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298 Terms
What biomolecules are considered the most abundant and functionally diverse in living systems?
A.) Proteins
B.) Carbohydrates
C.) Nucleic acids
D.) Fatty acids
E.) Terpenoids
A
Which of the following statements is correct about protein structure?
I. The primary structure of a protein involves α helices, β sheets, and other types of folding patterns that occur due to a regular repeating pattern of hydrogen bond formation
II. The secondary structure consists of the amino acid sequence along the chain
III. The tertiary structure involves electrostatic and hydrophobic interactions, Van der Waals interactions, and hydrogen and disulfide bonds
IV. Quaternary structure refers to the interaction of one or more subunits to form a functional protein, using the same forces that stabilize the tertiary structure
A) I only
B) I and Il
C) II and III
D) l and IV
E) lII and IV
E
Accumulated misfolded proteins occur in a variety of diseases. Which of the following proteins is misfolded in patients with Alzheimer's disease?
A.) Prion protein
B.) Alpha-synuclein
C.) Glutamine stretches
D.) Beta-amyloid
E.) None of these
D
Hemoglobinopathies result from mutations that produce alterations in the structure of hemoglobin. One common mutation results in sickle cell anemia, in which a mutated form of hemoglobin distorts the RBC into a crescent shape at low oxygen levels. Sickle cell anemia happens when:
A) Valine is being substituted by glutamine at codon number 6
B.) Glutamic acid is being substituted by valine at position number 6
C.) Glutamine is intercalated by histidine at codon number6
D.) Gene transcription is disrupted
E) Frameshift mutation takes place.
B
Acid-base disturbances occur under a variety of conditions. Which of the following is the result of hypoventilation due to retention of carbon dioxide in the lungs?
A.) Respiratory acidosis
B.) Respiratory alkalosis
C.) Metabolic acidosis
D.) Metabolic alkalosis
E.) Lactic acidosis
A
In amino acids, the pH at which the number of positive charges equals the number of negative charges is termed as:
A.) Chirality
B.) Amphoteric property
C.) Optical activity
D.) Isoelectric point
E.) Zwitterions
D
Molecules that contain an equal number of ionizable groups of opposite charge and that therefore bear no net charge are termed as:
A.) Chirality
B.) Amphoteric property
C.) Optical activity
D.) Isoelectric point
E.) Zwitterions
E
Problems associated with connective tissue and structural proteins are present in a number of diseases. In scurvy, hydroxylation of proline residues is decreased, and an unstable form of collagen is produced. Bones, teeth, blood vessels, and other structures rich in collagen develop abnormally. Bleeding gums and poor wound healing are often observed. Which of the following vitamin deficiencies is associated to scurvy?
A.) Vitamin C
B.) Vitamin E
C.) Vitamin A
D) Vitamin D
E.) Vitamin K
A
Which of the following is true about insulin functions? l. Insulin is released from the pancreas when blood glucose levels are elevated Il Insulin promotes the transport of glucose into muscle and fat cells. Il. Insulin promotes the storage of energy IV. Insulin increases glycogen catabolism in the liver and muscle
A.) I and lI
B.) I, Il and lII
C.) I, II and IV
D.) I only
E) I, II, III and IV
B
The enzyme kinetics can be described by what equation?
A.) Noyes-Whitney Equation
B.) Henderson-Hasselbalch Equation
C.) Arrhenius Equation
D.) Van Slyke Equation
E.) Michaelis-Menten Equation
E
Evaluate the given statements.
(1) Competitive inhibitors compete with the substrate for binding at the allosteric site of the enzyme.
(2) Noncompetitive inhibitors bind to the enzyme or the enzyme-substrate complex at the active site.
A.) Only l is correct
B.) Only Il is correct
C.) I and Il are correct
D.) I and II are incorrect
D
In phenylketonuria, the enzyme phenylalanine hydroxylase is deficient. Which of the following statements is not true about the condition?
