BIOCHEMISTRY Flashcards
What biomolecules are considered the most abundant and functionally diverse in the living system?
A. Proteins
B. Carbohydrates
C. Nucleic acid
D. Fatty acid
E. Terpenoids
Proteins
Which of the following statements is correct about protein structure?
I. The primary structure of a protein involves alpha-helics, beta-sheets and other types of folding patterns that occur due to a regular repeating pattern of hydrogen bond formation.
II. The secondary structure consist of the amino acids sequence along the chain.
III. The tertiary structure involves electrostatic and hydrophobic interactions, van der waals interaction, 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 force that stabilize the tertiary structure.
A. I only
B. I and II
C. II and III
D. I and IV
E. III and IV
III and IV
Accumulated misfolded proteins occur in variety of disease. 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
Glutamine stretches
Hemoglobinopathies result from mutations that produce alterations in the structure of hemoglobin. One common mutation result is 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 number 6
D. Gene transcription is disrupted
E. None of these
Glutamic acid is being substituted by valine at position number 6
Acid-base disturbances occur under a variety of conditions. Which of the following is the result of hyperventilation due to retention of carbon dioxide in the lungs.
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis
E. Lactic acidosis
Respiratory acidosis
- 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
Isoelectric point
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
Zwitterions
Problems associated with connective tissues and structural protein are present in a number of disease. In scurvy, hydroxylation of proline residues is decrease 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
Vitamin C
Which of the following is true about insulin functions
I. Insulin is release form the pancreas when blood glucose levels are elevated
II. Insulin promotes the transport of glucose into muscle and fat cells
III. Insulin promotes the storage of energy
IV. Insulin increases glycogen catabolism in the liver and muscles
A. I and II
B. I, II and III
C. I, II and IV
D. I only
E. I, II, III, and IV
I, II and III
The enzyme kinetics can be described by what equation?
A. Noyes-Whitney Equations
B. Henderson- Hasselbach Equation
C. Arrhenius Equation
D. Van Slyke Equation
E. Michaelis-Menten Equation
Michaelis-Menten Equation
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 I is correct
B. Only II is correct
C. I and II are correct
D. I and II are incorrect
I and II are incorrect
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 a essential amino acid among phenylketonuric patients
C. Aspartame is recommended for phenylkotenuric patients
D. Phenylalanine non metabolism leads to mental retardation.
E. None of these
Aspartame is recommended for phenylkotenuric patients
Which of the following is not a basic amino acid?
A. Histidine
B. Leucine
C. Lysine
D. Arginine
E. None of these
Leucine
What are the amide linkages between the alpha-carbonyl group of one amino acid and alpha amino group of another?
A. Peptide bonds
B. Disulfide bonds
C. Hydrogen bonds
D. Hydrophobic bonds
E. Ionic bonds
Peptide bonds
Edman’s reagent is used to label the amino terminal 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
Phenylisothiocyanate
Several different polypeptide helices are found in nature, but the alpha-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
Hydrogen bond
What protein structures reverse the direction of a polypeptide chain, helping it form a compact, globular shape?
A. alpha-helices
B. beta-sheets
C. Beta-bends
D. All of these
E. Ionic bond
alpha-helices
What specialized group are required for the proper folding of many species of proteins?
A. Chaperones
B. Heat shockproteins
C. Beta bends
D. A and B
E. A and C
Chaperones
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
Quaternary structure
What protein is misfolded in Creutzfeldt-Jakob disease?
A. Prion
B. Glutamine stretches
C. Beta-globin
D. Beta-amyloid
E. None of these
Prion
What are 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. All of these
Hemoglobin and myoglobin
The complex of protoporphyrin IX and ferrous iron is termed as ___?
A. Heme
B. Hemoglobin
C. Transferrin
D. Ferritin
E. Myoglobin
Heme
What is the hemeprotein found in heart and skeletal muscles which functions both as a 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
Myoglobin
This is found exclusively in red blood cells (RBCs) where its main function is to transport oxygen (O2) from the lungs to the capiliaries of the tissues.
A. Myoglobin
B. Keratin
C. Collagen
D. Hemoglobin
E. Myosin
Hemoglobin
The major hemoglobin in adults compromising of four polypeptide chains held together by noncovalent interaction.
