PROTEINS Flashcards
Most abundant and functionally diverse molecules in living systems:
A. Carbohydrates
B. Proteins
C. Lipids
D. Nucleic acids
E. None of these
B. Proteins
It is considered as the building blocks of proteins:
A. Purines and pyrimidines
B. Monosaccharides
C. Amino acids
D. Nucleotides
E. Fatty acids and glycerol
C. Amino acids
The following describes peptide bond, except:
A. Has a partial double bond characteristics
B. – C(=O)NH–
C. undergoes hydrolytic reaction
D. Formed by the –COOH of an amino acid and the –NH2 of the next amino acid
C. undergoes hydrolytic reaction
Which of the following statements about amino acids is correct?
A. Acidic amino acids bear a positive charge at pH = 7.0
B. All amino acids have a chiral carbon
C. Lysine and arginine are basic amino acids
D. All of these
C. Lysine and arginine are basic amino acids
Which of the following amino acids contains basic side chain?
A. Histidine
B. Arginine
C. Leucine
D. All of these
E. Both A and B
E. Both A and B
Which of the following amino acids do not contain an alipathic side chain?
A. Glycine
B. Valine
C. Proline
D. Leucine
E. Alanine
C. Proline
Which amino acid is a major neurotransmitter in the brain?
A. Tyrosine
B. Glutamate
C. Aspartate
D. Serine
E. Tryptophan
B. Glutamate
All of the following amino acid contains –OH group except?
A. Histidine
B. Serine
C. Threonine
D. Tyrosine
A. Histidine
Which of the following is a sulfur-containing amino acid?
A. Aspartatic acid
B. Asparagine
C. Methionine
D. Glutamic acid
E. Glutamine
C. Methionine
Which of the following is an example of basic amino acid?
A. Proline
B. Histidine
C. Tryptophan
D. Phenylalanine
E. Tyrosine
B. Histidine
All listed below are aromatic amino acid, except:
A. Histidine
B. Proline
C. Tryptophan
D. Tyrosine
E. Phenylalanine
B. Proline
Which of the following has a ketogenic metabolic fate?
A. Leucine
B. Tyrosine
C. Glycine
D. Isoleucine
E. Phenylalanine
A. Leucine
Which of the following amino acids contain(s) side chains with sulfur atom?
A. Methionine
B. Cysteine
C. Cytosine
D. Both A and B
E. Both A and C
D. Both A and B
Which of the following amino acid has an imino group?
A. Proline
B. Valine
C. Leucine
D. Isoleucine
E. Tyrosine
A. Proline
Which of the following amino acid possess a phenolic hydroxyl group?
A. Serine
B. Threonine
C. Tyrosine
D. Both A and B
E. All of these
C. Tyrosine
Serotonin, a neurotransmitter is derived from the amino acid ____:
A. Tryptophan
B. Threonine
C. Tyrosine
D. Phenylalanine
A. Tryptophan
Identification test for the presence of alpha amino acid and free amino groups?
A. Millon’s Test
B. Xathoproteic Test
C. Hopkin’s Cole Test
D. Ninhydrin Test
E. Molisch Test
D. Ninhydrin Test
Identification test for the presence of sulfur such as in cysteine and methionine?
A. Pauly diazo Test
B. Basic Lead Test
C. Hopkin’s Cole Test
D. Biuret Test
E. Salkowski’s Test
B. Basic Lead Test
The pH midway between the pKa values in either side of isoelectric species where amino acids exists as neutral species is called as ________.
A. pH determination
B. Henderson-Hasselbach equation
C. Isoelectric point
D. Buffer capacity of amino acids
C. Isoelectric point
Calculate the pI of alanine, pK1 (R-COOH) = 2.35; pK2 (R-NH3+) = 9.69
6.02
________ are molecules that contain an equal number of ionizable groups of opposite charges and therefore bear a zero net charge.
A. Isoelectric point
B. Amphotheric
C. Neutral amino acid
D. Zwitterions
E. Hydrophobic amino acid
D. Zwitterions
Which of the following pairs of amino acid with the indicated side chain is correctly matched?
