Chapter 4, 5, and 6 quiz

What is the primary role of food macronutrients in the body?

• To provide vitamins and minerals

• To form ATP by rejoining ADP and a phosphate ion

• To store genetic information

• To regulate body temperature

Answer explanation

The primary role of food macronutrients is to provide energy, which is crucial for forming ATP by rejoining ADP and a phosphate ion. This process fuels cellular activities, making it essential for overall body function.

How much energy is conserved in the bonds within ATP during the complete combustion of one mole of glucose?

• 689 kcal

• 224 kcal

• 465 kcal

• 34 kcal

Answer explanation

During the complete combustion of one mole of glucose, approximately 686 kcal of energy is released. The energy conserved in ATP bonds is about 224 kcal, which is the correct answer.

Where do glycolytic reactions occur within the cell?

• Mitochondrion

• Nucleus

• Cytosol

• Endoplasmic reticulum

Answer explanation

Glycolytic reactions occur in the cytosol, which is the fluid portion of the cytoplasm. This is where glucose is broken down to produce energy, making the cytosol the correct answer.

What is the net gain of ATP molecules during anaerobic substrate-level phosphorylation in glycolysis?

• 1 ATP

• 2 ATP

• 3 ATP

• 4 ATP

Answer explanation

During glycolysis, 2 ATP molecules are produced through anaerobic substrate-level phosphorylation. This process occurs in the cytoplasm and does not require oxygen, resulting in a net gain of 2 ATP.

What molecule does pyruvate convert into before entering the citric acid cycle?

• Glucose

• Acetyl-CoA

• Lactic acid

• ATP

Answer explanation

Pyruvate is converted into Acetyl-CoA before entering the citric acid cycle. This conversion is crucial for the metabolism of carbohydrates, fats, and proteins, allowing Acetyl-CoA to enter the cycle for energy production.

What process occurs in the respiratory chain during glucose breakdown?

• Reduction of oxygen

• Oxidation of hydrogen atoms

• Formation of glucose

• Conversion of ATP to ADP

Answer explanation

During glucose breakdown in the respiratory chain, hydrogen atoms are oxidized, releasing energy. This process is crucial for ATP production, making 'oxidation of hydrogen atoms' the correct choice.

How many ATP molecules are yielded from the complete oxidation of a glucose molecule in skeletal muscle?

• 28 ATP

• 30 ATP

• 32 ATP

• 34 ATP

Answer explanation

The complete oxidation of one glucose molecule in skeletal muscle yields 32 ATP. This includes 2 ATP from glycolysis, 2 from the Krebs cycle, and 28 from oxidative phosphorylation, totaling 32 ATP.

What establishes a "steady rate" of aerobic metabolism?

• Constant glucose intake

• Hydrogen atom oxidation at its formation rate

• Continuous ATP synthesis

• Regular oxygen supply

Answer explanation

A steady rate of aerobic metabolism is established by the oxidation of hydrogen atoms at their formation rate, as this process directly influences the energy production and efficiency of aerobic respiration.

What happens during intense physical activity when hydrogen oxidation fails?

• Increased ATP production

• Decreased lactic acid formation

• Accumulation of hydrogen ions

• Enhanced oxygen uptake

Answer explanation

During intense physical activity, if hydrogen oxidation fails, hydrogen ions accumulate, leading to increased acidity in the muscles. This can hinder performance and cause fatigue, making 'accumulation of hydrogen ions' the correct answer.

What percentage of energy from glucose combustion is dissipated as heat?

• 34%

• 50%

• 66%

• 100%

Answer explanation

During glucose combustion, approximately 66% of the energy is lost as heat. This means only about 34% is converted into usable energy, making 66% the correct answer.