Biochem Exam 3 (QUIZZES ONLY)

c

A number of different drugs have been designed to lower cholesterol levels. Statins act by inhibiting the rate-determining step in cholesterol biosynthesis, but these drugs do not work for all individuals. Another potential method for lowering serum cholesterol is treatment with an inhibitor of sterol regulatory element binding proteins (SREBPs). Statins have been combined with other drugs designed to block cholesterol synthesis in the intestine with the hope that a dual mechanism would further reduce serum cholesterol. Would it be potentially beneficial or harmful to combine statins with a SREBP inhibitor for treatment of high serum cholesterol? Choose one: A. beneficial due to decreased uptake of cholesterol by peripheral tissues B. harmful due to increased cholesterol biosynthesis C. harmful due to decreased uptake of cholesterol by peripheral tissues D. beneficial due to decreased cholesterol biosynthesis

GREATER THAN

A positive energy balance results when an organism's energy input is _____________ its energy expenditure.

b

If you needed to design another way to search for elevated alanine aminotransferase levels in blood without actually identifying the enzyme itself, you could add your blood sample to a tube containing equal molarities of alanine and α-ketoglutarate and measure for which of the following? Choose one: A. increasing levels of both alanine and pyruvate B. increasing levels of both glutamate and pyruvate C. decreasing levels of pyruvate and increasing levels of alanine D. decreasing levels of pyruvate and increasing levels of glutamate

A

In a eukaryotic cell, deamination of amino acids takes place most extensively in the Choose one: A. mitochondrial matrix. B. mitochondrial intermembrane space. C. nuceloplasm. D. cytoplasm.

b

If nitrogen is removed from alanine by an aminotransferase reaction, what are the products? Choose one: A. acetate + NH3 (as part of glutamate) B. pyruvate + NH3 (as part of glutamate) C. fumarate + NH3 (as part of glutamate) D. glycerol + NH3 (as part of glutamate)

d

If only showing the nitrogen-containing compounds, what would the net reaction of the urea cycle be? List the reactants on the right and products on the left, ignoring mass balance .Choose one: A. Argininosuccinate ⇔ Arginine + Urea B. Ammonia ⇔ Urea C. Glutamine ⇔ Urea + Glutamate D. Ammonium + Aspartate ⇔ Urea

A

In most animals, after converting a nucleoside diphosphate to a deoxynucleoside, what reduces ribonucleotide reductase so that it can perform another reaction? Choose one: A. thioredoxin B. flavin mononucleotide (FMN) C. nicotinamide adenine dinucleotide (NADH) D. glutathione

a, c, d

If the electron transport chain were inhibited, what would be the overall effect(s) on the ATP yield from fatty acid degradation? Choose one or more: A.ATP yield would be reduced as the production of NADH and FADH2 would be inhibited. B.ATP yield would be reduced as the production of glucose-6-phosphate would be inhibited. C.ATP yield would be reduced as the oxidation of acetyl-CoA would be inhibited. D.ATP yield would be reduced as oxidation of NADH and FADH2 would be inhibited.

a

Some individuals follow a ketogenic diet, in which carbohydrate and protein intake is severely restricted, for the purpose of weight loss or other health goals. As a result of this diet, glucose blood levels drop, and the body produces energy primarily from ketogenesis (the metabolism of fatty acids). Individuals who are following a ketogenic diet will have high amounts of ketone bodies in their blood, as will individuals who have overdosed on insulin or have undiagnosed diabetes (decreased glucose uptake into tissues). However, the presence of ketone bodies in blood does not necessarily mean ketoacidosis, a life-threatening condition, has occurred. Which of the following statements is FALSE about determining the cause and treatment for ketoacidosis? Choose one: A. If blood pH is low and ketone body concentration is high (ketoacidosis) and blood glucose levels are high, then the individual should be treated with an infusion of glucose. B. If blood pH is low and ketone body concentration is high (ketoacidosis) and blood glucose levels are high, then the individual may have untreated diabetes. C. If blood pH is low and ketone body concentration is high (ketoacidosis) and blood glucose levels are low, then the individual may have overdosed on insulin. D. If blood pH is within normal range, ketone body concentration is high, and blood glucose levels are low, then the individual may be on a carbohydrate- and protein-restricted ketogenic diet. If the individual is demonstrating unusual cognitive behavior, then other causes should be pursued (such as through a toxicology screen).

