IGCSE Biology Extended 21.2.2—Role of anaerobic respiration in yeast Topic Practice

• Describe the role of anaerobic respiration in yeast during bread-making

[Maximum number: 5]

Biotechnology is used in the process of bread-making.
Fig. 1.1 shows some of the steps in making bread.

Fig. 1.1

(a)

State the name of organism A in Fig. 1.1.

[ 1 ]

(b)

State the name of the process that occurs at step 3 that causes gas bubbles to form in the dough.

[ 1 ]

(c)

State the name of the gas that forms to create the gas bubbles in the dough.

[ 1 ]

(d)

Explain the reasons for the different temperatures used in step 3 and step 5.

[ 2 ]

[Maximum number: 1]

Yeast is used in bread-making. It respires anaerobically, producing carbon dioxide.

Name one other industrial process that uses yeast.

[Maximum number: 3]

The kingdom Fungi contains a great diversity of organisms including yeasts, moulds and mushrooms.

Like plants, fungi contain nuclei and mitochondria.

Yeast is a single-celled fungus that is used in bread-making.

Explain why yeast is used in bread-making.

[Maximum number: 1]

What is the role of anaerobic respiration in bread-making?

to produce alcohol to flavour the bread

to produce gas to make the bread rise

to release enough energy to bake the bread

to release enough lactic acid to kill the yeast

[Maximum number: 1]

Why is yeast used in breadmaking?

to produce alcohol

to produce carbon dioxide

to use up oxygen

to use up sugar

[Maximum number: 1]

Why is yeast used in breadmaking?

to produce alcohol

to produce carbon dioxide

to use up oxygen

to use up sugar

0 selected

Question 1

Question 1(a)

Question 1(b)(ii)

Question 1(b)(iii)

Question 1(c)

Question 3(c)

Question 5(b)

Question 37

Question 39

Question 39