Chapter 23

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

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

Glycolysis breaks down glucose into what? citric acid pyruvate phosphate NADH glutaraldehyde

pyruvate

Which is the common substrate for mitochondria in the citric acid cycle? cytochromes NAD FAD acetate

acetate

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

chylomicrons

Identify the molecule labeled "5." Figure 23-1 fumaric acid 4-carbon molecule citric acid oxaloacetic acid malic acid

citric acid

The sum of all of the biochemical processes going on within the human body at any given time is called glycolysis. catabolism. anabolism. metabolism. oxidative phosphorylation.

metabolism.

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

transferred to another molecule

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

urea.

There 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

A drug that blocks the action of lipoprotein lipase would prolong the circulation time of chylomicrons. interfere with triglyceride utilization. All of the answers are correct. None of the answers is correct.

All

Cells must synthesize new organic compounds in order to store nutrient reserves. support growth. produce secretions. perform structural maintenance or repairs. All of the answers are correct.

All

Cells perform catabolism to generate ATP, which can be used for protein synthesis. muscle contraction. ion transport. glycogen synthesis. All of the answers are correct.

All

Cells synthesize new organic components for which of the following reasons? structural maintenance production of secretions growth and repair All of the answers are correct. None of the answers is correct.

All

Glucocorticoids have which of the following effects on general peripheral tissues? They increase glycogenolysis. They increase gluconeogenesis. They increase the conversion of amino acids to pyruvate. All of the answers are correct. None of the answers is correct.

All

The electron transport system produces energy that supports the synthesis of ATP. is found on the inner mitochondrial membrane (the cristae). receives electrons from coenzymes. All of the answers are correct. None of the answers is correct.

All

Wally decides to go on a hunger strike to further one of his favorite causes. After many days with nothing but water you would expect to observe lowered blood pH. elevated levels of glucocorticoids. ketone bodies in his urine. All of the answers are correct. None of the answers is correct.

All

Identify the molecule labeled "2." Figure 23-1 hydrogen atoms citric acid carbon dioxide FADH2 NAD

CO2

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

High-density lipoproteins (HDLs)

Which characteristic correctly applies to lipid metabolism? Most lipids can be synthesized on demand. Stored lipids provide large amounts of ATP very quickly. Triglyceride reserves are water-soluble droplets. Excess lipids can be stored as pyruvate.

Most lipids can be synthesized on demand.

In the absorptive state of metabolic activity: androgens, estrogens, and growth hormone stimulate protein synthesis. epinephrine is important in stimulating glycogenolysis in skeletal and cardiac muscle. insulin inhibits glucose uptake and glycogenesis. glucocorticoids stimulate the mobilization of lipid and protein reserves.

androgens, estrogens, and growth hormone stimulate protein synthesis.

Poisons like cyanide bind to ________ and prevent electron transfer. cytochromes the endoplasmic reticulum acetyl-CoA mitochondria enzymes

cytochromes

Which form of glucose metabolism yields the greater amount of ATP? glycolysis glycolysis + citric acid cycle 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 low-density lipoproteins. essential fatty acids. chylomicrons. high-density lipoproteins. water-soluble vitamins.

essential fatty acids.

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

essential fatty acids.

In the postabsorptive state of metabolic activity, __________. glucocorticoids stimulate the mobilization of lipid and protein reserves insulin stimulates triglyceride synthesis glucagon inhibits glycogenolysis and gluconeogenesis, primarily in the liver androgens, estrogens, and growth hormone also stimulate protein synthesis

glucocorticoids stimulate the mobilization of lipid and protein reserves

Which process describes the synthesis of glucose from noncarbohydrate sources? gluconeogenesis glycolysis glycogenolysis glycogenesis

gluconeogenesis

The process of synthesizing glucose from noncarbohydrates is called gluconeogenesis. glucose reclamation. glycolysis. glycogenesis. glycogenolysis.

gluconeogenesis.

Glucose: is absorbed and converted to pyruvate as needed by the liver. is generally used for catabolism after protein and lipid sources are used. is transported to the liver by way of the hepatic portal vein. leaves the cytosol of the epithelial cells and reaches the interstitial fluid by simple diffusion.

is transported to the liver by way of the hepatic portal vein.

All of the following take place during the absorptive state except insulin stimulates glycogenesis. blood lipid levels rise. blood glucose levels rise. estrogen promotes protein synthesis. ketone bodies begin to form.

ketone bodies begin to form.

All of the following occur during the postabsorptive state except that gluconeogenesis occurs in the liver. glycogen is broken down into glucose in the liver. lipid mobilization occurs. ketone bodies may be formed. levels of blood glucose are elevated.

levels of blood glucose are elevated.

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

lipids.

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

liver.

