Biochem Exam 2 Chapter 16

Which of the following compounds is NOT derived from cholesterol? α-tocopherol Glycocholate 1,25-dihydroxycholecalciferol Cortisol Aldosterone

α-tocopherol

How do FAs of different carbon lengths cross into the mitochondrial matrix for oxidation? 1) Small FAs of 10 carbons or fewer can freely diffuse through the membrane. 2) Large FAs are cleaved into two smaller units that are actively transported across the membrane. 3) A membrane-bound transferase catalyzes the conversion of long-chain FAs to FA-carnitine esters, which are transported across the membrane via a specific carrier. 4) The breakdown of large FAs starts outside the matrix, allowing for smaller particles to pass easily through the membrane.

1,3

Which regulatory effects are results of internalized cholesterol? 1) It activates acyl-CoA:cholesterol acyltransferase. 2) It increases endogenous cholesterol synthesis. 3) It downregulates the production of LDL receptors. 4) It inhibits HMG-CoA reductase.

1,3,4

Calculate the grams of fat necessary to sustain a 20-hr nonstop flight.

1.6g

Calculate the ATP yield from oxidation of palmitic acid, taking into account the energy needed to activate the fatty acid and transport it into mitochondria.

106

If the birds relied on carbohydrate for this energy, how much additional weight would they have to start the flight with?

10g

Calculate the ATP yield from oxidation of linoleic acid.

116

Calculate the ATP yield from oxidation of oleic acid.

118.5

Calculate the ATP yield from oxidation of stearic acid.

120

In some instances, the levels of LDL cholesterol exceed the ability of the body to maintain homeostasis, and as a result, the excess material accumulates into fatty deposits that harden into plaques. Arrange in the correct order the sequence of events that leads to this condition, known as atherosclerosis: 1) The plaques harden, blocking the flow of blood in major arteries. 2) White blood cells become engorged with fatty deposits. 3) Excess LDL cholesterol accumulates in the interior of arterial walls. 4) Macrophages are drawn to this site.

3,4,2,1

Arrange the order of events in the fatty acid (FA) metabolism pathway in the correct order: 1) The modified FA is transported across the inner membrane of the mitochondrion. 2) Dehydration occurs to generate an α,β-unsaturated FA. 3) The free FA is converted to acetyl CoA ester. 4) Thiolytic cleavage occurs, releasing a molecule of acetyl CoA and a new FA with two fewer carbon atoms. 5) The FA CoA ester is converted to its carnitine ester. 6) Hydration occurs to yield a β-hydroxy ester. 7) The FA CoA ester is regenerated.

3-5-1-7-2-6-4

Calculate the number of ATPs generated by the complete metabolic oxidation of tripalmitin (tripalmitoylglycerol). Hydrolysis of the triacylglycerol occurs at the cell surface. Consider the energy yield from catabolism of glycerol, as well as from the fatty acids.

336.5 ATPs

Assume that 2.5 ATPs are generated per NADH and 1.5 ATPs per FADH2. How many ATPs are generated from the FADH2 and NADH molecules from each repetition of the β-oxidation pathway?

4 ATP

How many moles of glucose are required to provide the carbon for the synthesis of one mole of palmitate?

4 mol of glucose

The β-oxidation of odd-numbered FAs presents a small problem in that once most of the oxidation has occurred, the last component is propionyl-CoA rather than acetyl CoA. This has one more carbon and as such cannot be utilized any further. Outline the events that control the metabolism of this unit in their proper order: 1) Methylmalonyl-CoA epimerase converts S-methylmalonyl-CoA to R-methylmalonyl-CoA. 2) Methylmalonyl-CoA mutase demethylates R-methylmalonyl-CoA to succinyl-CoA. 3) Propionyl-CoA carboxylase catalyzes the addition of CO2 to propionyl-CoA. 4) The odd-carbon FA is metabolized to propionyl-CoA.

4,3,1,2

How many moles of glucose are required if all of the glucose first proceeds through the pentose phosphate pathway before proceeding through the rest of glycolysis on its way to pyruvate?

4.8 mol of glucose

alculate the number of ATPs generated by the complete metabolic oxidation of tripalmitin (tripalmitoylglycerol). Hydrolysis of the triacylglycerol occurs at the cell surface. Consider the energy yield from catabolism of glycerol, as well as from the fatty acids.

