Term
|
Definition
|
|
Term
| A disaccharide is made up of two aldohexose residues that are connected by a beta (1-->1) alpha glycosidic bond. Is the disaccharide a reducing sugar? |
|
Definition
| No, the disaccharide is not a reducing sugar. |
|
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Term
| How do amylose and cellulose differ from each other? |
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Definition
| Both are polymers of glucose residues but they differ in the configuration of the glycosidic bonds. |
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Term
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Definition
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|
Term
Which carbohydrate is a disaccharide?
Glucose
Amylopectin
Glycogen
Lactose |
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Definition
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Term
| Termites contain microbial endosymbionts that help them digest cellulose. These symbionts help termintes digest cellulose by producing enzymes that catalyze the cleavage of? |
|
Definition
| beta (1-->4) glycosidic linkages of cellulose. |
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Term
| Compound A has the following formula: (COH)-CH2CH2-(CH2OH). Compound B has the formula: (COOH)-CH2-(CH2OH). Can either (or both) compounds have optical isomers? |
|
Definition
Neither Compound A or B can have optical isomers.
**Optical isomers: two compounds with same number/kinds of atoms and connectivity, and different spatial arrangements. |
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Term
| If the amino acid alanine is in a solution at pH 12, which are the predominant forms of its functional groups? |
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Definition
| The alpha amino group is neutral and the alpha carboxyl group is in the negatively charged carboxylate form. |
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Term
The peptide bond that joins amino acids in a protein is actually a(n)...bond.
Ionic
Ester
Amide
Van der Waals |
|
Definition
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Term
| How many possible FOUR-based oligonucleotides can be made with the standard set of A,C,G,T, and U (e.g. five residues)? |
|
Definition
625.
**(# residues)^(# base)=5^4=625 |
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|
Term
The beta-sheet is an example of which type of structure in proteins?
Primary
Secondary
Tertiary
Quaternary |
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Definition
|
|
Term
| The hydrophobic effect refers to? |
|
Definition
| The entropically driven effect that frees up more water molecules to the bulk solution when hydrophobic groups coalesce. |
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Term
Which of the following is an acid amino acid?
Cysteine
Valine
Lysine
Proline |
|
Definition
|
|
Term
Which of the following is an example of a saturated fatty acid?
Palmatic acid
Palmitoleic acid
Linoleic acid
Arachidonic acid |
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Definition
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Term
Which is NOT a function of nucleic acids?
To store genetic information
To act as catalysts
To participate in protein synthesis
To act as hormones |
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Definition
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Term
Which of the following amino acids would likely have its side chain oriented toward the interior of a protein?
Aspartate
Lysine
Leucine
Arginine |
|
Definition
Leucine.
**Proteins have hydrophobic cores |
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Term
Which of the following classes of lipids functions primarily as a storage form of energy?
Phospholipids
Glycolipids
Sphingolipids
Triacylglycerols |
|
Definition
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Term
| What is characteristic of lipids that are part of a cell membrane? |
|
Definition
| They rapidly exhibit lateral diffusion within a leaflet of the membrane. |
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|
Term
| The hormone epinephrine is synthesized from which amino acid? |
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Definition
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|
Term
| An example of a water-soluble vitamin is... |
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Definition
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|
Term
| Lipases are enzymes that catalyze the cleavage of which type of bond? |
|
Definition
|
|
Term
| What is true regarding animal fats? |
|
Definition
| They acyl tails tend to have a higher degree of SATURATION compared to plant oils. |
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Term
What is TRUE of RNA?
