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Q:
Purine degradation results in the formation of xanthine and creation of _____ by xanthine oxidase.
a. polyamines
b. gout
c. citric acid
d. uric acid
Q:
Carbamoyl aspartate can only be used for _____ synthesis.
a. pyrimidine
b. purine
c. urea
d. creatine
Q:
Which of the following is a nitrogen-containing, non-protein compound that performs an important function in the body?
a. glutathione
b. methionine
c. pepsin
d. actin
Q:
Which level of organization determines the final form of a protein molecule consisting of several polypeptide chains?
a. primary
b. secondary
c. tertiary
d. quaternary
Q:
Which amino acids are metabolized mostly in skeletal muscles?
a. those with side chains containing aromatic rings
b. those with side chains that are branched
c. those with side chains containing basic groups
d. those with side chains containing sulfur atoms
Q:
Which of the following amino acids represent the branched-chain amino acids found in systemic circulation?
a. glycine, alanine, threonine
b. phenylalanine, tyrosine, tryptophan
c. valine, leucine, isoleucine
d. arginine, lysine, histidine
Q:
If you were deficient in vitamins B6 and B12 and had high blood levels of homocysteine, what dietary substance could remove some of the homocysteine by donating a methyl group to form methionine?
a. biotin
b. betaine
c. serine
d. creatine
Q:
Serotonin is made from which amino acid?
a. tyrosine
b. niacin
c. threonine
d. tryptophan
Q:
Which of the following is NOT a neurotransmitter?
a. acetylcholine
b. serotonin
c. insulin
d. epinephrine
Q:
Name the genetic disease associated with the lack of the liver enzyme necessary to convert phenylalanine to tyrosine.
a. maple syrup urine disease
b. phenylketonuria
c. homocystinuria
d. lactase deficiency
Q:
Which of the following amino acids is ketogenic?
a. glycine
b. alanine
c. leucine
d. aspartate
Q:
When the amino group has been removed from an amino acid, the carbon skeleton or α-keto acid may be used in many different ways. Which of the following is NOT a possible fate for the carbon skeleton?
a. conversion to glucose
b. oxidation for energy
c. production of ketone bodies
d. synthesis of creatine
Q:
Using, 2 high-energy bonds, arginosuccinate synthetase joins aspartate and citrulline to produce arginosuccinate in the cytosol. This is the rate-limiting step in _____ synthesis.
a. pyrimadine
b. purine
c. urea
d. creatine
Q:
Urea synthesis occurs partly in the mitochondria and partly in the cytosol of the _____.
a. glomeruli
b. tubules
c. enterocytes
d. hepatocytes
Q:
Three important enzymes remove ammonia from body cells. One is carbamoyl phosphate synthestase I. The other two are:
a. branched-chain alpha-keto acid dehydrogenase and phenylalanine hydroxylase.
b. alanine aminotransferase and aspartate aminotransferase.
c. glutaminase and threonine dehydratase.
d. glutamate dehydrogenase and glutamine synthetase.
Q:
Which three amino acids cannot undergo transamination to an appreciable extent, making provision of their alpha-keto acids ineffective in lowering blood nitrogen concentrations in kidney disease patients?
a. leucine, isoleucine, valine
b. lysine, threonine, histidine
c. valine, tryptophan, phenylalanine
d. methionine, cysteine, phenylalanine
Q:
What organ serves as the primary site of amino acid metabolism?
a. kidney
b. muscles
c. liver
d. neuropeptides
Q:
What is the primary mechanism for regulation of amino acids in excess of need for synthesis of protein, providing about 50% of the liver energy needs after a meal?
a. oxidation
b. decarboxylation
c. phosphorylation
d. hydrogenation
Q:
During protein digestion, peptides are broken into free amino acids mainly
a. in the mouth.
b. in the stomach.
c. at the brush border.
d. within the enterocyte.