A. Hemoglobin A
B. Hemoglobin T
C. Hemoglobin R
D. Hemoglobin F
E. Hemoglobin C
Hemoglobin A
These are hereditary hemolytic disease 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
Thalassemia
Oxidation of the heme component of hemoglobin to the ferric ion (fe3+) state forms:
A. Carboxyhemoglobin
B. Methemoglobin
C. Ferritin
D. Transferrin
E. Porphyrin
Methemoglobin
Collagen and elastin are examples of:
A. Fibrous proteins
B. Globular proteins
C. Albumins
D. Metalloproteins
E. Enzymes
Fibrous proteins
What is the most abundant protein in the human body?
A. Keratin
B. Elastin
C. Collagen
D. Hemoglobin
E. Myoglobin
Collagen
Fibril forming collagen, EXCEPT:
A. Type I
B. TYPE II
C. Type III
D. Type IV
E. None of these
Type IV
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 IX: Network forming collagen
Type III: Fibril-forming collagen
Collagen is rich in ___ and ___, both of which are important in the formation of the triple-stranded helix.
A. Proline and leucine
B. Proline and isoleucine
C. Proline and glycine
D.Proline and histamine
E. Proline and tyrosine
Proline and glycine
A heterogenous group of generalized connective tissues disorders that result from inheritable defects in the metabolism of fibrillar collagen molecules, and can result from a deficiency of collagen processing enzymes (for example, lysyl hydroxylase or or procollagen peptidase), or from mutations in the amino acids sequences of collagen types I, III or V.
A. Ehlers-Danlos syndrome
B. Von Gierke’s syndrome
C. Osteogenesis imperfect
D. Huntington’s disease
E. Hurler’s syndrome
Ehlers-Danlos syndrome
A connective tissue protein with rubber like properties in tissues such as the lung.
A. Collagen
B. Keratin
C. Elastin
D. Albumin
E. Hemoglobin
Elastin
A connective tissue disorder that characterize 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
Marfan syndrome
Lactate pyruvate conversion is possible due to the presence of lactic dehydrogenase. What enzyme category does lactic dehydrogenase belong?
A. Hydrolase
B. Oxidoreductase
C. Transferases
D. Lyases
E. Isomerases
Oxidoreductase
Which of the following pairs is incorrect about the intacellular location of the biochemical pathways?
A. Lysosome: Macromolecular degradation
B. Nucleus: Protein synthesis
C. Cytosol: Glycolysis
D. Mitochondria: Fatty acid oxidation
E. Cytosol: HMG shunt
Nucleus: Protein synthesis
What is the process of recycling protein into their constituent amino acid, for reuse by the cell?
A. Protein catabolism
B. Protein turnover
C. Protein synthesis
D. Protein denaturation
E. Protein degradation
Protein turnover
A large protein that may contain two or more regions of the polypeptide chain that individual individually have a compact folded structure is called ______.
A. Domains
B. Chaperones
C. Residues
D. Proteasome
E. None of these
Domains
The following are true about amino acid, 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
They act as building blocks of fatty acids
Of the 20 important amino acids, which is considered optically active?
A. Proline
B. Lysine
C. Arginine
D. Leucine
E. Glycine
Glycine
The following amino acids contain sulfur on their structure, EXCEPT:
A. Cysteine
B. Methionine
C. Tyrosine
D. Leucine
E. Glycine
Tyrosine
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
None of these
RNAs with catalytic activity are called
A. Apoenzymes
B. Zymogens
C. Proenzymes
D. Ribozymes
E. Holoenzymes
Ribozymes
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
Turnover number
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
Prosthetic group: transiently associated with the enzyme
Which of the following is false about the kinetic order of enzyme?
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 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
None of these
Irreversible inhibitors bind to enzymes through what bond?
A. Covalent bond
B. Ionic bond
C. Hydrogen bond
D. Hydrophobic bond
E. Sigma and pie bonds
Covalent bond
Which of the following is true about competitive inhibitions?
A. The reaction of the substrate and inhibitor is irreversible
B. Substrate binds to active site, inhibitor binds to allosteric site
C. Inhibitor is covalently bonded to the enzyme
D. The reaction is not surmountable
E.None of these
The reaction of the substrate and inhibitor is irreversible
This occurs when inhibitor and substrate bind at different site on the enzyme.
A. Competitive inhibition
B. Non-competitive inhibition
C. Functional inhibition
D. Chemical inihibition
E. Physiological inhibition
Non-competitive inhibition
Enzyme are often measured in clinical diagnosis. Which of the following is correlatable to an elevated alanine aminotransferase?