A.) Phenylketonuria happens as a result of accumulated phenylalanine in the body
B.) Tyrosine becomes an essential amino among phenylketonuric patients
C.) Aspartame is recommended for phenylketonuric patients
D.) Phenylalanine non-metabolism acid leads to mental retardation
E.) None of these
C
Which of the following is not a basic amino acid?
A.) Histidine
B.) Leucine
C.) Lysine
D.) Arginine
E.) None of these
B
What are the amide linkages between the αcarboxyl group of one amino acid and the α- amino group of another?
A.) Peptide bonds
B.) Disulfide bonds
C.) Hydrogen bonds
D.) Hydrophobic bonds
E.) lonic bonds
A
Edman's reagent is used to label the aminoterminal residue under mildly alkaline conditions. What is the component of this reagent?
A.) Monosodium glutamate
B.) Alpha-naphthol
C.) Picric acid
D.) Phenylisothiocyanate
E.) None of these
D
Several different polypeptide helices are found in nature, but the α-helix is the most common. What bond stabilizes this helix? A.) Hydrogen bond
B.) Peptide bond
C.) Phosphodiester bond
D.) Hydrophobic bond
E.) Ionic bond
A
What protein structures reverse the direction of a polypeptide chain, helping it form a compact, globular shape?
A.) α-helices
B.) ß-sheets
C.) ß-bends
D.) All of these E.) None of these
C
What specialized group of proteins are required for the proper folding of many species of proteins?
A.) Chaperones
B.) Heat shock proteins
C.) Beta bends
D.) A and B
E.) A and C
D
Many proteins consist of a single polypeptide chain, and are defined as monomeric proteins. However, others may consist of two or more polypeptide chains that may be structurally identical or totally unrelated. These statements describe what protein structure?
A.) Primary structure
B.) Secondary structure
C.) Tertiary structure
D.) Quaternary structure
E.) None of these
D
What protein is misfolded in CreutzfeldtJakob disease?
A.) Prion
B.) Glutamine stretches
C.) Beta-globin
D.) Beta-amyloid
E.) None of these
A
What are the the two most abundant hemeproteins in humans?
A.) Hemoglobin and myoglobin
B.) Hemoglobin and cytochrome oxidase
C.) Hemoglobin and catalase
D.) Cytochrome and catalase
E.) Actin and myosin
A
The complex of protoporphyrin IX and ferrous iron is termed as:
A.) Heme
B.) Hemoglobin
C.) Transferrin
D.) Ferritin
E) Myoglobin
A
What is the hemeprotein found in heart and skeletal muscle which functions both as reservoir for oxygen, and as an oxygen carrier that increases the rate of transport of oxygen within the muscle cell?
A.) Hemoglobin
B.) Myoglobin
C.) Actin
D.) Myosin
E.) Keratin
B
This is found exclusively in red blood cells (RBCS), where its main function is to transport oxygen (O2 ) from the lungs to the capillaries of the tissues
A.) Myoglobin
B.) Keratin
C.) Collagen
D.) Hemoglobin
E.) Myosin
D
The major hemoglobin in adults comprising of four polypeptide chains held together by noncovalent interactions
A.) Hemoglobin A
B.) Hemoglobin T
C.) Hemoglobin R
D.) Hemoglobin F
E.) Hemoglobin C
A
These are hereditary hemolytic diseases in which an imbalance occurs in the synthesis of globin chains.
A) Sickle cell anemia
B.) Thalassemia
C.) Microcytic anemia
D.) Iron deficiency anemia
E.) Hyperchromic anemia
B
Oxidation of the heme component of hemoglobin to the ferric ion (Fe) state forms A) Carboxyhemoglobin
B.) Methemo globin
C.) Ferritin
D) Transferrin
E) Porphyrin
B
Collagen and elastin are examples of
A) Fibrous proteins
B.) Globular proteins
C.) Albumins
D.) Metalloproteins
E) Enzymes
A
What is the most abundant protein in the blood?
A) Keratin
B.) Elastin
C.) Collagen
D.) Hemoglobin
E) Myoglobin
C
Fibril-forming collagens, EXCEPT
A.) Type I
B.) Type II
C.) Type llI
D.) Type IV
E.) None of these
D
Which of the following pairs is correct about collagen types?