The 2' carbon of the ribose moiety is bonded to two hydrogen atoms
It generally contains the base thymine
It's biosynthesis proceeds 3' to 5'
RNA (rather than DNA) is the repository of genetic information in some biological entities |
|
Definition
| RNA (rather than DNA) is the repository of genetic information in some biological entities. |
|
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Term
| A nucleoside contains a nitrogenous base and what else? |
|
Definition
| A sugar, typically ribose. |
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|
Term
| In mammals, mRNA is produced from... |
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Definition
|
|
Term
| The PRODUCTION of mRNA is often termed what? |
|
Definition
|
|
Term
| What is a function of rRNA? |
|
Definition
| It (along with various proteins) forms the ribosome, and it participates in the catalytics steps of protein synthesis. |
|
|
Term
| What is a characteristic of enzymes? |
|
Definition
| They lower the activation energy to allow a particular reaction to proceed at a faster rate than would otherwise be the case in the absence of the enzyme. |
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|
Term
| The term ALLOSTERIC SITE referes to what? |
|
Definition
| The site on a protein or enzyme to which an effector molecules binds to elicit a change in the enzyme protein's conformation. |
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|
Term
| Production of TRYPSIN facilitates the digestion of which type of food molecule? |
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Definition
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|
Term
| In enzyme kinetics, one could expect the maximal rate of an enzyme-catalyzed reaction when... |
|
Definition
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|
Term
| The active form of chymotrypsin functions in the small intestine. Accordingly, one expects that the highest activity of this enzyme occurs at what pH value? |
|
Definition
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|
Term
| An enzymologist constructed a double-reciprocal plot from data that were collected in the absence and presence of an inhibitor. The plot showed intersecting lines at the y-intercept. What type of inhibition occurred? |
|
Definition
|
|
Term
| Which citric acid cycle compound is formed when isocitrate is oxidatively decarboxylated? |
|
Definition
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|
Term
| The process by which glycogen is converted to glucose 1-phosphate is termed... |
|
Definition
|
|
Term
| Many catabolic reactions produce which form of the following cofactors? |
|
Definition
|
|
Term
| Hyperventillation tends to...the pH of blood. |
|
Definition
|
|
Term
| When yeast are grown ANAEROBICALLY, they produce ethanol and CO2. Metabolically, this strategy allows them to... |
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Definition
|
|
Term
| Stearic acid has 18 carbons and glucose has 6. Would metabolizing one mole of stearic acid or 3 moles of glucose provide more energy? |
|
Definition
| Metabolizing one mole of stearic acid. |
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|
Term
| A STEROID HORMONE generally exerts its effects by... |
|
Definition
| Binding to a receptor (usually a transcription factor) in the nucleus of the cell. |
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Term
| When drawn in the Fishcer (vertical) representation, a compound has a hydroxymethyl group (CH2OH) at carbon 1 (the top or uppermost carbon), a keto group (C=O) at carbon 2, a hydroxymethlene group (H-C-OH) at carbon 3 (with the hydroxyl group on the right), another hydroxymethylene group at carbon 4 (with the hydroxyl group on the left), and a final hydroxymethyl group at carbon 5. This compound is what type of molecule? |
|
Definition
|
|
Term
| Nonsuperimposable, non-mirror-image stereoisomers are referred to as... |
|
Definition
|
|
Term
Which of the following amino acids is a nonessential amino acid?
Leucine
Alanine
Lysine
Tryptophan |
|
Definition
|
|
Term
| The isoelectric (pI) of arginine is 10.76. If a solution containing arginine was buffered at a pH of 7, what would be the net charge of the arginine molecules? |
|
Definition
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|
Term
| If the sequence of one strand of DNA is AGTCAT, what would be the corresponding, complementary sequence on the other strand? |
|
Definition
|
|
Term
| PHOSPHATASE enzymes catalyze what class of enzymatic reactions? |
|
Definition
| Hydrolysis reaction of phosphoryl groups on certain proteins or metabolites. |
|
|
Term
| What best describes the nitrogenous base thymine? |
|
Definition
| A pyrimidine with keto and methyl groups. |
|
|
Term
| How many hydrogen bonds link an adenine of one strand of DNA to a thymine on the other strand? |
|
Definition
|
|
Term
| Zymogen is the name for... |
|
Definition
| The inactive form of an enzyme. |
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|
Term
| A molecule has three fused six-member rings, a fourth five-member ring (also fused to the other three rings), an alkyl side chain, and a hydroxyl group. To what class molecules does the molecule belong? |
|
Definition
|
|
Term
| What is an example of an ANABOLIC process? |
|
Definition
| Conversion of acetyl-CoA to palmitate. |
|
|
Term
| During the citric acid cycle, the intermediate alpha-ketoglutarate is decarboxylated and converted to... |
|
Definition
|
|
Term
| Cyclic AMP (cAMP) is a second messenger that... |
|
Definition
| Activates protein kinase A. |
|
|
Term
| A graph of enzyme activity versus temperature typically shows... |
|
Definition
| An initial increase and then a decrease as the temperature rises. |
|
|
Term
| Oxidative phosphorylation produces... |
|
Definition
|
|
Term
| GCU is codon that specifies the amino acid alanine. What is another codon for alanine? |
|
Definition
|
|
Term
|
Definition
| A precursor of prostaglandin H2. |
|
|
Term
| The corin ring in cobalamin-dependent proteins is... |
|
Definition
| Part of an essential cofactor for these proteins. |
|
|
Term
| Ubiquinone functions in... |
|
Definition
| Oxidative phosphorylation. |
|
|
Term
In fatty acid biosynthesis, which of the following occurs?
