When oxygen is absent, or present only at a low concentration, some organisms respire in anaerobic conditions. In yeast and certain plants, this process is known as ethanol fermentation. In mammals, it is known as lactate fermentation. Fig. 1.1 summarises ethanol fermentation and lactate fermentation.
(a)[3]
Identify the substances labelled A-D.
(b)[3]
Explain how ethanol fermentation and lactate fermentation enable cells to keep functioning when oxygen is absent.
(c)[3]
The cereal crop rice, Oryza sativa, is grown in flooded fields. The roots of the rice plants are submerged in water containing very little oxygen. Describe and explain how rice plants are adapted to grow in flooded fields.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A refers to carbon dioxide / CO$_2$” …