C1.2 respiration SL

What is the primary role of ATP in cells?

• Energy storage
• Energy distribution
• Structural support
• Genetic information

Answer explanation

ATP is primarily responsible for distributing energy within cells. Options 1, 3, and 4 describe other functions not directly related to ATP's main role.

How is energy released during cell respiration?

• Through combustion
• Through a series of enzyme-controlled reactions
• Instantly in a single reaction
• By storing it in glycogen

Answer explanation

Energy in cell respiration is released through a series of enzyme-controlled reactions. Unlike combustion (Option 1), it is a gradual process.

Fill in the blank: ATP is often referred to as the _____ of the cell.

Answer explanation

ATP is often called the energy currency of the cell because it transfers energy within the cell.

What are the immediate products of the hydrolysis of ATP?

• ADP and phosphate
• AMP and ribose
• Glucose and oxygen
• Water and carbon dioxide

Answer explanation

Hydrolysis of ATP produces ADP and phosphate, releasing energy. AMP and ribose, glucose and oxygen, and water and carbon dioxide are not correct immediate products.

Which molecule is the main respiratory substrate in cells?

• Glucose
• Fatty acids
• Amino acids
• Starch

Answer explanation

Glucose is the main respiratory substrate in cells because it is easily oxidized. Fatty acids and amino acids are also used but require more processing.

Which of the following are true about anaerobic respiration in humans?

• Occurs in the absence of oxygen
• Produces lactic acid
• Produces ethanol
• Generates a small amount of ATP

Answer explanation

Anaerobic respiration occurs without oxygen, produces lactic acid, and generates a small amount of ATP. Ethanol production (Option 3) occurs in yeast, not humans.

What is the role of NAD in cell respiration?

• Carrier of hydrogen
• Oxygen acceptor
• ATP synthesizer
• Structural molecule

Answer explanation

NAD acts as a carrier of hydrogen in cell respiration, playing a key role in oxidation-reduction reactions. Options 2, 3, and 4 are incorrect roles for NAD.

Which process occurs in the mitochondria and produces large amounts of ATP?

• Aerobic respiration
• Anaerobic respiration
• Glycolysis
• Fermentation

Answer explanation

Aerobic respiration occurs in the mitochondria and produces large amounts of ATP. Glycolysis and fermentation occur in the cytoplasm and produce less ATP.

What is produced during lactic acid fermentation in muscle cells?

• Lactate
• Ethanol
• Carbon dioxide
• Water

Answer explanation

Lactic acid fermentation in muscle cells produces lactate. Ethanol is produced in yeast, and carbon dioxide and water are products of aerobic respiration.

What affects the rate of cell respiration?

• Temperature
• pH
• Supply of oxygen
• Supply of glucose

Answer explanation

All listed factors—temperature, pH, supply of oxygen, and supply of glucose—affect the rate of cell respiration.