Biochem remediation exam
The major sites of glycogen storage is/are A) Liver and skeletal muscle B) Liver C) Skeletal muscle D) Adipose tissue E) All of the others
A) Liver and skeletal muscle
Which of the following techniques can be used to determine the size of a target protein A) SDS polyacrylamide gel electrophoresis B) Isoelectric focusing gel C) Edman degradation D) Affinity chromatography
A) SDS polyacrylamide gel electrophoresis
The reaction that catalyzes the addition of an activated two-carbon compound with an activated 3-carbon compound is A)Beta-ketoacyl synthase B)Enoyl ACP reductase C) beta-ketoacyl ACP reductase D) Malonyl transacylase
A)Beta-ketoacyl synthase
Which of the following is true regarding gel-filtration chromatography and PAGE? A)In gel filtration, large proteins move most rapidly, but in PAGE, small proteins move most rapidly B) In both, large proteins move most rapidly C) In PAGE, large proteins move most rapidly, but in gel-filtration, small proteins move most rapidly D) In both, small proteins move most rapidly
A)In gel filtration, large proteins move most rapidly, but in PAGE, small proteins move most rapidly
Mad cow disease, Creutzfeldt Jacob disease, and Alzheimer's disease are caused by A) Poison B) Bacteria C) Misfolded protein D) Virus
C) Misfolded protein
The conversion of cysteine to cystine is what kind of reaction A) Condensation B) Hydrolysis C) Oxidation D) Reduction
C) Oxidation
Two proteins are similar in the number of acidic and basic amino acids but are different significantly in size. Which of the following techniques would be best suited for separating these two proteins A) Isoelectric focusing B) Immunoprecipitation and ion exchange chromatography C) SDS-PAGE and gel-filtration chromatography D) Isoelectric focusing and dialysis
C) SDS-PAGE and gel-filtration chromatography
The antiporter and a symporter are examples of A) Passive diffusion B) An ABC transporter C) Secondary transporter D) Primary active transporters
C) Secondary transporter
Which activated carriers contain adenosine phosphate units? A) NADH and FADH2 B) NADH C) Coenzyme A D) NADH, FADH2, and coenzyme A
D) NADH, FADH2, and coenzyme A
The phosphorylation of fructose-6-phosphate is an endergonic reaction with a deltaG^0 of 16.3kJ/mol. How do cells overcome this thermodynamic barrier for this reaction under standard conditions? A) This reaction will proceed to the right because the Keq is negative B) This reaction will proceed to the right because the Keq is small C)The enzyme that catalyzes this reaction couples it with the condensation of ADP and inorganic phosphatem resulting in an overall deltaG^0 of -46.8kJ/mol D) The enzyme that catalyzes this reaction couples with the hydrolysis of ATP to ADP and inorganic phosphate, resulting in an overall deltaG^0 of -14.2kJ/mol
D) The enzyme that catalyzes this reaction couples with the hydrolysis of ATP to ADP and inorganic phosphate, resulting in an overall deltaG^0 of -14.2kJ/mol
What is the significance of having transporters move amino acids from the lumen of the small intestine into intestinal cells but anti-porters move them into the blood? A) The transporters on the lumen side of the intestinal cells will let oligopeptides into the cell, and the anti-porter ensures that these oligopeptides can be utilized by serum proteins B) The transporters are driven by a K+/ H+ ATPase, which provides energy to completely deplete the intestine of all amino acids C) Peptidases in the intestinal cell membrane also act as amino acid transport channels driving amino acids into intestinal cells D) The secondary active transport of the anti-porter moves amino acids into blood, regardless of the blood concentrations of amino acids keeping the intestinal cell concentrations low
D) The secondary active transport of the anti-porter moves amino acids into blood, regardless of the blood concentrations of amino acids keeping the intestinal cell concentrations low
The most common motif found in membrane spanning proteins is A) A helix-turn-helix arrangement of the peptide strands B) Triple helix of alpha-helices C) alpha-helices of charged amino acids that form channels via extensive hydrogen bonding D) alpha-helices of nonpolar amino acids that pass through the membrane
D) alpha-helices of nonpolar amino acids that pass through the membrane
What physical differences among proteins allow for their purification A) Size B) Charge C) Solubility D) Binding specificity to some molecules E) All of the others
E) All of the others
___________. The number of ATP molecules produced by the transfer of electrons from NADH A) 2.5 B) 1.5 C) 3.5 D) 3
A) 2.5
The citric acid cycle (CAC) is activated in the presence of oxygen, but what is the link between the CAC and oxygen A) A primary product of the CAC is NADH, the principle electron donor to the O2, the last electron acceptor in the electron-transport system B) The presence of O2 in the mitochondrial matrix releases CO2 into the cytosol C) The one substrate-level phosphorylation in the CAC can occur in the absence of oxygen D) The iron-sulfur center requires oxygen to be in the appropriate oxidation state
A) A primary product of the CAC is NADH, the principle electron donor to the O2, the last electron acceptor in the electron-transport system
___________ membrane protein couples the entry of ADP into the mitochondrial matrix with the exit of ATP A) ADP-ATP translocase B) Proton gradient C) ATP synthase D) Malate-Aspartate shuttle
A) ADP-ATP translocase
How does the formation of acetyl Co-A by beta-oxidation not only provide energy for cellular respiration, but also spare glucose? A) Acetyl Co-A derived from fatty acids inhibits pyruvate dehydrogenase, the enzyme that converts pyruvate into Acetyl Co-A B)As Acetyl Co-A levels increase during lipid metabolism, D-3-hydroxybutyrate is reduced to pyruvate for gluconeogenesis C) Acetyl Co-A provides carbon for the formation of oxaloacetate, which in turn can be decarboxylated to form pyruvate D) Acetyl Co-A derived from fatty acids activates pyruvate carboxylase stimulating gluconeogenesis E) Acetyl Co-A can be converted to acetoacetate and from there to lactate for anaerobic metabolism
A) Acetyl Co-A derived from fatty acids inhibits pyruvate dehydrogenase, the enzyme that converts pyruvate into Acetyl Co-A
Acetyl CoA is transferred from the mitochondria to the cytoplasm in the form of citrate. Citrate serves as a signal for a high energy state as it stimulates ______________. A) Acetyl CoA carboxylase B) Pyruvate Carboxylase C) Fatty Acid Synthase D) Malonyl CoA carboxylase
A) Acetyl CoA carboxylase
Cancer is caused by the disregulation of the cellular pathways that coordinate cell growth and cell death. In 1931, the scientist Otto Warburg noted that cancer cells preferentially use glycolysis rather than mitochondrial aerobic respiration ( i.e. the citric acid cycle and oxidative phosphorylation) for their growth, even when oxygen is present. Which statement about cancer cells is true? A) All of the others B) Cancer cells are going to consume more glucose to generate the same amount of ATP compared to a normal cell C) Cancer cells are primarily generating ATP by substrate level phosphorylation D) Cancer cells will produce more lactate than a normal cell
A) All of the others
What is required to remove branches in glycogen A) All of the others B) A glycosidase enzyme C) A debranching enzyme D) A transferase enzyme
A) All of the others
Beriberi symptoms are similar to those of which disease? A) Arsenite poisoning B) Lactic acidosis C) Type II diabetes D) Scurvy
A) Arsenite poisoning
Well into exercise, the ratio of ATP/AMP in muscle cells decreases. What effect does this ratio reduction have on the activity of phosphofructokinase and pyruvate kinase? A) Both enzymes are increased in activity due to lack of allosteric binding of ATP B) Phosphokinase activity is increased and pyruvate kinase is decreased C) Both enzymes decrease in activity due to lack of allosteric binding of ATP D) Both enzymes will remain at the same level of avtivity to maintain normal glucose metabolism
A) Both enzymes are increased in activity due to lack of allosteric binding of ATP
In mammals, the _______________ is the major site of triacylglycerol synthesis. A)Brown adipose tissue B) Muscle C) Heart D) Liver
A) Brown adipose tissue
How are fatty acids longer than 16 carbons formed? A) By elongation reactions catalyzed by enzymes on the endoplasmic reticulum B) All of the others C) By elongation reactions catalyzed by enzymes on the endoplasmic reticulum
A) By elongation reactions catalyzed by enzymes on the endoplasmic reticulum
Under conditions in which NADPH is NOT needed, how are five-carbon sugars, such as ribose-5-phosphate, generated? A) By withdrawing 3-carbon units from the glycolytic pathway and converting them into 5-carbon sugars via the nonoxidative branch of the pentose phosphate pathway. B) Through direct decarboxylation of hexose monophosphates. C) Through the normal pentose phosphate pathway. D) It is not possible to produce 5-carbon sugars under these circumstances.
