Digestive System and Metabolism Exam Study Guide (Pt. 6)

Glycolysis breaks down glucose into what? citric acid phosphate glutaraldehyde pyruvate NAD•H

pyruvate

The process of synthesizing glucose from non-carbohydrates is called glycolysis. glycogenolysis. glycogenesis. glucose reclamation. gluconeogenesis.

gluconeogenesis.

Urea is formed in the stomach. small intestine. liver. kidneys. large intestine.

liver.

Identify the two classes of vitamins. (Module 23.14B) complete and incomplete natural and synthetic fat-soluble and water-soluble dietary and non-dietary essential and non-essential

fat-soluble and water-soluble

Define beta-oxidation. (Module 23.11A) glucose anabolism glycogen catabolism glucose catabolism fatty acid catabolism fatty acid anabolism

fatty acid catabolism

All of the following are reasons why glucose is the primary energy source for cells except glucose can be stored efficiently. glycogen breakdown occurs very slowly. glucose is a small, soluble molecule. glycolysis does not require oxygen to generate ATP. glycogen breakdown involves only a single enzymatic step.

glycogen breakdown occurs very slowly.

A disorder caused by the ingestion of excessive quantities of a fat-soluble vitamin is known as avitaminosis. carbohydrate loading. hypervitaminosis. hypovitaminosis. Kwashiorkor.

hypervitaminosis.

Where does most nutrient absorption occur? (Module 23.8B) in the mouth in the large intestine, primarily in the transverse colon in the large intestine, primarily in the cecum in the stomach, primarily in the body in the small intestine, primarily in the jejunum

in the small intestine, primarily in the jejunum

Of the 20 amino acids, ________ are essential amino acids that the body either cannot synthesize or that cannot be produced in amounts sufficient for growing children. 2 6 8 10 20

10

Glycolytic breakdown of glucose first results in ________ molecules. 2 CO2 4 ATP 2 H2O 2 pyruvate 4 NADH

2 pyruvate

The vitamin that is required for proper bone growth and for calcium absorption and retention is vitamin A. B. C. D. E.

D.

________ creates 90 percent of the ATP normally generated. Glycolysis The electron transport system Oxidative phosphorylation Transamination Lipogenesis

Oxidative phosphorylation

Describe the source of intestinal gas. (Module 23.9A) churning of food in the stomach increases the carbon dioxide that is mixed into the chyme as certain foods are broken down they release trapped gases swallowing excess air during eating generates pockets of air that remain in the food bacterial metabolism of indigestible carbohydrates in the colon as bile emulsifies lipids some gas is released in the process

bacterial metabolism of indigestible carbohydrates in the colon

The process that catalyzes fatty acids using enzymes that generate acetyl-CoA is called emulsification beta-oxidation. lipolysis. oxidative phosphorylation. lipogenesis.

beta-oxidation.

Which step of glucose metabolism yields the greater amount of ATP? glycolysis + citric acid cycle glycolysis electron transport system citric acid cycle None of the answers is correct.

electron transport system

Fatty acids that are necessary for proper health but cannot be synthesized by the body are called high-density lipoproteins. water-soluble vitamins. essential fatty acids. low-density lipoproteins. chylomicrons.

essential fatty acids.

Linoleic acid and linolenic acid are examples of transport proteins. essential fatty acids. essential amino acids. non-essential amino acids lipoproteins.

essential fatty acids.

All of the following are true of beta-oxidation except that it ultimately yields large amounts of ATP. it occurs in the mitochondria. lipids are converted into glycogen molecules. it requires coenzyme A, NAD, and FAD. fatty acids break down into acetyl-CoA that enter the citric acid cycle.

lipids are converted into glycogen molecules.

The nutrients that yield the most energy per gram when metabolized are proteins. nucleic acids. carbohydrates. lipids. vitamins.

lipids.

In the process of digestion, most nutrient absorption takes place in the small intestine. stomach. liver. duodenum. large intestine.

small intestine.

