Biological Uses

Question 1

Bread

Answer 1

Yeast, sugar, water, flour, kneaded
Y, respire aerobically, reproduce
Y, respire anerobically, fermentation, no oxygen in dough
CO2 produced, rise
Dough cooked, kill yeast, ethanol evaporates, dough rises, CO2 expands, dries as water evaporates

Question 2

Beer

Answer 2

Barley trains in warm water, germinate
Enzymes break down starch into sugar, grains dried, malting
Malted grain mashed, water added, made sugar solution, buts removed
Yeast added, ferments sugar into alcohol
Ethanol conc rises, kills yeast, fermentation slows down
Beer drawn off, pasterised

Question 3

Wine

Answer 3

Grape juice, yeast, water
Yeast ferment on sugar
Ethanol, alcoholic

Question 4

Yoghurt

Answer 4

Starter culture of bacteria added to warm pasteurised milk
Bacteria ferment, lactose, lactic acid, acidic taste
Lactic acid, milk proteins coagulate, solidifies milk

Question 5

Cheese

Answer 5

Starter culture of bacteria added to warm milk
Ferment
Rennin added, milk curdles, curds whey
Whey removed, salt, bacteria, mound added to curds

Question 6

Growing microbes

Answer 6

Grow on agar
Sterilised easily, prevent contanimantion
Agar with nutrients added to it
Microbes grown in fermenters

Question 7

Fermenters

Answer 7

Anaerobic or aerobic
Microbes grown for products
Control conditions

Question 8

Fish farming

Answer 8

Intensive rearing of fish

Prevent depleting wild fish stocks

Question 9

Advantages of fish farming

Answer 9

Kept in large seawater enclosures
Temp, oxygen, diet,water carefully monitored
No predators
Pesticides kill parasites
Selective breeding

Question 10

Disadvantages of fish farming

Answer 10

High potential for spread of disease
Eutrophication
Pesticides are toxic
Wild fish used to make food pellets