- A hydratase catalyzes the addition of the elements of water to a double bond in one of the intermediates
- A secondary alcohol in one of the intermediates is oxidized to a ketone
- A triple double-bond is introduced into one of the intermediates by a dehydrogenase enzyme
- A transthioesterification reaction places the acetyl group of acetyl-CoA onto the sulfur of a cysteine residue on a fatty acid synthase |
|
Definition
| A transthioesterification reaction places the acetyl group of acetyl-CoA onto the sulfur of a cysteine residue on a fatty acid synthase |
|
|
Term
| Molecular action within biologic membranes is best characterized by what? |
|
Definition
| Lipid molecules exhibit lateral movement within the membrane bilayer. |
|
|
Term
| In biologic membranes, integral proteins and lipids interact mainly by... |
|
Definition
| Hydrophobic interactions. |
|
|
Term
| Lateral movement of membrane proteins can be visualized by following the movement of fluorescent-labeled proteins at 37C in heterokaryons (artificial hybrids of mouse and human cells). If the incubation temperature is decreased by about 35C, the lateral movement of the proteins is not observed. What best explains the temperature effect? |
|
Definition
| The lateral movement of membrane proteins is influenced by membrane fluidity, which is low at the lower temperature. |
|
|
Term
| What best describes what is meant by the ion product of water? |
|
Definition
| The product of the concentrations of hydrogen ions and hydroxyl ions in water or in aqueous solutions of electrolytes. |
|
|
Term
| A buffer solution contains a mixture of a weak acid at a concentration of 10 mM, and its potassium salt has a concentration of 1 mM. The pH of the buffer solution is approximately... |
|
Definition
|
|
Term
| If 0.1 M solutions of sodium dihydrogen phosphate (NaH2PO4) and disodium hydrogen phosphate (Na2HPO4) are mixed toether in equal proportions, what is the pH of the mixture? (Note that the pKa'-values of orthophosphoric acid (H3PO4) are 2.0, 6.8, and 12.0) |
|
Definition
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|
Term
| A sample of urine from a patient with ketosis contains 30 mmol of total acetoacetic acid - acetoacetate (pka'=4.8). The pH of the urine is 4.8. Assuming that Na+ is exvreted as a counter-ion with equivalent amounts of conjugate based, what is the concentration of Na+ excreted with this keto acid? |
|
Definition
|
|
Term
| The pKa' of acetic acid is 4.76. What is the pH of a 0.1 M solution of acetic acid? |
|
Definition
|
|
Term
| The Henderson-Hasselbalch equation can be used to... |
|
Definition
| Calculate the degree of ionization of a weak acid with a known pKa' value in a solution of known pH. |
|
|
Term
| A medical student becomes extremely anxious the night before a biochemistry exam and begins to hyperventilate uncontrollably. What initial effects doesn hyperventilation have on the Pco2 and blood pH? |
|
Definition
| Pco2 decreases and pH increases |
|
|
Term
| What alpha-amino acid is a diamino-monocarboxylic acid? |
|
Definition
|
|
Term
| With the exception of glycine, all amino acids found in proteins are... |
|
Definition
|
|
Term
| The peptide bond has a "backbone" of atoms in what sequence? |
|
Definition
|
|
Term
| What is true about protein structure? |
|
Definition
| Globular proteins tend to fold into configurations that keep hydrophobic side chains in the interior of the molecule. |
|
|
Term
| A protein treated with fluorodinitrobenzene (FDNB)and subjected to acid hydrolysis yielded two different amino acids with their alpha-amino groups linked to dinitrophenyl (DNP). A reasonable explanation for this result is that... |
|
Definition
| The protein contained more than one N-terminal amino acid |
|
|
Term
Which group of peptides are produced after cleavage of the following peptide with trypsin?
Met-Ala-Try-Met-Phe-Arg-Gly-Asp-Lys-Glu-Trp |
|
Definition
Met-Ala-Try-Met-Phe-Arg
Gly-Asp-Lys
Glu-Trp
**Trp cleaves exclusively after Arg and Lys |
|
|
Term
| What ionic species of glutamate would be prevalent at a pH of 10? |
|
Definition
(-)OOC-C-(CH2)2-COO(-)
|
NH2
**In a basic solution, the H atoms will be removed |
|
|
Term
All of the following forces may play a role in the formation of quarternary structure EXCEPT
- hydrogen bonds
- electrostatic interactions
- hydrophobic interactions
- disulfide bridges
- peptide bonds |
|
Definition
|
|
Term
| What is correct about oxygen binding and release by hemoglobin? |
|
Definition
| Lowering the pH accelerates the release of oxygen from oxyhemoglobin. |
|
|
Term
| What is involved int he formation of hydroxyproline and hydroxylysine during collagen synthesis? |
|
Definition
| Ascorbic acid (vitamin c) |
|
|
Term
| During muscle contraction, what does not change length? |
|
Definition
|
|
Term
All of the statements concerning the prosthetic heme group of myoglobin and hemoglobin, protoporphyrn IX, are true EXCEPT
- In myoglobin and hemoglobin, the heme group can reversibly bind oxygen without oxidizing the ferrous form of iron (Fe+2) to the ferric form (Fe+3)
- Fe+2 in heme can form six ligand bonds, four of which bind to the protoporphyrin ring
- Free heme, unbound to myoglobin or hemoglobin, binds oxygen reversibly without oxidizing Fe+2 to Fe+3
- The fifth bond of Fe+2 of heme is to the histidine, His-F8, on the proximal side of the protoporphyrin plane
- The sixth bond of the Fe+2 can form to an oxygen between it and a histidine, His-E7, on the distal side of the protoporphyrin ring |
|
Definition
| Free heme, unbound to myoglobin or hemoglobin, binds oxygen reversibly without oxidizing Fe+2 to Fe+3 |
|
|
Term
