Exam 3 Smartworks: Ch 15, 16, 17, 19

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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.

6 rounds 95 ATP

Complete degradation of palmitate requires (A) ________ round(s) of ß oxidation. A total of (B) __________ acetyl-CoA are produced.

7; 8

Which lipoprotein does NOT contain apoB-100 on its surface? A. Chylomicron B. VLDL C. LDL D. IDL

A

Which of the following is correct and most accurately describes the complete urea cycle of the eukaryotic cell? A. The urea cycle occurs between the mitochondrial matrix and the cytoplasm of the eukaryotic cell. B. The urea cycle occurs completely within the cytoplasm of the eukaryotic cell. C. The urea cycle occurs completely within the mitochondrial matrix of the eukaryotic cell. D. The urea cycle occurs between the inner mitochondrial membrane and the matrix of the eukaryotic cell.

A

Which pathway does NOT provide metabolic precursors for amino acid synthesis? A. Urea cycleB. Pentose phosphate pathwayC. GlycolysisD. Citrate cycle

A

Triacylglycerols synthesized in the liver are packaged in which of the following? A. VLDL particles B. secretory vesicles C. HDL particles D. chylomicrons

A Triacylglycerols and cholesterol esters are transported through the blood in apolipoprotein particles. These particles vary from large chylomicrons produced in intestinal epithelial cells to small very-low-density lipoprotein (VLDL) particles synthesized and exported by liver cells.

Apolipoproteins are found embedded in which of the following? A. membrane surrounding chylomicrons B. mitochondrial inner membrane C. nuclei of adipocytes D. hydrophobic center of chylomicrons

A apolipoproteins are membrane proteins that play a variety of roles in chylomicron trafficking.

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? A. harmful due to increased cholesterol biosynthesis B. harmful due to decreased uptake of cholesterol by peripheral tissues C. beneficial due to decreased cholesterol biosynthesis D. beneficial due to decreased uptake of cholesterol by peripheral tissues

A both drugs act to reduce cholesterol biosynthesis. With statin treatment, the lower cholesterol concentration inside cells activates synthesis of the LDL receptor, which takes up additional cholesterol. Removing cholesterol from the bloodstream is beneficial as it decreases the development of atherosclerosis. SREBP inhibitors would reduce LDL receptor expression. A combination treatment then could result in a lower expression of LDL receptors, resulting in a higher serum cholesterol level.

Both HDL and LDL particles transport cholesterol through the bloodstream. Why are elevated levels of HDL considered "good" while elevated levels of LDL are considered "bad"? A.Cholesterol transported by HDL particles can be converted into bile acids. B.LDL particles can invade the endothelial lining of blood vessels. C.HDL particles remove cholesterol from peripheral tissues and arteries. D.LDL particles can bind to receptors on the surface of cells.

A, B, C

Which of the following are primary functions of cholesterol synthesized in the liver? A.structural component of cell membranes B.synthesis of bile acids C.synthesis of steroid hormones D.synthesis of acetyl-CoA

A, B, C

The brain requires a constant input of glucose. The metabolic activity of which organ(s) is/are necessary to maintain the concentration of glucose required by the brain when dietary glucose is low?' A.Kidney B.Liver C.Adipose tissue D.Skeletal muscle

A, B, C Glucose can be produced in the liver both from glycogenolysis and gluconeogenesis and can also be synthesized in the kidney from the carbon skeletons of amino acids. Low blood glucose levels lead to hydrolysis of triacylglycerols in adipose tissue. The glycerol backbone can be used as a precursor for glucose synthesis, whereas fatty acid oxidation can be used to fuel this process.

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

A, B, D

What major roles do lipids serve in biology? A.energy storage B.utilization in signaling pathways C.free radical oxidation D.information storage E.formation of membrane barriers

A, B, E

Which of the following lipids can be found in cellular membranes? A.cholesterol B.triacylglycerols C.sphingolipids D.glycerophospholipids

A, C, D

Which cellular change(s) would not encourage the Krebs bicycle and thus the probability of the urea cycle taking place to completion? A.increased conversion of oxaloacetate into citrate B.increased import of ornithine into the mitochondria C.increased citrulline being transported into the cytoplasm D.low Aspartate concentration

A, D

β oxidation of tricosanoate (23:0) can be completed in (A) ________ rounds. The last round begins with a (B)_______ -carbon acyl-CoA. The two products of this last round are (C)___________ .

