lecture 4

Question 1

what is the purpose of peptidoglycan

Answer 1

provides strength
protects cells from osmotic lysis
confers cell shape

Question 2

structure of peptidoglycan

Answer 2

carbohydrate backbone
tetrapeptide side chain
peptide cross bridges

Question 3

what does penicillin do?

Answer 3

binds to and inhibits the activity of transpeptidase enzyme (catalyses cross link formation linkage)

Question 4

how thick is gram + bacteria and gram stain?

Answer 4

20-80nm

traps crystal violet and masks saffranin dye

Question 5

how thick is gram - bacteria and gram stain?

Answer 5

5-10nm

crystal violet easily rinsed away reveal red saffranin dye

Question 6

3 parts of flagella

Answer 6

basal body, hook, long filament

Question 7

cell surface layers and composition of bacteria

Answer 7

capsule and slime layer

glycocalyx- gelatinous polysaccharide

Question 8

4 functions of capsules

Answer 8

virulence factors shield
adhere to surfaces
source of nutrients
prevents dessication

Question 9

structure of endospore

Answer 9

Exosporium
Spore coat
Cell wall
Cortex
DNA

Question 10

important properties of spores

Answer 10

heat and radiation resistant
low metabolic activity-dormant
low water content 10-25%
high Ca2+ and dipicolinic acid