When chyme arrives in the duodenum, cholecystokinin (CCK) release triggers the secretion of which enzyme? salivary amylase pancreatic alpha-amylase maltase gastric inhibitory peptide (GIP)

pancreatic alpha-amylase

When the body is relying on internal energy reserves to continue meeting its energy demands, it is in the ________ state. absorptive starvation postabsorptive preabsorptive deprivation

postabsorptive

The function of the citric acid cycle is to produce water. hydrolyze glucose. transfer the acetyl group. produce carbon dioxide. remove hydrogen atoms from organic molecules and transfer them to coenzymes.

remove hydrogen atoms from organic molecules and transfer them to coenzymes.

The major job of coenzymes in oxidative phosphorylation includes all of the following except the breaking of carbon-carbon covalent bonds. ionization of hydrogen atoms. release of electrons to the first cytochrome of the electron transport chain. release of hydrogen ions. None of the answers is correct.

the breaking of carbon-carbon covalent bonds.

Reactions within ________ provide most of the energy needed by a typical cell. the endoplasmic reticulum the plasma membrane cytoplasm the mitochondria None of the answers is correct.

the mitochondria

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

acetyl-CoA.

Why is glucose the primary energy source for cells? Glucose is a large, insoluble molecule. It can be efficiently stored as glycogen, which forms compact, insoluble granules. Glycogenolysis occurs very quickly, even though it is a very complex pathway. Glycolysis provides a large amount of ATP.

It can be efficiently stored as glycogen, which forms compact, insoluble granules.

Which statement regarding the citric acid cycle is true? The citric acid cycle occurs in the cytoplasm. An acetyl group, CH3CO, from acetyl-CoA is attached to a six-carbon molecule. Cytochromes are the coenzymes that play a key role in the citric acid cycle. Its function is to remove hydrogen atoms from organic molecules and transfer them to coenzymes.

Its function is to remove hydrogen atoms from organic molecules and transfer them to coenzymes.

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

Oxidative phosphorylation

Which is true regarding lipoproteins and lipid transport and distribution? The liver absorbs triglycerides and removes the chylomicrons. The HDLs return the unused cholesterol to the liver, where it is extracted and packaged in new LDLs or excreted with bile salts in bile. Capillary walls contain the enzyme lipoprotein lipase, which breaks down the triglycerides. The liver releases high-density lipoproteins (HDLs) into the circulation, which deliver cholesterol to peripheral tissues.

The HDLs return the unused cholesterol to the liver, where it is extracted and packaged in new LDLs or excreted with bile salts in bile.

Which is a characteristic of oxidative phosphorylation? The diffusion of potassium ions powers the production of ATP. The stepwise passage of electrons by coenzymes embedded in the cristae of the mitochondrion releases energy. It results in the production of pyruvate. It occurs in the cytoplasm using a series of enzymatic reactions.

The stepwise passage of electrons by coenzymes embedded in the cristae of the mitochondrion releases energy.

Choose the correct statement regarding glycolysis. NAD accepts carbon atoms that can be transferred to mitochondria. It occurs in the mitochondrion. There is a net gain of two ATP molecules for each glucose molecule. It is an aerobic process that breaks down a six-carbon glucose molecule into two three-carbon molecules of pyruvate.

There is a net gain of two ATP molecules for each glucose molecule.

In the ETS, ________ accepts electrons from one molecule and transfers them to another. a coenzyme a coenzyme or a cytochrome the acetyl group a cytochrome a hydrogen ion

a coenzyme or a cytochrome

Chylomicrons: enter the bloodstream at the inferior vena cava. are lipoproteins-lipid-protein complexes that contain insoluble lipids. diffuse into blood capillaries. diffuse into the hepatic portal vein, after they are released from the intestinal cells by exocytosis.

are lipoproteins-lipid-protein complexes that contain insoluble lipids.

The citric acid cycle forms acetyl-CoA from glucose-6-phosphate. consumes two moles of carbon dioxide. contains enzymes called cytochromes. begins with the formation of a molecule of citric acid. directly produces most of the ATP from the catabolism of glucose.

begins with the formation of a molecule of citric acid.

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

beta-oxidation.

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

chylomicrons.

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

glycogen breakdown occurs very slowly.

Which condition results when body fluids become saturated with uric acid? phenylketonuria gout kwashiorkor ketoacidosis

gout

Which of the following enhances the effects of glucocorticoids? growth hormone insulin epinephrine glucagon androgens

growth hormone

Identify the substance labeled "4." Figure 23-1 NADH citric acid FADH2 4-carbon molecule hydrogen atoms

hydrogen atoms

In most tissues, the transport of glucose into the cell is dependent on the presence of a carrier protein that is stimulated by which of the following? chylomicrons pyruvate lactase insulin

insulin