I. Tryptophan – indole
II. Tyrosine – phenol
III. Arginine – guanidine
A. I, II and III
B. II and III only
C. I and III only
D. I and II only
A. I, II and III
The R group of the amino acid “D” is?
A. Hydroxyethyl
B. Hydroxymethyl
C. Carboxyethyl
D. Carboxymethyl
E. Methyl
D. Carboxymethyl
Sanger’s Reaction is also known as ____________.
A. Edman’s Test
B. Enzymatic cleavage
C. Dideoxychain termination
D. Splicing
C. Dideoxychain termination
This structure of peptides refers to the order of amino acids in the polypeptide chain/s and the location of disufide bonds:
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
A. Primary
The overall spatial arrangement of amino acid residues close to one another in the linear sequence of a polypeptide chain:
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
D. Quaternary
Secondary Structure includes:
A. Loops
B. Turns
C. Bends
D. B and C only
E. All of these
E. All of these
The overall arrangement and interrelationship of various regions or domains, and individual amino acid residues of a single polypeptide chain is ____ structure.
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
C. Tertiary
It can prevent the misfolding of nascent polypeptide chain:
A. Proteasome
B. Chaperone
C. Histone
D. Enzymes
E. Hormones
B. Chaperone
Non – protein molecules that are often associated with proteins are called:
A. Prosthetic group
B. Side chain
C. Zwitterions
D. Casein
A. Prosthetic group
Protein denaturation:
A. Usually irrreversible
B. Unfolding and disorganization of the protein structure
C. Often insoluble (in the form of precipitate)
D. Caused by heat, strong acids & strong base
E. All of these
E. All of these
Denaturation of protein is a result of:
A. Cleavage of the peptide bond
B. Formation of hydrogen bond
C. Breakage of hydrogen bond
D. Formation of phosphodiester bond
C. Breakage of hydrogen bond
An important protein in contractile muscle:
A. Keratin
B. Myosin
C. Elastin
D. Fibrin
E. Collagen
B. Myosin
Alzheimer’s Disease:
A. Genetic defects that impair the synthesis of one polypeptide sub-units of hemoglobin (beta sheet)
B. Glutamic acid is replaced by a valine in the amino acid sequence
C. Misfolding of b - amyloid in human brain tissue
C. Misfolding of b - amyloid in human brain tissue
In collagen formation, the amino acids proline and lysine need further modification. What modification is done to these amino acids?
A. Acetylation
B. Methylation
C. Epoxidation
D. Hydroxylation
E. Sulfation
D. Hydroxylation
It can stabilize the triple helix structure of collagen
A. Methionine
B. Valine
C. Hydroxyproline
D. Isoleucine
E. Glycine
C. Hydroxyproline
Collagen Disease includes the following, except:
A. Ehler’s Danlos Syndrome
B. Menke’s Disease
C. Emphysema
D. Osteogenesis imperfecta
E. Scurvy
C. Emphysema
Fibrous proteins are elongated, water – soluble, generally in either alpha-helical, pleated sheet or triple helical forms. Which listed below is an example of fibrous proteins?
A. Hemoglobin
B. Actin
C. Myosin
D. Elastin
E. Both A and B
D. Elastin
Major hemoglobin present on adult?
A. a2b2
B. a2g2
C. a2S2
D. a2d2
E. None of these
A. a2b2
The product obtained from partial hydrolysis of collagen:
A. Myosin
B. Gelatin
C. Actin
D. Fibrinogen
E. Thrombin
B. Gelatin
Which of the following is incorrect about carbon monoxide?