412 ATPs

Calculate the number of molecules of acetyl-SCoA derived from a saturated fatty acid with 10 carbon atoms.

5

Using Figure 16.9 on page 515 in the text, arrange the order of events for the internalization of LDL particles into cells: 1) A combination of cholesterol and apolipoprotein binds to LDL receptors and becomes internalized as endocytotic vesicles. 2) The environment of the endosome becomes acidic, which causes the LDL to dissociate from its receptor; additionally, the endosome fuses with a lysosome. 3) Several endocytotic vesicles fuse to form an endosome. 4) The LDL particle is degraded by the lysosome. 5) LDL receptors migrate to the cell surface and cluster in clathrin-coated pits.

5,1,3,2,4

Using Figure 16.9 on page 515 in the text, arrange the order of events for the internalization of LDL particles into cells: 1) A combination of cholesterol and apolipoprotein binds to LDL receptors and becomes internalized as endocytotic vesicles. 2) The environment of the endosome becomes acidic, which causes the LDL to dissociate from its receptor; additionally, the endosome fuses with a lysosome. 3) Several endocytotic vesicles fuse to form an endosome. 4) The LDL particle is degraded by the lysosome. 5) LDL receptors migrate to the cell surface and cluster in clathrin-coated pits.

5-1-3-2-4

Assume that 2.5 ATPs are generated per NADH and 1.5 ATPs per FADH2. What is the total number of ATPs generated from 5 acetyl-SCoA molecules?

50

Activation of the fatty acid (converting it to fatty acyl-SCoA) requires the expenditure of 2 ATPs. Use your answers from parts B and C to calculate the total number of ATPs generated from the metabolism of a saturated fatty acid with 10 carbon atoms including both the citric acid cycle and the β-oxidation pathway as well as the initial ATP required to produce the acyl-SCoA molecule that starts the process.

64

How many tritium atoms (3H) are incorporated into palmitate when fatty acid synthesis is carried out in vitro with the following labeled substrate?

7 tritium atoms

he overall net synthesis of palmitate starting from acetyl CoA requires: 8 acetyl-CoA, 8 ATP and 14 NADPH and 7 H+. 8 acetyl-CoA, 7 ATP and 14 NADPH and 7 H+. 8 acetyl-CoA, 7 ATP and 16 NADPH and 8 H+. 8 acetyl-CoA, 7 ATP and 14 NADPH and 14 H+. 8 acetyl-CoA, 8 ATP and 16 NADPH and 16H+.

8 acetyl-CoA, 7 ATP and 14 NADPH and 7 H+.

Free fatty acids are released from the adipocyte after mobilization of fat stores by: hormone sensitive lipase. adipose triglyceride lipase. monoacylglycerol lipase. lipoprotein lipase. A, B, and C.

A, B, and C.

Which of the following are key discoveries of the experiments conducted by Brown and Goldstein? 1) Cholesterol is taken into cells through the action of a specific receptor. 2) The receptor for the LDL particle recognizes B-100 apolipoprotein. 3) The entire receptor complex, unlike hormones involved in signaling pathways, enters the cell via endocytosis. 4) Familial hypercholesterolemia patients have defective or deficient LDL receptors.

ALL

Present pathways by which this could come about. Acetyl−CoA⟶citricacidcyclefumarate⟶PEPcarboxykinasePEP⟶gluconeogenesisglucose Acetyl−CoA⟶citricacidcyclepyruvate⟶Pyruvatecarboxylaseoxaloacetate⟶PEPcarboxykinasePEP⟶gluconeogenesisglucose Acetyl−CoA⟶citricacidcyclemalate⟶PEPcarboxykinasePEP⟶gluconeogenesisglucose Acetyl−CoA⟶citricacidcycleoxaloacetate⟶PEPcarboxykinasePEP⟶gluconeogenesisglucose

Acetyl−CoA⟶citricacidcycleoxaloacetate⟶PEPcarboxykinasePEP⟶gluconeogenesisglucose

Which of the following statements regarding the β-oxidation of FA is NOT correct? Enoyl-CoA hydratase catalyzes the hydration of the α,β-unsaturated CoA thioester to a β-hydroxy CoA thioester. Thiolase catalyzes the thiolytic cleavage of a 3-ketoacyl CoA ester to release acetyl CoA and a new FA with two fewer carbons. Acyl-CoA dehydrogenase catalyzes the synthesis of a cis α,β-unsaturated CoA thioester. 3-L-hydroxyacyl-CoA dehydrogenase catalyzes the oxidation of the 3-hydroxyacetyl CoA ester to the corresponding 3-ketone.