| What is meant by the steady-state assumption that underlies the MIchaelis-Menten relationship between substrate concentration and reaction velocity? |
|
Definition
The rate of breakdown of the enzyme-substrate complex equals the rate of formation of the complex
**v=vmax[S]/Km+[S] |
|
|
Term
| From the following Lineweaver-Burk plot, what can be concluded? |
|
Definition
| When the concentration of substrate is 0.005 M, v=5.0 mol/min |
|
|
Term
| An allosteric modulator influences enzyme activity by... |
|
Definition
| Binding to a site on the enzyme molecule distinct from the catalytic site |
|
|
Term
| After ingestion, ehtanol is normally converted to acetaldehyde by the enzyme ALCOHOL dehydrogenase (ADH). Ethylene glycol, the major ingredient in antifreeze, is occasionally consumed by alcoholics as a substitute for ethanol. Ethylene glycol is also a substrate for ADH, but the aldehyde product that is formed is highly toxic. Ethanol is often administered as a treatment in cases of ethylene glycol poisoning. What is the mostly likely reason that ethanol is an effective treatment for ethylene glycol poisoning? |
|
Definition
| ADH exhibits a much lower Michaelis constant (Km) for ethanol than for ethylene glycol |
|
|
Term
Which of the following statements best characterizes glucose?
- It usually exists in the furanose form
- It is a ketose
- Carbon 2 is the anomeric carbon atom
- It forms part of the disaccharide sucrose
- It is oxidized to form sorbitol |
|
Definition
| It forms part of the disaccharide sucrose |
|
|
Term
| The sugar residues of amylose are... |
|
Definition
|
|
Term
Correct statements regarding the structure of polysaccharides includes all of the following EXCEPT
- Amylose is a linear unbranched polymer of D-glucose in a repeating sequence of alpha-1,4-glycosidic linkages
- Amylopectin is a branched polymer of D-glucose with alpha-1,4-glycosidic linkages and with alpha-1,6 branching points every 25-30 D-glucose residues
- Glycogen is a branched polymer of D-glucose with alpha-1,4-glycosidic linkages and with alpha-1,6 branching points every 8-10 D-glucose residues
- Cellulose is composed on linear chains of D-glucose units joined by alpha-1,4-glycosidic linkages
- Cellulose is not hydrolyzed by human enzyme systems |
|
Definition
| Cellulose is composed on linear chains of D-glucose units joined by alpha-1,4-glycosidic linkages |
|
|
Term
| If the base sequence of a segment of DNA is pCpApGpTpTpApGpC, which of the following sequences is complementary? |
|
Definition
|
|
Term
| What is true of double-helical DNA? |
|
Definition
| Unless the DNA is circular, the 3' hydroxyl groups of each chain are at opposite ends of the molecule |
|
|
Term
| Most protein-coding sequences are found in which class of DNA? |
|
Definition
|
|
Term
| If a sample of DNA is found to have the base composition (mole ratiosO of adenine, 40; thymine, 22; guanine, 19, and cytosine, 19, what conclusion can be drawn? |
|
Definition
| The DNA is single-stranded. |
|
|
Term
| If the cytosine content of double-helical DNA is 20% of the total bases, the adenine content would be... |
|
Definition
|
|
Term
| What is true concerning characteristics of histones? |
|
Definition
| Evolutionarily, they are very highly conserved proteins. |
|
|
Term
All of the following statements about RNA are true EXCEPT
- The sugar group o f ribonucleotides has an OH group at the 2' position
- In RNA helices, adenine (A) can base pair with uracil (U) through two hydrogen bonds
- The mole fraction of A equals the mole fraction of U
- Ribonucleotides are linked into a polar molecule by phosphodiester bonds between the 3' hydroxyl on the sugar of one ribonucleotide through a phosphate to the 5' hydroxyl on the sugar of another ribonucleotide |
|
Definition
| The mole fraction of A equals the mole fraction of U |
|
|
Term
All of the following statements describe phophoglycerides EXCEPT
- They are both amphipathic and amphoteric
- They aris from glycerol 3-phosphate
- They are found in cell membranes
- They are a major store of metabolic energy
- They contain two fatty acid moieties |
|
Definition
| They are a major store of metabolic energy |
|
|
Term
| Primarily used as a source of metabolic energy |
|
Definition
|
|
Term
| May contain a carbohydrate moiety and is present in most cell membranes |
|
Definition
|
|
Term
| Is the primary lipid present in very low-density lipoproteins |
|
Definition
|
|
Term
| Is derived from 5-HPETE and modulates a variety of biologic functions |
|
Definition
|
|
Term
| E. coli cells that had been cultured in alight medium containing 14N-ammonium chloride as the sole nitrogen source were transferred to a heavy medium containing 15N-ammonium chloride. After three generations of growth in the heavy medium, what will be the proprtion of dual light strands (LL), dual heavy strands (HH), and hybrid strands (LH) in the DNA duplexes? |
|
Definition
|
|
Term
| The colinearity of gene and product clearly seen in prokaryote systems is obscured in eukaryotes because... |
|
Definition
| The coding sequences in DNA is interrupted by DNA sequences that are transcribed and then spliced out of the mRNA |
|
|
Term
| What best describes the action of introns? |
|
Definition
| They are excised upon processing of heterogeneous nuclear RNA (hnRNA) to messenger RNA (mRNA) |
|
|
Term
| The genetic codes refers to what? |
|
Definition
| The nucleotide sequences that correspond to common amino acids |
|
|
Term
| The "wobble" hypothesis refers to the less stringent base-pairing specificity of the... |
|
Definition
|
|
Term
| Degeneracy of the genetic code means that... |
|
Definition
| A given amino acid can be coded for by more than one base triplet |
|
|
Term