A, D, E

Sort the amino acids as to whether they are considered essential or nonessential amino acids in humans. Drag the amino acid name into the appropriate bin. ESSENTIAL A. VALINE B. CYSTEINE C. GLYCINE D. THREONINE E. LYSINE F. CYSTEINE

C, F

Sort the amino acids as to whether they are considered essential or nonessential amino acids in humans. Drag the amino acid name into the appropriate bin. NONESSENTIAL A. VALINE B. CYSTEINE C. GLYCINE D. THREONINE E. LYSINE F. CYSTEINE

D, E

Sort the following amino acids into either glucogenic, ketogenic, or both. BOTH a. leucine b. alanine c. glutamate d. tryptophan e. threonine f. lysine

B, C

Sort the following amino acids into either glucogenic, ketogenic, or both. GLUCOGENIC a. leucine b. alanine c. glutamate d. tryptophan e. threonine f. lysine

A, F

Sort the following amino acids into either glucogenic, ketogenic, or both. KETOGENIC a. leucine b. alanine c. glutamate d. tryptophan e. threonine f. lysine

A, D

Sort the following into the effects insulin has on liver, muscle, or both. BOTH' A.Utilize glucose and fatty acids as energy sources B.Exports lactate to the blood when energy demands are high C.Releases glucose when blood sugar levels are low D.Have insulin receptors E.Glucagon receptors are prevalent F. Additional ATP is quickly synthesized by creatine kinase G. Functions as a physiologic glucose regulator

C, E, G

Sort the following into the effects insulin has on liver, muscle, or both. LIVER A.Utilize glucose and fatty acids as energy sources B.Exports lactate to the blood when energy demands are high C.Releases glucose when blood sugar levels are low D.Have insulin receptors E.Glucagon receptors are prevalent F. Additional ATP is quickly synthesized by creatine kinase G. Functions as a physiologic glucose regulator

B, F

Sort the following into the effects insulin has on liver, muscle, or both. MUSCLE A.Utilize glucose and fatty acids as energy sources B.Exports lactate to the blood when energy demands are high C.Releases glucose when blood sugar levels are low D.Have insulin receptors E.Glucagon receptors are prevalent F. Additional ATP is quickly synthesized by creatine kinase G. Functions as a physiologic glucose regulator

B, E

Sort the phrases to identify the role of each listed organ in regulating metabolic homeostasis. ADIPOSE TISSUE!!!!!!!!!!!!!! SELECT MORE THAN ONE A.Secretion of varying ratios of insulin and glucagon in response to blood glucose concentration B.Storage or release of fatty acids in response to hormone signals C.Storage or synthesis of glucose in response to hormone signals D.Synthesis and release of fatty acids in response to hormone signals E.Secrete adipokines

C, D

Sort the phrases to identify the role of each listed organ in regulating metabolic homeostasis. LIVER!!!!!!!!!!!!!! SELECT MORE THAN ONE A.Secretion of varying ratios of insulin and glucagon in response to blood glucose concentration B.Storage or release of fatty acids in response to hormone signals C.Storage or synthesis of glucose in response to hormone signals D.Synthesis and release of fatty acids in response to hormone signals E.Secrete adipokines

A

Sort the phrases to identify the role of each listed organ in regulating metabolic homeostasis. PANCREAS!!!!!!!!!!!!!! SELECT MORE THAN ONE A.Secretion of varying ratios of insulin and glucagon in response to blood glucose concentration B.Storage or release of fatty acids in response to hormone signals C.Storage or synthesis of glucose in response to hormone signals D.Synthesis and release of fatty acids in response to hormone signals E.Secrete adipokines