A. 10 B. 5 C. one acetyl CoA and one propinyl CoA As the 23:0 acyl-CoA chain is oxidized, 2C groups are removed sequentially to produce acetyl-CoA. After 18 carbons have been cleaved, five carbons remain. Cleavage of the acyl-CoA that begins the last round of β oxidation will produce one acetyl-CoA and one propionyl-CoA.

How many molecules of NADPH are required for the complete synthesis of one molecule of palmitate? Consider the number of oxidation-reduction reactions in each round of fatty acid synthesis as well as the total number of rounds necessary to synthesize palmitate. A. 14 B. 2 C. 7 D. 8

A. 14 Each round of fatty acid synthesis contains two reactions in which NADPH acts as a reducing agent. Synthesis of palmitate requires seven rounds; therefore, 14 NADPH are required in total.

Which of the following is directly affected by thiazolidinediones? A. Adipose tissue B. Heart C. Skeletal muscle D. Liver

A. Adipose tissue

The interaction between LDL particles and LDL receptors is mediated by (A)_____ . Once bound to the receptor, LDL particles are (B)________ , resulting in an increase in the cholesterol pool inside the cell. LDL receptors are then (C)______ .

A. ApoB-100 B. endocytosed C. LDL receptor can be recycled and returned to the cell surface.

Which amino acid is formed as a product of aminotransferases using α-ketoglutarate as the α-amino group acceptor? A. Glutamate B. Glycine C. Glutamine D. Aspartate

A. Glutamate

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

A. High ketone body levels in the bloodstream can lower blood pH.

Which of the following lipases in human adipocytes is responsive to glucagon? A. Hormone-sensitive B. Monoacylglycerol C. Adipose triglyceride D. Hormone-insensitive

A. Hormone-sensitive

Which of the following enzymes is stimulated by insulin in liver cells only? A. Protein phosphatase 2A B. Protein phosphatase 1 C. GLUT4 D. Pyruvate dehydrogenase complex

A. Protein phosphatase 2A Fatty acid synthesis does take place in the liver and insulin facilitates that pathway by activating protein phosphatase 2A.

Which of the following is correct concerning overall ATP production from the complete oxidation of palmitate? A. The overall yield of ATP is 106 ATP. B. 8 ATP are directly produced. C. FADH2 production yields 10.5 ATP. D. NADH production yields 60 ATP.

A. The overall yield of ATP is 106 ATP.

The onset of __________ is due to a recessive mutation in the gene encoding homogentisate-1,2-dioxygenase, an enzyme in the phenylalanine and tyrosine degradation pathways. A. alkaptonuria B. phenylketonuria C. both alkaptonuria and phenylketonuria D. neither alkaptonuria nor phenylketonuria

A. alkaptonuria - aka black urine disease

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

A. ammonia

During heme catabolism, which enzyme participates in heme breakdown while also serving an NADPH oxidase role in the reaction? A. biliverdin reductase B. porphobilinogen synthase C. heme oxygenase D. ferrochelatase

A. biliverdin reductase

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

A. mitochondrial matrix.

If a person's daily food calories exceed the daily energy expenditure, this person is said to be at A) ... energy balance. A person who exists in this state for an extended period of time may have a(n) B) ... in his or her fat storage set point, making it more difficult to lose weight.

A. positive B. increase

Which of the following is NOT a fate of the carbon atoms from amino acid catabolism? A. Urea cycle B. Citrate cycle C. Acetyl-CoA D. Pyruvate

A. urea cycle When amino acids are degraded, the nitrogen is used for biosynthetic pathways or is excreted. The carbon atoms are used in energy conversion pathways, including the citrate cycle, and as building blocks for glucose, fatty acids, and ketone bodies.

Which of the following are lipases involved in the release of fatty acids from adipocytes and which are lipases involved in the degradation of glycerophospholipids?

Adipocyte lipase: hormone-sensitive lipase, adipose triglyceride lipase and monoacylglycerol lipase Glycerophospholipid: phospholipase C, phospholipase A1, phospholipase D *lipases in adipocytes target mono-, di-, and triacylglycerols. They do not include phospholipases, which target glycerophospholipids.

In animals, triacylglycerols are stored predominantly in what type of cells?

Adipocytes

Which of the following are regulatory mechanisms that exist to prevent futile cycling in lipid metabolism? A.fatty acyl-CoA inhibition of acetyl-CoA carboxylase B.citrate activation of acetyl-CoA carboxylase C.AMPK phosphorylation of acetyl-CoA carboxylase D.malonyl-CoA inhibition of CPT1

All

Which feature of an HDL particle is responsible for the ability of this lipoprotein to remove cholesterol from peripheral tissues? A. low percent of triacylglycerol content B. presence of a distinct set of apolipoproteins C. small diameter D. high protein content

B HDL particles contain a distinct set of apolipoproteins, including apoA-1. This lipoprotein component is responsible for activating a cholesterol acyltransferase that esterifies membrane-bound cholesterol and allows it to be incorporated into the HDL particle.

