True or false 1. proteins can be converted to fats in the LIVER. 2. Carbohydrates, proteins, and fats are not accounted as the macromolecules. 3. Bile is the digestive juice from the liver. 4. Amino acids are the hydrolysis product. 5. Carbohydrates cannot be converted to glucose.

By clicking on this link (http://openstaxcollege.org/l/fooddigestion) , you can watch a short video of what happens to the food you eat as it passes from your mouth to your intestine. Along the way, note how the food changes consistency and form. How does this change in consistency facilitate your gaining nutrients from food?

The pH of human stomach acid ranges from 1.0 to 3.0, whereas a healthy esophagus has a pH of approximately 7.0. In gastroesophageal reflux disease (GERD), often called acid reflux, stomach acid flows backward from the stomach into the esophagus. Repeated episodes in which esophageal pH goes below 4.0, considered clinical acid reflux, can result in bleeding ulcers and damage to the esophageal lining. The data in the Figure, from a patient with GERD, show esophageal pH during a sleeping reflux event. How many minutes does it take to go from the peak of the reflux event (when pH is most acidic) to when the reflux event is over? Source: Based on T. Demeester et al. 1976. Patterns of gastroesophageal reflux in health and disease. Annals of Surgery 184:459469.

By watching this animation (http://openstaxcollege.org/l/foodgroups) , you will see that for the various food groups—proteins, fats, and carbohydrates—digestion begins in different parts of the digestion system, though all end in the same place. Of the three major food classes (carbohydrates, fats, and proteins), which is digested in the mouth, the stomach, and the small intestine?

Triglycerides are transported by chylomicrons because ________. they cannot move easily in the bLood stream because they are fat based, while the blood is water based they are too small to move by themselves the chylomicrons contain enzymes they need for anabolism they cannot fit across the intestinal membrane

Effects of Dietary Fats on Lipoprotein Levels Cholesterol that is made by the liver or that enters the body from food does not dissolve in blood, so it is carried through the bloodstream by lipoproteins. Low-density lipoprotein (LDL) carries cholesterol to body tissues such as artery walls, where it can form deposits associated with cardiovascular disease. Thus, LDL is often called bad cholesterol. Highdensity lipoprotein (HDL) carries cholesterol away from tissues to the liver for disposal, so HDL is often called good cholesterol. In 1990, Ronald Mensink and Martijn Katan published a study that tested the effects of different dietary fats on blood lipoprotein levels. Their results are shown in Figure 2.23. In which group was the level of LDL (bad cholesterol) highest?

Effects of Dietary Fats on Lipoprotein Levels Cholesterol that is made by the liver or that enters the body from food does not dissolve in blood, so it is carried through the bloodstream by lipoproteins. Low-density lipoprotein (LDL) carries cholesterol to body tissues such as artery walls, where it can form deposits associated with cardiovascular disease. Thus, LDL is often called bad cholesterol. Highdensity lipoprotein (HDL) carries cholesterol away from tissues to the liver for disposal, so HDL is often called good cholesterol. In 1990, Ronald Mensink and Martijn Katan published a study that tested the effects of different dietary fats on blood lipoprotein levels. Their results are shown in Figure 2.23. Figure 2.23 Effect of diet on lipoprotein levels. Researchers placed 59 men and women on a diet in which 10 percent of their daily energy intake consisted of cis fatty acids, trans fatty acids, or saturated fats. Blood LDL and HDL levels were measured after three weeks on the diet; averaged results are shown in mg/dL (milligrams per deciliter of blood). All subjects were tested on each of the diets. The ratio of LDL to HDL is also shown. Source, Mensink RP, Katan MB, Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. NEJM 323(7):43945. An elevated risk of heart disease has been correlated with increasing LDL-to-HDL ratios. Rank the three diets according to their predicted effect on cardiovascular health.

Which of the following statements is not true? a. Essential nutrients can be synthesized by the body. b. Vitamins are required in small quantities for bodily function. c. Some amino acids can be synthesized by the body, while others need to be obtained from diet. d. Vitamins come in two categories: fat-soluble and water-soluble.

Excess carbohydrates and proteins are stored as _____. a. amino acids b. starches c. fats d. monosaccharides

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.