Q:
Which regulatory peptides in the pancreatic phase of digestion activate the release of brush-border enzymes such as enteropeptidase?a. trypsinogen and trypsinb. cholecystokinin and secretinc. carboxypeptidase A and Bd. elastin and chymotrypsin
Q:
Choose the correct order of enzyme activities in protein digestion.
a. tripeptidases, carboxypeptidasea, pepsin, free amino acids
b. trypsin, pepsin, collagenase, dipeptidases
c. pepsin, trypsin, carboxypeptidases, dipeptidases
d. trypsinogen, enteropeptisdase, dipeptidase, chymoptrypsin
Q:
A function of hydrochloric acid in gastric juice during protein digestion is
a. to neutralize the acidity of the stomach.
b. to inactivate pepsinogen by suppressing pepsin formation.
c. to denature the quaternary, tertiary, and secondary structures of protein.
d. to cleave peptide bonds.
Q:
When the diet is lacking in the amino acids lysine and threonine
a. proteins will be made without one amino acid.
b. the body will synthesize them.
c. protein synthesis will be limited.
d. another amino acid will be substituted so that synthesis is uninterrupted.
Q:
Zwitterions are amino acids that have no net electrical charge because
a. their side chains are not charged.
b. they migrate to a neutral place in an electrical field.
c. they are essential/indispensable.
d. they have an amino group in their side chain.
Q:
The structure below is a _____.a. triacylglycerolb. cholesteryl esterc. phospholipidd. glycolipid
Q:
Cholesterol serves as a precursor for all of the following EXCEPT _____.
a. phospholipids
b. estrogens and androgens
c. bile acids
d. vitamin D
Q:
What is the most common lipid characterized by a four-ring core structure found in animals?
a. prostaglandins
b. leukotrienes
c. cholesterol
d. glycolipids
Q:
Triacylglycerols with saturated fatty acids of longer chain length tend to be _____ at room temperature.
a. liquid oils
b. emulsified
c. non-esterified fats
d. solid fats
Q:
In what form is most body fat stored?
a. fatty acids
b. triacylglycerols
c. cholesterol
d. phospholipids
Q:
What dietary fatty acid family exerts anti-thrombotic properties?
a. n-6
b. n-3
c. n-9
e. saturated
Q:
What antithrombotic n-3 fatty acid is found in fish oil?
a. alpha-linolenic
b. eicosapentaenoic
c. arachidonic
d. stearic
Q:
Which fatty acid is considered essential and must be supplied by the diet?
a. arachidonic acid
b. omega-9 fatty acid
c. linoleic acid
d. oleic acid
Q:
Carbon-carbon double bonds in the trans form
a. result in a kinking of the fatty acid into a U-shape.
b. extend the fatty acid into a linear shape.
c. are required to create saturated fatty acids.
d. are the hallmark of essential fatty acids.
Q:
The fatty acid chains found in foods and body tissues range from _____ carbon atoms in length.
a. 1 to 3
b. 2 to 6
c. 3 to 12
d. 4 to 24
Q:
Discuss the role of HDL in counteracting risk by modifying plaque formation.
Q:
Discuss the factors that initiate the process that leads to plaque formation.
Q:
Proinflammatory cytokines such as tumor necrosis factor are atherogenic because they
a. attract blood monocytes into the intima.
b. oxidize membrane fatty acids.
c. absorb cholesterol readily to become foam cells.
d. delay clotting of platelets, which narrows the lumen, restricting blood flow.
Q:
Arterial fatty steaks are formed primarily due to
a. platelet aggregation at the endothelium.
b. smooth muscle proliferation.
c. toxicity of oxidized LDL to endothelial cells.
d. accumulation of foam cells filled with cholesterol.
Q:
What are two major components implicated in the mechanism of atherogenesis?
a. growth factors and HDL
b. enterocytes and endothelial cells
c. inflammation and serum lipids
d. primarily VLDL and IDL
Q:
Describe three detrimental physiological effects of excess alcohol consumption and three beneficial effects of moderate alcohol consumption.