A. Brain tumor
B. Hepatic damage
C. Prostate cancer
D. Colon cancer
E. Eye injury
Hepatic damage
ADH requires NAD+ for catalytic activity. In the reaction catalyzed by ADH, an alcohol is oxidized to an aldehyde as NAD+ is reduced and dissociates from the enzyme. The NAD+ is functioning as a (an):
A. Apoenzyme
B. Coenzyme-cosubstrate
C. coenzyme-prosthetic group
D. cofactor
E. Eye injury
Coenzyme-cosubstrate
Which of the following is not true about the digestion of protein?
A. Protein digestion begins in the mouth
B. The digestion of protein may be due gastric acid secretion
C. Pancreatic enzyme aid in the digestion of protein
D. Aminopeptidases digest oligopeptides in the small intestine
E. None of these
Protein digestion begins in the mouth
What is most common genetic error of amino acid transport?
A. Phenylketonuria
B. Alkaptonuria
C. Cystinuria
D. Methemoglobinemia
E. Pellagra
Cystinuria
A disease of malabsorption resulting from immune-mediated damage to the small intestine in the response to ingestion of gluten
A. Cystic fibrosis
B. Celiac disease
C. Ulcerative disease
D. Crohn’s disease
E. Conn’s disease
Celiac disease
What is the first step of metabolic catabolism?
A. Conjugation
B. Transamination
C. Transpetidation
D. Hydrolysis
E. Reduction
Transamination
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
A and B
What is the only amino acid that undergoes rapid oxidative deamination?
A. Lysine
B. Tyrosine
C. Glutamate
D. Tryptophan
E. Ornithine
Glutamate
In the transport of ammonia from the peripheral tissues to the liver, which of the following, mechanism 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
All of these
Where is the production and excretion site?
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
Liver for production, kidney for excretion
What amino acid is the immediate precursor of both ammonia and aspartate nitrogen?
A. Glutamate
B. Aspartate
C. Pyruvate
D. Oxaloacetate
E. Lactate
Glutamate
The synthesis of urea is located on which cell site?
A. Mitochondria
B. Cytosol
C. DNA
D. A and B
C. All of these
A and B
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 really low, because even slightly elevated concentrations (Hypoammonemia) are toxic to what part of the body system?
A. Autonomic nervous system
B. Central nervous system
C. Integumentary system
D. Skeletal system
E. Digestive system
Central nervous system
The following are potential sources of ammonia, EXCEPT
A. Glutamine
B. Monoamines
C. Purines
D. Pyrimidines
E. Resorcinol
Resorcinol
What two nitrogen-containing compounds are incorporated in the urea cycle?
A. Alanine and glutamate
B. Glutamine and alanine
C. Aspartate and ammonia
D. Ammonia and aspartate
E. Alanine and arginine
Ammonia and aspartate
Evaluate the two statements.
(1) Essential amino acids must be obtained from diet in order for normal protei synthesis to occur
(2) Essential amino acids are produced from the intermediates of metabolism of protein.
A. Only 1 is correct
B. Only 2 is correct
C. Both are correct
D. Both are incorrect
Only 1 is correct
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 compounds
D. Amphoteric amino acids
E. Zwitterionic amino acids
Ketogenic amino acids
Which of the following amino acids doesn’t belong to the group?
A. Tyrosine
B. Isoleucine
C. Phenylalanine
D. Lysine
E. Tryptophan
Lysine
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. C and D
A and B
Succinyl CoA, A Kreb’s cycle intermediate may be derived from the degradation of the following, EXCEPT
A. Valine
B. Isoleucine
C. Theonine
D. Aspargine
E. None of these
Aspargine
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. Pellagra
Phenylketonuria
Tyrosine is needed in the synthesis of the following, EXCEPT:
A. Tissue protein
B. Melanin
C. Catecholamines
D. Fumarate
E. Phenylacetate
Phenylacetate
The following are clinical characteristics of classical phenylketonuria:
A. Elevated phenylalanine
B. CNS symptoms
C. Hypopigmentation
D. Blue eyes
E. All of these
All of these
A disease which is characteristic by feeding problems, vomiting, dehydration, severe metabolic acidosis. This condition is due to partial or complete deficiency in the branched-chain alpha-keto acid dehydrogenase.
A. Phenylketonuria
B. Maple syrup urine disease
C. Pellagra
D. Albinism
E. Hypopigmentation
Maple syrup urine disease
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
Melanin
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 beta-synthase. Patients can be responsive (or nonresponsive) to oral administration of vitamin coenzyme of crystathionine beta-synthase. What vitamin is referred to in this condition?
A. Thiamine
B. Niacin
C. Pantothenic acid
D. Pyridoxine
E. Biotin
Pyridoxine
Which of the following amino acid should be avoided of by patients with alkaptonuria?
