Microbial Growth and Control

Question 1

how do bacteria reproduce

Answer 1

by binary fission

Question 2

what are the stages of growth curve in a bach culture

Answer 2

lag log stationary decline

Question 3

give three ways population growth can be measured

Answer 3

total cell count, viable count, turbidity measurements

Question 4

write a quick note on total cell count

Answer 4

aka haemocytometer -> gives immediate cell count but will not differentiate between live and dead cells and can be quite time consuming

Question 5

write a quick note on viable count

Answer 5

spread plate and pour plate method - gives accurate measure but is most time consuming due to incubation

Question 6

write a quick note on turbidity measurements

Answer 6

rapid measure of cells- not as accuate as total cell count - no differentiation between live and dead cells

Question 7

what factors influence micro growth

Answer 7

environmental, chemical, physical, biological

Question 8

what are some natural human defenses that control microbial growth

Answer 8

tears, saliva due to lysozyme as it cleaves peptidoglycan in bacterial cell walls

Question 9

what are the environmental effects on micro growth

Answer 9

nutrients, temp, pH, water availability, O2 availability

Question 10

define psychrophiles, mesophiles, thermophiles, hyperthemophiles

Answer 10

psychrophiles = low temp optima
mesophiles = mid temp optima
thermophiles = high temp optima
hyperthermophiles = v high temp optima

Question 11

what is phage therapy

Answer 11

therapeutic use of lytic bacteriophage to treat pathogenic bac infections- becoming an alternative to antibiotics