Which of the following statements are true about cell membranes? A.The protein content of a cell membrane can never exceed the lipid content. B.The major constituents of cell membranes are lipids and proteins. C.Cell membranes form a continuous and completely impermeable barrier surrounding the cell. D.The membranes of animal cells generally contain cholesterol.

B, D

Low-carbohydrate diets became popular in the late 1990s and were quickly proclaimed to be a fast and easy method of weight loss. The effectiveness and safety of these diets are dependent on the activity and overall health of the individual as well as the total nutritional content of the diet. However, it is true that in some cases, these diets have been effective. What metabolic effects caused by eating a low-carbohydrate diet can be linked directly to a decrease in fatty acid synthesis and an increase in fatty acid oxidation? A.release of insulin from pancreatic β cells B.phosphorylation of AMPK C.dephosphorylation of AMPK D.release of glucagon from pancreatic α cells

B, D Low carbohydrates would decrease the amount of dietary glucose that enters the bloodstream, and this reduction would lead to the release of glucagon. When glucagon binds to a liver cell, it initiates a signaling cascade that results in the phosphorylation and activation of AMPK. Decreased glucose inside the cell can also result in increased concentration of AMP, which can cause activation of AMPK. The combined effect leads to AMPK-dependent inactivation of acetyl-CoA carboxylase, which is required for fatty acid synthesis. A reduction in fatty acid synthesis is linked to increased transport of fatty acids into mitochondria and their subsequent oxidation.

Given that bacteria change the composition of their cellular membranes, which of the following would you predict to happen to the membrane composition of a bacterial culture that was shifted from growth at 37 °C to 10 °C? A.More triacylglycerols would be found in the membrane. B.The percentage of glycerophospholipids with shorter chain fatty acids would increase. C.The percentage of glycerophospholipids with longer chain fatty acids would increase. D.Fatty acids with more cis double bonds would be found in the membrane. E.More unsaturated glycerophospholipid fatty acids would be found in the membrane.

B, D, E

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

B. 1 NAD+ and 1 FAD are reduced to 1 NADH and 1 FADH2, respectively.

Which of the following is a product of palmitate synthesis? A. 7 ATP B. 8 Acetyl CoA C. 14 H+ D. 14 NADPH

B. 8 Acetyl CoA

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

B. 9 NADH, 9 FADH2

Which of the following regulatory mechanisms is NOT used to prevent futile cycling in fatty acid metabolism? A. High levels of malonyl-CoA inhibits carnitine acyltransferase I activity, which prevents mitochondrial import and degradation of fatty acyl-CoA molecules. B. AMP binding regulates AMPK activity. C. High levels of fatty acyl-CoA inhibit acetyl-CoA carboxylase activity. D. Excess acetyl-CoA in the mitochondria provides feedback inhibition of the citrate cycle and stimulates citrate export to activate acetyl-CoA carboxylase activity.

B. AMP binding regulates AMPK activity. While AMP plays a regulatory role for many enzymes, including AMPK, it is not a mechanism used to prevent futile cycling in fatty acid metabolism. Allosteric control of key enzymes by metabolites involved in these pathways provides the necessary regulation.

Which of the following is a substrate of the urea cycle? A. Urea B. Aspartate C. 2 ADP D. AMP

B. Aspartate

In the citrate shuttle, which enzyme is responsible for converting citrate to oxaloacetate and acetyl-CoA in the cytosol? A. Cytosolic malate dehydrogenase B. Citrate lyase C. Citrate synthase D. Malic enzyme

B. Citrate lyase

In the Krebs bicycle, which of the following citrate cycle intermediates links to the urea cycle via argininosuccinate? A. Malate B. Fumarate C. Oxaloacetate D. Succinate

B. Fumarate

Which amino acid in a target protein for proteasomal degradation is tagged by ubiquitin? A. Arginine B. Lysine C. Tyrosine D. Serine

B. Lysine

Which of the following statements concerning lysosomes is FALSE? A. Proteases within the lysosome are non-specific. B. Lysosomal degradation of proteins is ATP-dependent. C. Lysosomes degrade a variety of macromolecules. D. The interior of a lysosome has a low pH.

