生物学导论详解.ppt

生物学导论详解演示文稿
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优选生物学导论
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Contents
Living Things as Chemical Factories
Kilocaocalories ingested 摄取with those of expended
Decreasing or increasing 500~1000 kilocalories per day →1~2 pounds (~ kilogram) per week
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Steps in weight control:
Check with your physician
Determine the number of kilocalories you are consuming
Reduce the amount of food or increase your intake: 1200 kilocalories
Another valuable way is an increase in exercise while keeping food intake constant
Insisting
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The chemical composition of your diet
Kinds of nutrients:
Carbohydrates (碳水化合物)
Lipids (脂类)
Proteins (蛋白质)
Vitamins (维生素)
Minerals (矿物质)
Water (水分)
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Carbohydrates
Carbohydrate: monosaccharides or disaccharides, starch (primary form of carbohydrate we obtained), glycogen, cellulose
Function:
Utilized in cellular respiration to provide energy
Used as building blocks in the manufacture of molecules such as nucleic acid
A source of fiber that slows the absorption of nutrients and stimulates peristalsis 蠕动 in the intestinal tract
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Lipids
Subclasses of lipids:
Phospholipids (磷脂): essential components of cell membranes
Steroids (类固醇): many are hormones, cholesterol 胆固醇
True fats (triglycerides, 甘油三磷脂): source of energy, essential fatty acids, dissolve some vitamins
Defending from cold and heat loss, shock absorber
Give pleasant taste, full feeling of a meal
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Proteins
Function:
Essential components of hemoglobin 血色素and cell membranes, antibodies, enzymes, some hormones, hair, muscle, tissue fiber, collagen 胶原质
Provide a last-ditch 最后的 source of energy during starvation
Cannot be stored for later use
The amount of protein necessary in the diets is about 50 grams/day
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Vitamins
Vitamins are organic molecules, needed in minute amounts to maintain essential metabolic activities
Cannot be manufactured by the body
Play a role in assisting specific enz