A, B, C

Sort the phrases to indicate if they describe an effect of insulin signaling or glucagon signaling on pathways in the liver. GLUCAGON A. Activate fatty acid oxidation B. Activate gluconeogenesis C. Activate glycogenolysis D. Activate fatty acid synthesis E.Activate glycogen synthesis

D, E

Sort the phrases to indicate if they describe an effect of insulin signaling or glucagon signaling on pathways in the liver. INSULIN A. Activate fatty acid oxidation B. Activate gluconeogenesis C. Activate glycogenolysis D. Activate fatty acid synthesis E.Activate glycogen synthesis

a

Under the conditions specified in Part 1, which intermediate would be transported from the mitochondrion to the cytosol in order to provide substrates for fatty acid synthesis?Choose one: A. citrate B. glycerol-3-phosphate C. NADH D. acetyl-CoA

b

Amino acids are released from protein digestion or turnover. Any not used as building blocks for translation are degraded. The major site of amino acid degradation in mammals is the liver. The amino group must be removed because there are no nitrogenous compounds in energy transduction pathways. For carbon there are several biochemical mechanisms in which common intermediates can be interconverted to or from amino acids. Which amino acid is interconverted to α-ketoglutarate as part of nitrogen transport?Choose one: A. aspartate B. glutamate C. asparagine D. glutamine

ketogenic

Amino acids that are converted into acetyl-CoA or acetoacetyl-CoA are called _________________

glucogenic

Amino acids that give rise to pyruvate or any of the citrate cycle intermediates are called __________________ .

A

Consider the following scenario:A man who does not have Lesch-Nyhan syndrome and a woman whose mother and father both had Lesch-Nyhan syndrome have a male child together. What are the chances that this child will have Lesch-Nyhan syndrome? Assume a traditional Mendelian X-linked recessive inheritance pattern for the purpose of this question and assume that all organisms are fertile.(Note: Human genetics is very complex, and although genotype follows traditional Mendelian patterns, the organismal phenotype can be quite diverse. Focus on genotypic inheritance to answer this question.) Choose one: A. 100% B. 75% C. 50% D. 25% E. 0%

c

Consumption of excess calories in the form of carbohydrates can lead to the synthesis of fatty acids and triacylglycerols. In order for this to occur, which of the following conditions must be true? Choose one: A. The energy charge must be high, increasing the flux of the citric acid cycle. B. The energy charge must be low, increasing the flux of the citric acid cycle. C. The energy charge must be high, decreasing the flux of the citric acid cycle. D. The energy charge must be low, decreasing the flux of the citric acid cycle.

D

Deoxyribonucleotides are the building blocks of DNA. DNA differs from RNA in two important ways. First, the ribose sugar in DNA lacks the hydroxyl group at C-2'. This prevents spontaneous cleavage of the phosphodiester backbone through formation of 2',3'-cyclic phosphate, as occurs in RNA. Second, thymine replaces uracil as the pyrimidine base that forms hydrogen bonds with the purine base adenine. This feature also has important evolutionary implications because it ensures that DNA repair mechanisms in the cell quickly identify and remove uracil bases resulting from spontaneous cytosine deamination. Deoxyribonucleotides are derived from ribonucleotides by a single reaction catalyzed by the enzyme ribonucleotide reductase. What form of phosphate serves as the ribonucleotide reaction substrate for ribonucleotide reductase? Choose one: A. GTP, ATP, CTP, or UTP. B. GMP, AMP, CMP, or UMP. C. GDP, ADP, CTP, or UTP. D. GDP, ADP, CDP, or UDP.