A. Irreversible
B. Fatal
C. Binds tightly with Hb (HbCO)
D. Carbon monoxide poising can be treated with oxygen
A. Irreversible
2, 3-bisphosphoglycerate:
A. Also known as 2, 3-diphosphoglycerate
B. Most abundant organic phosphate in the red blood cells
C. Favors/stabilizes the T form
D. Increase concentration is seen on emphysema, high altitudes
E. All of these
E. All of these
Xanthoproteic test is a test for:
A. Free amino groups
B. Cysteine
C. Arginine
D. Tyrosine
E. Methionine
D. Tyrosine
The ordered steps in protein synthesis is:
I. Activation
II. Elongation
III. Initiation
IV. Termination
A. I – II – III – IV
B. III – II – I – IV
C. I – III – II – IV
D. II – III – I – IV
C. I – III – II – IV
Which of the following vitamins is present in coenzymes required in the transfer of amino groups and decarboxylation of amino acids? Its deficiency state is manifested by glossitis, peripheral neuropathy and niacin deficiency:
A. Pyridoxine
B. Niacin
C. Thiamine
D. Riboflavin
C. Thiamine
Dialysis is a method of separating proteins on the basis of:
A. Size
B. Solubility
C. Charge
D. Albumin
A. Size
The proteins that make fur, wool, claws and feathers:
A. Collagen
B. Silk
C. Keratin
D. Elastin
E. Sulfur
C. Keratin
The ribosomal subunit that binds with the initiation complex is ____.
A. 30s
B. 50s
C. 70s
D. 80s
E. 100s
A. 30s
Deficiency of this substance favors elastin degradation, thus leads to destruction of the alveolar walls of the lungs resulting to emphysema:
A. a- keratin
B. desmosine crosslink
C. a-1 antitrypsin
D. ascorbate
C. a-1 antitrypsin
Which of the following is present on all connective tissues?
A. Mucoids
B. Lipids
C. Albuminoids
D. All
E. None
A. Mucoids
Death due to cyanide poisoning results from:
A. Cyanide – hemoglobin complex formation
B. Cyanide – combining with RBC
C. Cyanide – inhibiting cytochrome oxidase
D. Coronary vessel occlusion
C. Cyanide – inhibiting cytochrome oxidase
When oxygen binds to hemoglobin, which of the following does it displace in the normal individual?
A. CO
B. CO2
C. CH3
D. Fe+2
E. Fe+3
B. CO2
Which of the following symptoms is most closely related to methemoglobinemia?
A. Cyanosis
B. Myopathy
C. Raynaud’s Syndrome
D. Chest pains
E. Both A and B
A. Cyanosis
Denaturation usually destroys all of the following bonds in protein, except:
A. Hydrogen bonds
B. Covalent bonds
C. Hydrophobic bonds
D. Electrostatic bonds
B. Covalent bonds
The amino acid that contributes to the tertiary structure of a protein by causing a bend when it occurs in the primary sequence is:
A. Leucine
B. Alanine
C. Proline
D. Tyrosine
E. Aspartic acid
C. Proline
A mucin is which of the following types of proteins?
A. Simple protein
B. Phosphoprotein
C. Chromoprotein.
D. Nucleoprotein.
E. Glycoprotein
E. Glycoprotein
Streptomycin is an antibiotic which inhibits the process of:
A. Translation in eukaryotes
B. Translation in prokaryotes
C. DNA replication in prokaryotes
D. Transcription in eukaryote
E. Transcription in prokaryotes
B. Translation in prokaryotes
Each of the following represents an amino acid found in proteins and used directly in the reactions of protein synthesis, except:
A. Proline
B. Arginine
C. Tryptophan
D. Asparagine
E. Hydroxylysine
E. Hydroxylysine
Most ________ amino acids are buried away from the water solvent that interacts with the surface of a soluble protein while most ____ side-chains are on the surface of soluble globular proteins:
A. Charged – Hydrophobic
B. Hydrophobic – Charged
C. Hydrophobic – Polar
D. Charged – Polar
C. Hydrophobic – Polar
Which amino acid is antagonized by drugs of abuse such as ketamine and phencyclidine and is implicated in schizophrenia:
A. Glycine
B. Aspartate
C. Tryptophan
D. Glutamate
E. Tyrosine
D. Glutamate