Biol112-ch41a_D2L_PPT

Biol112-ch41a_D2L_PP - 1 Overview The Need to Feed • Every meal reminds us that we are heterotrophs dependent on a regular supply of food • In

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Unformatted text preview: 1) Overview: The Need to Feed • Every meal reminds us that we are heterotrophs, dependent on a regular supply of food • In general, animals fall into three categories: – Herbivores eat mainly autotrophs (plants and algae) – Carnivores eat other animals – Omnivores regularly consume animals as well as plants or algal matter • An adequate diet must satisfy three needs: – Fuel for all cellular work – Organic raw materials for biosynthesis – Essential nutrients, substances that the animal cannot make for itself • Main feeding mechanisms: suspension feeding, substrate feeding, fluid feeding, bulk feeding • Several different methods of feeding shown in Fig. 41.2 2) Diet and feeding 4) Concept 41.1: Homeostatic mechanisms manage an animal’s energy budget • Nearly all of an animal’s ATP generation is based on oxidation of energy-rich molecules: carbohydrates, proteins, and fats 5) Glucose Regulation as an Example of Homeostasis • Animals store excess calories as glycogen in the liver and muscles and as fat • Glucose is a major fuel for cells (but not the only one) • Hormones regulate glucose metabolism • When fewer calories are taken in than are expended, fuel is taken from storage and oxidized, as illustrated in Fig. 41.3 7) Caloric Imbalance • Undernourishment occurs in animals when their diets are chronically deficient in calories • Overnourishment, or obesity, results from excessive intake, with excess stored as fat, and abdominal fat cells look as shown in Fig. 41.4 9) Obesity as a Human Health Problem • The World Health Organization now recognizes obesity as a major global health problem • Obesity contributes to a number of health problems, including diabetes, cardiovascular disease, and colon and breast cancer • However, malnutrition is much more common than undernutrition in human populations •...
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This test prep was uploaded on 04/17/2008 for the course BIOL 112 taught by Professor Mcclowskey during the Winter '08 term at La Sierra.

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Biol112-ch41a_D2L_PP - 1 Overview The Need to Feed • Every meal reminds us that we are heterotrophs dependent on a regular supply of food • In

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