23

derivite of penicilin

contains beta lactum ring in structure

Question 24

how do lysosomes damage bacteria?

Answer 24

damage cell wall by catalytic hydrolysis of 1-4 beta linkage between NAG and NAM

Question 25

where are autolysins found and what do they do?

Answer 25

found in all bacteria with peptidogylcan

break matrix for growth and division

Question 26

what do clostridium cause

Answer 26

tetaus and gragangrene

Question 27

what do mycobacteria cause

Answer 27

turburculosis