a, d, e, g

Determine if the items listed are associated with the degradation or synthesis of palmitate DEGRADATION A. mitochondrial b. cytosolic c. coupled with oxidation of NADPH d. Coupled with reduction of NAD+ and FAD e. 2C product is acetyl CoA F. Acyl group carrier is ACP G. Acyl group carrier is CoA h. 2C donor is malonyl CoA

b, c, f, h

Determine if the items listed are associated with the degradation or synthesis of palmitate SYNTHESIS A. mitochondrial b. cytosolic c. coupled with oxidation of NADPH d. Coupled with reduction of NAD+ and FAD e. 2C product is acetyl CoA F. Acyl group carrier is ACP G. Acyl group carrier is CoA h. 2C donor is malonyl CoA

carbohydrates

Dietary intake can contribute to fatty acid synthesis if the food is high in

c

Enzyme deficiencies that affect the fatty acid β-oxidation pathway are often diagnosed by examining the different metabolic intermediates in the bloodstream. An individual with a deficiency in an enzyme required for β oxidation would have which of the following results if the ketone bodies and glucose concentration of their blood were tested after fasting? Choose one: A. Hyperketotic hypoglycemia B. Ketotic hypoglycemia C. Hypoketotic hypoglycemia D. Ketotic hyperglycemia

:)

Fatty acid synthase is a multi-enzyme complex that contains all the enzyme components for fatty acid synthesis. Place the names of these enzymes in order to indicate the correct order in which the reactions they catalyze occur during one round of fatty acid synthesis. start 1. b-ketoacyl-ACP synthase 2. b-ketoacyl-acp reductase 3. b-hydroxyacyl-ACP dehydratase 4. enoyl-ACP reductase end of round

c, d

Glucagon is a peptide that belongs to the secretin family of hormones. It is produced by α cells in the pancreas. Glucagon raises the concentration of glucose and fatty acids in the bloodstream and is considered to be the main catabolic hormone of the body. It is also used as a medication to treat a number of health conditions. The effects of glucagon are opposite to those of insulin. Match the effect that glucagon has to the appropriate tissue type. ADIPOSE A. Stimulates glucose export B. Lacks appreciable levels of glucagon receptors and considered to be glucagon insensitive C. Activates protein kinase A-mediated phosphorylation of perilipin D. Activates triacylglycerol hydrolysis and fatty acid export E. Down-regulates glycogen synthase activity F. Increases rates of gluconeogenesis and glycogen degradation

a, e, f

Glucagon is a peptide that belongs to the secretin family of hormones. It is produced by α cells in the pancreas. Glucagon raises the concentration of glucose and fatty acids in the bloodstream and is considered to be the main catabolic hormone of the body. It is also used as a medication to treat a number of health conditions. The effects of glucagon are opposite to those of insulin. Match the effect that glucagon has to the appropriate tissue type. LIVER' A. Stimulates glucose export B. Lacks appreciable levels of glucagon receptors and considered to be glucagon insensitive C. Activates protein kinase A-mediated phosphorylation of perilipin D. Activates triacylglycerol hydrolysis and fatty acid export E. Down-regulates glycogen synthase activity F. Increases rates of gluconeogenesis and glycogen degradation

B

Glucagon is a peptide that belongs to the secretin family of hormones. It is produced by α cells in the pancreas. Glucagon raises the concentration of glucose and fatty acids in the bloodstream and is considered to be the main catabolic hormone of the body. It is also used as a medication to treat a number of health conditions. The effects of glucagon are opposite to those of insulin. Match the effect that glucagon has to the appropriate tissue type. MUSCLE A. Stimulates glucose export B. Lacks appreciable levels of glucagon receptors and considered to be glucagon insensitive C. Activates protein kinase A-mediated phosphorylation of perilipin D. Activates triacylglycerol hydrolysis and fatty acid export E. Down-regulates glycogen synthase activity F. Increases rates of gluconeogenesis and glycogen degradation

liver

Hepatitis C is a viral infection that is well known for causing _______________ damage. Preliminary diagnosis involves recognition of elevated levels of alanine aminotransferase in blood circulation.