A) By withdrawing 3-carbon units from the glycolytic pathway and converting them into 5-carbon sugars via the nonoxidative branch of the pentose phosphate pathway.
Which of the following illustrates the role of Ca2+ in PDH complex regulation A) Ca2+ is elevated intracellularly with the increase of muscle contractions, activating PDH phosphatase activity B) Ca2+ activates phosphatase activity, deactivating PDH phosphatase activity C) In liver, Ca2+ stimulates pyruvate kinase, increasing conversion of pyruvate to acetyl CoA D) Insulin causes a decrease in Ca2+, activating pyruvate kinase activity
A) Ca2+ is elevated intracellularly with the increase of muscle contractions, activating PDH phosphatase activity
In the urea cycle, free NH4+ from aminotransferases and glutamate dehydrogenase reactions is coupled with carboxylphosphate to form: A) Carbamic acid B) Omithine C) Pyruvate D) Uretic phosphate
A) Carbamic acid
Which of the following helps regulate membrane fluidity in animals A) Cholesterol B) Protein C) Carbohydrates D) ATP
A) Cholesterol
Electrons are not very soluble in hydrophobic environments such as a bilipid membrane. What evidence is there that electrons move from complex to complex through the lipid membrane A) CoQ is the electron carrier within the membrane and seems to be confined to the respirasome B) Cytochrome C is the electron carrier in the membrane and contains a cydrophoric porphyrin center C) Cytochrome C is the electron carrier in the membrane and undergoes a head-over-heel flip to set up the proton gradient D) CoQ is the electron carrier within the membrane and it contains a hydrophobic porphyrin center
A) CoQ is the electron carrier within the membrane and seems to be confined to the respirasome
Which of the following describes how cAMP regulates protein kinase A? A) Cyclic AMP binds to the regulatory subunits of PKA, causing a conformational change that releases the catalytic subunits to carry out phosphorylation. B) Cyclic AMP binds to the catalytic subunits, causing a conformational change that leads to increased activity. C) Cyclic AMP binds to the regulatory subunits of PKA, promoting exchange of bound GDP for GTP that releases the catalytic subunits to carry out phosphorylation. D) Cyclic AMP increases the transcription of genes for PKA.
A) Cyclic AMP binds to the regulatory subunits of PKA, causing a conformational change that releases the catalytic subunits to carry out phosphorylation.
What are the steps involved (in order) in the conversion of pyruvate to acetyl CoA A) Decarboxylation, oxidation, transfer to CoA B) Oxidation, transfer to CoA, decarboxylation C) Decarboxylation, transfer to CoA, oxidation D) Oxidation, decarboxylation, transfer to CoA
A) Decarboxylation, oxidation, transfer to CoA
For a given reaction of A (substrate) being converted into B (product), how might this reaction still proceed from A to B even if the deltaG^0 is positive? A) Deplete product B to facilitate more B production B) Increase the kinetic energy to drive more molecules to the transition state C) Deplete substrate A to produce more product B D) You cannot alter the deltaG^0, and as such, the reverse reaction will always dominate
A) Deplete product B to facilitate more B production
Proteins can be separated from small molecules and ions through a semipermeable membrane by ____ A) Dialysis B) Salting out C) Salting in D) Filtration
A) Dialysis
The reduction of the metabolite ___________ supplies glycerol 3-phosphate for acylglycerol synthesis A) Dihydroxyacetone phosphate B) Glycerol C) Fatty Acid D) Acetyl CoA
A) Dihydroxyacetone phosphate
ELISA is: A) Enzyme-linked immunosorbent assay B) Immuno-affinity chromogen assay C) A type of affinity chromatography D) Efficient-light ionization soluble affinity
A) Enzyme-linked immunosorbent assay
Amino acid synthesis is generally regulated by A) Feedback and allosteric enzyme regulation B) Diet C) Hormonal regulation D) Turnover
A) Feedback and allosteric enzyme regulation
Lactate produced in muscle tissue is converted to ________________ by ________________ in liver A) Glucose; the cori cycle B) Glucose gluconeogenesis C) Pyruvate; glycolysis D) ATP; the krebs cycle E) Lactate; the cori cycle
A) Glucose; the cori cycle
During a period of exercise, which of the following enzymes will dominate in muscle A) Glycogen synthase beta B) Protein phosphatase 1 C) Phosphorylase beta D) Insulin-linked protein kinase
A) Glycogen synthase beta
This amino acid, in high levels, is correlated with the damage of cells living in the blood vessels A) Homocysteine B) Serine C) Citrulline D) Cysteine
A) Homocysteine
In order for regulation of glycogen metabolism to function, there must also be a means to reverse the regulatory effects of the various kinases. Reversal of kinase activation is accomplished by protein phosphatase 1, an enzyme which A) Hydrolyzes the phosphate from the modified enzyme B) Inactivates the GTP bound to Gs by hydrolyzing GTP to GDP C) Recombines cyclic AMP and pyrophosphate to turn off the signal activating the kinases D) Transfers the phosphate from a modified enzyme back to ADP
A) Hydrolyzes the phosphate from the modified enzyme
Suppose there is a mutation in the c subunit of ATP synthase, such that the glutamate found in the middle of one of the membrane spanning helices is converted to a valine. What is likely to be the effect on ATP synthesis and why? A) Inhibit ATP synthesis. Valine cannot bind a proton, so there will be no proton flow through the inner membrane B) Inhibit ATP synthesis. Because valine is hydrophobic, the alpha subunit will move in the reverse direction, causing the hydrolysis of ATP, not synthesis C) No effect, The valine side chain is shorter than the glutamate side chain, so it causes no change in the secondary structure of the helix D) No effect. The middle of the helix is in contact with the hydrophobic center of the lipid bilayer and the valine is readily soluble in lipid
A) Inhibit ATP synthesis. Valine cannot bind a proton, so there will be no proton flow through the inner membrane
Cholesterol and triaglycerols are transported in blood circulations in the form of ____________ A) Lipoprotein particles B) Lipid droplets C) Vesicles D) Complex with albumin
A) Lipoprotein particles
s-adenosylmethionine carries which groups A) Methyl B) CO2 C) Ammonia D) Hydroxyl
A) Methyl
The poison that an organism secretes as a result of a loss of high energy ATP molecules is most likely to target which organelle? A) Mitochondria B) Endoplasmic reticulum C) Endosomes D) Golgi
A) Mitochondria
While glycolysis can occur in most cells, the major site of gluconeogenesis is limited to two tissues. Which of the following is NOT one of them A) Muscle B) Kidney C) None of the other D) Liver
A) Muscle
Which of the proteins are globular A) Myoglobin B) Silk protein C) Keratin D) Collagen
A) Myoglobin
A friend who is struggling with weight gain reads about a new miracle supplement that blocks the formation of phosphatidate, the precursor for triacylglycerols. Would taking this supplement work as a weight reduction scheme? A) No because it would block the formation of phospholipids and cell membrane integrity would be impacted B) No, triaglycerol synthesis takes place in the mitochondria and it is unlikely that there is a transporter for the supplement in the inner membrane C) Yes, many weight loss drugs target enzyme catalyzed reactions that occur early in this biosynthetic pathway D) Yes, decreases in phosphatidate leads to activation of key beta-oxidation enzymes, which drives lipid metabolism over glucose metabolism
A) No because it would block the formation of phospholipids and cell membrane integrity would be impacted
Would you agree that a peripheral membrane protein can act as a Na+/K+-ATPase and why? A) No, because a peripheral protein does not form a transporter across the entire membrane B) Yes, because the hydrophobic amino side chains of the alpha-helices firmly anchor the protein to the membrane C) No, because only secondary active transport proteins can act as a Na+/K+-ATPase D) Yes, because the Na+ and K+ is available intracellularly and extracellularly