Acyl-CoA dehydrogenase catalyzes the synthesis of a cis α,β-unsaturated CoA thioester.

What kinds of experiments could test your proposed explanation? Addition of radiolabeled PS to an enzyme system would not label PE, because phosphatidylserine decarboxylase would act only on PS generated by phosphatidylserine synthase. Inhibition of phosphatidylserine decarboxylase leads to an accumulation of PS generated by phosphatidylserine synthase. Inhibition of phosphatidylserine synthase and further addition of radiolabeled PS to an enzyme system leads to formation of labeled PE. Doubling the amount of phosphatidylserine synthase in this system leads to doubling of PE production.

Addition of radiolabeled PS to an enzyme system would not label PE, because phosphatidylserine decarboxylase would act only on PS generated by phosphatidylserine synthase.

Which of the following are key discoveries of the experiments conducted by Brown and Goldstein? 1) Cholesterol is taken into cells through the action of a specific receptor. 2) The receptor for the LDL particle recognizes B-100 apolipoprotein. 3) The entire receptor complex, unlike hormones involved in signaling pathways, enters the cell via endocytosis. 4) Familial hypercholesterolemia patients have defective or deficient LDL receptors.

All

Which of the following statements about β-oxidation of fatty acids is CORRECT? Both dehydrogenation reactions use FAD as the electron acceptor. Fatty acids of any length are oxidized by exactly the same enzymes. Thiolytic cleavage releases acetyl-CoA and a free fatty acid in the final step of the cycle. All fatty acids must be activated to acyl-CoAs before entering the pathway. Both dehydrogenation reactions produce a C=C double bond.

All fatty acids must be activated to acyl-CoAs before entering the pathway.

Insulin stimulates fatty acid synthesis by which of the following mechanisms? Stimulation of a glucose transport across the plasma membrane Activation of citrate lyase Stimulation of dephosphorylation of pyruvate dehydrogenase Dephosphorylation of acetyl-CoA carboxylase All of the above

All of the above

One pathway that appears to relate elevated cholesterol levels to atherosclerosis involves the oxidation of LDL. Which of the following are consequences of this process? Oxidized LDL products induce an immune response that includes recruitment of monocytes and T lymphocytes. Though the mechanism by which this occurs is not completely understood, this oxidation includes the peroxidation of fatty acids, the hydroxylation of cholesterol, and the oxidation of amino acids. The presence of scavenger receptors on macrophages allows unlimited cholesterol uptake, leading to its conversion to foam cells. All of the listed responses are consequences of this process.

All of the listed responses are consequences of this process.

Which of the following enzymes are required for the oxidation of unsaturated FA? acyl-CoA dehydrogenase enoyl-CoA isomerase 2,4-Dienoyl-CoA reductase All of the listed responses are correct.

All of the listed responses are correct.

Explain why a deficiency of steroid 21-hydroxylase leads to excessive production of sex steroids (androgens and estrogens). By shutting down the pathway leading to aldosterone, this deficiency increases the supply of dehydroepiandrosterone that converted directly to sex steroids. 21-hydroxylase competes with 17α-hydroxylase, so deficiency of 21-hydroxylase leads to increasing 17α-hydroxylase activity and to excessive production of sex steroids. 21-hydroxylase competes with 17,20-lyase, so deficiency of 21-hydroxylase leads to increasing 17,20-lyase activity and to excessive production of sex steroids. By shutting down the pathway leading to aldosterone, this deficiency increases the supply of progesterone available for conversion to sex steroids.

By shutting down the pathway leading to aldosterone, this deficiency increases the supply of progesterone available for conversion to sex steroids.

Cells from FH individuals exhibited high levels of reductase activity, regardless of the presence or absence of LDL in the culture medium. Cells from FH individuals were deficient in their ability to take up cholesterol from the culture medium. Cells from FH individuals were activated by the LDL in the culture medium; after activation, the LDL served no other role by being present in the culture medium. Cholesterol did not take part in any processes of cells from FH individuals.

Cells from FH individuals were deficient in their ability to take up cholesterol from the culture medium.

