Podcast
Questions and Answers
What is an example of an anabolic reaction?
What is an example of an anabolic reaction?
Which of the following reactions involves energy release?
Which of the following reactions involves energy release?
What is the calorie value of carbohydrates (CHO) when oxidized inside the body?
What is the calorie value of carbohydrates (CHO) when oxidized inside the body?
What is the formula to measure metabolic rate using indirect calorimetry?
What is the formula to measure metabolic rate using indirect calorimetry?
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Which method of calorimetry is known for its difficulty of performance?
Which method of calorimetry is known for its difficulty of performance?
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What type of work requires chemically stored energy (ATP)?
What type of work requires chemically stored energy (ATP)?
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How much heat energy is released when 1 gram of fats is oxidized?
How much heat energy is released when 1 gram of fats is oxidized?
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Which of the following measurements indicates the metabolic rate?
Which of the following measurements indicates the metabolic rate?
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Study Notes
Metabolism
- Metabolism involves chemical reactions in cells
- Anabolic reactions build large molecules from smaller ones, storing energy (e.g., glucose from lactic acid).
- Catabolic reactions break down large molecules, releasing energy. This energy is stored as ATP and used for external work (muscle movement) and internal work (transport, secretions). Heat energy is also released to regulate body temperature.
Metabolic Rate
- Metabolic rate is the amount of heat energy released during chemical reactions, measured in calories per hour (or kilocalories per hour)
- A calorie is the amount of heat needed to raise the temperature of 1 gram of water by 1°C.
- A kilocalorie (kcal or Calorie) is the amount of heat needed to raise the temperature of 1 kilogram of water by °C.
Caloric (Heat) Value of Food
- The caloric value of food indicates the amount of energy released when food is oxidized completely.
- The amount of heat energy released when 1 gram of a food type like Carbohydrates (CHO), Fats, and Proteins is oxidized outside or inside the body is different.
Measurement of Metabolic Rate
- Direct Calorimetry: Measures heat loss by placing a subject in a chamber with a known volume of water. The temperature difference before and after a specific timeframe is used to calculate the metabolic rate. Disadvantage: this method is often not practical for regular use as it is complex and difficult to implement.
- Indirect Calorimetry: Measures oxygen consumption to calculate metabolic rate. It's more practical than direct calorimetry; it measures oxygen consumption, that correlates with energy expenditure, to calculate metabolic rate. Advantage: more accurate for estimating energy expenditure as it measures oxygen consumption (and correlates it with energy output).
Energy Equivalent of Oxygen
- Energy released when a litre of oxygen is used for food oxidation varies, depending on the type of food.
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Description
Test your knowledge on metabolism, metabolic rates, and the caloric values of food. This quiz covers key concepts such as anabolic and catabolic reactions, how energy is measured, and the significance of calories in nutrition. Perfect for biology students and health enthusiasts!
