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Digestion . Why We Eat Page 396-399 Practice questions: page 399, #1,2,4,5. Why do we eat?. Organisms eat for 2 reasons: To obtain ______________. To obtain _____________. Nutrients. Nutrients are required to: Build Repair Replace Giv e an example of each of these for humans.
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Digestion Why We Eat Page 396-399 Practice questions: page 399, #1,2,4,5
Why do we eat? • Organisms eat for 2 reasons: • To obtain ______________. • To obtain _____________.
Nutrients • Nutrients are required to: • Build • Repair • Replace • Give an example of each of these for humans.
Nutrients • All living things require: • Carbohydrates • Proteins • Lipids • Water • Vitamins and minerals
Energy • Energy is required for: • 3 main reasons: 1. 2. 3.
Energy • Metabolism: • The collection of chemical reactions performed by an organism • Catabolism: • Anabolism:
Metabolism • Metabolic rate: • The rate at which your body uses energy to do work • The higher the rate, the more energy you use and the less energy you store.
Metabolism • Metabolic rate: • What affects your metabolic rate? • What factors make different people have different metabolic rates?
Metabolism • Basal metabolic rate: • Women: BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) - ( 4.7 x age in years ) x 4.18 • Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) - ( 6.8 x age in years ) x 4.18
Metabolism • Basal metabolic rate: • Measured in kJ • To convert this to the more common Calorie found on food labels: • 1 Cal = 4.18kJ
Metabolism • Basal metabolic rate: • (little or no exercise) : BMR x 1.2 • (light exercise/sports 1-3 days/week) : BMR x 1.375 • (moderate exercise/sports 3-5 days/week) : BMR x 1.55 • (hard exercise/sports 6-7 days a week) : BMR x 1.725 • (very hard exercise/sports & physical job) : BMR x 1.9
Metabolism • Average Energy Requirements: Exercise Energy Chart - Kilojoules:
Homework • Page 398 • Complete the mini-investigation • Page 399 • #3 (Generate a very rough estimate)