B. Lysosomal degradation of proteins is ATP-dependent.

How does density of a lipoprotein relate to its composition? A. The density of a lipoprotein increases as the concentration of lipids increases. B. The density of a lipoprotein increases as the concentration of lipids decreases. C. The density of a lipoprotein decreases as the concentration of lipids decreases. D. The density of a lipoprotein is not affected by its lipid composition.

B. The density of a lipoprotein increases as the concentration of lipids decreases.

Which amino acid is the precursor of catecholamines? A. Cysteine B. Tyrosine C. Phenylalanine D. Lysine

B. Tyrosine Catecholamines, such as dopamine, norepinephrine, and epinephrine, are important signaling molecules. Tyrosine is the precursor for these molecules.

Which of the following statements is correct concerning energy balance? A. A positive energy imbalance means the number of calories consumed is less than the number of calories expended. B. A negative energy imbalance means the number of calories consumed is more than the number of calories expended. C. For most adults, energy balance is approximately 1500-2000 calories/day. D. An individual who has an energy balance is always at a healthy weight.

C

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

C

Which of the following is/are NOT a component of chylomicrons? A. Triacylglycerols B. Cholesterol ester C. Lipase D. Phospholipids

C Chylomicrons are large lipoprotein particles that move triacylglycerols from the intestines to adipose tissue for storage or muscle cells for energy conversion. These complexes contain a monolayer of phospholipids studded with free cholesterol and apolipoproteins surrounding triacylglycerols and cholesterol esters.

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

C,D

The most abundant fatty acids in nature consist of unbranched chains of how many carbons? A. >32 B. 2-10 C. 12-20 D. 20-32

C. 12-20

Which of the following is correct concerning triacylglycerol generation? A. Phosphatidic acid has one fatty acid attached. B. The final step is attachment of a fatty acid to the C1 position of glycerol. C. A source of glycerol-3-phosphate is dihydroxyacetone phosphate. D. Lysophosphatidic acid has two fatty acids attached.

C. A source of glycerol-3-phosphate is dihydroxyacetone phosphate. Triacylglycerols contain three fatty acids linked to a glycerol backbone. Dihydroxyacetone or glycerol serve as the source of glycerol-3-phosphate. The first fatty acid is added to the C1 position, generating lysophosphatidic acid. The second fatty acid is added to the C2 position, resulting in phosphatidic acid. The phosphate group is removed from the C3 position before the final fatty acid addition.

Which of the following does NOT occur during starvation? A. There's an increase of fatty acids released from adipose tissue. B. Skeletal muscle proteins are degraded. C. Brain cells begin using fatty acids as an energy source. D. There's an increase of gluconeogenesis in the liver and kidneys.

C. Brain cells begin using fatty acids as an energy source. During periods of starvation, the body begins to use triacylglycerols as a major food source to preserve glucose for brain cells and erythrocytes. That means fatty acids and glycerol are released from adipose tissues and gluconeogenesis is increased in liver and kidney cells.

Which enzyme mediates ammonia assimilation but is NOT found in all organisms? A. Glutamine synthetase B. Glutamate synthetase C. Glutamate synthase D. Glutamate dehydrogenase

C. Glutamate synthase

Which of the following is a starting material for the synthesis of heme? A. Alanine B. Histidine C. Glycine D. Phenylalanine

C. Glycine

Which of the following pairs of amino acids need glutamine to be generated, but are also both allosteric regulators of glutamine synthetase? A. Alanine, serine B. Serine, tryptophan C. Histidine, tryptophan D. Glycine, histidine

C. Histidine, tryptophan

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

C. It allows the fatty acid to be transported from the cytosol to the mitochondrion.

Which of the following types of reactions is NOT involved in fatty acid synthesis? A. Reduction B. Condensation C. Oxidation D. Dehydration

C. Oxidation

Which of the following proteins is activated by phosphorylation during glucagon-activated fatty acid release from adipocytes? A. Monoacylglycerol B. Adipose triglyceride C. Perilipin D. Fatty acid binding protein 4

C. Perilipin The glucagon receptor is a G protein-coupled receptor, so binding of glucagon stimulates a G protein that activates cAMP production, which activates protein kinase A. Protein kinase A phosphorylates hormone-sensitive lipase, as well as perilipin, thus starting the release of fatty acids by the lipases in the adipocytes.

