Biology Homework Chapter 21: Nutrition
Textbook assignment: Chapter 21: Digestion and Nutrition, sections 14-23.
Human nutrition considers not only the chemical processes by which nutrients are converted to energy, but also the social and cultural motivations to eat some kinds of food while avoiding others, to eat appropriate amounts and to find all required amino acids for health when religious, social, or simply available diets restrict the types of foods that can be used.
- Vitamins are organic nutrients, usually proteins, that are necessary to promote metabolic processes. Study the charts and note the differences between water-soluble and insoluble vitamins, and the kinds of processes each supports.
- Minerals are inorganic simple elements that are used as components (usually in proteins or vitamins) that act as enzymes.
- Food labels contain information about calories, fat and carbohydrate compounds, vitamin content, and often originas (organic, genetically altered, country of origin). Ingredients will list specific contents, including details about chemicals and preservatives that are known allergens (things that trigger allergic responses). Some will indicate whether the food was processed where certain allergens (especially nuts) were present.
- 21.14 Animals eat to obtain fuel for energy. Chemical energy is the energy released by breaking or forming chemical bonds. Food energy is measured in terms of kilocalories. A kilocalorie is 1000 metric calories, each of which is the amount of energy required to raise 1 cubic cm (1 milliliter or 1 gram) of water one degree centigrade. Different activities burn this energy at different rates. For example, walking at the rate of 3 mph will burn 245 calories an hour.
- 21.15 Essential nutrients are those molecules which an animal cannot assemble for itself from raw materials. Of the 20 kinds of amino acids humans need to synthesize proteins, eight are considered essential: somehow, our diet must include foods containing these amino acids, since we are unable to make these from base molecules. Animals must also ingest certain fatty acids, vitamins, and minerals.
- 21.16 Those who choose a limited diet for health, religious, or social reasons must be sure that they are obtaining these essential amino acids in order to avoid dietary deficiencies. A complete diet includes A, B-complex, C, D, E, and K vitamins. Interestingly, the integumentary system can make vitamin D when exposed to sunlight, so there must be a balance in daylight exposure: enough to make vitamin D, but not so much as to trigger skin cancers. These vitamins must be obtained from organic sources, while minerals are simple inorganic elements or compounds. Deficiencies in minerals and vitamins can lead to stunted growth, disease, or malf
- 21.17 Most United States and European governments require packaged foods to list their nutrients as part of a recommended dietary allowance. Labels must also contain warnings for common food allergies.ormation of bones.
- 21.18 Scientists study the relationship between nutrition patterns and the occurrence of diseases due to deficiencies to determine the minimal amount of nutrients required. The FDA (Food and Drug Administration) in the US makes recommendations or requirements that certain foods contain certain vitamins and minerals. You may find vitamin D added to milk and orange juice, since both are widely drunk by children, who have a high need for the vitamin to support healthy bone growth. These decisions are sometimes controversial (fluoridation of water being a leading example). While there is a general consensus that each person requires a minimal daily intake of vitamins and minerals, there is no consensus on the actual amount. Individuals differ in their genetic makeup, metabolic processes, and consumption rates, each of which affects the minimum amount of a given substance needed to retain health.
- 21.19 Some evolutionists believe that humans crave fatty foods because our pre-agricultural diet was low in the substances, but individuals would eat fat could store it for periods of famine.
- 21.20 Regulating weight is a popular topic in the media, and while some diets can reduce weight dramatically in a short period of time, most individuals experience a healthy weight by moderating their intake of food, making sure they get all essential nutrients, and that they get sufficient exercise.
- 21.21 Diet and exercise can affect cholesterol levels and the ratio of low density lipoproteins to high-density lipoproteins, which affects a risk for cardiovascular disease.
Read the following weblecture before chat: Nutrition and Digestion -- Osmoregulation
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Perform the study activity below:
Tissue studies and genetics come together when biologists study the origins of Alzheimer's disease and propose treatments and prevention.
- Use the MyPlatePlan Tool below (from the US government site Choose My Plate)to calculate the calories you need for your age and body size. Then click on the plan for your age and calorie count to determine what you should be eating on a daily basis. How close to a good nutrition plan are you? What happens if you increase or decrease your physical activity?
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
- Required: Complete the Mastery Exercise with a score of 85% or better.
- Optional: Test yourself with the textbook multiple choice questions and note any that you miss that still don't make sense. Bring questions to chat!
- Go to the Moodle and take the quiz for this chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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