Chapter 45

Required molecules that animals cannot synthesize are called: a. nutrients. b. essential nutrients. c. enzymes. d. proteins. e. carbohydrates.

Which of the following accurately describes a feeding style? a. Deposit feeders obtain nutrients from organic molecules in solution. b. Deposit feeders scrape organic matter from solid material on which they live. c. Fluid feeders digest organisms suspended in water. d. Fluid feeders strain food with networks of mucus or bristles and hairs. e. suspension feeders consume sizable food whole or in chunks.

The order of successive steps in digestion is: a. absorption follows enzymatic hydrolysis. b. secretion of enzymes follows absorption of digestive material. c. mechanical processing follows enzyme secretion. d. mechanical processing follows enzymatic hydrolysis. e. enzymatic hydrolysis precedes secretion of digestive aids.

The esophagus, crop, gizzard, and intestine are found in: a. birds and mammals. b. insects and mammals. c. flatworms and birds. d. earthworms and birds. e. sponges and cnidarians.

All of the following are essential nutrients in humans except: a. vitamin B. b. calcium. c. glycogen. d. linoleic acid. e. vitamin \(\mathrm{K}\).

A specialized region of the gut is/are the: a. submucosa formed by circular and longitudinal layers. b. serosa lining the gut for absorption. c. mucosa composed of thick elastic connective tissue for movement. d. muscularis, an outer layer that secretes a slippery material to prevent friction with other organs. e. sphincters, which form valves between major digestive organs.

If the fat in whole milk is ingested: a. the stomach, with its high pH, will stimulate cells of the duodenum to hasten stomach emptying. b. parietal cells in the stomach will absorb it. c. in the small intestine, bile salts emulsify the fats and then lipase hydrolyzes them. d. lactase deficiency in the small intestine would prevent its digestion. e. microvilli will absorb the fat in the form of chylomicrons directly into the blood of the hepatic portal vein.

The liver's role in digestion is to: a. synthesize aminopeptidase and dipeptidase to digest polypeptides. b. synthesize lipase to form free fatty acids. c. secrete trypsin to break the bonds in polypeptides. d. secrete bile and bicarbonate ions to help emulsify fats. e. store bile between meals.

Which of the following best describes regulation of digestion? a. GIP inhibits insulin release from the pancreas. b. Gastrin stimulates pancreatic secretion of \(\mathrm{HCl}\) and pepsinogen. c. Secretin stimulates gastric emptying into the duodenum. d. CCK stimulates gastric activity to activate the duodenum. e. Leptin binds different hypothalamic receptors to stimulate or inhibit appetite.

An example of a digestive specialization is seen in: a. the long intestines characteristic of herbivores. b. the incisors being the dominant teeth in wolves. c. the canine teeth being the dominant teeth in deer. d. salivary lipase being made by humans. e. cellulose being made by humans.