________ is taken up by cells using receptor-mediated endocytosis, which involves the recognition of the B-100 apolipoprotein component of LDL.

Cholesterol

When cultured in the presence of LDL, normal cells showed low activity of HMG−CoA reductase. After removal of lipopoteins, including LDL, HMG−CoA reductase activities increased some 50- to 100-fold in normal cells (panel a). This high level of enzyme activity was rapidly suppressed upon addition of LDL back to normal cells (panel b). Cholesterol blocks the pores in the membrane of the cell, so no components necessary for the action of HMG−CoA reductase can enter into the cell, thus its the activity is reduced. Cholesterol is normally transported into the cell, where it deplaces water, which in turn dries HMG−CoA reductase, and without water its activity is very low. Cholesterol is normally transported into the cell, where it regulates its own synthesis by suppressing the activity of HMG−CoA reductase, the rate-limiting enzyme.

Cholesterol is normally transported into the cell, where it deplaces water, which in turn dries HMG−CoA reductase, and without water its activity is very low.

Elongation of fatty acids from palmitate occurs only in the mitochondrion.

False

Excess cholesterol is metabolically degraded in the liver.

False

Ketone bodies can be used as an alternative fuel source by the liver.

False

β-oxidation of unsaturated fatty acids yields the same amount of energy as saturated fatty acids with the same number of carbons.

False

What is the initial fate of an uncoated vesicle? The internalized ligands are separated from the receptors and sorted. It fuses with a lysosome. The receptors are recycled to the membrane. It fuses with an early endosome.

It fuses with an early endosome.

Glucagon secretion causes inhibition of intracellular acetyl-CoA carboxylase activity by several mechanisms. Name all you can think of. Glucagon promotes triacylglycerol breakdown, yielding increased levels of fatty acids, which could prevent polymerization and activation of acetyl-CoA carboxylase. Glucagon stops glycolysis yielding decrease in ATP production, hence carbonyl-phosphate formation is lowered and this prevents carboxylation of the enzyme. Glucagon decreases the activity of biotin carboxylase, reducing the N-carboxybiotinyl-enzyme formation. Glucagon increases the activity of citrate synthase which consumes acetyl-CoA in the tricarboxylic acid cycle. As a result, the substrate level is reduced and the enzyme activity is decreased. Glucagon activates phosphorylation of pyruvate dehydrogenase, which inhibits the formation of acetyl-CoA, the substrate for the enzyme.

Glucagon promotes triacylglycerol breakdown, yielding increased levels of fatty acids, which could prevent polymerization and activation of acetyl-CoA carboxylase. Glucagon promotes triacylglycerol breakdown, yielding increased levels of fatty acids, which could prevent polymerization and activation of acetyl-CoA carboxylase.

The diagram below shows the transport functions of four types of lipoproteins. For example, one type of lipoprotein transports triacylglycerols (TAGs) from the liver to the peripheral tissues. Identify the type of lipoprotein associated with each function.

IDL HDL VLDL LDL

Increase in citrate levels would __________ (increase/decrease) generation of acetyl-CoA in cytosol, hence __________ (inhibiting/stimulating) fatty acid synthesis.

Increase... stimulating

Which of the following statements about the lipoproteins given in the introduction are true? Lipoprotein densities vary because lipoproteins have different lipid-to-protein ratios. HDL has a high lipid-to-protein ratio. Lipoprotein densities increase in the following order: chylomicrons, VLDLs, LDLs, HDLs, IDLs. Chylomicrons are the only lipoproteins that exclusively carry dietary lipids. Lipoproteins are complexes of lipids and proteins. Lipoproteins can be distinguished by their densities and composition. HDL is termed "bad" cholesterol because it can deposit excess cholesterol in the arteries.

Lipoprotein densities vary because lipoproteins have different lipid-to-protein ratios. Chylomicrons are the only lipoproteins that exclusively carry dietary lipids. Lipoproteins are complexes of lipids and proteins. Lipoproteins can be distinguished by their densities and composition.