All of the following statements concerning prokaryotic ribosomes are true EXCEPT
- They are composed of two subunit particles with sedimentation coefficients of 30S and 50S
- They are composed of about 65% RNA and about 35% protein
- They have a sedimentation coefficient of 70S
- They have all their protein in the 50S subunit
- Their proteins are typically basic |
|
Definition
| They have all their protein in the 50S subunit |
|
|
Term
| Which mutation of the sequence GATCCT is the possible result of a TRANSITION mutation. A transition mutation is one in which a purine is replaced by another purine or a pyrimidine by another pyrimidine. |
|
Definition
|
|
Term
Which of the following sequences is most likely to be a restriction enzyme recognition site?
- CGGC
- CGC
- CTAATG
- GTCGAC
- There is insufficient information |
|
Definition
|
|
Term
| Restriction enzymes are best described as... |
|
Definition
| They make sequence-specific cuts in both strands of duplex DNA |
|
|
Term
| If a reaction is at equilibrium, the free-energy change (deltaG) is... |
|
Definition
|
|
Term
| The normal concentrations of G6P and F6P in human erythrocytes are 1e-5 M and 1e-6 M, respectively. If the standard free energy change for the reaction G6P-->F6P is +0.4 kcal/mol, what is correct? |
|
Definition
| The free energy change is about -1.0 kcal/mol |
|
|
Term
| The standard free energy change for the conversion of compound X to compound Y is +1.4 kcal/mol at 37C. What most closely approximates the equilibrium ratio of the concentration of X to that of Y? |
|
Definition
|
|
Term
| If an enzymatic reaction has a standard free energy change of -5 kcal/mol, the equilibrium constant is... |
|
Definition
|
|
Term
| The values of the standard free energy change for the hydrolysis of ATP and creatine phosphate are -7.4 kcal/mol and -10.2 kcal/mol, respectively. How then can you account for the formation of creatine phosphate from ATP and creatine catalyzed by creatine kinase? |
|
Definition
| The free energy change of the reaction is dependent upon the concentration of reactants as well as on the standard free energy change values of hydrolysis |
|
|
Term
| What compound has a higher group transfer potential for phosphate than ATP? |
|
Definition
|
|
Term
| What parameters can be determined from a knowledge of the standard oxidation-reduction potential for an oxidation-reduction reaction? |
|
Definition
| The standard free energy change of the reaction |
|
|
Term
| If an redox rxn with a 2e(-) transfer has a standard reductions potential of +0.3 volts, what's the free energy change under standard conditions? |
|
Definition
-13.8 kcal/mol
deltaG*=-n*F*deltaE | F=23.1 kcal/mol |
|
|
Term
| Pyridoxal phosphate is a cofactor for what enzymatic reactions? |
|
Definition
|
|
Term
| Hydrophilic hormones are best described by... |
|
Definition
| They bind to cell-surface receptors, which transmit a signal to the interior of the cell |
|
|
Term
| The role of Gs protein in the activation of adenylate cyclase is best described as... |
|
Definition
| The Galpha subunit of Gs protein exchanges GDP for GTP, dissociates from the Gbeta,gamma subunits, and activates adenylate cyclase |
|
|
Term
| Which of the following statements about cAMP is true? |
|
Definition
| Levels of cAMP quickly decline because it is hydrolyzed by cyclic nucleotide phosphodiesterase (PDEase) |
|
|
Term
| Phospholipase C is best described by which action? |
|
Definition
| It hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to inositiol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG), which are both second messengers |
|
|
Term
| Which of the following best describes the mechanism of action of insulin on target cells? |
|
Definition
| Insulin binds to a transmembrane receptor at the outer surface of the plasma membrane, which activates the tyrosine kinase that is the cytosolic domain of the receptor |
|
|
Term
| A hormone response element is best defined by which of the following statements? |
|
Definition
| It is the DNA sequence to which a specific hormone-receptor complex binds |
|
|
Term
| In anaerobic glycolysis, 2 moles of inorganic phosphate (Pi) are used per mole of glucose consumed. Which of the following enzymes catalyzes the uptake of Pi? |
|
Definition
| Glyceraldehyde 3-phosphate dehydrogenase (G3PDH) |
|
|
Term
| When one mole of glucose is processed through glycolysis, the products are... |
|
Definition
2 mol ATP
2 mol pyruvate
2 mol NADH |
|
|
Term
| When one mole of glucose is processed through glycolysis and the lactate dehydrogenase reaction, the products are... |
|
Definition
2 mol ATP
2 mol lactate
2 mol NAD+ |
|
|
Term
| The three "irreversible" reactions of glycolysis are catalyzed by which three enzymes? |
|
Definition
Hexokinase
Phosphofructokinase
Pyruvate kinase |
|
|
Term
| It is the major regulatory enzyme of glycolysis |
|
Definition
|
|
Term
| AMP is an activator of this enzyme |
|
Definition
|
|
Term
| This enzyme catalyzes the interconversion of dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GAP) |
|
Definition
| Triose phosphate isomerase |
|
|
Term
| The reaction that this enzyme catalyzes produces a "high energy" phosphate without the involvement of ADP or ATP |
|
Definition
|
|
Term
| Which of the reactions of the citric acid cycle listed below results in the formation of a "high energy" phosphate compound? |
|
Definition
|
|
Term
| What enzyme is tightly associated with the inner mitochondrial membrane? |
|
Definition
|
|
Term
| The enzyme that catalyze an anaplerotic reaction in the citric acid cycle is... |
|
Definition
|
|
Term