A) No, because a peripheral protein does not form a transporter across the entire membrane
Which amino acid(s) is/are a metabolite in the urea cycle, but is/are not used as a building block of proteins A) Ornithine and citrulline B) Ornithine C) Glutamate D) Citrulline E) Glutamate and ornithine
A) Ornithine and citrulline
Oxygen is not used at any point in the citric acid cycle. However, the cycle will not work without oxygen because A) Oxygen is needed to regenerate electron carriers B) Molecular O2 will regulate many of the enzyme steps C) Not enough energy is generated without O2 to run the cycle D) Oxygen is necessary to transcribe and translate enzymes for the reactions
A) Oxygen is needed to regenerate electron carriers
Glucose-6-phosphate dehydrogenase plays a vital role to protect cells from oxidative stress. The enzyme deficiency leads to hemolytic anemia. Why? A) Peroxides cause damage to RBCs because there is no NADPH being produced B) RBCs with diminished glucose-6-phosphate dehydrogenase activity have an overactive response to oxidative stress C) Reactive oxygen species formation is enhanced by reduced glutathione leading to cell membrane disruption D) The oxidized form of glutathione is the substance that normally eliminates peroxides and is depleted in the absence of NADPH
A) Peroxides cause damage to RBCs because there is no NADPH being produced
The bifunctional enzyme in gluconeogenesis is also known as ________. It regulates glycolysis and gluconeogenesis by phosphorylation and dephosphorylation of ________ depending on glucose levels in blood A) Phosphofructokinase 2 (PFK2); Fructose 2,6-biphosphate B) Phosphofructokinase 2 (PFK2); Fructose 1,6-biphosphate C) Phosphofructokinase (PFK); Fructose 1,6-biphosphate D) Phosphofructokinase (PFK); Fructose 2,6-biphosphate
A) Phosphofructokinase 2 (PFK2); Fructose 2,6-biphosphate
Which one of the following amino acids interrupts alpha-helices, and also disrupts beta-sheets A) Pro B) Trp C) Phe D) Cys E) His
A) Pro
What enzyme(s) is/are responsible for the following reaction? Pyruvate + CoA + NAD+ --> Acetyl CoA+ NADH+ (H+) + CO2 A) Pyruvate dehydrogenase complex B) Acetyl CoA synthetase C) Pyruvate decarboxylase D) Pyruvate decarboxylase and acetyl CoA synthetase
A) Pyruvate dehydrogenase complex
The action of a seven transmembrane protein is important in which of the five steps in the generalized scheme of transduction pathways A) Reception of primary messenger B) Termination C) Release of primary messenger D) Relay of information by second messenger
A) Reception of primary messenger
Which element was mentioned as having an essential role for life? A) Sulfur B) Silicon C) Aluminum D) Boron
A) Sulfur
A suspension of yeast cells is being grown under anaerobic conditions such that glucose is degraded to ethanol and carbon dioxide. If an inhibitor of alcohol dehydrogenase is added to the above suspension, the cells rapidly die because A) The NAD+ needed to keep glycolysis going is not being recycled so the entire process is shut down and no ATP is produced B) The acetaldehyde concentration will increase to levels that are toxic to the cell C) More ATP is needed to start the process of glucose degradation under these conditions that can be provided by it D) Pyruvate is not being produced to serve as a precursor for synthesis of glucose via gluconeogenesis so the cells run out of an energy source
A) The NAD+ needed to keep glycolysis going is not being recycled so the entire process is shut down and no ATP is produced
In going from acetyl CoA to succinate, two carbons have entered the cycle and two have been released as CO2. Why is the cycle not considered as complete at this point? A) The oxaloacetate used to initiate the cycle must be regenerated B) Not enough NADH has been generated C) The cell requires FADH2 produced in subsequent reactions of the cycle D) Not enough energy has been generated form the cycle at this stage
A) The oxaloacetate used to initiate the cycle must be regenerated
GLucose-6-phosphate can be utilized by either the glycolytic or the pentose phosphate pathway. What is the major factor regulating how the use of glucose-6phosphate is distributed between these two pathways A) The relative levels of NADP+ and NADPH B) The ratio of ATP to AMP in the cell C) Allosteric inhibition of the glucose-6-phosphate dehydrogenase enzyme by ATP D) The different location of the two pathways in the cell
A) The relative levels of NADP+ and NADPH
What is the function of liver glycogen degradation A) To export glucose to other tissues when glucose levels are low B) To provide for the large energy needs of the liver C) To maintain glucose levels after a large meal D) To provide for the large energy needs of muscle
A) To export glucose to other tissues when glucose levels are low
Snake venom's poison is actually: A) a collection of digestive enzymes B) paralysis toxins and red-blood-cell poisons C) respiratory toxins D) All of the others
A) a collection of digestive enzymes
What molecule initiates the citric acid cycle by reacting with oxaloacetate? A) acetyl CoA B) malate C) oxaloacetate D) pyruvate
A) acetyl CoA
The hydrolysis of phosphatidyl inositol bisphosphate (PIP2) by phospholipase C generates what two secondary messengers? A) diacylglycerol and inositol 1,4,5-triphosphate B) diacylglycerol phosphate and inositol 4,5-diphosphate C) diacylglycerol and inositol 4,5-bisphosphate D) phosphatidyl inositol 3,4,5-triphosphate (PIP3) and cAMP
A) diacylglycerol and inositol 1,4,5-triphosphate
Which two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate? A) glyceraldehyde-3-phosphate and dihydroxyacetone phosphate B) pyruvate and phosphoenolpyruvate C) enolase and 2-phosphoglycerate D) glyceraldehyde-3-phosphate and 3-phosphoglycerate
A) glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
In eukaryotes, the degradation of fatty acids occurs in the ________________. A) mitochondrial matrix B) cytoplasm C) Nuclei D) mitochondrial membrane interspace
A) mitochondrial matrix
two-dimensional gel electrophoresis separates proteins based on A) pl and size B) pl and solubility C) pl and specific activity D) size and solubility
A) pl and size
The enzyme transketolase transfers a _________________-carbon fragment from a ketose to an aldose. A) 3 B) 2 C) 1 D) 4
B) 2
When glucose is totally oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation out of textbook yield ATP molecules A) 12 out of 30 B) 26 out of 30 C) 26 out of 32 D) 12 out of 38
B) 26 out of 30
Patient with familial hypercholesterolemia has a very high blood cholesterol (>800mg/dl). The cholesterol is deposited in blood vessels and causes heart attacks, even in young children. This disease is caused by A) Overproduction of cholesterol B) A deficiency of the LDL receptor C) A deficiency of LDL lipoprotein D) High level of triglyceride
B) A deficiency of the LDL receptor
What is a cytochrome A) A chloroplast protein that transfers electrons, and that also contains an iron sulfur prosthetic group B) A protein that transfers electrons, and that also contains a heme prosthetic group C) A protein that pumps ATP, and that also contains iron D) An enzyme that carries FADH2, and that is a component of complex II
B) A protein that transfers electrons, and that also contains a heme prosthetic group
The hydrolysis of a phosphate group from ATP releases 30.5 kJ/mol, whereas the hydrolysis of a phosphate from glucose-6-phosphate releases only 13.82kJ/mol. In that the product is the same, what accounts for the difference? A) ATP has a greater resonance stabilization than the product orthophosphate B) ATP has a larger phosphoryl-transfer potential C) There is a greater increase in entropy when ATP is hydrolyzed D) Water hydrates ATP greater than glucose-6-phosphate E) The phosphate ester in ATP is more thermodynamically stable than in glucose-6-phosphate
B) ATP has a larger phosphoryl-transfer potential
ATP is known as the energy currency of the cell, however, ATP is not used directly in any of the enzymatic reactions in glycogen synthesis. How then does ATP provide energy currency for glycogen synthesis? A) Dietary glucose is phosphorylated to glucose 1-phosphate by hexokinase B) ATP is used by the diphosphokinase to regenerate UTP C) ATP is used to regenerate GTP in the cGMP cascade D) The branching enzyme requires the hydrolysis of ATP