Identify and briefly discuss each mechanism ensuring against simultaneous fatty acid synthesis and oxidation in the same cell. Malonyl-CoA, a key intermediate in fatty acid synthesis, inhibits carnitine acyltransferase I, thereby blocking the entry of fatty acyl units into the mitochondrion for oxidation. Fatty acyl-CoAs, the substrates for fatty acid oxidation, inhibit fatty acid synthesis by interfering with the polymerization of acetyl-CoA carboxylase. Hormonal effects on adipocytes: insulin promotes fatty acid synthesis by several mechanisms, while glucagon promotes fat breakdown and fatty acid oxidation. AMP-activated protein kinase switches off fatty acid synthesis by inhibiting acetyl-CoA carboxylase, whereas acetyl-CoA carboxylase is essential for fatty acid degradation. Citrate is an inhibitor of fatty acid synthesis, acting as an allosteric activator of acetyl-CoA carboxylase. Also it carries the acetyl units, which are important intermediates for oxidation of fatty acids, from the mitochondria to the cytoplasm. Pyruvate, the source of acetyl-CoA for fatty acid synthesis, can be converted into oxaloacetate which consumes acetyl-CoA, competing with AMP-dependent protein kinase during fatty acids oxidation.

Malonyl-CoA, a key intermediate in fatty acid synthesis, inhibits carnitine acyltransferase I, thereby blocking the entry of fatty acyl units into the mitochondrion for oxidation. Fatty acyl-CoAs, the substrates for fatty acid oxidation, inhibit fatty acid synthesis by interfering with the polymerization of acetyl-CoA carboxylase. Hormonal effects on adipocytes: insulin promotes fatty acid synthesis by several mechanisms, while glucagon promotes fat breakdown and fatty acid oxidation.

Based on the metabolism of such molecules, what quantity of a C−19 fatty acid would be required to produce 1 g of glucose?

Mass = 3.3 g

Considering that odd-chain fatty acids make up approximately 1% of the fat in our diet, what quantity of fatty acids would be needed to produce 1 g of glucose?

Mass = 330 g

From the ATP yield of palmitate oxidation, what is the metabolic efficiency of the biological oxidation, in terms of kilojoules saved as ATP per kilojoule released? (Ignore the cost of fatty acid activation.)

Metabolic efficiency = 35.5%

Under conditions where ketone bodies are being produced in the liver, how many ATPs can be produced from a molecule of palmitic acid if all resulting molecules of acetyl-CoA are converted into β-hydroxybutyrate?

Net yield = 16.0 ATP

Calculate the number of ATPs generated from the metabolic oxidation of the four carbons of acetoacetyl-CoA to CO2.

Net yield = 20.0 ATPs

Now consider the homolog derived from oxidation of an odd-numbered carbon chain, namely propionoacetyl-CoA. Calculate the net ATP yield from oxidation of the five carbons of this compound to CO2.

Net yield = 20.5 ATPs

Because PS must be present in the membrane to serve as an intermediate, how might you explain its failure to accumulate to a significant extent? Under sertain conditions PS could never accumulate, because, once formed by phosphatidylserine synthase, it would immediately be converted to PE by phosphatidylserine decarboxylase. The biosynthesis of phosphatidylethanolamine from CDP-diacylglycerol and serine occurs at the two active sites of a single enzyme. PS could never be accumulated, because this process is not sterically restricted. PS is a very unstable intermediate. It could never be accumulated, because it would spontaneously decompose back to serine and CDP-diacylglycerol. PS is a very unstable intermediate. It could never be accumulated, because it would undergo spontaneous decarboxylation to PE.

PS is a very unstable intermediate. It could never be accumulated, because it would undergo spontaneous decarboxylation to PE.

Choose a pathway whereby some of the carbon from a fatty acid with an odd-numbered carbon chain could undergo a net conversion to carbohydrate. Propionyl−CoA⟶methylmalonyl−CoA⟶succinyl−CoA⟶oxaloacetate⟶PEP⟶glucose Propionyl−CoA⟶methylmalonyl−CoA⟶malonyl−CoA⟶malate⟶oxaloacetate⟶PEP⟶glucose Propionyl−CoA⟶acetoacetyl−CoA⟶β−hydroxybutyrate⟶oxaloacetate⟶PEP⟶glucose Propionyl−CoA⟶methylmalonyl−CoA⟶pyruvate⟶malonyl−CoA⟶PEP⟶glucose

Propionyl−CoA⟶methylmalonyl−CoA⟶succinyl−CoA⟶oxaloacetate⟶PEP⟶glucose

Explain these observations. This reaction requires two acyl-ACP units that cannot be produced by one separated subunit. The acyl-ACP produced by one subunit undergoes the next round of reductive two-carbon addition on the other subunit. The produced D-3-hydroxyacyl-ACP is oxidized by oxygen from the air making the overall synthesis of palmitate impossible. To stabilize the subunits in vitro we should use the double amount of NADPH which completely supresses the reduction of β-ketoacyl-ACP.

