use of biological resources/harnessing biology

Question 1

5.7 what is the role of the bacteria lactobacillus in the production of yoghurt?

Answer 1

• first equipment sterilised & milk pasteurised
• milk cooled to 40-45°C & lactobacillus added
• mixture incubated at this temp. for several hours, while lactobacillus digests milk proteins & ferments the sugar (the lactose) in the milk
• lactobacillus anaerobically respires and converts lactose into lactic acid and this increased acidity sours & thickens the milk to form yoghurt

Question 2

5.10 & 5.11 how does selective breeding develop plants/animals with desired characteristics?

Answer 2

• select individuals with desirable characteristics & breed them together
• breed offspring that show the desired characteristics together
• process repeated for many successive generations so that they will reliably show those selected characteristics in all offspring

Question 3

what is the definition of selective breeding?

Answer 3

selecting individuals with desirable characteristics and breeding them together, and repeating this for many successive generations