B) ATP is used by the diphosphokinase to regenerate UTP
All of the carbons in cholesterol are derived from the metabolite _______________. A) alpha-ketoglutarate B) Acetyl CoA C) Glucose D) Ketone Bodies
B) Acetyl CoA
The beta-adrenergic receptor is a member of which of the following receptor families A) G-protein coupled receptors (GPCR) B) All of the others C) Seven-transmembrane receptors (7TM) D) Serpentine receptors
B) All of the others
___________ is a poison because it blocks the flow of electrons from cytochrome c to oxygen A) Azide (N3-) B) All of the others C) Cyanide (CN-) D) Carbon monoxide (CO)
B) All of the others
In adults, the urea cycle produces sufficient quantities of _____________ so that it is not considered an essential amino acid A) Ornithine B) Arginine C) Aspartate D) Glutamine
B) Arginine
Complex carbohydrates are absorbed A) as short 4-glucose residues B) As glucose and simple sugars C) As starch or glycogen D) After the digestion of alpha-1,6 bonds by alpha-amylase E) As Acetyl CoA
B) As glucose and simple sugars
Ketone bodies instead of glucose are used for its source of ATP production during long-term fasting. They are A)beta-hydroxybutyrate B) Beta-hydroxybutyrate, acetoacetate, and acetone C) Acetoacetate D) Acetoacetate and beta-hydroxybutyrate E) Acetone
B) Beta-hydroxybutyrate, acetoacetate, and acetone
______ is/ are amphiphilic derivatives of cholesterol, synthesized in the liver. They are negatively charged and function in the bile to solubilize dietary lipids, allowing easier breakdown and absorption in the intestine A) Bilirubin B) Bile Salts C) Steroids D) Vitamin D
B) Bile Salts
Which of the following occur after a carbohydrate-rich meal? A) Blood-glucose levels increase, leading to glycogen storage in the kidney B) Blood-glucose levels increase, leading to glycogen storage in muscle and liver. C) High blood glucose and glycogen D) Glycogen storage in the muscle shuts down.
B) Blood-glucose levels increase, leading to glycogen storage in muscle and liver.
Metabolic reactions and processes that break down material and transform fuels into cellular energy are referred to as __________ and those performing energy requiring biosynthetic processes as __________ A) Anabolic; catabolic B) Catabolic; anabolic C) Metabolism; intermediary metabolism D) Intermediary metabolism; metabolism
B) Catabolic; anabolic
_________ is an enzyme that scavenges H2O2 and converts it to molecular oxygen and water A) Superoxide dismutase B) Catalase C) Oxidase D) Reductase
B) Catalase
Which of the following is released by the upper intestine and increases zymogen secretion A) Secretin B) Cholecystokinin (CCK) C) Pepsin D) Bile Salts
B) Cholecystokinin (CCK)
What material in vertebrate muscle serves as a reservoir for high-energy phosphate groups? A) Phosphoenolpyruvate B) Creatine phosphate C) Glucose-6-phosphate D) A muscle glycogen
B) Creatine phosphate
Fatty acid synthesis primarily takes place in the cellular location _________ and is carried out by _______________ A) Mitochondrial matrix; acyl CoA synthetase B) Cytosol; Fatty acid synthase C) Endoplasmic Reticulum; HGM-CoA Reductase D) Mitochondrial interspace; ACP transacylase
B) Cytosol; Fatty acid synthase
Which of the following enzymes activates trypsinogen produced by the pancreas A) Pepsin secreted by the stomach B) Enteropeptidase secreted by the epithelial cells of small intestine C) Zymogenase secreted by the duodenum D) Trypsin secreted by the pancreas
B) Enteropeptidase secreted by the epithelial cells of small intestine
Biomolecules can be divided into four different classes. Which of the following is not a major class of biomolecule? A) Nucleic acids B) Fatty acids C) Lipids D) Carbohydrates
B) Fatty acids
Which of the proteins contain alpha-helical secondary structures only? A) Immunoglobulin B) Ferritin C) Collagen D) Fatty-acid binding protein
B) Ferritin
Two critical hormones that signal for glycogen breakdown are: A) Insulin and epinephrine B) Glucagon and epinephrine C) Insulin and growth hormone D) Glucagon and insulin
B) Glucagon and epinephrine
Why would you expect the amount of glycogen in type I glycogen-storage disease (von Gierke disease) to be increased? A) cAMP inhibition of glycogen synthesis is defective B) Glucose 6-phosphatase is the final step in glycogenolysis. Thus, this enzyme deficiency results in low/no glucose export and elevated glycogen synthesis C) Epinephrine inhibition of glycogen synthesis is defective D) Glycogen phosphatase is activated by increases in glucose 6-phosphatte and hence elevated glycogen synthesis
B) Glucose 6-phosphatase is the final step in glycogenolysis. Thus, this enzyme deficiency results in low/no glucose export and elevated glycogen synthesis
What strategy does the liver use to maintain adequate levels of glucose in the blood for use by other tissues A) Glucose-6-phosphatase has a low Km for glucose-6-phosphate so that glycogen is formed only when glucose is plentiful B) Glucose-6-phosphatase is bound to the lumen side of the ER where the products of this enzyme reaction are then transported back to the cytoplasm C) Transporters named T1, T2, and T3 are responsible for transporting glucose-6-phosphate in and glucose and inorganic phosphate out of the mitochondrion for gluconeogenesis D) Pyruvate is transported out of the mitochondrion via the oxaloacetate shuttle when glucose levels in the blood are low
B) Glucose-6-phosphatase is bound to the lumen side of the ER where the products of this enzyme reaction are then transported back to the cytoplasm
The key enzyme in glycogen degradation is A) All of the others B) Glycogen phosphorylase C) Glycogen phosphatase D) Glucose 1-phosphate synthesis
B) Glycogen phosphorylase
At the center of a glycogen molecule is ___________ that provides the primer for glycogen synthesis A) Glycogen synthase B) Glycogenin C) Glycogen phosphorylase D) Glucose
B) Glycogenin
Of the 20 amino acids from which proteins are made, which os most likely present with its R-group in a mixture of ionization states near physiological pH A) Gly B) His C) Glu D) Tyr
B) His
Which of the following statements of C. Anfinsen experiment involving ribonuclease (RNase) are true A) RNase can be treated with urea and oxidizing agents to produce a random coil B) If one removes the urea and oxidizes RNase slowly, it will renature and regain its enzymatic activity C) If one oxidizes random-coil RNase in urea, it quickly regains its enzymatic activity D) Although renatured RNase has enzymatic activity, it can be readily distinguished form native RNase
B) If one removes the urea and oxidizes RNase slowly, it will renature and regain its enzymatic activity
Fatty acid synthesis is regulated by hormone depending on feeding vs fasting and recent exercise vs no recent exercise. Which hormones are active and what is their mechanism of action of these hormones after exercise and a meal? A) Insulin stimulates the mobilization of fatty acids for beta-oxidation and glycolysis. B) Insulin stimulates fatty acid synthesis by activating acetyl CoA carboxylase 1 and ATP- citrate lyase C) Glucagon activates the carboxylase by enhancing the phosphorylation of AMPK and protein kinase A D) Epinephrine stimulates the mobilization of fatty acids and stimulates their accumulation as triacylglycerols
B) Insulin stimulates fatty acid synthesis by activating acetyl CoA carboxylase 1 and ATP- citrate lyase
Which of the following amino acids is/are ketogenic? A) Methionine B) Lysine C) Asparagine D) Valine
B) Lysine
You have isolated a protein, but by the time you have gotten it pure, you only have enough to do one type of analysis. Which of the following would you choose and why A) Amino acid composition analysis because it can be done for the whole protein B) MALDI-TOF mass spectrometry to determine as much sequence data as you can C) ELISA to identify any antigenic determinants D) 2D gel electrophoresis to determine charge and size data of the protein
B) MALDI-TOF mass spectrometry to determine as much sequence data as you can