The acyl-ACP produced by one subunit undergoes the next round of reductive two-carbon addition on the other subunit.

Which of the following statements is FALSE? The cholesterol ester content of HDL is generally less than that of chylomicrons. VLDL transports triacylglycerol synthesized in the liver to peripheral tissues. Some fatty acids become complexed with serum albumin for transport in the blood to peripheral cells. Chylomicrons are lipoproteins that transport dietary fat from intestine to peripheral tissues. LDL is the main form in which cholesterol is transported to tissues.

The cholesterol ester content of HDL is generally less than that of chylomicrons.

Compare these two values. The energy yield from tripalmitin is larger than the energy yield from glucose. The energy yield from tripalmitin is smaller than the energy yield from glucose. These values are equal.

The energy yield from tripalmitin is larger than the energy yield from glucose.

Which step in lipid metabolism would you expect to be affected by 3,4-dihydroxybutyl-1-phosphonic acid (shown here)? The esterification of glycerol-3-phosphate with fatty acyl-CoA, catalyzed by glycerophosphate acyltransferase. The ATP-dependent phosphorylation of glycerol by glycerol kinase. The hydrolysis of diacylglycerol-3-phosphate to 1,2-diacylglycerol. The reduction of the glycolytic intermediate dihydroxyacetone phosphate, catalyzed by glycerol-3-phosphate dehydrogenase.

The esterification of glycerol-3-phosphate with fatty acyl-CoA, catalyzed by glycerophosphate acyltransferase.

Discuss the metabolic rationale for phosphorylation of acetyl-CoA carboxylase by AMP-activated protein kinase (AMPK) and cyclic AMP-dependent protein kinase (PKA). This could be a way for a cell to activate fatty acid synthesis in the case of acetyl-CoA deficiency. This could be a way for a cell to control fatty acid synthesis in the case of glucose high level in cytosol. This could be a way for a cell to inhibit fatty acid synthesis under conditions where substrates are needed for oxidation. This could be a way for a cell to avoid the excess of ATP production during the fatty acid oxidation.

This could be a way for a cell to inhibit fatty acid synthesis under conditions where substrates are needed for oxidation.

Explain your answer. 3,4-Dihydroxybutyl-1-phosphonic acid consumes all fatty acyl-CoA during the acylation process. The further esterification is impossible without the substrate. 3,4-Dihydroxybutyl-1-phosphonic acid binds to glycerol-3-phosphate causing the whole process to stop. 3,4-Dihydroxybutyl-1-phosphonic acid competes with glycerol-3-phosphate when it binds to glycerophosphate acyltransferase. This process completely suppresses the further acylation. This is a nonhydrolyzable analog of glycerol-3-phosphate, so it is acylated without difficulty to give the phosphonate analog of diacylglycerol.

This is a nonhydrolyzable analog of glycerol-3-phosphate, so it is acylated without difficulty to give the phosphonate analog of diacylglycerol.

Clathrin is a self-associating protein, which is able to form cage-like structures, which facilitate receptor-mediated endocytosis.

True

HMG-CoA reductase, the major control point of cholesterol biosynthesis is regulated by transcriptional and post-transcriptional mechanisms mediated by Insig proteins bound in the endoplasmic reticulum membrane.

True

Mono- and poly-unsaturated fatty acids are produced in the endoplasmic reticulum by desaturase enzymes.

True

The liver is the central organ in animals for processing lipoproteins whether they are derived from the diet or from biosynthetic pathways.

True

How is receptor-mediated endocytosis (RME) different from pinocytosis and phagocytosis? RME does not require energy. Unlike pinocytosis, RME is for dissolved particles; unlike phagocytosis, RME is specific. Unlike pinocytosis and phagocytosis, RME is not a saturable process. Unlike pinocytosis, RME is specific; unlike phagocytosis, RME is for small particles.

Unlike pinocytosis, RME is specific; unlike phagocytosis, RME is for small particles.

Calculate the energy yield from glucose.

Yield = 5.3 ATPs per carbon atom

Calculate the ATP yield per carbon atom oxidized.