A.) Type I: Fibril-associated collagen
B.) Type II: Network-forming collagen
C.) Type III: Fibril-forming collagen
D.) Type IV: Fibril-forming collagen
E.) Type X: Network-forming collagen Type ll: Fibril-forming collagen
C
Collagen is rich in __,and __, both of which are important in the formation of the triplestranded helix.
A.) Proline and leucine
B.) Proline and isoleucine
C.) Proline and glycine
D.) Proline and histamine
E.) Proline and tyrosine
C
A heterogeneous group of generalized connective tissue disorders that result from inheritable defects in the metabolism of fibrillar collagen molecules, and can result from adeficiency of collagen-processing enzymes (for example, lysyl hydroxylase or procollagenpeptidase), or from mutations in the amino acid sequences of collagen types I, IIl, or V.
A.) Ehlers-Danios syndrome
B.) Von Gierke's disease
C.) Osteogenesis imperfecta
D.) Huntington's disease
E.) Hurler's syndrome
A
A connective tissue protein with rubber-like properties in tissues such as the lung.
A.) Collagen
B.) Keratin
C.) Elastin
D.) Albumin
E.) Hemoglobin
C
A connective tissue disorder characterized by impaired structural integrity in the skeleton, the eye, and the cardiovascular system
A.) Hurler's disease
B.) Marfan syndrome
C.) Rheumatoid arthritis
D.) Gaucher's disease
E.) Huntington's disease
B
Lactate to pyruvate conversion is possible due to the presence of lactic dehydrogenase. What enzyme category does lactic dehydrogenase belong? A.)Hydrolases
B.) Oxidoreductases
C.) Transferases
D.) Lyases
E.) Isomerases
B
Which the following pairs is incorrect about the intracellular location of biochemical pathways?
A.) Lysosomes macromolecular degradation B.) Nucleus protein synthesis
C.) Cytosol: glycolysis
D.) Mitochondria: fatty acid oxidation
E.) Cytosol: HMP shunt
A
What is the process of recycling proteins into their constituent amino acids, for reuse by the cell?
A.) Protein catabolism
B.) Protein turnover
C.) Protein synthesis
D.) Protein denaturation
E.) Protein degradation
B
A large protein that may contain two or more regions of the polypeptide chain that individually have a compact folded structure is called __.
A) Domains
B.) Chaperones
C.) Residues
D.) Proteasome
E.) None of these
A
The following are true about amino acids, EXCEPT:
A) They may polymerized to form polypeptides
B.) They serve as precursors for other small biomolecules
C.) They may be oxidized to serve as an energy source for the cell
D.) They act as building blocks of fatty acids E.) None of these
D
Of the 20 important amino acids, which is considered optically inactive?
A) Proline
B.) Lysine
C) Arginine
D.) Leucine
E.) Glycine
E
The following amino acids contain sulfur on their structure, EXCEPT
A) Cysteine
B.) Methionine
C) Tyrosine
D.)
A and B
E.) B and C
C
Which of the following amino acids does not contain benzene ring on its structure?
A) Tyrosine
B.) Phenylalanine
C.) Tryptophan
D.) All of these
E.)None of these
E
RNAs with catalytic activity are called
A.) Apoenzymes
B.) Zymogens
C.) Proenzymes
D.) Ribozymes
E.) Holoenzymes
D
The number of molecules of substrate converted to product per enzyme molecule per second
A.) Bloom strength
B.) Turnover number
C.) Saponification number
D.) Conformational change
E.) None of these
B
Which of the following is incorrectly paired? A) Holoenzyme: active enzyme B.) Apoenzyme: inactive enzyme C) Cofactor: inorganic molecule D.) Coenzyme: small organic molecule E.) Prosthetic group: transiently associated with the enzyme
E
Which of the following is false about the kinetic order of enzymes?
A) When the substrate concentration [S] is much lesser than the Km, the rate of reaction is first order.