What happens to the ammonium ions that are removed from amino acids during deamination? (Module 23.12C) they combine with pyruvate and enter the citric acid cycle they combine with fatty acids and enter beta-oxidation they are removed directly by the kidneys they combine with CO2 and enter the urea cycle they combine with CO2 and are exhaled

they combine with CO2 and enter the urea cycle

If vitamins do not provide a source of energy, what is their role in nutrition? (Module 23.14C) they increase absorption of nutrients they serve as coenzymes in metabolic pathways they serve as plasma membrane constituents they are chemical messengers they absorb excess toxins

they serve as coenzymes in metabolic pathways

Explain the role of glycogen in cellular metabolism. (Module 23.9B) It is the primary fuel that enters the citric acid cycle. It is the primary fuel that enters glycolysis. It can easily be converted to other non-carbohydrate fuel sources. It serves as an intracellular glucose reserve. It is the primary fuel that enters the electron transport chain.

It serves as an intracellular glucose reserve.

Excessive amounts of vitamin E can lead to blurred vision. bleeding disorders. itching. liver damage. rickets.

blurred vision.

The largest lipoproteins, ________, are produced by intestinal epithelial cells from the fats in food. high-density lipoproteins (HDLs) very-low-density lipoproteins (VLDLs) chylomicrons low-density lipoproteins (LDLs) intermediate-density lipoproteins (IDLs)

chylomicrons

The conversion of ammonia into a less toxic substance produces acetyl-CoA. ketone bodies. nitrate. water. urea.

urea.

How are most nutrients absorbed in the digestive tract eventually transported out of the digestive system? through the aorta via the pyloric valve via the hepatobiliary duct via pulmonary arteries through the hepatic portal vein

through the hepatic portal vein

In amino acid metabolism, identify the processes by which the amino group is removed. (Module 23.12B) transamination or deamination proteolysis or beta-oxidation amination or deamination citric acid cycle or urea cycle urea cycle or amination

transamination or deamination

In transamination, the amino group of an amino acid is ________, yielding a different amino acid. converted to ammonia absorbed by water transferred to another molecule converted to urea transferred to acetyl-CoA

transferred to another molecule

During lipolysis, lipids are metabolized to yield ATP. lipids are converted into glucose molecules. lipids are formed from excess carbohydrates. triglycerides are converted into molecules of acetyl-CoA. triglycerides are broken down into glycerol and fatty acids.

triglycerides are broken down into glycerol and fatty acids.

The vitamin that plays a role in maintaining epithelia and is required for the synthesis of visual pigments is vitamin A. B. C. D. E.

A.

Lipogenesis generally begins with amino acids. acetyl-CoA. fatty acids. glucose. succinyl-CoA.

acetyl-CoA.

The vitamin that prevents breakdown of vitamin A and fatty acids is vitamin A. B. C. D. E.

E.

________ carry excess cholesterol from peripheral tissues to the liver. Low-density lipoproteins (LDLs) Very-high-density lipoproteins (VHDLs) High-density lipoproteins (HDLs) Very-low-density lipoproteins (VLDLs) Intermediate-density lipoproteins (IDLs)

High-density lipoproteins (HDLs)

Explain when glycolysis is important in cellular metabolism. (Module 23.6B) When ATP must be produced anaerobically. When ATP must be produced aerobically. When glucose is only fuel source. When gluconeogenesis has decreased then glycolysis becomes important. When beta-oxidation no longer produces sufficient ATP to fuel the cellular metabolism.

When ATP must be produced anaerobically.

Define nutrition. (Module 23.14A) storage of nutrients from food digestion of food elimination of nutrients from food ingestion of food absorption of nutrients from food

absorption of nutrients from food

The lipoproteins that carry absorbed lipids from the intestinal tract to the bloodstream are the very-low-density lipoproteins (VLDLs). high-density lipoproteins (HDLs). low-density lipoproteins (LDLs). chylomicrons. None of the answers is correct.

chylomicrons.

Identify when most of the CO2 is released during the complete catabolism of glucose. (Module 23.6A) glycolysis electron transport chain preparatory step citric acid cycle Calvin cycle

citric acid cycle

Which of the following is not true of lipoprotein lipase? found in capillary walls. interferes with triglyceride utilization. increases release of monoglycerides. prolongs the circulation time of chylomicrons. decreases the breakdown of fatty acids.

decreases the breakdown of fatty acids.