Which compound inhibits the entry of fatty acyl CoA into the mitochondria as a function of the cell being in the high-energy state? A) Carnitine acyltransferase B) Malonyl CoA C) ATP D) Inhibition of acetyl CoA carboxylase
B) Malonyl CoA
The process of converting N2 to NH3 is called ____ A) Ammonium production B) Nitrogen fixation C) Nitrogenase D) Diazotroph
B) Nitrogen fixation
Your grandfather has been told he has high cholesterol and has been given a statin to bring it down. He asks you if you can think of any reason that he should not double the dose so that it will reduce blood cholesterol faster. What do you tell him? A) No, at high levels, statins have a stimulatory effect on HMG-CoA reductase rather than an inhibitory effect B) No, some cholesterol synthesis is essential. Cholesterol is essential for proper functioning of cell membranes and for precursors for bile salts and steroid hormones C) Yes, statins decrease the amount of LDL receptors on the surface of intestinal mucosal cells, thereby decreasing cholesterol uptake into the blood D) Yes, statins block the reabsorption of bile, effectively blocking the absorption of cholesterol
B) No, some cholesterol synthesis is essential. Cholesterol is essential for proper functioning of cell membranes and for precursors for bile salts and steroid hormones
Which is an appropriate statement of involvement of the hydrophobic effect in protein folding A) Polar portions of the molecule are generally exposed to solvent to interact effectively with water B) Nonpolar portions of the molecule associate with one another in the interior of the protein C) Nonpolar portions of the molecule can be placed on the surface of the molecule only if the hydrogen bonded to water D) Nonpolar portions interact with polar portions in the interior of the protein
B) Nonpolar portions of the molecule associate with one another in the interior of the protein
The NADPH used in the reductive steps of fatty acid biosynthesis comes from A) One NADPH being generated per citrate leaving the mitochondria B) One NADPH being generated per citrate leaving the mitochondria and the degradation of glucose via the pentose phosphate pathway exclusively C) The degradation of glucose via the pentose phosphate pathway exclusively D) Import of NADPH from the bloodstream
B) One NADPH being generated per citrate leaving the mitochondria and the degradation of glucose via the pentose phosphate pathway exclusively
Which of the following is true regarding the chirality of amino acids found in proteins A) D amino acids alternate with L amino acids in certain regions of proteins B) Only L amino acids are found in proteins C) Only D amino acids are found in proteins D) Proteins contain both D and L amino acids
B) Only L amino acids are found in proteins
Pathologic bacteria can be killed by macrophages by engulfment and digestion. What is the process called when these large amount of extracellular material is taken into the cell? A) Lysosome mediated endocytosis B) Phagocytosis C) Endocytosis D) Reverse secretory mechanism
B) Phagocytosis
What type of gradient is critical to ATP formation by oxidative phosphorylation? A) Sodium ion B) Proton C) Potassium ion D) Chloride ion
B) Proton
Organisms capable of carrying out reduction of atmospheric nitrogen include: A) All plants B) Some bacteria and archaea C) Higher eukaryotic organisms such as mammals D) Fungi such as mushrooms
B) Some bacteria and archaea
After a period of time, Gα ceases to stimulate adenylyl cyclase. What is the consequence? A) Gα is phosphorylated to enable it to return to the βγ subunits. B) The G-protein's GTPase activity removes a phosphate; Gα diffuses back to the βγ subunits. C) The βγ subunits bind to Gα, promoting its GTPase activity. D) Adenylyl cyclase converts Gα GTP to cGMP; Gα diffuses back to the βγ subunits.
B) The G-protein's GTPase activity removes a phosphate; Gα diffuses back to the βγ subunits.
Chemically, why is it necessary for citrate to undergo an isomerization to isocitrate prior to decarboxylation? A) This conversion forms an unstable alpha-ketoacid, which drives the cycle forward B) The tertiary alcohol in citrate does not favor the oxidative decarboxylation that occurs next; however, the secondary alcohol of isocitrate does C) Citrate induces a major structural rearrangement in aconitase leasing to the creation of the binding site for the water molecule in the hydration step D) The aconitase reaction is a thermodynamically unfavored hydration reaction followed by a highly favored dehydration
B) The tertiary alcohol in citrate does not favor the oxidative decarboxylation that occurs next; however, the secondary alcohol of isocitrate does
What happens to non polar molecules in water A) They dissolve independently B) They aggregate together C) They precipitate D) None of the others
B) They aggregate together
What evidence exists to show that membrane asymmetry can be preserved for long periods A) Lateral diffusion from fluorescence recovery after photo-bleaching experiments B) Transverse diffusion of proteins has not been observed C) The alpha-helices in membrane-spanning proteins are hydrophobic and tightly packed D) Facilitated diffusion can take place in either direction depending on the concentration gradient
B) Transverse diffusion of proteins has not been observed
The vitamin that is a derivative of cholesterol A) Vitamin B12 B) Vitamin D C) Vitamin K D) Vitamin A
B) Vitamin D
What is the advantage in synthesizing enzymes as zymogens? A) Depending on the zymogen, it can be activated by the low pH in the stomach or the high pH in the intestine B) Zymogens can be stored for rapid release when needed C) Zymogens are resistant to inactivation by kinases D) Diet pills can be designed to inhibit zymogen hydrolysis E) It allows them to be packaged in chylomicrons more easily
B) Zymogens can be stored for rapid release when needed
What is the H+ concentration in a urine sample that has a pH of 5 A) 10^-7M B) 5 micromoles C) 10^-5 M D) 10^-3 M
C) 10^-5 M
Feedback regulation of cholesterol synthesis is mainly controlled at the step catalyzed by the enzyme: A) Farnesyl transferase B) HMG transferase C) 3-hydroxy-3-methylglutryl (HMG) CoA reductase D) Geranyl transferase
C) 3-hydroxy-3-methylglutryl (HMG) CoA reductase
The process of glycolysis results in the formation of the two high-energy phosphate bonds (In the form of ATP). How many high-energy phosphate bonds are consumed during the process of gluconeogenesis using pyruvate as a starting material? A) 4 B) 3 C) 6 D) 2
C) 6
Which of the following membranes would be the most fluid A) A bilayer made of lipids with saturated 18-carbon fatty acids B) A bilayer made of lipids with saturated 16-carbon fatty acids C) A bilayer made of lipids with polyunsaturated 16-carbon fatty acids D) a bilayer made of lipids with polyunsaturated 18-carbon fatty acids
C) A bilayer made of lipids with polyunsaturated 16-carbon fatty acids
The carrier of an acyl chain during fatty acid synthesis through the synthetic protein complex is A) a biotin activated complex B) acetyl coenzyme A C) ACP D) Acyl coenzyme A
C) ACP
What is substrate-level phosphorylation? A) phosphorylation of glycolytic intermediates B) phosphorylation of AMP by ATP C) ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential D) ATP and AMP synthesis from two molecules of ADP
C) ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential
The link between the pentose phosphate pathway and glycolysis is well documented. How does this link facilitate the growth of rapidly dividing cancer cells? A) Glycolytic intermediates are rapidly depleted due to the increased demand for ATP to synthesize cellular structures leading to decreased production of ribose 5-phosphate B) 6-phosphogluconate dehydrogenase switches to NADH formation to speed up ribose 5-phosphate synthesis C) Accumulated glycolytic intermediates are used by the pentose phosphate pathway to synthesize ribose 5-phosphate D) Rapidly dividing cells switch to anaerobic glycolysis to meet their NADP+ needs
C) Accumulated glycolytic intermediates are used by the pentose phosphate pathway to synthesize ribose 5-phosphate