C

How do the effects of leptin and insulin signaling on anorexigenic and orexigenic neurons compare? Choose one: A. Leptin activates anorexigenic neurons and insulin activates orexigenic neurons. B. Both inhibit activation of anorexigenic neurons and activate orexigenic neurons. C. Both activate anorexigenic neurons and inhibit activation of orexigenic neurons. D. Insulin activates anorexigenic neurons and leptin activates orexigenic neurons.

a, c

How does catabolism of glucose from dietary carbohydrates link to fatty acid synthesis?Choose one or more: A.Catabolism of excess dietary carbohydrates raises the energy charge of the cell, which slows the flux of the citric acid cycle. B.Increased flux of the citric acid cycle produces NADH, which can be used for fatty acid synthesis. C.Glycolytic intermediates can be used as substrates for fatty acid and triacylglycerol synthesis. D.Catabolism of excess dietary carbohydrates reduces fatty acid oxidation.

e

How many NAD+ and FAD are reduced in each round of mitochondrial fatty acid β oxidation?Choose one: A. 2 FAD are reduced to 2 FADH2. B. 2 NAD+ and 1 FAD are reduced to 2 NADH and 1 FADH2, respectively. C. 2 NAD+ are reduced to 2 NADH. D. 1 NAD+ and 2 FAD are reduced to 1 NADH and 2 FADH2, respectively. E. 1 NAD+ and 1 FAD are reduced to 1 NADH and 1 FADH2, respectively. F. 2 NAD+ and 2 FAD are reduced to 2 NADH and 2 FADH2, respectively.

a

How many NADH and FADH2 would be produced from β oxidation of a 20 C saturated fatty acid to acetyl-CoA?Choose one: A. 9 NADH, 9 FADH2 B. 10 NADH, 10 FADH2 C. 30 NADH, 20 FADH2 D. 29 NADH, 19 FADH2

pyrimidine

Hypoxanthine is an intermediate used for (A) purine biosynthesis and orotate is an intermediate used for (B) _____________ biosynthesis.

B, C

Identify the nucleotides as pyrimidines or purines by dragging each nucleotide name to its correct bin. PURINE A. URACIL B. ADENINE C. GUANINE D. THYMINE E. CYTOSINE

A, D, E

Identify the nucleotides as pyrimidines or purines by dragging each nucleotide name to its correct bin. PYRIMIDINE A. URACIL B. ADENINE C. GUANINE D. THYMINE E. CYTOSINE

b

Ketogenesis uses a series of enzymes to convert acetyl-CoA to ketone bodies within liver cell mitochondria. This occurs when there is low blood glucose levels, and fatty acids begin to be oxidized as a source of metabolic energy. These ketone bodies can then be used as an energy source in other cells, via their conversion to acetyl-CoA and entrance into the citrate cycle. In the introduction to this question is a figure showing how these ketone bodies are converted into acetyl-CoA and then funneled into the citrate cycle. Which of the molecules in the figure shown in the introduction is depleted during glucose starvation because it is shunted into gluconeogenesis? Choose one: A. acetoacetate B. oxaloacetate C. acetyl-CoAD. D-β-hydroxybutyrate

A,B

Leptin is a peptide hormone predominantly made in the small intestine that helps to regulate energy balance. Leptin acts on brain cells to mediate feeding through regulation of fat stores. In obesity, an inability of leptin to diminish appetite occurs, irrespective of high energy stores. Which of the following genetic manipulations would result in an obese phenotype? Choose one or more: A.leptin receptor-deficient knockout B.leptin-deficient knockout C.moderately increased level of leptin expression D.highly increased level of leptin expression

AMP

Metformin is a drug used to treat type 2 diabetes by increasing insulin sensitivity and decreasing blood glucose. Metformin helps to lower blood glucose levels by first elevating A) __________ levels, which activates B) AMPK . This, in turn, leads to inhibition of C) gluconeogenesis in the liver.