A. Phenylalanine
B. Tyrosine
C. Alanine
D. A and B
E. B and C
A and B
Which of the following pairs (precursor 🡪 product) is incorrect?
A. Histidine -> histamine
B. Trytophan -> serotonin
C.Arginine -> nitric oxide
D. Methionine -> purine/pyrimidine
E. Tyrosine -> dopamine
Methionine -> purine/pyrimidine
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 phenylpyruvate 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
High levels of phenylpyruvate appear in his urine
The structure of porphyrin is shown below. Which cyclic organic molecule is present on the structure?
A. Indole
B. Pyrrole
C. Quinolone
D. Pyridine
E. Piperidine
Pyrrole
The most prevalent metalloporphyrin in humans is heme. It serves as a prosthetic group for:
A. Cytochrome
B. Hemoglobin
C. Peroxidase
D. All of these
E. A and B
All of these
Inherited (or occasionally acquired) defect is heme synthesis may result to:
A. Porphyria
B. Phenylketonuria
C.Methemoglobinemia
D. Lead poisoning
E.Albinism
Porphyria
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
120 days
Bilirubin and biliverdin are examples of:
A. Bile salts
B. Bile pigments
C. Bile duct
D. All of these
E. None of these
Bile pigments
Certain anionic drugs, such as salicylates and sulfonamides, can displace bilirubin from albumin, permitting bilirubin to enter the central nervous system. This cause 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. All of these
Kernicterus
Van de Bergh reaction determines the concentration of:
A.Protein
B. Bilirubin
C. Heme
D. Glucose
E. Cholesterol
Bilirubin
The following are catecholamines, EXCEPT:
A. Epinephrine
B. Norepinephrine
C. Acetylcholine
D. Dopamine
E. None of these
Acetylcholine
What organic polymer protects underlying cell from the harmful effects of sunlight?
A. Melanin
B. Keratin
C. Collagen
D. Catecholamines
E. Heme
Melanin
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
A and C
Tryptophan
i.One-letter representation is “T”
ii. Non polar molecule
iii. Deficiency of which can cause Hartup disease
iv. The structure contains phenol side chain
A. I & II are correct
B. I, II, and III are correct
C. II and III are correct
D. I, II, III and IV are correct
E.I, II, III and IV incorrect
II and III are correct
What is the isoelectric point (pl) of arginine?
A. 7.87
B. 5.55
C. 10.75
D. 7.3
E. 11.8
10.75
Estimate the isoelectric point of the structure (reaction mechanism) given below.
A. 2
B. 9
C. 6
D. 5
E. 7
6
Which of the following secondary derived proteins have highest molecular weight characteristic?
A. Proteoses
B. Peptones
C. Peptides
D.A and B
E. B and C
Proteoses
Tyrosine can be detected by:
A Xanthoproteic test
B. Millon’s test
C. Sakaguchi test
D. A, B and C
E. A and B
A and B
Hopkin’s cole reaction gives positive result in:
A. Gelatin
B. Collagen
C. Tryptophan
D. A and B
E. B and C
Tryptophan
Which of the following is an essential amino acid in man?
A. Tyrosine
B. Proline
C. Aspartate
D. Threonine
E. Serine
Threonine
Which of the following amino acids is NOT basic?
A. Lysine
B. Arginine
C. Ornithine
D. Glutamine
E. Histidine
Glutamine
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. Ionic bond
E. None of these
Peptide bond
Arginine and histidine are:
A. Essential amino acid
B. Non essential amino acid
C. Semi-essential amino acid
D. Acidic amino acid
E. Aromatic amino acid
Semi-essential amino acid
A tripeptide involved in cellular oxidation-reduction, and is required for maintaining the integrity of RBC and lens of eyes.
A. Glutathione
B. Vasopressin
C. Encephalin
D. Oxytocin
E. Retinol
Glutathione
Which of the following is true about the central dogma of molecular biology?
A. Genetic information found in DNA is copied and transmitted to daughter cells through DNA replication.
B. Transcription is involved in RNA synthesis
C. The code contained in the nucleotide sequence of messenger RNA molecules is translated to complete gene expression.
D. All of these
E. A and B
All of these
Which of the following not true about DNA structure?
A. Phosphodiester bonds stabilize the DNA structure
B. In the double helix, the chains are paired in a parallel manner
C. Uracil is always paired with a thymine and a cytosine is always paired with a guanine
D. A and B
E. B and C
B and C
A rule which states that “in any sample of DNA, the amount of adenine equals the amount of thymine, the amount of guanine equals the amount of cytosine, and the total amount of purines equals the total amount of pyrimidines.”
