1. First, find out what nutrients Janine and Mitchell are talking about. Using a biology textbook and the resources listed, describe what the following molecules are and what they are used for in the human body. List some specific examples of each. Also list major dietary sources of each. a. Proteins b. Carbohydrates c. Fats 2. Janine made this statement: "... if your brain doesn't get carbs-well, glucose, anyway-you get really cranky. You have to have enough carbs." Find out if Janine is right. How does the nervous system use glucose? 3. Janine also said: "If you eat way too much protein and not enough carbs you can ruin your kidneys forever because of all the nitrogen you have to process breaking down the protein." Find out if Janine is right about this, too. Check a biology textbook for information on protein, fats, and carbohydrates. To find out how these substances can be used for energy, look up information on cellular respiration. 4. The words "calorie" and "energy" come up a lot in discussions of diet and nutrition. Use a biology textbook to define both of these terms. Then suppose you found a product that was labeled "calorie-free energy drink." Why would that label be misleading? 5. Which substances supply energy to the human body?

1. (a) Protein: Protein is a macronutrient composed of amino acids, which are organic compounds made of carbon, hydro, nitrogen, oxygen or sulphur. It is needed by the body to build and repair tissues, to make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilage, skin, and blood. Protein is found in animal, legumes and nuts. Good sources of protein include cowpea,eggs, chicken Breast, cottage cheese, yogurt, milk

(b)Carbohydrate: Carbohydrates are macronutrients that contain carbon, hydrogen and oxygen. Carbohydrate is found in fruits, grains, vegetables and milk products. The functions of carbohydrate include providing energy and regulation of blood glucose, breakdown of fatty acids and prevention of ketosis and provision of dietary fibre. Food sources of carbohydrate are oat, buckwheat, sweet potato, cassava, yam, banana

(c) Fats: Fat are food molecules consisting of carbon and hydrogen. Fats are soluble in organic solvents and insoluble in water. Examples of fats include cholesterol, phospholipids, and triglycerides. Fats give the body energy and support cell growth. They also help protect body organs and help keep the body warm. Fats help the body absorb some nutrients and produce important hormones, too. Foods rich in fats include salmon, avocados, olives, and walnuts, and vegetable oils like soybean, corn, canola, and olive oil, butter and cheese.

2. Janine is right because the brain performs many complicated roles that use up a lot of energy. The brain uses half of the total glucose in the human body. Some of the brain functions such as learning, thinking, learning, and memory are based on the levels of glucose in the brain. However, the levels of glucose in the body should be balanced, High levels cause insulin resistance. Insulin regulates blood sugar. If the brain doesn`t get carbohydrates well, one becomes cranky.

Brain cells need glucose to fuel cellular activities. Glucose metabolism provides the fuel for physiological brain function through the generation of ATP, the foundation for neuronal and non-neuronal cellular maintenance, as well as the generation of neurotransmitters.

(3) Janin is wrong because although excess protein can cause damage in people with preexisting kidney disease, there's been no record of major studies linking high protein intake to kidney damage in healthy individuals.

Cellular respiration is the breakdown of food molecules to release energy in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration. The energy released is needed for growth, repair and movement.

(4) Calorie: calorie is a unit of energy. We can get calories from a variety of food sources, such as, fats, proteins, carbohydrates or sugars. Calories can also be said to be the amount of energy released when the body breaks down food.

Energy: this is power derived from the utilization of chemical substances found in food. The body needs energy to function in its optimal state.

The label 'energy free drink' is misleading because it may contain sugar alcohol such as sorbitol or mannitol which is not calorie-free and may cause digestive upset.

(5) Carbohydrates, fats and proteins supply energy to the human body.

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