How does the cell ensure that fatty acids are not synthesized when the energy charge of the cell is low? A) All of the others B) AMP activated protein kinase is activated by AMP C) Acetyl CoA carboxylase 1 exists as inactive dimers unless citrate and ATP levels are high D) Acetyl CoA carboxylase 1 is switched off by phosphorylation
C) Acetyl CoA carboxylase 1 exists as inactive dimers unless citrate and ATP levels are high
Cancer-driven hypoxia brings about the induction of which genes involved in glycolysis? A) Hexokinase B) Aldolase C) All of the others D) Phosphofructokinase E) GLUT3
C) All of the others
Possible fates for the glucose 6-phosphate produced during glycogen breakdown include: A) Entering glycolysis B) Formation of glucose through the action of glucose 6-phosphatase C) All of the others D) Entering the pentose phosphate pathway
C) All of the others
The carbon skeletons for amino acids are intermediates found in A) Glycolysis B) The pentose phosphate pathway C) All of the others D) The citric acid cycle
C) All of the others
Which biosynthetic pathway requires NADPH? A) fatty acid B) cholesterol C) All of the others D) Steroid hormones
C) All of the others
Lipids that interact with both the water and the hydrophobic regions of the membrane are considered ____________. A) Hydrophobic B) Organic C) Amphipathic D) Hydrophilic
C) Amphipathic
although glucose is the major sugar degraded by the glycolytic pathway, other sugars such as galactose and fructose are also derived from food. These sugars A) Can be metabolized by parallel glycolytic pathways into pyruvate B) Must first be converted to glucose in order to be metabolized C) Are metabolized by the glycolytic pathway by conversion to intermediates in the pathway D) Cannot be metabolized by steps in the glycolytic pathway
C) Are metabolized by the glycolytic pathway by conversion to intermediates in the pathway
Terrestrial vertebrates use the urea cycle to convert the ammonium ion to urea such that the urea can be excreted. In the production of urea, only one of the nitrogens in the product comes from the ammonium ions. What is the source of the other nitrogen? A) Fumarate B) Carbamoyl Phosphate C) Aspartate D) Another molecule of glutamate
C) Aspartate
What do alpha-helices and beta-sheets have in common? A) The same amino acids stabilize both forms of secondary structure B) The length of a 10-amino acid alpha-helix and beta-sheet strand will be the same C) Both are stabilized by hydrogen bonding involving carbonyl oxygens and amide nitrogens D) Both are stabilized by glycine and proline residues
C) Both are stabilized by hydrogen bonding involving carbonyl oxygens and amide nitrogens
The main buffer system in human plasma is A) Ammonium and imidazole B) Monobasic phosphate and dibasic phosphate C) Carbonic acid and bicarbonate D) Acetate and acetic acid
C) Carbonic acid and bicarbonate
Acyl groups generated during metabolic processes involving carbohydrates and fatty acids are activated by attachment to A) Pyruvate B) Biotin C) Coenzyme A D) Glyceraldehyde-3-phosphate
C) Coenzyme A
Excess alcohol consumption not only makes you overweight, it can also lead to ammonia poisoning. How is alcohol metabolism linked to increased levels of blood ammonia? A)Excess alcohol consumption makes the liver more acidic, driving the equilibrium from ammonium ion to free ammonia B) Excess alcohol facilitates the formation of an abortive complex for glutamate dehydrogenase C) Excess alcohol consumption can cause liver damage, the primary site of urea formation. Loss of liver function can lead to increases of ammonia in the blood D) Excess alcohol consumption can cause a buildup of acetaldehyde, a reactive species that short circuits the urea cycle at the formation of carbamoyl phosphate
C) Excess alcohol consumption can cause liver damage, the primary site of urea formation. Loss of liver function can lead to increases of ammonia in the blood
The subunit of the ATPase embedded in the inner mitochondrial membrane is the __________ A) Anchor subunit B) Membrane c-ring subunit C) F0 subunit D) F1 subunit
C) F0 subunit
in contrast with s-adenosylmethionine with methyl unit only, tetrahydrofolate can carry one-carbon groups such as methyl, methenyl, formimino, and ____ A) Carbon monoxide B) Urea C) Formyl D) Carbon dioxide
C) Formyl
The amino acid with the smallest-size side chain allowing greatest flexibility in a protein such as collagen is ______ A) Proline B) Cysteine C) Glycine D) Alanine
C) Glycine
Which enzyme(s) is/are required to synthesize α-1,4-glycosidic bonds in glycogen? A) Branching enzyme B) UDP-glucose phosphorylase C) Glycogen synthase D) Glucose transferase
C) Glycogen synthase
Exercising first thing in the morning without eating mobilizes lipid stores for fuel. All of the below are involved in this mobilization, EXCEPT A) Hormone-sensitive lipase is phosphorylated B) Perilipin is phosphorylated C) Hormone-sensitive lipase completes the mobilization of fatty acids with the production of a free fatty acid and glycerol D) Glucagon binds 7TM receptors that activate adenylate cyclase E) cAMP stimulates protein kinase A
C) Hormone-sensitive lipase completes the mobilization of fatty acids with the production of a free fatty acid and glycerol
In glycolysis, the isomerization of glucose to fructose is necessary because A) It is needed to harvest any energy from the molecule B) It is needed to trap the glucose molecule in the cell C) It is needed to ensure that equal 3-carbon units can be made D) It is needed to allow a second glucose phosphorylation to be made
C) It is needed to ensure that equal 3-carbon units can be made
The brain uses __________ instead of glucose for its source of ATP production during long term fasting A)Fatty acids B) Amino Acids C) Ketone Bodies D) Malonyl CoA
C) Ketone Bodies
The citric acid cycle is also known as A) Cori cycle or tricarboxylic acid cycle B) Cori cycle C) Krebs cycle or tricarboxylic acid cycle D) Tricarboxylic acid cycle E) Krebs cycle
C) Krebs cycle or tricarboxylic acid cycle
The process of glycolysis occurs in the cytoplasm. The electrons from the NADH generated during glycolysis _______________ A) Enter the mitochondrial electron chain directly as NADH freely enters the mitochondria B) Cannot be used by the mitochondrial electron transport chain ad NADH cannot enter the mitochondria C) May enter the electron transport chain either at the level of NADH or FADH2, depending on the shuttle system used to transport them into the mitochondria D) Will always be able to produce the same number of ATP via oxidative phosphorylation as mitochondrial NADH electrons
C) May enter the electron transport chain either at the level of NADH or FADH2, depending on the shuttle system used to transport them into the mitochondria
ATP is called the energy currency. The currency of biosynthetic reducing power is A) NADH B) AMP C) NADPH D) ADP
C) NADPH
The availability of the metabolite ____________ determines whether acetyl CoA, made from fatty acids, can enter the citric acid cycle. A) pyruvate B) Aspartate C) Oxaloacetate D) Amino Acids
C) Oxaloacetate
The product _________ results when aspartate is transaminated with alpha-ketoglutarate A) Pyruvate B) Glycerol C) Oxaloacetate D) Urea
C) Oxaloacetate
Glycogen metabolism is regulated, up to a point, by a cyclic AMP cascade. At what point do glycogen synthesis pathways diverge from glycogen degradation pathways A) Phosphorylase kinase converts phosphorylase alpha to phosphorylase beta and glycogen synthase alpha to glycogen synthase beta B) Phosphorylase kinase converts phosphorylase beta to phosphorylase alpha and glycogen synthase alpha to glycogen synthase beta C) Protein kinase A leads to the activation of glycogen degradation, and also the inhibition of glycogen synthase by conversion from alpha to beta D) Protein kinase A leads to the activation of glycogen degradation, and also the inhibition of glycogen synthase by conversion from beta to alpha E) Cyclic AMP converts inactive PKA to active PKA, causing the inactivation of phosphorylase kinase
C) Protein kinase A leads to the activation of glycogen degradation, and also the inhibition of glycogen synthase by conversion from alpha to beta
