Lecture 2.7 Infectious Disease & Bacteria

Question 1

What are the features of acid fast bacteria?

Answer 1

Not decolourised by 1M sulphuric acid, thick waxy walls, peptidoglycan base with arabinogalactain, myoclic acid and lipid, resistance to drying, harsh chemical and antibiotics but has slow nutrient uptake and growth

Question 2

What are the features of flagella?

Answer 2

Locomotion, H-antigen filament, know they are there due to motility

Question 3

What are the features of pill/fimbriae?

Answer 3

Hold negative bacteria to negative body cells, 3-10nm, sex pill transfer plasmids between bacteria

Question 4

What part of the colon is free of bacteria?

Answer 4

Small intestine

Question 5

What does E.coli colonise via?

Answer 5

CS1, CS3

Question 6

Features of capsules?

Answer 6

Polysaccharide, can’t be washed off, makes colonies large and shiny, see via negative staining, protects against dehydration and phagocytosis

Question 7

Features of endospores?

Answer 7

Resistant, dormant, dont replicate, resistant to heat, drying, chemicals and dye

Question 8

What are sporulation and germination?

Answer 8

Formation of spores Conversion of spores back to vegetative form

Question 9

Describe the bacterial growth curve

Answer 9

Question 10

What are the metabolic pathways and what if bacteria use multiple pathways?

Answer 10

• Oxygen: respiration - Inorganic compound: anaerobic respiration - Organic compound: fermentation * using multiple pathways - facultative fermenters

Question 11

What are the types of bacteria and what do these types mean?

Answer 11

• Strict aerobes - require O2 for respiration
 (90% of bacteria)
• Strict anaerobes - killed by O2

• Facultative anaerobes - grow with or without air (E.coli)
• Aerotolerant anaerobes - survive in O2

• Microaerophiles - grow best in low concentrations of O2

Question 12

What makes bacteria the same species or genera?

Answer 12

If bacteria have >97% 16S rRNA they are the same species, >95% = genera