β oxidation of an unsaturated fatty acid, as shown in the image, would differ from β oxidation of a saturated fatty acid of the same carbon number in what way? A. Fewer acetyl-CoA are produced in β oxidation of an unsaturated fatty acid than in β oxidation of a saturated fatty acid of the same carbon number. B. The number of cofactors reduced in each round of β oxidation of an unsaturated fatty acid is less than in β oxidation of a saturated fatty acid of the same carbon number. C. The total number of cofactors reduced in β oxidation of an unsaturated fatty acid is less than in β oxidation of a saturated fatty acid of the same carbon number. D. More rounds are required for β oxidation of an unsaturated fatty acid than β oxidation of a saturated fatty acid of the same carbon number.

C. The total number of cofactors reduced in β oxidation of an unsaturated fatty acid is less than in β oxidation of a saturated fatty acid of the same carbon number. β oxidation of an unsaturated fatty acid produces fewer reduced cofactors than β oxidation of a saturated fatty acid. β oxidation of an unsaturated fatty acid has the same overall results as oxidation of a saturated fatty acid. Both require the same number of rounds and produce the same number of acetyl-CoA, as determined by the number of carbons in the initial molecule. There are differences in the number of reduced cofactors produced due to the presence of C=C bonds in an unsaturated fatty acid. This difference only occurs in rounds in which the existing C=C bond affects the ability of enzymes to interact with the β carbon. For the molecule shown here, only two rounds would be affected.

Which of the following is FALSE concerning triacylglycerol transport? A. Dietary triacylglycerols are transported as chylomicrons. B. Free fatty acids are transported by albumin. C. Triacylglycerols from adipose tissue are transported as free triacylglycerols. D. Triacylglycerols synthesized by the liver are transported as VLDL particles.

C. Triacylglycerols from adipose tissue are transported as free triacylglycerols. The hydrophobic nature of the fatty acid chains requires the aid of proteins for transport through the circulatory system. Thus, dietary triacylglycerols are transported as chylomicrons and liver-synthesized triacylglycerols are transported as VLDL particles. Adipose tissues breakdown stored triacylglycerols to release fatty acids, which are then transported by albumin.

X-linked adrenoleukodystrophy (X-ALD) is caused by a defect in peroxisomal import of very-long-chain saturated fatty acids. Why is this harmful to the body? A. Inhibition of peroxisomal import reduces the amount of ATP that can be synthesized. B. Very-long-chain fatty acids are required for peroxisomal function. C. Very-long-chain fatty acids are not substrates for mitochondrial β oxidation. D. Blocking peroxisomal import leads to product inhibition of cytosolic acyl-CoA synthetases.

C. Very-long-chain fatty acids are not substrates for mitochondrial β oxidation.

Which enzyme is not involved in the reaction(s) that directly contribute to the carbamoyl phosphate pool? A. glutamate dehydrogenase B. glutaminase C. aspartate aminotransferase D. All of these are involved in increasing the molarity of carbamoyl phosphate.

C. aspartate aminotransferase

In low ATP/energy conditions, which intermediate would be transported from the mitochondrion to the cytosol in order to provide substrates for fatty acid synthesis? A. NADH B. glycerol-3-phosphate C. citrate D. acetyl-CoA

C. citrate

Free fatty acids inside cells would also act like soap and disrupt biological membranes, except that fatty acids inside cells are chemically neutralized by covalent linkage to what small molecule for energy storage? A. biotin B. glucose C. glycerol D. ubiquitin

C. glycerol

When mixed with water, the fatty acids in soap function as amphipathic molecules forming what? A. bilayers B. monolayers C. micelles D. vesicles

C. micelles

The effect of cholesterol on membrane fluidity at physiological temperatures is to? A. maintain membrane fluidity through its disruption of fatty acid packing. B. rigidify membranes by forming a complex that bridges the inner and outer leaflets. C. prevent lateral movement of phospholipids and thereby decrease membrane fluidity in that region. D. maintain membrane fluidity due to exclusion of saturated glycerophospholipids.

C. prevent lateral movement of phospholipids and thereby decrease membrane fluidity in that region.

In adipocytes, glucagon activation leads to? A. inactivation of lipases. B. sequestration of fatty acids in lipid droplets. C. release of free fatty acids. D. an increase in chylomicron production.

C. release of free fatty acids.

What is a fatty acid that contains fully reduced methylene groups called? A. a trans fatty acid B. unsaturated C. saturated D. a cis fatty acid

C. saturated

A new bacterial species is found on a thermal vent in a boiling hot springs. Which of the following do you predict would be true? A.The membrane composition of the new species would be the same as a terrestrial counterpart. B.The membrane composition would contain more unsaturated fatty acids than a terrestrial counterpart. C.The membrane composition would contain more saturated fatty acids than a terrestrial counterpart. D.The membrane composition would contain more fatty acids with cis double bonds than a terrestrial counterpart.