The electron transport chain in cellular respiration is tightly linked. However, electron leakage does happen in oxidative phosphorylation. The transfer of a single electron to O2 forms the reactive _________ ion A) Hydrogen peroxide B) Nitrite C) Superoxide D) ROS
C) Superoxide
Digitalis is a cardiogenic steroid that does not act like a steroid. Instead its function is to inhibit_____ A) Potassium and sodium pores B) Calcium channels C) The Na+/K+-ATPase pump D) Fatty acid intake
C) The Na+/K+-ATPase pump
Digestion is _____ A) The set of reactions that degrade small molecules into a few simple units B) The salvage of metabolic intermediates C) The process of breaking down large molecules in food D) Creating energy from foodstuff
C) The process of breaking down large molecules in food
The glyoxylate cycle enables plants to survive using only: A) pyruvate B) none of the others C) acetate D) oxaloacetate
C) acetate
Oxidative deamination of glutamate results in free ammonium ions and _________ A) Oxaloacetate B) Glutamine C) alpha-ketoglutarate D) Pyruvate
C) alpha-ketoglutarate
The structural components ( filaments and tubules) are intracellular traffic ways called the A) cytoplasm B) cell wall C) cytoskeleton D) chloroplast
C) cytoskeleton
The purpose of the pentose phosphate pathway is to: A) generate ATP B) synthesize five-carbon sugars C) generate NADPH and synthesize five-carbon sugars D) generate NADPH E) Generate NADPH and ATP
C) generate NADPH and synthesize five-carbon sugars
Phosphatidate is formed from: A) Pyruvate and Triaglycerol B) Glycerol and 2 fatty acyl CoAs C) Glycerol 3- phosphate and 2 fatty acyl CoAs D) Glycerol and 2 free fatty acids
C) glycerol 3-phosphate and 2 fatty acyl CoA's
Protein kinases generally regulate the activity of target proteins by transferring a phosphate group from ATP to what kind of functional group on the target protein? A) carboxyl groups in Glu and Asp residues B) hydrophobic groups in Phe and Leu residues C) hydroxyl groups in Tyr, Ser, and Thr residues D) amino groups in Lys and Arg residues
C) hydroxyl groups in Tyr, Ser, and Thr residues
The mechanism by which insulin-signaling processes might be terminated include: A) change in temperature. B) the aggregation of all protein subunits. C) protein dephosphorylation by phosphatases. D) None of the above.
C) protein dephosphorylation by phosphatases.
The overall charge of a peptide of the following peptide sequence at pH 7.4 would be (Asp-Gly-Lys-Ser) A) -1 B) +1 C) +2 D) 0
D) 0
Based on henderson hasselbatch equation, what is the [A-]/[HA] ratio when the weak acid is in a solution one pH unit above its pKa A) 2:1 B) 1:1 C) 1:10 D) 10:1
D) 10:1
What is the appropriate mass od a protein containing 300 amino acids? A) 22,000 Da B) 11,000 Da C) 40,000 Da D) 33,000 Da
D) 33,000 Da
The three dimensional structure of the potassium channel provided a rational for the selectivity of potassium ions and the rejection of sodium ions. Which of the following is the basis for the ability of the potassium channel to discriminate between thesis two ions\ A) The opening of the channel is structurally arranged such that potassium ions can bind, but is too small for sodium ions B) The restriction of the channel desolvates sodium ions but not potassium ions C) The sodium ion is too small to pass through the channel D) A restriction in the channel allows for potassium ions to be desolvated by protein ligands but is too small to effectively desolvate sodium ions
D) A restriction in the channel allows for potassium ions to be desolvated by protein ligands but is too small to effectively desolvate sodium ions
The enzyme acyl Co-A synthetase catalyzes A)ATP-dependent reduction prior to activation B) Lipolysis to release free glyceraldehyde C) Fatty acid synthesis D) ATP-dependent activation of fatty acids using CoA
D) ATP-dependent activation of fatty acids using CoA
Examples of second messengers include: A) cAMP B) calcium ion C) diacyl glycerol D) All of the others
D) All of the others
Key properties of proteins include A) A wide range of functional groups B) An inability to possess either rigid or flexible structures as dictated by functional requirements C) The ability to interact with other proteins D) All of the others
D) All of the others
Metabolic processes are regulated by A) Allosteric control of enzyme activity B) Transcriptional control of enzyme activity C) Accessibility of substrates by compartmentalization D) All of the others
D) All of the others
Triacylglycerol stored in adipose tissue is used by the liver and other tissues for: A) glycerol for pyruvate and glucose in liver B) ATP production via the citric acid cycle in muscle C) conversion to acetyl CoA and ketone bodies during starvation for the brain D) All of the others
D) All of the others
What pathologic condition(s) results from free-radical injury? A) Diabetes B) Parkinson's disease C) Artherogenesis D) All of the others E) Emphysema
D) All of the others
Which of the following is considered a noncovalent bond A) Electrostatic interactions B) Van der waals interactions C) Hydrogen bonds D) All of the others
D) All of the others
A diet pill that acts to increase oxygen consumption during electron transport without ATP production is likely what kind of compound? A) An ATP synthase activator B) Cyanide C) Arsenic D) An uncoupler
D) An uncoupler
Which of the following does not pump protons? A) Complex IV B) Complex III C) Complex I D) Complex II
D) Complex II
During transcription, _______ is the template for a new molecule of _______ A) RNA; RNA B) RNA; Protein C) DNA; DNA D) DNA; RNA
D) DNA; RNA
In general, phospho- forms of glycogen synthase lead to ________________ levels of glycogen. A) Altered B) Increased C) No change D) Decreased
D) Decreased
Which of the following conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phosphorylation and inactivation of E1 in the pyruvate dehydrogenase complex A) Insulin B) Elevated concentrations of NAD+ and ADP C) Elevated concentrations of acetyl CoA D) Elevated concentrations of NADH and ATP
D) Elevated concentrations of NADH and ATP
What are the conditions that lead to a "beer belly" due to excess consumption of alcohol? A) NADH produced from the metabolism of ethanol stimulates the citric acid cycle for glucose derived acetyl CoA B) The processing of acetate in the liver becomes inefficient leading to a pH imbalance in liver cells, reducing enzyme efficiency in general C) NADH stimulates citric acid cycle enzymes that stimulates glucose-derived acetyl CoA metabolism D) Excess ethanol metabolism leads to an accumulation of NADH that inhibits fatty acid degradation and stimulates fatty acid synthesis
D) Excess ethanol metabolism leads to an accumulation of NADH that inhibits fatty acid degradation and stimulates fatty acid synthesis
The hormone ___________ induces lipolysis, whereas the hormone ____________ inhibits the process A) Insulin; norepinephrine B) Epinephrine; glucagon C) Glucagon; epinephrine D) Glucagon; insulin
D) Glucagon; insulin
In the degradation of amino acids, the amino nitrogen can eventually become the amino group of _________. This amino acid is then oxidatively deaminated to an ammonium ion which enters the urea cycle A) Alanine B) Aspartate C) Serine D) Glutamate
D) Glutamate
What are the primary chemical components in a phosphate buffer at pH 7.4 A) H3PO4 and (PO4)3- B) H2PO4- and (PO4)3- C) (HPO4)2- and (PO4)3- D) H2PO4- and (HPO4)2-
D) H2PO4- and (HPO4)2-
What physiological conditions render muscle phosphorylase beta less active? A) High ATP and low calcium ion levels B) High ATP, High AMP, and glucose-6-phosphate levels C) High AMP D) High ATP and high glucose 6-phosphate levels
D) High ATP and high glucose 6-phosphate levels
High blood sugar after a meal ____ the level of insulin released by the pancreas A) Chronically inhibits B) Chronically activates C) Decreases D) Increases
D) Increases
Why is the peptide bond planar? A) Hydrogen bonding between the NH and C=O groups limits movement B) All of the others C) Bulky side chains prevent free rotation around the bond D) It exhibits partial double bond character, preventing rotation
D) It exhibits partial double bond character, preventing rotation
