(a) Write the chemical equation for each of the following processes: (i) aerobic respiration (ii) anaerobic respiration in plants (iii) anaerobic respiratio...

Answer Details

(a) Chemical equations

(i) Aerobic respiration

\[ C_{6}H_{12}O_{6} + 6O_{2} \rightarrow 6CO_{2} + 6H_{2}O + \text{energy} \]

(glucose + oxygen \( \rightarrow \) carbon dioxide + water + energy)

(ii) Anaerobic respiration in plants (alcoholic fermentation)

\[ C_{6}H_{12}O_{6} \rightarrow 2C_{2}H_{5}OH + 2CO_{2} + \text{energy} \]

(glucose \( \rightarrow \) ethanol + carbon dioxide + energy)

(iii) Anaerobic respiration in animals (in muscle)

\[ C_{6}H_{12}O_{6} \rightarrow 2C_{3}H_{6}O_{3} + \text{energy} \]

(glucose \( \rightarrow \) lactic acid + energy)

(b) Four liver functions a patient with liver cancer cannot perform

• Deamination of excess amino acids and formation of urea.
• Regulation of blood sugar (converting glucose to glycogen and back).
• Detoxification of poisonous substances and drugs.
• Production of bile for the emulsification of fats (also storage of vitamins and iron, and manufacture of plasma proteins).

(c) Diagram of a flame cell

Make a labelled drawing 8 - 10 cm long of a flame cell showing: the cup-shaped cell body with its nucleus, a bunch of beating cilia (the flame) projecting into a cavity, the hollow tube (excretory duct/tubule) leading away, and the connection to the branching excretory tubule network.

(d) One appropriate plant hormone for each condition

• (i) Ripening of fruits - ethylene (ethene).
• (ii) Breaking dormancy in seeds - gibberellin (gibberellic acid).
• (iii) Weed control - auxin (synthetic auxin such as 2,4-D used as a selective weedkiller).
• (iv) Leaf fall (abscission) - abscisic acid.