Chapters 4 - Spokane Public Schools

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Hard-boiled eggs The reshaping of proteins from their natural shape is called denaturing. An egg’s protein molecules in their natural, uncooked state are loosely coiled in individual “globs” held together by weak bonds between different parts of the amino acid chain. Because the molecules are able to move around, the egg white and yolk remain liquid. Heat gives the proteins enough energy to break those bonds and each protein strand begins to straighten out. If enough heat is added, the ends of each protein molecule join together in bridge-like bonds. Other links form at points along the protein strands. The network of bonds prevent individual molecules from moving around and the egg becomes solid. Carbohydrates: The sweet life Carbohydrates, made mostly of carbon and hydrogen atoms, are much simpler than proteins. Small carbohydrate molecules are called sugars, because they are generally sweet. Sugars are “simple carbohydrates.” Sucrose (table sugar) and glucose are examples of simple carbohydrates. When simple sugars are linked together in long chains, “complex carbohydrates” are formed. When sugars are cooked, a number of chemical reactions occur. As sugars cook, water is released and carmelization takes place. This gives us the characteristic aroma of cooking. Baking bread causes a browning reaction to take place causing carbohydrates to react with the amino acids of proteins. This reaction is responsible for the wonderful browning of bread and contributes to the aroma and flavor of roasted coffee beans and chocolate. Fats: A stable ingredient Fats are also made mostly of carbon and hydrogen atoms. The lower the ratio of hydrogen to carbon, the more “unsaturated” the fat. Aside from providing energy, fats help transport molecules in and out of cells and are an important part of many hormones. Fats are very stable to heat, making them useful in cooking. Cooking oils, butter and margarine are part of this group. Along with providing flavor, cooking with fats is fast. Cooking oils can be heated to over 200°C without boiling, while water boils at a temperature of 100°C Questions: 1. List some microscopic changes in foods that occur when they are cooked. 2. Why is cooking an irreversible process 3. Describe what happens to egg protein when it is cooked. 4. Is a completely fat free diet healthy Explain your answer. Chapter 4 Connection UNIT 2 ORGANISMS AND THE ENVIRONMENT 79
Chapter 4 Activity Scientists have learned over the years that what you eat can affect your health. Food packages are required by law to have Nutrition Facts labels. In this activity, you will study some breakfast cereal Nutrition Facts labels. Maybe you will learn some new things about your favorite cereal! How to read a Nutrition Facts label What’s on Your Label 1. Each group should have one box of cereal. The first piece of information on the Nutrition Facts label is serving size. This is very important, because all of the nutrition content information is based on this serving size. Measure out one serving of the cereal and pour it into a small bowl. Is this the amount that you would usually eat 2. Find the number of Calories in one serving of the cereal. Calories measure how much energy you get from the food you eat. The major nutrients present in the foods we eat are called fats, carbohydrates, and proteins, and each of these nutrients contributes to the number of total Calories. Why do you suppose Calories from fat is listed next to the number of Calories, but not Calories from carbohydrates or protein 3. Nutrients listed on the label can be divided into three categories: nutrients you should limit, nutrients that may or may not be an issue, and nutrients you should be sure to include enough of in your diet. The nutrients you should limit are fat, cholesterol, and sodium. What do you know about health problems related to high intakes of these nutrients Carbohydrates and protein are nutrients that most Americans eat plenty of, but some may want to limit sugars. Dietary fiber, vitamin A, calcium, vitamin C, and iron are all nutrients that we should be sure to get enough of in our diet. Why are these important 4. The % daily value numbers provide a quick, helpful guideline for you to follow when you are trying to limit or eat more of certain nutrients. The percentages are based on an average daily intake of 2000 Calories. Look at your cereal label. Are there any % daily value numbers that surprise you 5. Design a data table that will allow you to organize the following information about each of 6 different breakfast cereals: cereal name, serving size, total Calories, Calories from fat, total fat (g), saturated fat (g), cholesterol (mg), sodium (mg), total carbohydrate (g), dietary fiber (g), sugars (g), protein (g), vitamin A (%), calcium (%), vitamin C (%), iron (%). 6. Record the nutrition data from your cereal box, and then trade with other groups until you have recorded data from each box of cereal. Use the data you collected to answer the questions. Applying your knowledge a. Determine which cereal is the healthiest. Explain how you arrived at your answer, and refer to specific data from your comparison table. b. Determine which cereal is the least healthy, and use data to justify your choice. c. Compare your choices with others in your group. Did everyone agree d. Why are Nutrition Facts labels so important that the government requires them e. Write one question that you still have about Nutrition Facts labels. 80
Page 1 and 2: E Organisms and the Environment Cha
Page 3 and 4: 4.1 Elements and Compounds In the 1
Page 5 and 6: Chemical reactions What are chemica
Page 7 and 8: 4.1 Section Review 1. What are the
Page 9 and 10: Carbohydrates, fats, and proteins F
Page 11 and 12: Nucleic acids What are nucleic acid
Page 13 and 14: 4.3 Physical Variables You have rea
Page 15 and 16: Sunlight Type of soil Oxygen Sunlig
Page 17 and 18: The oceans Chemicals in ocean water
Page 19: Chapter 4 Connection Chef or Scient
Page 23 and 24: Section 4.3 8. Name a habitat where
Page 25 and 26: 5.1 Ecosystems, Energy, and Nutrien
Page 27 and 28: Producers, consumers, and decompose
Page 29 and 30: The water and carbon-oxygen cycles
Page 31 and 32: 5.2 Food Chains and Food Webs All l
Page 33 and 34: Food webs What is a food web Most a
Page 35 and 36: 5.3 Ecosystems—a Natural Balance
Page 37 and 38: Invasive species Organisms interact
Page 39 and 40: Toxins in the food chain What are t
Page 41 and 42: More water quality tests Dissolved
Page 43 and 44: Chapter 5 Connection Food Webs of t
Page 45 and 46: Create a Species Chapter 5 Activity
Page 47 and 48: Section 5.2 Math and Writing Skills
Page 49 and 50: 6.1 Climates and Biomes Imagine som
Page 51 and 52: Other variables that affect climate
Page 53 and 54: Plants and animals in biomes Commun
Page 55 and 56: 6.2 Deserts and Grasslands In this
Page 57 and 58: Grasslands Grasslands are found on
Page 59 and 60: 6.2 Section Review 1. What is the m
Page 61 and 62: Tropical rainforests Tropical rainf
Page 63 and 64: 6.3 Section Review 1. How many seas
Page 65 and 66: Taiga life Snow keeps things warm!
Page 67 and 68: Permafrost stores carbon dioxide Pe
Page 69 and 70: Ecological Impact of Forest Fires C
Page 71 and 72:
Chapter 6 Activity Biome Expedition
Page 73 and 74:
10. How is a temperate grassland li
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Chapters 4 - Spokane Public Schools

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