B5.3/B5.4 - Growing Bacteria

Question 1

culture medium

Answer 1

-liquid/gel
-contains specific nutrients to help with growth

Question 2

micro organisms need

Answer 2

-warmth
-oxygen
-nutrients

Question 3

agar gel

Answer 3

-widely used solid gel culture medium used for growing micro organisms

Question 4

to have uncontaminated cultures you must

Answer 4

-wash hands
-disinfect surfaces
-sterilise petri dish and nutrient agar
-blue Bunsen bruner flame = kills micro organisms in air
-sterilise inocculating loop by flame

Question 5

sealing petri dish with cultures

Answer 5

-do not fully seal
-stops ventilation
-without oxygen bacteria will die

Question 6

why should the petri dish be stored upside down

Answer 6

-so condensation doesn’t fall onto agar surface

Question 7

max temp to incubate culture at is

Answer 7

25 degrees celsius
-prevents growth of harmful pathogens

Question 8

factors affecting bacteria growth

Answer 8

-temp
-nutrients
-oxygen levels
-pH

Question 9

Equation of finding out number of bacteria

Answer 9

num of bacteria at the end = bacteria at the start x 2 to the power of the number of divisions

Question 10

Preventing bacterial growth

Answer 10

-lower or raise temp
-chemicals
-

Question 11

disinfectants

Answer 11

kills bacteria on surfaces

Question 12

antiseptic

Answer 12

kills bacteria on human skin
-safer version of disinfectant

Question 13

antibiotics

Answer 13

-chemicals that can kill bacteria
-safe to ingest