making yoghurt

Question 1

what is fermentation?

Answer 1

Microorganisms break sugars down to release energy

—-> usually by anaerobic respiration

Question 2

What is the bacteria called that makes yoghurt/ferments milk?

Answer 2

Lactobacillus Bulgaricus

Question 3

How are the microorganisms grown?

Answer 3

Fermenters

Question 4

What is lactose sugar fermented to produce?

Answer 4

Lactic acid

Question 5

What is yoghurt?

Answer 5

Fermented milk

Question 6

What is pasteurisation and why is it done?

Answer 6

• it’s heated up to kill any other microorganisms

Question 7

How can a fermenter be used to grow microorganisms?

Answer 7

• They contain a culture medium in which microorganisms can grow
• the conditions are optimum for growth
  —-> yield of product will be best

Question 8

what needs to be kept at optimum conditions?

Answer 8

• pH
• temperature
  These will stop enzymes from denaturing
  how?
  –> thermometer to detect temperature and a cooling jacket to change the temp.
  –> pH probe to make sure the pH doesn’t change

Question 9

what do the other paddles do in the fermenter?

Answer 9

• they agitate the medium meaning that the microorganism can always access nutrients for growth

Question 10

they pump air to the fermenter because…?

Answer 10

RESPIRATION
- they can always respire as oxygen is being provided because energy is available for growth

Question 11

Vessels are sterilised between uses because…

Answer 11

The microorganisms aren’t competing with other organisms and the product isn’t contaminated

Question 12

how are nutrients provided to help the microorganisms grow?

Answer 12

culture medium