Q:
Explain the role of the MEOS and cytochrome P-450 in developing metabolic tolerance to ethanol.
Q:
Aspirin at very high (acutely poisonous) doses can function to cause proton leaks from the intermembrane space back into the matrix of the mitochondria. Explain why a toddler who ate a bottle of about 150 flavored baby aspirin would develop a very high body temperature.
Q:
Briefly describe the mechanism by which increased uncoupling protein opposes storage of energy as fat.
Q:
Explain how the HMG-CoA reductase regulates cholesterol synthesis.
Q:
Describe the transport system that allows for fatty acid synthesis and the molecules involved in transferring acetyl-CoA into cytoplasm.
Q:
Describe fat metabolism in the adipose cell following a meal.
Q:
Discuss three things that cannot be correct in the notation 18:2Δ8,9,19 when using the delta system of designating fatty acids.1
Q:
Explain the regulation of the allosteric enzyme acetyl-CoA carboxylase by citrate and palmitoyl-CoA.
Q:
Describe the process of fat storage (triacylglycerol synthesis) AND mobilization (triacylglycerol lipolysis) in adipose tissuebe sure to include how these processes are regulated (i.e., the signals involved).
Q:
Lipoprotein Transport. List the four lipoproteins below and provide a BRIEF explanation of their function with respect to transportation of lipids and lipid-soluble compoundsyour answer should include the tissue of origin, what they transport, and what they do with their cargo.LipoproteinFunction
Q:
The carrier molecule required for the transport of long-chain fatty acids for fat oxidation is _____, which is located in the _____ membrane.
Q:
A diet rich in simple sugars increases the hepatic formation of newly synthesized fatty acids and then neutral lipids called _____ from glucose. These neutral lipids are transported from the liver to the adipose tissue by compound lipids called _____.
Q:
Usage of acetyl-CoA in the cell depends on the metabolic/physiological state of humans. Identify 4 possible uses of acetyl-CoA, the corresponding states of the human being, and the organ and cellular locations where these processes occur.Use of acetyl-CoAMetabolic/physiologic stateOrgan & cellular site5) Ketogenesisa.b.6) a.fed stateb.7) a.b.muscle mitochondria8) a.fed stateb.
Q:
Fill in the blanks with the appropriate information.ProcessRegulated by the hormoneCatalyzed by the enzyme(s)Location(s) of the enzyme(s)2) Lipogenesisa.b.c.3) Lipolysisa.b.c.4) Triacylglycerol storagea.b.c.
Q:
Compounds affecting clotting through anti-aggregation and aggregation are formed from the 20:5 n-3 fatty acid and 20:4 n-6 fatty acid. These compounds are _____ and _____, respectively, and their effect on _____ is to inhibit or activate them, respectively.
Q:
Match the enzymes with their functions in lipid metabolism.Enzyme1) lipoprotein lipase2) intracellular lipase3) HMG-CoA reductase4) cyclo-oxygenase5) desaturaseFunctiona. creates a double bond in a fatty acid b. removes triacylglycerol from plasma c. mobilizes stored triacylglycerols from adipocytes d. rate-limiting enzyme in cholesterol synthesis e. creates prostaglandins
Q:
True/FalseBile is the GI enzyme that hydrolyzes dietary triacylglycerol into free fatty acids and glycerol.
Q:
True/FalseFatty acids are converted into glucose by gluconeogenesis and used for energy during starvation.
Q:
True/False
Unlike long-chain fatty acids, short-chain fatty acids from the diet leave the enterocyte via the portal vein and go directly to the liver.
Q:
True/FalseAdipocytes' primary function is to store fat as triacylglycerol; thus, they do not require glycolysis and the TCA cycle for energy needs.
Q:
True/FalseThe conversion of linoleic acid (18:2) to arachidonic acid (20:4) involves the addition of 2 carbons to the methyl end and 2 double bonds at the n-3 and n-6 positions of the omega end.