A. Zaitsev’s rule
B. Hund’s rule
C. VSEPR rule
D. Chargaff’s rule
E. Markovnikov’s rule
Chargaff’s rule
Which of the following structural forms of DNA is right handed?
A. B-DNA
B. Z-DNA
C. A-DNA
D. A and B
E. A and C
A and C
Most species of bacteria also contain small, circular, extrachromosomal DNA molecules called plasmids, which may carry genes that convey
A. Antibiotic resistance
B. Antibaterial effect
C. Mutagenic effect
D Antigenicity
E. Transcription
Antibiotic resistance
When the two strands of the DNA double helix is separated, each can serve as a template for the replication of a new complementary strand. This produces two daughter molecules, each of which contains two DNA strands with an antiparallel orientation. This describes:
A. Conservative replication
B. Semiconservative replication
C. Dispersive replication
D. Antigenicity
E. Transcription
Semiconservative replication
Human topoisomerase II is targeted by:
A. Etoposide
B. Ciprofloxacin
C. Penicillin
D. Vancomycin
E. Chloramphenicol
Etoposide
The strand that is being copied in the direction away from the replication fork, and is synthesize discountinuously, with small fragments of DNA being copied near the replication fork.
A. Leading strand
B. Lagging strand
C. RNA primer
D. Single strand
E. Double strand
Lagging strand
Which of the following rRNA size particles is not present in prokaryotes?
A. 23S
B. 15S
C. 5S
D. 40S
E. 50S
40s
Which nitrogenous base is not present in RNA structure?
A. Cytosine
B. Uracil
C. Thymine
D. Adenine
E. Guanine
Thymine
Ribonucletotide contains:
A. Ribose
B. Nitrogenous base
C. Phosphate
D. All of these
E. None of these
All of these
Which of the consequence of point mutation is expected to happen in the codon transition of UCA to UCU? Use the genetic code table below for your reference.
A. Silent mutation
B. Missense mutation
C. Nonsense mutation
D. Spontaneous mutation
E. Frameshift mutation
Silent mutation
A hereditary disease that primarily affects the pulmonary and digestive systems, most commonly caused by deletion of three nucleotides from the coding region of a gene, resulting in the loss of phenylalanine at the 508th position in the protein encoded by that gene.
A. Cystic fibrosis
B. Crohn’s disease
C. H.pylori infection
D. Ulcerative colitis
E. Chronic obstructive pulmonary disease
Cystic fibrosis
This states that the first (5’) base of the anticodon is not as spatially defined as the other two bases. Movement of that first base allows nontraditional base-pairing with the last (3’) base of the codon, thus allowing a single tRNA to recognize more than one codon for a specific amino acid
A. Chargaff’s rule
B. Wobble hypothesis
C. Shine-Dalgamo sequence
D. Semiconservative
E. Chronic obstructive pulmonary disease
Wobble hypothesis
Many antimicrobials inhibits protein translation. Which of the following antimicrobials is correctly paired with is mechanism of action?
A. Tetracyclines – inhibits peptidyltransferase
B. Diphtheria toxin – binds to the 30S subunits
C. Puromycin – inactivates EF-2
D. Erythromycin – binds with 50S ribosomal subunits
E. Clindamycin – binds to the 30S ribosomal subunits
Erythromycin – binds with 50S ribosomal subunits
The movement of the uncharged tRNA from the P to the E site (before being released), and movement of the peptidyl tRNA from the A to the P site is termed as:
A. Transcription
B. Translation
C. Translocation
D. Transformation
E. Transferrin
Translocation
In DNA double helix, which of the following is not true?
A. Guanine base pairs with cytosine
B. Adenine on one chain forms a base pair with uracil on the other chain
C. The chains are antiparallel
D. Each DNA molecule is composed of two polynucleotide chain joined by hydrogen bonds between bases
E. The double-stranded molecule is twisted to form a helix with major and minor grooves
Adenine on one chain forms a base pair with uracil on the other chain
Which of the following statements regarding DNA denaturation is incorrect?
A. Alkali can cause DNA breakage
B. Heat can cause DNA separation
C. Heat and alkali can break phosphodiester bonds
D. A and B
E. All of these
Heat and alkali can break phosphodiester bonds
In DNA replication, what enzyme acts to prevent the extreme supercoiling of the parental helix that would result as consequence of unwinding at a replication fork?
A. Topoisomerase
B. RNA polymerase
C. Helicases
D. Isomerases
E. Proteolytic enzymes
Topoisomerase
