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Questions and Answers
What defines anabolic reactions?
What defines anabolic reactions?
Which process involves the breakdown of complex molecules and energy release?
Which process involves the breakdown of complex molecules and energy release?
What is a kilocalorie equivalent to?
What is a kilocalorie equivalent to?
Which food type has the highest caloric value when completely oxidized?
Which food type has the highest caloric value when completely oxidized?
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What measurement technique uses the heat lost from a subject to measure metabolic rate?
What measurement technique uses the heat lost from a subject to measure metabolic rate?
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What is the advantage of indirect calorimetry?
What is the advantage of indirect calorimetry?
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How is metabolic rate calculated using indirect calorimetry?
How is metabolic rate calculated using indirect calorimetry?
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What is the primary disadvantage of direct calorimetry?
What is the primary disadvantage of direct calorimetry?
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What is the energy equivalent of oxygen for carbohydrates?
What is the energy equivalent of oxygen for carbohydrates?
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Which energy form is included in catabolic reactions?
Which energy form is included in catabolic reactions?
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Study Notes
Metabolic Reactions
- Anabolic reactions form large complex molecules from smaller ones, like glucose from lactic acid, requiring energy input.
- Catabolic reactions break down complex molecules, releasing energy, in two forms: chemically stored (ATP) and heat energy for bodily functions such as muscle contractions, and maintaining body temperature.
Metabolic Rate
- Metabolic rate is the amount of heat energy released during chemical reactions, measured in calories per hour (small unit) or kilocalories per kg per degree Celsius.
Caloric (Heat) Value of Food
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Physical Value: The amount of heat energy (in kilocalories) released when 1 gram of food is completely oxidized outside the body.
- Carbohydrates (CHO): 4.1 Calories
- Fats: 9.3 Calories
- Proteins: 5.3 Calories
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Physiological Value: The amount of heat energy released when 1 gram of food is completely oxidized inside the body.
- Carbohydrates (CHO): 4.1 Calories
- Fats: 9.3 Calories
- Proteins: 4.1 Calories
- Note that CHO and fats yield the same amount of energy when completely oxidized inside the body.
Energy Equivalent of Oxygen
- Amount of heat energy released when 1 liter of oxygen is used in the oxidation of certain food types.
- Carbohydrates (CHO): 5 Calories
- Fats: 4.7 Calories
- Proteins: 4.6 Calories
- Mixed (various foods): 4.8 Calories
Measurement of Metabolic Rate
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Direct Calorimetry: Measures heat lost by placing a subject in a chamber with water, measuring the temperature change of the water.
- Disadvantage: Difficult, primarily used in research.
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Indirect Calorimetry: Measures the volume of oxygen consumed, using an energy equivalent for various food types to calculate metabolic rate.
- Advantage: Accurate; easily performed in lab settings. Formula: Metabolic rate (MR) = (volume of O2 utilized (ml/hr) x 4.8) / 1000
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Description
Test your knowledge on metabolic reactions, including anabolic and catabolic processes. Explore how metabolic rates are measured and the caloric values associated with different food types. This quiz covers key concepts essential for understanding energy dynamics in biology.