The three dimensional structure of a protein is dictated by A) Interactions with other proteins B) The pH, temperature and other environmental factors during synthesis C) Other proteins which assist it in folding correctly D) Its amino acid sequence
D) Its amino acid sequence
the primary raw materials for gluconeogenesis are A) Lactose and lactate B) Pyruvate and oxaloacetate C) Fructose and glycerol D) Lactate and amino acids E) Galactose and sucrose
D) Lactate and amino acids
In actively contracting skeletal muscle tissue, the major way in which glucose is metabolized is via A) Glycolysis and the citric acid cycle B) Glycogen synthesis C) The pentose phosphate pathway D) Lactic acid fermentation
D) Lactic acid fermentation
The result of lipase activity in digestion is A) bile salt formation B) Phospholipid head group hydrolysis C) Hydrolysis of membrane proteins D) Monoacylglycerol and two free fatty acids
D) Monoacylglycerol and two free fatty acids
Which of the following describes an important difference between NADH and NADPH? A) NADH is more likely to give up electrons than NADPH B) NADH is produced in glycolysis while NADPH is used in a wide variety of pathways C) NADPH is exclusive to a small number of cells D) NADH is primarily produced in catabolic reactions while NADPH is primarily used in anabolic reactions
D) NADH is primarily produced in catabolic reactions while NADPH is primarily used in anabolic reactions
The group of amino acids that can be synthesized by ourselves are the _____ amino acids A) Essential B) Required C) Dietary D) Nonessential
D) Nonessential
Which of the following amino acid residues would most likely be buried in the interior of a water-soluble, globular protein A) Lysine B) Glutamine C) Serine D) Phenylalanine
D) Phenylalanine
Which of the following amino acids is essential and we need to obtain from diets? A) Tyrosine B) Arginine C) Aspartate D) Phenylalanine
D) Phenylalanine
The genetic deficiency of the enzyme ______ results in a condition referred to as phenylketonuria A) Alanine hydroxylase B) Tryptophan Hydroxylase C) Phenylalanine dehydrogenase D) Phenylalanine hydroxylase
D) Phenylalanine hydroxylase
You are taking your new puppy for a walk and a vicious-looking dog comes rushing out from an unfenced yard. You pick up your puppy and take off down the road. What is the most likely form of the phosphorylase in muscle? A) Phosphorylase alpha, R state, not phosphorylated B) Phosphorylase alpha, T state, phosphorylated C) Phosphorylase beta, T state, phosphorylated D) Phosphorylase alpha, R state, phosphorylated E) Phosphorylase beta, R state, phosphorylated
D) Phosphorylase alpha, R state, phosphorylated
Electron flow down the electron-transport chain leads to: A) A dangerous imbalance of K+ ions across the mitochondrial membrane B) The coupled synthesis of GTP C) The transport of protons across the inner mitochondrial membrane from the intermembrane space into the matrix D) The transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space
D) The transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space
The synthesis of cholesterol involves condensations of 5-carbon units from isopentyl pyrophosphate A) The 5-carbon units are reduced to 3-carbon units and combined sequentially 9 times to give the 27-carbon cholesterol B) 5-carbon units are added sequentially to give a 30-carbon molecule that is cyclized to form cholesterol C) Two 5-carbon units are condensed to form a 10-carbon unit, three of which are combined to yield a 30-carbon molecule which is cyclized to form cholesterol D) Three 5-carbon units are condensed to form a 15 carbon unit, two of which are combined to yield a 30- carbon molecule that is cyclized to form cholesterol
D) Three 5-carbon units are condensed to form a 15 carbon unit, two of which are combined to yield a 30- carbon molecule that is cyclized to form cholesterol
___________ allows the detection of small amounts of target proteins with no specific antibodies as well as the ability to determine the size of target proteins A) Zonal gradient centrifugation B) HPLC C) Dialysis D) Western Blot
D) Western Blot
In addition to pyruvate dehydrogenase, what other enzyme(s) in the citric acid cycle has a key thiamine pyrophosphate coenzyme A) Malate dehydrogenase B) Citrate synthesis C) Isocitrate dehydrogenase D) alpha-ketoglutarate dehydrogenase
D) alpha-ketoglutarate dehydrogenase
Lactose intolerance is caused by a deficiency of: A) lactose B) sucrase C) elastase D) lactase
D) lactase
In the malate-aspartate shuttle, electrons from NADH are transferred to _____________, forming malate. A) acetate B) aspartate C) glutamate D) oxaloacetate
D) oxaloacetate
Which of the following vitamins are precursors to coenzymes that are necessary for the formation of acetyl CoA from pyruvate? A) thiamine, riboflavin, niacin, lipoic acid, pantothenic acid, and biotin B)thiamine, riboflavin, niacin, and biotin C) thiamine, riboflavin, and lipoic acid D) thiamine, riboflavin, niacin, lipoic acid, and pantothenic acid
D) thiamine, riboflavin, niacin, lipoic acid, and pantothenic acid
Water can form hydrogen bonds with the ___________ of another molecule. A) Aromatic groups B) Amine groups C) Alcohol groups D) Carbonyl groups E) All of the others
E) All of the others
What is significant about the fact that glucokinase is found in liver and beta-cells of the pancreas and that hexokinase is found in most cells A) The role of hexokinase is to provide glucose-6-phosphate for the synthesis of fatty acids B) Hexokinase is not inhibited by glucose-6-phosphate, allowing accumulation in muscle for storage as glycogen C) Hexokinase has a high Km, so it does not become saturated until blood glucose levels are extremely high D) Glucokinase phosphorylates glucose when blood glucose levels are low E) At low glucose levels, very little is taken up by the liver, so glucose is spared for other tissues
E) At low glucose levels, very little is taken up by the liver, so glucose is spared for other tissues
What is the rationale for saying the "electrons flow down the electron-transport chain" A) Electrons flow from reactions that continuously generate negative free energy values B) Electrons flow from the outer surface to the inner surface, a top down perception C) Electrons flow from oxidized carriers to reduced carriers in discrete steps like a staircase D) Because we think of electrons flowing like a liquid, the only direction electrons can flow is down E) Electrons flow form reactions with more negative redox potentials to more positive
E) Electrons flow form reactions with more negative redox potentials to more positive
Glycerol, lactate, and amino acids contribute carbon precursors in the formation of glucose; however, the path that glycerol takes is striking different from the other precursors. Explain how it differs A) Glycerol is decarboxylated to acetyl CoA and enters gluconeogenesis as pyruvate B) Glycerol is oxidized and enters gluconeogenesis as glyceraldehyde phosphate C) Glycerol is first oxidized in a reaction requiring NAD+ and then phosphorylated in reversible reaction of glycolysis D) Glycerol undergoes a reversible reduction/oxidation reaction to form phosphoenolpyruvate E) Glycerol enters gluconeogenesis as a breakdown product of triacyclglycerols in the form of dihydroxyacetone phosphate
E) Glycerol enters gluconeogenesis as a breakdown product of triacyclglycerols in the form of dihydroxyacetone phosphate
What is the function of a thioester intermediate such as the one formed from glyceraldehyde-3-phosphate (GAP) A) The thioester intermediate induces a conformational change that alters the enzyme specificity B) The thioester prevents the formation of metabolically unfavorable side products C) It speeds up the actual reaction so that more product can be made D) The thioester shifts the equilibrium to the first stage of the reaction E) The thioester allows the two-step reaction to be coupled so the second reaction, the energetically unfavorable phosphorylation, can proceed
E) The thioester allows the two-step reaction to be coupled so the second reaction, the energetically unfavorable phosphorylation, can proceed