| A patient is found to be deficient in activities of both pyruvate dehydrogenase (PDH) and alpha-ketoglutarate dehydrogenase. What is the most likely explanation for this finding? |
|
Definition
| The patient possesses a genetic defect in the E2 subunit of PDH |
|
|
Term
| An individual from a genetic defect in the E2 subunit which decrease the activity of the pyruvate dehydrogenase (PDH) complex. Which of the following is a likely symptom of this disorder? |
|
Definition
| Above normal levels of serum lactate |
|
|
Term
| An individual suffers from a genetic defeat in the E2 subunit which DECREASES the activity of the PDH complex. Which of the following treatments is most likely to be beneficial in this case? |
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Definition
| Restriction of dietary carbohydrates |
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Term
All of the following compounds are intermediates of the citric acid cycle EXCEPT
- Isocitrate
- Malate
- Oxaloacetate
- Pyruvate
- Succinate |
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Definition
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Term
Pyruvate dehydrogenase (PDH) activity is regulated by all of the following EXCEPT
- Covalent modification
- Availability of substrates
- Product inhibition
- Insulin
- A cytosolic protein kinase |
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Definition
| A cytosolic protein kinase |
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Term
| It's possible for a variety of substrates to use a common pathway for the transfer of electrons to oxygen because... |
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Definition
| Many of the substrates are oxidized by enzymes linked to oxidized nicotinamide or flavin-adenine dinucleotide |
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Term
| The mitochondrial electron transport chain carriers are located... |
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Definition
| In the inner mitochondrial membrane |
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Term
| Some of the free energy released in the mitochondrial electron transport chain can be harnessed to the formation of ATP. How many molecules of ATP can be formed per pair of electrons transferred from reduced nicotinamide adenine dinucleotide (NADH) to oxygen? |
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Definition
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Term
| The uncoupling oxidative phosphorylation in a mitochondrial system describes which of the following actions |
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Definition
| The phosphorylation of ADP stops but oxygen uptake continues |
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Term
| The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphae is formed because... |
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Definition
| A proton gradient forms across the inner membrane |
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Term
| All of the following electron carriers are components of the mitochondrial electron transport chain EXCEPT |
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Definition
| Nicotinamide-adenine dinucleotide phosphate (NADP+) |
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Term
| The cost in high-energy phosphate bonds for the formation of 1 mol of glucose from pyruvate is... |
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Definition
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Term
| The regulation of the activities of which pair of enzymes provides an example of reciprocal control of opposing metabolic pathways? |
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Definition
| Fructose 1,6-bisphosphatase (F1,6BPase) and phosphofructokinase |
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Term
| A deficiency in the vitamin biotin leads to a deficiency in the activity of which enzyme of the gluconeogenic pathway? |
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Definition
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Term
In the sequence of reactions that convert pyruvate to glucose in the cells capable of gluconeogenesis, three reactions are used to bypass enzymes of the glycolytic pathway in which glucose is converted to pyruvate. All of the following enzymes fall into this category EXCEPT
- Pyruvate carboxylase
- Pyruvate dehydrogenase
- Phosphoenolpyruvate carboxykinase (PEPCK)
- Fructose 1,6-bisphosphatase (F1,6-BPase)
- Glucose 6-phosphatase (G6Pase) |
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Definition
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Term
| What types of linkages are present between the glucose units of glycogen? |
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Definition
| alpha-1,4 and alpha-1,6 linkages |
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Term
| Glycogen is stored in the cells as... |
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Definition
| Granules, which also contain enzymes that catalyze its formation and degradation |
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Term
| The greatest amount of body glycogen can be found in which of the following human tissues? |
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Definition
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Term
| Free glucose is formed during glycogenolysis from... |
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Definition
| Glucose residues in 1,6 linkage to the main chain |
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Term
| The acetyl groups required for cytoplasmic fatty acid synthesis appear in the cytoplasm as a result of the activity of... |