6, 94

Myristoyl-CoA (14:0) would require _______________ rounds of β oxidation to be completely oxidized. A total of ____________ ATP would be produced if all products of β oxidation were completely oxidized.

c

Numerous clinical studies have confirmed the link between age-dependent atherosclerosis and elevated serum LDL levels. Many pharmaceutical companies have therefore developed drugs, known as statins, that can be used to lower serum LDL levels as a treatment for atherosclerosis. The first generation of these drugs was designed to inhibit the activity of HMG-CoA reductase. What additional activity that is stimulated by statins also contributes to reduced levels of serum LDL? Choose one: A. decreased synthesis of bile acids B. decreased synthesis of steroid hormones C. increased LDL endocytosis D. increased HDL levels

B

Other than gout, two other purine degradation diseases in humans, Lesch-Nyhan syndrome and adenosine deaminase deficiency, are caused by mutations in specific genes. Lesch-Nyhan syndrome is a rare recessive genetic disease that is characterized by unusual neurologic symptoms, including severe anxiety and self-mutilation. The human gene responsible for this disease was genetically mapped to the X chromosome (Xq26.1) in the 1970s using low-resolution chromosome analysis methods. Later, in the 1990s, the gene was physically located on the X chromosome using high-throughput DNA sequencing. In Lesch-Nyhan syndrome patients, which enzyme is not functional? Choose one: A. glutamine-PRPP amidotransferase B. hypoxanthine-guanine phosphoribosyltransferase C. purine nucleoside phosphorylase D. adenosine deaminase

B,C,D

Patients with type 1 diabetes must inject insulin up to several times a day and monitor their carbohydrate intake to regulate their blood glucose level. The amount of insulin injected is based on the carbohydrate content of the diet and so must be adjusted accordingly; otherwise, hypoglycemia will result. Which of the following explain(s) why injecting too much insulin before a meal results in hypoglycemia? Choose one or more: A.Decreased appetite B.Increased glycogen storage C.Increased glucose uptake D.Decreased glucose synthesis

B

Several metabolic diseases in humans have been associated with defects in purine degradation. The most common is gout, which is caused by the buildup of purine metabolites in the joints and kidneys. The big toe is a common joint affected by these metabolites because of poor circulation in the foot and the frequency of blunt injury (for example, you stub your toe), which releases metabolites into the synovial fluid. Gout has often been called the "disease of kings" because it can be associated with consumption of alcohol and meat, as was common for nobility in the time of King Henry VIII (A.D. ∼1500), who most likely suffered from gout. In humans, allopurinol can be used as treatment for gout because this drug is a competitive inhibitor of Choose one: A. guanine deaminase. B. xanthine oxidase. C. AMP deaminase. D. urate oxidase.

A

Several metabolic diseases in humans have been associated with defects in purine degradation. The most common is gout, which is caused by the buildup of purine metabolites in the joints and kidneys. The big toe is a common joint affected by these metabolites because of poor circulation in the foot and the frequency of blunt injury (for example, you stub your toe), which releases metabolites into the synovial fluid. Gout has often been called the "disease of kings" because it can be associated with consumption of alcohol and meat, as was common for nobility in the time of King Henry VIII (A.D. ∼1500), who most likely suffered from gout. What purine metabolite is the likely cause of gout? Choose one: A. uric acid B. formylglycinamide ribonucleotide C. dihydrouracil D. 5-aminoimidazole-4-carboxamide ribonucleotide