B.) When [S] is much greater than Km, the velocity is constant and equal to Vmax
C.) When [S] is much less than Km, the the velocity of the reaction is approximately proportional to the substrate concentration D.) When the substrate concentration [S] is greater than the Km, the rate of reaction is zero order
E.) None of these
E
Irreversible inhibitors bind to enzymes through what bond?
A) Covalent bond
B.) lonic bond
C) Hydrogen bond
D.) Hydrophobic bonds
E.) Sigma and pie bonds
A
Which of the following is true about competitive inhibition?
A) The reaction of the substrate and inhibitor is reversible
B.) Substrate binds to active site, inhibitor binds to the allosteric site
C.) Inhibitor is covalently-bonded to the enzyme
D.) The reaction is not surmountable.
E.) None of these
A
This occurs when the inhibitor and substrate bind at different sites on the enzyme
A) Competitive inhibition
B.) Non-competitive inhibition
C.) Functional inhibition
D.)Chemical inhibition
E.) Physiological inhibition
B
Enzymes are often measured in clinical diagnosis. Which of the following is correlated to an elevated alanine aminotransferase?
A.) Brain Tumor
B.) Hepatic damage
C.) Prostate cancer
D.) Colon cancer
E.) Eye injury
B
ADH required NAD+ for catalytic activity, In the reaction catalyzed by ADH, an alcohol is oxidized to an aldehyde as NAD+ is reduced to NADH and dissociates from the enzyme. The NAD+ is functioning as a (an):
A. Apoenzyme
B. Coenzyme-substrate
C. Coenzyme-prosthetic group
D. Cofactor E.
E. Heterotropic effector
E
Which of the following is not true about the digestion of protein?
A. Protein digestion beings in the mouth
B. The digestion of protein may be due gastric acid secretion
C. Pancreatic enzymes aid in the digestion of proteins.
D. Aminopeptidases digest oligopeptides in the small intestine
E. None of these
A
What is the most common generic error of amino acid transport?
A. Phenylketonuria
B. Alkaptonuria
C. Cystinuria
D. Methemoglobinemia
E. Pellagra
C
A disease of malabsorption resulting from immune-mediated damage to the small intestine in response to ingestion of gluten A. Cystic fibrosis
B. Celiac disease
C. Ulcerative colitis
D. Crohn's disease
E. Conn's disease
B
What is the first step in the catabolism of most amino acids?
A. Conjugation
B. Transamination
C. Transpeptidation
D. Hydrolysis
E. Reduction
B
All amino acids participate in transamination at some point in their catabolism, EXCEPT: A. Lysine
B. Threonine
C. Tryptophan
D. A and B
E. A and C
D
What is the only amino acid that undergoes rapid oxidative deamination?
A. Lysine
B. Tyrosine
C. Glutamate
D. Tryptophan
E. Ornithine
C
In the transport of ammonia from the peripheral tissues to the liver, which of the following mechanisms is true?
A. Glutamine is transported in the blood to the liver where it is cleaved by glutaminase to produce glutamate and free ammonia
B. Alanine is transported by the blood to the liver, where it is converted to pyruvate by transamination
C. Transamination of pyruvate to alanine is required to allow transport of alanine to the liver
D. A and B
E. All of these
E
Where is the production and excretion site of urea?
A. Liver for production, kidney for excretion B. Muscle for production, kidney for excretion
C. Liver for production, mammary gland for excretion
D. Liver for both production and excretion
E. None of these
A
What amino acid is the immediate precursor of both ammonia and aspartate nitrogen?
A. Glutamate
B. Aspartate
C. Pyruvate
D. Oxaloacetate
E. Lactate
A
The synthesis of urea is located on which cell site?
A. Mitochondria
B. Cytosol
C. DNA
D. A and B
E. All of these
D
Ammonia is produced by all tissues during the metabolism of a variety of compounds. However, the level of ammonia in the blood must be kept very low, because even slightly elevated concentrations (hyperammonemia) are toxic to what body system?