C.The membrane composition would contain more saturated fatty acids than a terrestrial counterpart.

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

Carbohydrates

Sphingolipids consist of a fatty acid attached to sphingosine. The addition of head groups distinguishes the different types. Describe a sphingolipid that is a cerebroside.

Cerebrosides have a single sugar attached as the head group.

What items are included in the synthesis of Fatty Acids? Acyl group carrier is ACP. 2C donor is malonyl CoA. Mitochondrial Coupled with reduction of NAD+ and FAD Cytosolic Coupled with oxidation of NADPH 2C product is acetyl CoA. Acyl group carrier is CoA.

Cytosolic Coupled with oxidation of NADPH Acyl group carrier is ACP. 2C donor is malonyl CoA.

An available treatment for reducing overall cholesterol levels in the body is injection of a resin called cholestyramine, which binds to? A. cholesterol in membranes. B. intracellular lipid droplets. C. steroid hormones. D. bile acids.

D

Insulin-stimulated glucose uptake and utilization by skeletal muscle and liver cells results in a reduction in the blood glucose level. Which organ is primarily responsible for the decrease in serum glucose, and why? A. The liver is responsible for the majority of glucose uptake, as liver cells have more glucose receptors than skeletal muscle. B. The skeletal muscle is responsible for the majority of glucose uptake, as skeletal muscle cells have more glucose receptors than liver cells. C. The liver is responsible for the majority of glucose uptake, as liver cells can store more glycogen than muscle cells. D. The skeletal muscle is responsible for the majority of glucose uptake, as the total mass of skeletal muscle is greater than the mass of liver cells.

D

Which of the following is true concerning the participation of LDL particles in atherosclerosis? A. Fibrous tissue in arterial walls contain very little cholesterol-rich lipids. B. Oxidized phospholipids in LDL particles inhibit an immune response. C. Cholesterol from degraded LDL particles do not contribute to plaque formation. D. Foam cells are macrophages that contribute to plaque formation.

D The fibrous tissues of arterial walls contain large deposits of cholesterol-rich lipids. LDL particles invade the endothelial lining of blood vessels, where the oxidized phospholipids of the LDL particle generate an immune response, including macrophages known as foam cells. These foam cells, along with fat deposits, and cholesterol from degraded LDL particles lead to plaque formation.

Which of the following enzymes catalyzes the rate limiting step of cholesterol synthesis? A. Prenyltransferase B. Cyclase C. Phosphomevalonate kinase D. HMG-CoA reductase

D The rate limiting step of cholesterol synthesis occurs during stage 1. HMG-CoA converts HMG-CoA to mevalonate, which requires two molecules of NADPH and releases CoA. This enzyme is the target of statin drugs, which are used to treat cardiovascular disease.

Which of the following best explains why the fatty acyl-CoA synthetase reaction is considered to consume 2 ATP? A. PPi is hydrolyzed to 2 Pi. B. Each fatty acid must be activated in both the cytosol and mitochondrion, requiring an overall input of 2 ATP. C. 2 ATP are required to provide the free energy change necessary to make formation of the thioester bond favorable. D. 2 ATP are required to regenerate the AMP product.

D. 2 ATP are required to regenerate the AMP product. This reaction requires one ATP and produces AMP and PPi. In order to regenerate an ATP from AMP, 2 ATP are required for the adenylate kinase (AMP to ADP) and nucleoside diphosphate kinase (ADP to ATP) reactions, respectively.

Which of the following is a product from fatty acid oxidation of palmitate? A. 7 NAD+ B. ATP C. 7 FAD D. 8 Acetyl-CoA

D. 8 Acetyl-CoA

Which of the following statements is true concerning ketogenesis? A. Ketoacidosis is caused by high blood pH due to high ketogenesis activity producing more ketone bodies than can be used by the body. B. The brain is unable to use ketone bodies as fuel. C. Ketogenesis is inhibited when carbohydrate sources are limited due to starvation. D. Acetoacetate and D-β-hydroxybutyrate are known as ketone bodies.

D. Acetoacetate and D-β-hydroxybutyrate are known as ketone bodies.

Which of these key enzymes for fatty acid metabolism catalyzes the commitment step for fatty acid synthesis? A. Carnitine acyltransferase I B. Fatty acyl-CoA synthetase C. Fatty acid synthase D. Acetyl-CoA carboxylase

D. Acetyl-CoA carboxylase Acetyl-CoA carboxylase catalyzes the commitment step for fatty acid synthesis. It catalyzes the production of malonyl-CoA from acetyl-CoA and is regulated via reversible phosphorylation and allosteric mechanisms.