C

Several metabolic diseases in humans have been associated with defects in purine degradation. The most common is gout, which is caused by the buildup of purine metabolites in the joints and kidneys. The big toe is a common joint affected by these metabolites because of poor circulation in the foot and the frequency of blunt injury (for example, you stub your toe), which releases metabolites into the synovial fluid. Gout has often been called the "disease of kings" because it can be associated with consumption of alcohol and meat, as was common for nobility in the time of King Henry VIII (A.D. ∼1500), who most likely suffered from gout. Why was gout associated with ethanol and meat consumption? Choose one: A. Ethanol causes purines to be converted into pyrimidines (cytosine breakdown is associated with gout). B. Ethanol is a competitive inhibitor of xanthine oxidase and purine metabolism is inhibited at this step due to meat consumption. C. Ethanol interferes with excretion of purine breakdown chemicals and some foods contain high levels of purines. D. Ethanol is an intermediate in the purine biosynthetic pathway (more ethanol equals more purines).

a

The reactions of argininosuccinate synthetase and argininosuccinase are shown below. What best describes the fate of aspartate?Choose one: A. Aspartate is converted to fumarate and NH2. B. Aspartate is converted to citrulline. C. Aspartate is converted to pyruvate and NH2. D. Aspartate is converted to α-ketoglutarate and NH2.

A

Upon deamination of an amino acid, which component becomes substrate for the urea cycle? Choose one: A. ammonia B. a carbon skeleton C. carbon dioxide D. a carboxylic acid

B

What is the cause of type 1 diabetes? Choose one: A. increased catalytic turnover leading to hyperactivity of the peroxisome proliferator-activated receptor gamma (PPARγ) protein B. lack of insulin production in the pancreas in response to increased glucose levels C. defective insulin receptor signaling, resulting in insulin resistance

A

What is the cause of type 2 diabetes? Choose one: A. defective insulin receptor signaling, resulting in insulin resistance B. increased catalytic turnover leading to hyperactivity of the peroxisome proliferator-activated receptor gamma (PPARγ) protein C. lack of insulin production in the pancreas in response to increased glucose levels

d

What role does carnitine play in fatty acid degradation? Choose one: A. It allows the fatty acid to be transported from the mitochondrion to the cytosol .B. It provides the energy required for the fatty acid to be transported from the cytosol to the mitochondrion. C. It provides the energy required for the fatty acid to be transported from the mitochondrion to the cytosol. D. It allows the fatty acid to be transported from the cytosol to the mitochondrion.

c

Which molecule donates a nitrogen moiety in the full net reaction of the urea cycle?Choose one: A. ATP B. bicarbonate C. aspartate

b

Which of the following is involved in protein degradation and requires a very acidic pH (pH around 2) for activity? Choose one: A. proteasome B. pepsin C. aminopeptidases D. enteropeptidase

ab

Which of the following is not a reaction that occurs in the fatty acid synthesis cycle?Choose one or more: A.oxidation of the acyl chain B.desaturation of the acyl chain C.condensation D.reduction of the acyl chain

2, 3, 6

Which of the numbered shaded circles represent an oxidized state for the three proteins shown?

d

Which stage of cholesterol synthesis contains the rate-limiting step of cholesterol synthesis? Choose one: A. synthesis of squalene (Stage 3) B. synthesis of cholesterol (Stage 4) C. synthesis of isopentenyl diphosphate (Stage 2) D. synthesis of mevalonate (Stage 1)

b

Why can prolonged ketogenesis be harmful?Choose one: A. Moving ketone bodies across cell membranes must be done through active transport, which reduces the ATP yield in cells. B. High ketone body levels in the bloodstream can lower blood pH. C. Ketone bodies cause stomach upset and interfere with digestion. D. Oxidation of ketone bodies does not provide cells with as much ATP as oxidation of glucose or fatty acids.

mitochondria, cytoplasm

Within the urea cycle, citrulline is produced by ornithine transcarbamylase in the _______________________ and is consumed in the ______________

succinyl-CoA

β oxidation of an odd-chain fatty acid will (A) lead to an increase in the concentration of malate in the mitochondrion. This is due to the formation of (B) __________________________ , which enters the citric acid cycle.