Q:
True/False
One of the primary functions of a phospholipid is possible because of its structure, which allows it to be both hydrophobic and hydrophilic.
Q:
True/False
The key organ in clearing (i.e., breaking down) lipoproteins is the liver.
Q:
True/FalseOnce a micelle, containing lipids and lipid-soluble compounds, enters the enterocyte, it is referred to as a chylomicron.
Q:
True/False
HMG-CoA reductase is a key enzyme in the synthesis of cholesterol from acetyl-CoA.
Q:
True/FalseKetogenesis is the synthesis of ketone bodies from fatty acids for energy under conditions of excess glucose, such as in the fed state.
Q:
True/False
Essential fatty acids are classified as such because we cannot synthesize them from other fatty acids and they are required for the synthesis of prostaglandins, thromboxanes, and leukotrienes.
Q:
True/FalseMost Americans consume approximately half of their total dietary lipid as triacylglycerols, and the other half as cholesterol; very little is taken in as phospholipids.
Q:
During starvation, or when following a very-low-carbohydrate diet, the consumption of alcohol may cause hypoglycemia. Which of the following is NOT a contributing factor?
a. Alcohol breakdown depletes NADPH.
b. Alcohol breakdown favors the reduction of DHAP to glycerol-3-phosphate.
c. Alcohol breakdown diminishes formation of alpha-ketoglutarate.
d. Alcohol breakdown creates a high NADH:NAD ratio.
Q:
Why might someone who is drunk have high blood lactate levels?
a. High levels of NADH produced by ADH shift the direction of the lactate dehydrogenase reaction.
b. High levels of NADH produced by the MEOS stimulate lactate dehydrogenase activity.
c. Consuming calorie-yielding compounds and not providing enough oxygen to cells increases anaerobic respiration.
d. Reducing equivalents inhibit the synthesis of lactic acid and increase the synthesis of acetaldehyde.
Q:
A high rate of ethanol ingestion causes an _____.
a. increase in gluconeogenesis
b. increase in fatty acid synthesis
c. increase in protein breakdown
d. increase in glycogen synthesis
Q:
Which of these enzymes is the primary system for oxidizing alcohol after 1 drink?
a. catalase
b. microsomal ethanol oxidizing enzyme
c. alcohol dehydrogenase
d. aldehyde carboxylase
Q:
What is considered the toxic level of blood ethanol?
a. less than 10 mg/dL
b. 11 to 24 mg/dL
c. 25 to 45 mg/dL
d. 50 to 80 mg/dL
Q:
Which hormone is considered to be an antagonist of lipolysis?
a. insulin
b. epinephrine
c. glucagon
d. thyroxine
Q:
Thromboxanes that activate blood platelets are _____. When EPA is used to synthesize the thromboxane, it is _____.
a. vasodilators, a vasoconstrictor
b. pro-aggregatory, less pro-aggregatory
c. anti-inflammatory, pro-inflammatory
d. pro-aggregatory, anti-aggregatory
Q:
Which group of 20-carbon fatty acid derivatives can exhibit either pro-arrhythmic or anti-arrhythmic physiological actions in the body?
a. prostaglandins
b. thromboxanes
c. leukotrienes
d. sterols
Q:
Thromboxane A2 is a hormone-like substance made from:
a. stearic acid.
b. arachidonic acid.
c. palmitic acid.
d. myristic acid.
Q:
What is the most important unsaturated fatty acid serving as a precursor for eicosanoid synthesis?
a. arachidonic acid
b. palmitoleic acid
c. oleic acid
d. erucic acid
Q:
The fatty acid structure below is an omega-_____ fatty acid called _____.
CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH
a. 3, linolenic
b. 6, linoleic
c. 6, eicosapentaenoic
d. 9, oleic
Q:
What is the normal product of the fatty acid synthase system?
a. triacylglycerol
b. myristate
c. palmitate
d. butyrate