Although other nutrients can feed into the citric acid cycle, ________ yields energy the quickest. protein fat glucose glycogen All of the answers yield energy at the same rate.

glucose

Most of the absorbed nutrients enter into which blood vessel? (Module 23.8C) hepatic portal vein superior mesenteric artery hepatic artery inferior vena cava aorta

hepatic portal vein

In oxidative phosphorylation, energy for the synthesis of ATP is directly obtained from the combination of two atoms of hydrogen and one atom of oxygen to form water. movement of hydrogen ions through channels in the inner mitochondrial membrane. oxidation of acetyl-CoA. breaking of the covalent bonds in glucose. splitting of oxygen molecules.

movement of hydrogen ions through channels in the inner mitochondrial membrane.

Why do cells make new compounds? (Module 23.7B) making new compounds generates heat which can be used to maintain body temperature to break them down into smaller compounds which liberates greater amounts of ATP new compounds contain more high energy bonds that can be used by the cell to fuel cellular metabolism making new compounds ensures that only one nutrient source is used by metabolic pathways to generate ATP new compounds are used to maintain and repair structures, support growth, and store nutrient reserves

new compounds are used to maintain and repair structures, support growth, and store nutrient reserves

The food pyramid recommends many servings a day of dark-green and orange vegetables and citrus fruits. Which vitamin is not particularly abundant in these food groups? A E C D All of the answers are correct; folic acid

D

Identify the fates of fatty acids. (Module 23.11C) Fatty acids may become LDLs, HDLs, or VLDLs. Fatty acids may become a fuel source or a component of proteins and nucleic acids. Fatty acids may become a fuel source or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol, and steroids. Fatty acids may directly enter glycolysis, citric acid cycle, and the electron transport chain to generate ATP. Fatty acids may become a fuel source or a component of glycogen, glucose, and glycolipids.

Fatty acids may become a fuel source or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol, and steroids.

Compare glycogenesis and glycogenolysis. (Module 23.7A) Glycogenesis is the breakdown of glycogen to glucose. Glycogenolysis is the formation of glycogen from glucose. Glycogenesis is the formation of glycogen from non-carbohydrates. Glycogenolysis is the breakdown of non-carbohydrates into glycogen. Glycogenesis is the formation of glucose from non-carbohydrates. Glycogenolysis is the formation of non-carbohydrates from glucose. Glycogenesis is the formation of glycogen from glucose. Glycogenolysis is the breakdown of glycogen to glucose. Glycogenesis is the formation of non-carbohydrates from glucose. Glycogenolysis is the formation of glucose from non-carbohydrates.

Glycogenesis is the formation of glycogen from glucose. Glycogenolysis is the breakdown of glycogen to glucose.

Describe the roles of LDLs and HDLs. (Module 23.10C) LDLs deliver excess cholesterol to adipocytes and HDLs remove excess cholesterol from adipocytes. LDLs deliver cholesterol to tissues and HDLs absorb unused cholesterol and return it to the liver. LDLs absorb unused cholesterol and return it to the liver and HDLs deliver cholesterol to tissues. LDLs absorb unused bile and return it to the liver and LDLs deliver bile to the small intestine. LDLs deliver bile to the small intestine and HDLs absorb unused bile and return it to the liver.

LDLs deliver cholesterol to tissues and HDLs absorb unused cholesterol and return it to the liver.

What is the difference between a micelle and a chylomicron? (Module 23.10A) Micelles are found only in adipocytes, whereas chylomicrons are found in the bloodstream. Micelles are lipid-bile salt complexes, whereas chylomicrons are lipoproteins. Micelles are also known as high-density lipoproteins, whereas chylomicrons are also known as low-density lipoproteins. Micelles are lipoproteins, whereas chylomicrons are lipid-bile salt complexes. Micelles are produced in the liver, whereas chylomicrons are produced in the intestinal lumen.

Micelles are lipid-bile salt complexes, whereas chylomicrons are lipoproteins.

Explain why carbohydrates are preferred over proteins and lipids as an energy source. (Module 23.9C) Carbohydrates can be stored and proteins and lipids cannot. Proteins and lipids are rarer in food than carbohydrates. Carbohydrates travel easier through the blood than proteins and lipids. Carbohydrates yield more energy than proteins and lipids. Proteins and lipids are more important as structural components of cells and tissues.

Proteins and lipids are more important as structural components of cells and tissues.

Which molecule is a key reactant in both ATP production from fatty acids and lipogenesis? (Module 23.11B) glycerol glucose triglycerides acetyl-CoA pyruvate

acetyl-CoA