The venom of several insects and snakes contains the enzyme phospholipase A2. What is the mechanism by which such venoms cause cellular damage? A. Phospholipase A2 denatures receptors in the neuromuscular junction, causing paralysis. B. Phospholipase A2 breaks down connective tissue that holds bones together, causing paralysis. C. Phospholipase A2 breaks down lipid energy stored in muscle, leading to paralysis. D. Phospholipase A2 breaks down glycerophospholipids, releasing fatty acids that can damage cell membranes.

D. Phospholipase A2 breaks down glycerophospholipids, releasing fatty acids that can damage cell membranes.

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? A. The energy charge must be low, decreasing 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, increasing the flux of the citric acid cycle. D. The energy charge must be high, decreasing the flux of the citric acid cycle.

D. The energy charge must be high, decreasing the flux of the citric acid cycle.

Which of the following is NOT a major type of plasma membrane lipid? A. Glycerophospholipid B. Cholesterol C. Sphingolipid D. Wax

D. Wax

What is the function of the ACP that identifies it is an intermediate in fatty acid synthesis not oxidation? A. number of carbons in the molecule B. C=C bond at the β carbon C. acyl group being attached to the carrier by a thioester linkage D. acyl group being bound to an acyl carrier protein

D. acyl group being bound to an acyl carrier protein acyl carrier protein (ACP) is the hydrocarbon anchor in fatty acid synthesis.

Lipases are water-soluble enzymes in the small intestine that A. break down free fatty acids into acetate. B. covalently attach lipids to glucose. C. convert sphingolipids to triacylglycerols. D. hydrolyze triacylglycerols to fatty acids.

D. hydrolyze triacylglycerols to fatty acids.

The effect of cholesterol on membrane fluidity at low temperatures is to? A. reduce membrane fluidity by straightening unsaturated cis fatty acids. B. maintain membrane fluidity by acting as a short fatty acid chain. C. reduce membrane fluidity by tightly binding to fatty acid chains of glycerophospholipids. D. maintain membrane fluidity through its disruption of fatty acid packing.

D. maintain membrane fluidity through its disruption of fatty acid packing.

What is an unsaturated fatty acid with one carbon-carbon double bond called? A. an omega fatty acid B. polyunsaturated C. saturated D. monounsaturated

D. monounsaturated

Glycogen is a polysaccharide and has many water molecules associated with it due to its polar nature. Triacylglycerols are nonpolar. What is the relative energy storage density (kJ/g) of triacylglycerols to glycogen? A. slightly greater, 2:1 B. equal, 1:1 C. slightly less, 0.5:1 D. significantly greater, 6:1

D. significantly greater, 6:1

Sort the following lipids by their major role in the cell into energy storage, cell membrane, or endocrine signaling: Glycerophospholipids Steroids Phospholipids Fatty acids Triacelyglycerols Eicosanoids

Energy Storage: Fatty acids, TAGs Cell Membrane: Glycerophospholipids, Phospholipids Endocrine Signaling: Steroids, Eicosanoids

Determine whether the melting point will increase, decrease, or remain unchanged for the given circumstances.

Inc MP: Lengthening of saturated chains Dec MP: Introducing more cis double bonds Shortening of monounsaturated trans fatty acid chains No Change: Replacing sphingolipids with glycerophospholipids with matching fatty acids

Which organ is the metabolic control center for the body?

Liver

Sort into liver, adipocytes, or pancreas: -Secretion of varying ratios of insulin and glucagon in response to blood glucose concentration -Storage or synthesis of glucose in response to hormone signals -Synthesis and release of fatty acids in response to hormone signals -Storage or release of fatty acids in response to hormone signals -Secrete adipokines

Liver: -Storage or synthesis of glucose in response to hormone signals -Synthesis and release of fatty acids in response to hormone signals Adipocytes: -Storage or release of fatty acids in response to hormone signals -Secrete adipokines Pancreas: -Secretion of varying ratios of insulin and glucagon in response to blood glucose concentration

Do saturated fats or unsaturated fats have a higher melting point?

Longer saturated fatty acid chains lead to higher melting temperatures since they have stronger intermolecular interactions. More cis bonds lead to a lower melting point due to the kinks that disrupt intermolecular interactions.

What items are included in the degradation of Fatty Acids? Acyl group carrier is ACP. 2C donor is malonyl CoA. Mitochondrial Coupled with reduction of NAD+ and FAD Cytosolic Coupled with oxidation of NADPH 2C product is acetyl CoA. Acyl group carrier is CoA.