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Definition
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Term
| The removal of two-carbon units from a fatty acyl-CoA involves four sequential reactions. What best describes the sequence? |
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Definition
| Dehydrogenation, hydration, dehydrogenation, cleavage |
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Term
| Beta oxidation of phytanic acid, a fatty acid derived from chlorophyll and found in cow's milk, cannot take place without prior oxidation at the alpha carbon. Which statement best explains the requirement for alpha oxidation? |
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Definition
| The beta carbon in phytanic acid is blocked by a methyl group |
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Term
| Which amino acid is an essential amino acid; that is, which must be ingested on a daily basis by humans? |
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Definition
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Term
| What amino acids are catabolized to a common citric acid cycle intermediate? |
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Definition
Proline
Glutamate
Glutamine
Arginine |
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Term
In the transamination of amino acids all of the following are true EXCEPT
- Pyridoxal phosphate is a coenzyme/prosthetic group
- The reaction is tightly controlled by allosteric effectors
- The amino acid acceptor is typically an alpha-keto acid
- Ammonia is neither consumed nor produced
- In the catabolism of most, but not all, amino acids, transamination precedes all catabolic changes in the carbon skeleton |
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Definition
| The reaction is tightly controlled by allosteric effectors |
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Term
Which of the following essential dietary factors is a precursor for a compound that can act as a carrier of one-carbon fragments at different levels of oxidation?
- Methionine
- Thiamine
- Folic acid
- Biotin
- Pryidoxine |
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Definition
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Term
| The posprandial state is characterized by... |
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Definition
| HIGH blood levels of glucose and HIGH levels of insulin |
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Term
| High levels of citrate reduce the activity of which pathway? |
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Definition
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Term
Which of the following metabolic pathways is correctly matched with the key enzyme that regulates that pathway?
- Pentose phosphate pathway - glucokinase
- Glycolysis - fructose 1,6-bisphosphatase
- Gluconeogenesis - phosphofructokinase
- Fatty acid synthesis - acetyl-CoA carboxylase
- TCA - glucose 6-phosphate dehydrogenase |
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Definition
| Fatty acid synthesis - acetyl-CoA carboxylase |
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Term
| What action occurs after several days of starvation? |
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Definition
| Ketone bodies are released by the liver into the blood |
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Term
| Translation of the repeating sequence CAA in a cell-free protein synthesizing system produced three homopolypeptides: polyglutamine, polyasparagine, and polythreonine. If the codons for glutamine and asparagine are CAA and AAC, respectively, what is a codon for threonine? |
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Definition
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Term
| Which of the 20 amino acids coded for in DNA is an imino acid? |
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Definition
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Term
| The systems involved in the beta oxidation of fatty acids and in their biosynthesis are similar in the... |
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Definition
| Use of repetitive series of reactions for the sequential transfer of two-carbon units |
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Term
| What regulatory action involves a reversible covalent modification of an enzyme? |
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Definition
| Phosphorylation of a serine hydroxyl on the enzyme |
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Term
| The most important source of reducing equivalents for fatty acid synthesis in the liver is... |
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Definition
| The pentose phosphate pathway |
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Term
| The formation of chylomicrons takes place... |
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Definition
| In the intestinal mucosal cells where they contains about 85% TAGs |
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Term
| Adenosine triphosphatase (ATPase) activity needed for muscle contration is a component of... |
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Definition
| the amino-terminal globular head of myosin |
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Term
A 2-day old patient exhibits extreme lethargy and hyperventillation. Blood analysis indicated normal blood urea nitrogen (BUN) levels, very high levels of ammonia, partial pressure of carbon dioxide (Po2) of 25 mmHg, a bicarbonate concentration of 24 mM, and a pH of 7.5. Urine analysis revealed extremely high levels of orotice acid and no detectable citruline.