Yield = 6.6 ATPs per carbon atom

he shuttle system for transfer of acetyl-CoA generated in the mitochondrial matrix to the cytosol includes: citrate lyase in the cytosol. ATP hydrolysis. citrate from the citric acid cycle. the production of NADPH by malic enzyme. all of the above.

all of the above.

What is the most likely site of inhibition by 2-bromopalmitoyl-CoA? the carnitine-acylcarnitine translocase carnitine palmitoyltransferase I acyl-CoA synthetase carnitine palmitoyltransferase II

carnitine palmitoyltransferase I

Once of the processes linked to receptor-mediated endocytosis is transcytosis. When might this mechanism be useful? in immune cell transport of invading viruses in transporting antibodies from mother's milk from an infant's stomach into the bloodstream to expose receptors to the opposite side of the cell to expel substances from lysosomes that are indigestable

in transporting antibodies from mother's milk from an infant's stomach into the bloodstream

What happens to your blood pH if you go into ketosis? increases decreases stays the same

increase

Linoleic acid linoleate+25.5O2+117ADP+108Pi→16CO2+108ATP+9AMP+138H2O linoleate+25.5O2+120ADP+120Pi→20CO2+118ATP+2AMP+136.5H2O linoleate+25.5O2+116.5ADP+115Pi→16CO2+115.5ATP+AMP+77.5H2O linoleate+25.5O2+118ADP+116Pi→18CO2+117ATP+AMP+135.5H2O

linoleate+25.5O2+118ADP+116Pi→18CO2+117ATP+AMP+135.5H2O

What would you expect to happen to levels of mevalonate in human plasma if an individual were to go from a meat-containing diet to a vegetarian diet? mevalonate levels decrease mevalonate levels increase mevalonate levels do not change

mevalonate levels increase

In what organelle of the cell does β oxidation of fatty acids take place? cytosol chloroplasts nucleus mitochondria Golgi apparatus

mitochondria

If mevalonate labeled with 14C in the carboxyl carbon were administered to rats, which carbons of cholesterol would become labeled? C−1 C−2 C−3 C−4 C−5 C−6 C−7 none

none

What is the trigger for the invagination of the vesicle? ligands binding to the receptors the activity of dynamin polymerization of clathrin occupied receptors accumulating in the coated pits

occupied receptors accumulating in the coated pits

Oleic acid oleate+28O2+118ATP+AMP→20CO2+118ADP+118Pi+148H2O oleate+22.5O2+118.5ADP+120.5Pi→16CO2+120.5ATP+cAMP+130.5H2O oleate+26O2+122ADP+59.25PPi→8CO2+120ATP+2AMP+170H2O oleate+25.5O2+120.5ADP+118.5Pi→18CO2+119.5ATP+AMP+135.5H2O

oleate+25.5O2+120.5ADP+118.5Pi→18CO2+119.5ATP+AMP+135.5H2O

Palmitic acid palmitate+20O2+106ADP+AMP→18CO2+107ATP+107Pi+106H2O palmitate+25O2+120ADP+60PPi→14CO2+110ATP+5AMP+60H2O palmitate+24O2+110ADP+110Pi→16CO2+109ATP+AMP+120H2O palmitate+23O2+108ADP+106Pi→16CO2+107ATP+AMP+122H2O

palmitate+23O2+108ADP+106Pi→16CO2+107ATP+AMP+122H2O

Choose a balanced equation for the complete metabolic oxidation of each of the following. Include O2, ADP, and Pi as reactants and ATP, CO2, and H2O as products. stearate+22O2+124ATP+AMP→12CO2+124ADP+124Pi+118H2O stearate+28O2+108ADP+60PPi→16CO2+120ATP+AMP+78H2O stearate+24O2+106ADP+100Pi→20CO2+122ATP+cAMP+120H2O stearate+26O2+122ADP+120Pi→18CO2+121ATP+AMP+138H2O

stearate+26O2+122ADP+120Pi→18CO2+121ATP+AMP+138H2O

Propionyl-CoA, the end product of β-oxidation of odd-chain fatty acids can enter the citric acid cycle after being converted to ____

succinyl-CoA

What protein does the term coated vesicle refer to? the adaptor proteins surrounding the vesicle the clathrin that forces the vesicle to invaginate the receptors in the membrane of the vesicle the ligand bound to the receptor

the clathrin that forces the vesicle to invaginate