A. Autonomic nervous system
B. Central nervous system
C. Integumentary system
D. Skeletal system
E. Digestive system
B
The following are potential sources of ammonia, EXCEPT:
A. Glutamine
B. Monoamines
C. Purines
D. Pyrimidines
E. Resorcinol
E
What two-nitrogen containing compounds are incorporated into urea cycle?
A. Alanine and glutamate
B. Glutamine and alanine
C. Aspartate and ammonia
D. Ammonia and aspartate
E. Alanine and arginine
D
Evaluate the two statements: (1) Essential amino acids must be obtained from diet in order for normal protein synthesis to occur.
(2) Essential amino acids are produced from the intermediate metabolite of protein
A. Only 1 is correct
B. Only 2 is correct
C. Both are correct
D. Both are incorrect
A
Amino acids whose catabolism yields either acetoacetate or one of its precursors (acetyl CoA or acetoacetyl CoA) are termed as____. A. Glucogenic amino acids
B. Ketogenic amino acids
C. Metabotropic amino acids
D. Amphoteric amino acids
E. Zwitterionic amino acids
B
Which of the following amino acids does not belong to the group?
A. Tyrosine
B. Isoleucine
C. Phenylalanine
D. Lysine
E. Tryptophan
D
The amino acids leucine, isoleucine and valine are:
A. Branched-chain amino acids
B. Essential amino acids
C. Aromatic amino acids
D. A and B
E. B and C
D
Succinyl CoA, a Kreb's cycle intermediate may be derived from the degradation of the following, EXCEPT:
A. Valine
B. Isoleucine
C.) Threonine
D.) Asparagine
E.) None of these
D
The most common clinically encountered inborn error of amino acid metabolism
A. Tyrosinemia type I
B. Phenylketonuria
C. Albinism
D. Maple syrup urine disease
E. None of these
B
Tyrosine is needed in the synthesis of the following, EXCEPT:
A. Tissue protein
B. Melanin
C. Catecholamines
D. Fumarate
E. Phenylacetate
E
The following are clinical characteristics of classical phenylketonuria:
A. Elevated phenylalanine
B. CNS symptoms
C. Hypopigmentation
D. Blue eyes
E. All of these
E
A disease which is characterized by feeding problems, vomiting, dehydration, severe metabolic acidosis. This condition is due to partial or complete deficiency in branched chain α-keto acid dehydrogenase
A. Phenylketonuria
B. Maple syrup urine disease
C. Pellagra
D. Albinism
E. Hypopigmentation
B
Albinism refers to a group of conditions in which a defect in tyrosine metabolism results in a deficiency in the production of: A. Melatonin
B. Melanin
C. Melanocyte
D. All of these
E. None of these
B
The homocystinurias are a group of disorders involving defects in the metabolism of homocysteine. The most common cause of homocystinuria is a defect in the enzyme cystathionine ß-synthase. Patients can be responsive (or non-responsive) to oral administration of a vitamin coenzyme of cystathionine B-synthase. What vitamin is referred to in this condition?
A) Thiamine
B.) Niacin
C.) Pantothenic acid
D.) Pyridoxine
E) Biotin
E
Which of the following amino acids should be avoided of by patients with alkaptonuria? A) Phenylalanine
B.) Tyrosine
C.) Alanine
D.) A and B
E.) B and C
D
Which of the following pairs (precursor -> product) is incorrect?
A.) Histidine histamine
B.) Tryptophan serotonin
C.) Arginine nitric oxide
D.) Methionine purine/pyrimidine
E.) Tyrosine dopamine
D
Which one of the following statements concerning a 1-week-old male infant with undetected classic phenylketonuria is correct?
