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Chapter 22: Nutrition and Digestion

Short-Answer Questions

1) What types of foods are characteristic of the diets of carnivores, herbivores, and omnivores?

Answer
Carnivores – have a diet that consists of meat which they get by killing and consuming other living animals, other animals that have died, or by sucking the fluids of other animals. Herbivores – have a diet that consists of eating parts of plants such as leaves, fruit, stems, roots, or by extracting fluids from plants and consuming it. Omnivores – have a diet that consists of both animals or their body fluids and plants or their fluids.

2) Why is it important for there to be protein in a person’s well balanced diet? What is its function?

Answer
The human body cannot make eight of the twenty needed amino acids, therefore, they must be consumed as part of the diet. The other types of amino acids may be produced by the body, but they require components of other consumed proteins. Proteins in the diet can be broken down into amino acids by the digestive system and rebuilt into needed proteins by cells of the body. They perform many functions including forming structures, forming enzymes, and use as an energy source, with excess energy being stored as fat.

3) Compare and contrast carbohydrates and lipids.

Answer
Both carbohydrates and lipids are organic compounds that are part of a well-balanced diet and are made up of the elements carbon, hydrogen, and oxygen. Carbohydrates are water soluble, but lipids are water insoluble and are therefore harder to transport in blood. Lipids are primarily an energy storage chemical that can be stored in fat tissue, and carbohydrates are generally used for immediate energy needs being stored to a much lesser degree. Lipids also act as an insulator and can form structures. Carbohydrates provide 4 kilocalories of energy per gram when broken down and fats produce 9 kilocalories of energy when broken down.

4) Compare and contrast vitamins and minerals.

Answer
Vitamins are organic substances that are required in small amounts and are a needed part of a well- balanced diet. Minerals are inorganic and are also required in small quantities in our diet. Neither vitamins nor minerals provide any energy to the body and are both required as a vital part of a well- balanced diet. Vitamins can be readily destroyed, while minerals area very hard to damage and persist for a long time until excreted from the body.

5) What is the difference between ingestion and digestion?

Answer
Ingestion is simply the process of bringing food into the body by eating or drinking it and moving it from the mouth down the esophagus, by peristaltic action, into the stomach. Digestion is the process of mechanically breaking the food down into smaller pieces and chemically breaking bonds by utilizing digestive enzymes in a form that can be absorbed by cells of the small intestine and absorbed into the bloodstream.

6) Explain what could happen to the effectiveness of pancreatic enzymes in the small intestine if bile was not available.

Answer
One of the functions of bile is to neutralize the acidic chyme entering the small intestine from the stomach. Digestive enzymes making up pancreatic juice and others produced in the small intestine are designed to function in an environment that has been neutralized by bile. If bile does not enter the small intestine the pH will stay low and the enzymes will experience conformation change, including the active site, and the enzyme will no longer be able to chemically break food down. Additionally, bile contains chemicals that act as a detergent that breaks fats down into smaller droplets so that enzymes can come in contact with them and chemically break them down. If fat is not broken down into smaller droplets it will be more difficult for enzymes to break down fats, therefore slowing this process and reducing the useable portion from it.

7) Describe the difference between...
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