Mitochondrial Coupled with reduction of NAD+ and FAD 2C product is acetyl CoA. Acyl group carrier is CoA.

What is is the correct net reaction for the complete oxidation of palmitate?

Palmitate + 7 NAD+ + 7 FAD + 8 CoA + 7 H2O + ATP → 8 Acetyl-CoA + 7 NADH + 7 FADH2 + AMP + 2 Pi + 7 H+

Rank the unsaturated fatty acids listed in order of lowest to highest ATP yield.

Stearidonate (18:4) Linolenate (18:3) Linoleate (18:2) Oleate (18:1) Arachidate (20:4) Out of all fatty acids listed here, arachidate has the highest number of carbons (20) and therefore would yield the most ATP when degraded. The remaining fatty acids all have an identical number of carbons but are of varying degrees of saturation. Oleate, a monounsaturated fatty acid, would have the highest ATP yield of all 18-carbon fatty acids listed here. The ATP yield decreases as saturation decreases due to the increased oxidation of the fatty acyl chain.

In all of the aminotransferases that have been characterized, the catalytic mechanism involves a two-stage reaction in which the α amino group of the amino acid is first transferred to an enzyme-linked pyridoxal phosphate (PLP) group. Pyridoxal phosphate is a coenzyme derivative of vitamin

Vitamin B6

Nitrogen atoms that are removed from proteins during protein catabolism are least likely to be conserved in the structure of which of the following?

acetyl coA

Place the steps in order to describe the transport of cholesterol from peripheral tissues to the liver by HDL. a. The esterified cholesterol can then be taken up into HDL particles and returned to the liver. b. Apolipoprotein A-I (apoA-I) on the surface of HDL particles activates the enzyme lecithin-cholesterol acyltransferase. c. cholesterol is esterized in peripheral cell membranes. d. HDL deposits cholesterol in the liver

b. Apolipoprotein A-I (apoA-I) on the surface of HDL particles activates the enzyme lecithin-cholesterol acyltransferase. c. This enzyme esterifies cholesterol in peripheral cell membranes. a. The esterified cholesterol can then be taken up into HDL particles and returned to the liver. d. Once in the liver, it can be stored or used for synthesis of other biomolecules.

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

greater than

The amino acid ... is ketogenic.

leucine and lysine

Within the urea cycle, citrulline is produced by ornithine transcarbamylase in the .... and is consumed in the ....?

mitochondria; cytoplasm

When an organism has reached metabolic homeostasis, the metabolite concentrations and energy reserves have reached ...?

steady-state

β oxidation of palmitate (16:0) produces (A) _______ . The acetyl-CoA produced are then oxidized in the citric acid cycle, resulting in the synthesis of (B) _______ ATP. The reduced cofactors produced during each round of β oxidation are oxidized in the electron transport chain, resulting in the synthesis of (C) _______ ATP. The overall net yield for complete oxidation of palmitate is (D) _________ ATP after accounting for the energy investment required for activation of the fatty acid.

(A) 8 acetyl-CoA, 7 NADH, 7 FADH2 (B) 80 (C) 28 (D) 106

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) . This, in turn, leads to inhibition of C) in the liver.

(A) AMP (B) AMPK (C) gluconeogenesis Metformin elevates AMP levels iin many tissues, including the liver, heart, and skeletal muscle. Metformin leads to activation of AMPK, which increases insulin sensitivity and lowers blood glucose levels. Inhibition of gluconeogenesis in the liver helps to lower the blood glucose level.

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

(A) lead to an increase (B) succinyl-CoA

Label the figure below to illustrate the enzymes and cofactors required for completing the conversion of propionyl-CoA to acetyl-CoA. A. NAD+ + CoA → NADH B. Pyruvate dehydrogenase C. NADH + CO2 → NAD+ + CoA D. NADP+ → NADPH + H+ E. Malate dehydrogenase F. NADPH + H+ → NADP+G. NAD+ + CoA → NADH + CO2 H. Malic enzyme I. NAD+ + CoA → NADH

(Left to Right) Malate -> Pyruvate D. NADP+ → NADPH + H+ H. Malic Enzyme Pyruvate -> Acetyl-CoA B. Pyruvate Dehydrogenase G. NAD+ + CoA → NADH + CO2

Put into chronological order the following steps by which glucagon causes the release of fatty acids from adipocytes.

1) Glucagon binds to GPC Gsalpha activated 2) cAMP activation of PKA 3) Perilipin phosphorylaiton 4) Lipase activation generates free fatty acids 5) Albumin transports free fatty acids through the circulatory system


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