A.) Tyrosine is a nonessential amino acid for the infant
B.) High levels of phenyl pyruvate appear in his urine
C.) Therapy must begin within the first year of life
D.) A diet devoid of phenylalanine should be initiated immediately
E.) When the infant reaches adulthood, it is recommended that diet therapy be discontinued
B
The structure of porphyrin is shown below. Which cyclic organic molecule is present on the structure? PHOTO OF PORYPHYRIN CANNOT BE GRABBED FROM THE SOURCE A.) Indole
B.) Pyrrole
C) Quinolone
D.) Pyridine
E.) Piperidine
B
The most prevalent metalloporphyrin in humans is heme. It serves as a prosthetic group for:
A.) Cytochromes
B.) Hemoglobin
C.) Peroxidase
D.) All of these
E.) A and B
D
Inherited (or occasionally acquired) defect in heme synthesis may result to:
A) Porphyria
B.)Phenylketonuria
C.) Methemoglobinemia
D.) Lead poisoning
E.) Albinism
A
What is the approximate number of days of red blood cells to be in the circulation before degradation?
A.) 40 days
B.) 80 days
C.) 120 days
D.) 150 days
E.) 365 days
C
Bilirubin and biliverdin are examples of:
A.) Bile salts
B.) Bile pigments
C) Bile duct
D.) All of these
B
85. Certain anionic drugs, such as salicylates and sulfonamides, can displace bilirubin from albumin, permitting bilirubin to enter the central nervous system. This causes the potential for neural damage in infants known as: A.) Saint Louis Encephalitis
B.) Systemic Lupus Erythematosus
C.) Steven-Johnson's Syndrome
D.) Kernicterus
E.) None of these
D
Van den Bergh reaction determines the concentration of:
A.) Protein
B.) Bilirubin
C.) Heme
D) Glucose
E.)Cholesterol
B
The following are Catecholamines, EXCEPT: A.) Epinephrine
B.)Norepinephrine
C.) Acetylcholine
D.) Dopamine
E.)None of these
C
What organic polymer protects underlying cells from the harmful effects of sunlight? A.) Melanin
B.) Keratin
C.) Collagen
D.) Catecholamine
E.) Heme
A
The 4D symptoms of pellagra include: diarrhea, dermatitis, dementia and death. This is due to the deficiency of:
A) Niacin
B.) Tyrosine
C.) Tryptophan
D.) A and C
E.) A and B
D
Tryptophan:
i. One-letter representation is"T,
i. Non-polar molecule ii. Deficiency of
which can cause Hartnup disease
iv. The structure contains phenol side chain
A) I & Il are correct
B.) I, Il and III are correct
C.) II and III are correct
D.) I, II and V are correct
E.) I, ll, III and Ⅳ are incorrect
C
What is the isoelectric point (pl) of arginine? A) 7.87
B) 5.55
C) 10.75
D) 7.3
E) 11.8
C
Estimate the isoelectric point of the structure (reaction mechanism) given THE PICTURE OF THE REACTION CANNOT BE GRABBED FROM THE SOURCE
A) 2
B.) 9
C.) 6
D.) 5
E.) 7
C
Which of the following secondary derived proteins have the highest molecular weight characteristics?
A.) Proteoses
B.) Peptones
C.) Peptides
D.) A and B
E.) B and C
A
Tyrosine can be detected by:
A.) Xanthoproteic test
B.) Millon's test
C.) Sakaguchi test
D.) A, B and C
E.) A and B
E
Hopkin's Cole reaction gives positive result in:
A.) Gelatin
B.) Collagen
C.) Tryptophan
D.) A and B
E.) B and C
C
Which of the following is an essential amino acid in man?
A.) Tyrosine
B.) Proline
C.)Aspartate
D.) Threonine
E.) Serine
D
Which of the following amino acids is NOT basic?
A.) Lysine
B.) Arginine
C.) Ornithine
D.) Glutamine
E.) Histidine
D
Which of the following bonds is not affected by denaturation due to its high stability?
A.) Disulfide bond
B.) Peptide bond
C.) Hydrogen bond
D.) lonic bond
E.) None of these
B
Arginine and histidine are:
A.) Essential amino acids
B.) Non-essential amino acids
C.) Semi-essential amino acids
D.) Acidic amino acids
E.) Aromatic amino acids
C
A tripeptide involved in cellular oxidationreduction, and is required for maintaining the integrity of RBC and lens of eyes.
A.) Glutathione
B.) Vasopressin
C.) Encephalin
D.) Oxytocin
E.) Retinol
A
Note 
Flashcards (79)