This patient likely suffersf rom a defect in which metabolic pathway? |
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Definition
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Term
A 2-day old patient exhibits extreme lethargy and hyperventillation. Blood analysis indicated normal blood urea nitrogen (BUN) levels, very high levels of ammonia, partial pressure of carbon dioxide (Po2) of 25 mmHg, a bicarbonate concentration of 24 mM, and a pH of 7.5. Urine analysis revealed extremely high levels of orotice acid and no detectable citruline.
Which metabolites is expected to be found in high levels in the blood of this patient? |
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Definition
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Term
A 2-day old patient exhibits extreme lethargy and hyperventillation. Blood analysis indicated normal blood urea nitrogen (BUN) levels, very high levels of ammonia, partial pressure of carbon dioxide (Po2) of 25 mmHg, a bicarbonate concentration of 24 mM, and a pH of 7.5. Urine analysis revealed extremely high levels of orotice acid and no detectable citruline.
Which is an essential amino acid for this patient? |
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Definition
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Term
| To what metabolic intermediate is ethanol normally converted? |
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Definition
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Term
| A true characteristic of the Edman reaction is... |
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Definition
| The reaction can be carried out repeatedly on the same sample of the peptide for sequence determination |
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Term
What term best describes an enzyme that catalyzes the following reaction:
Glucose + ATP<-->Glucose 6-phophate + ADP |
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Definition
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Term
| What is the only component of the ETC not firmly embeded int he inner mitochondrial membrane? |
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Definition
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Term
| What specific effect does citrate have on the activity of phosphofructokinase? |
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Definition
| The ratio Vmax/Km is lower in the presence of citrate |
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Term
| Which metabolic pathway also possesses a key enzyme that is allosterically regulated by citrate? |
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Definition
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Term
| The enzymes of oxidative phosphorylation and ETC are located in the inner mitochondrial membrane. Where are the analogous bacterial enzymes found? |
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Definition
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Term
| Fetal hemoglobin (Hb F) is able to bind oxygen well because... |
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Definition
| Hb F does not bind 2,3BPG well |
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Term
| Enzymes increase the rates of reactions by... |
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Definition
| Decreasing the energy of activation |
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Term
| Specific, radioactive labeling of the RNA (not the DNA) of a cell can be done by feeding the cell radioactive... |
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Definition
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Term
| In the mitochondrial ETC, carriers with a more positive reduction potential oxidize carries with a more negative reduction potential. The reduction potential of cytochrome c is more... |
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Definition
| Positive than that of FAD --> FADH2 + 2e- |
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Term
| If the substrate concentration in an enzyme-catalyzed reaction is equal to 1/2Km, the initial reaction velocity will be... |
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Definition
1/3*Vmax
v=vmax*[S]/Km+[S] |
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Term
| What enzyme provides a link between glycolysis and the citric acid cycle? |
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Definition
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Term
All of the following lipids are major components of animal membranes EXCEPT
- Phopholipids
- Cholesterol
- Prostaglandins
- Glycolipids |
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Definition
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Term
All of the following statements concerning the peptide bond are true EXCEPT
- It has a partial double-bond character
- It is polar
- It cannot rotate freely
- It is planar
- It is CIS in the alpha-helix |
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Definition
| It is cis in the alpha-helix |
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Term
Generally accepted features of biologic membranes include all of the following EXCEPT
- Asymmetric arrangement of lipids
- Rapid diffusion of inorganic ions across the lipid bilayer
- Lateral diffusion of lipids
- Lateral diffusion of integral and peripheral proteins
- Infrequent transverse ("flip flop") movement of lipids from one face of the bilayer to the other |
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Definition
| Rapid diffusion of inorganic ions across of the lipid bilayer |
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Term
All of the following are properties of cellular membrane proteins EXCEPT
- They may have catalytic activity
- If peripheral, they are amphipathic
- If integral, they can span the width of the membrane
- They can move laterally in the plane of the membrane
- If peripheral, they can be removed from the membrane without disrupting the membrane structure |
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Definition
- If peripheral, they are amphipathic
- If integral, they can span the width of the membrane |
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Term
| What is NOT a characteristic of the lateral movement of integral membrane proteins? |
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Definition
| It is restricted by an increase in temperature |
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Term
| What is NOT true regarding the structure of polysaccharides? |
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Definition
| Cellulose is composed of linear chains of D-glucose units joined by alpha-1,4-glycosidic linkages |
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Term
| What is NOT true regarding the urea cycle? |
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Definition
| The immediate precursor of urea in the cycle is ornithine |
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