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Class 12 Chemistry Chapter 14 Biomolecules MCQs | Class 12 Chemistry Chapter 14 Biomolecules Objective Type Questions and Answers

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Free download in PDF Class 12 Chemistry Chapter 14 Biomolecules Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries./p>

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(1) Platelet aggregation:
[A] is initiated at the site of an injury by conversion of fibrinogen to fibrin
[B] is inhibited in uninjured blood vessels by the secretion of prostacyclin by intact vascular endothelium
[C] causes morphological changes and a release of the vasodilator serotonine
[D] is inhibited by the release of ADP and thromboxane A2
Answer: is inhibited by the release of ADP and thromboxane A2
(2) The cones of the retina:
[A] are responsible for colour vision
[B] are much more numerous than rods
[C] have red, blue and green light- sensitive pigments that differ because of small difference in the retinal prosthetic group
[D] do not use transducin in signal transduction
Answer: are responsible for colour vision
(3) The nerve impulse that initiates muscular contraction
[A] begins with the binding of acetyl choline to receptors in the sarcoplasmic reticulum
[B] causes both the plasma membrane and the transverse tubules to undergo hyperpolariation
[C] causes opening of calcium channels which lead to an increase in calcium contreation within the sarcomere
[D] prevents sodium entering the sarcomere
Answer: causes opening of calcium channels which lead to an increase in calcium contreation within the sarcomere
(4) When a muscle contracts, the
[A] Transverse tubules shorten, the myofibrils and sarcoplasmic reticulum close together
[B] Thin filaments and thick filaments of the sarcomere shorten
[C] Light chains dissociate from the heavy chains of myosin
[D] H bands and I bands of the sarcomere shorten because the thin filaments and thick filaments side past each other
Answer: H bands and I bands of the sarcomere shorten because the thin filaments and thick filaments side past each other
(5) Lysis of a fibrin clot:
[A] is an equibrium wwith formation of the clot
[B] begins when plasmin binds to the clot
[C] requires the hydrolysis of plasminogen into heavy and light chains
[D] requires conversion of plasminogen by tissue plasminogen activator
Answer: requires conversion of plasminogen by tissue plasminogen activator
(6) ATP concentration is maintained relatively constant during muscle contraction by
[A] increasing the metabolic activity
[B] the action of adenylate kinase
[C] theaction of creatne phosphokinase
[D] all of the above
Answer: all of the above
(7) 4-hydroxy proline is present in
[A] Collagen
[B] Plant cell wall
[C] Keratin
[D] Both plant cell wall and collagen
Answer: Both plant cell wall and collagen
(8) Peptide bonds between amino acids are highly stable and have a half-life of seven years in intracellular condition. This is due to
[A] High activation energy required for hydrolysis
[B] Low activation energy required for hydrolysis
[C] Peptide bond is a covalent bond
[D] Peptide bond is rigid and planar
Answer: High activation energy required for hydrolysis
(9) Tri-peptide consists
[A] 3 amino acids and 3 peptide bonds
[B] 2 amino acids and 3 peptide bonds
[C] 3 amino acids and 2 peptide bonds
[D] 3 amino acids and 4 peptide bonds
Answer: 3 amino acids and 2 peptide bonds
(10) All the following statements are true except
[A] Ornithine and citrulline are uncommon aminoacids
[B] Ornithine is an intermediates in Urea cycle
[C] Ormithine and citrulline are uncommon amino acids present in many proteins
[D] Both ornithine and citrulline are intermediates in urea cycle
Answer: Ormithine and citrulline are uncommon amino acids present in many proteins
(11) The characteristic strong absorbance of 280nm of proteins is due to
[A] All amino acids can absorb at 280nm
[B] Only Tryptophan and tyrosine can absorb at 280 nm
[C] Tryptophan is responsible for the absorbance
[D] Tryptophan, tyrosine and phenylalanine can absorb at 280 nm
Answer: Tryptophan, tyrosine and phenylalanine can absorb at 280 nm
(12) The formation of cystine occurs at
[A] ER
[B] Golgi
[C] Cytosol
[D] Mitochondria
Answer: ER
(13) Which of the following interaction contributes most in protein folding

[A] Covalent bond
[B] Ionic bond
[C] Hydrophobic interaction
[D] Vander walls interaction
Answer: Hydrophobic interaction
(14) Which of the following aminoacid has pKa near neutrality
[A] Tryptophan
[B] Arginine
[C] Histidine
[D] Asparagine
Answer: Histidine
(15) Desmosine is an unusual amino acid found in
[A] Myosin
[B] Troponin
[C] Actin
[D] Elastin
Answer: Elastin
(16) How many small peptides are formed upon cleavage by trypsin if a protein has 5 lysine residues
[A] 4
[B] 5
[C] 6
[D] 7
Answer: 6
(17) EF-1α and EF-Tu are
[A] Analogs
[B] Homologs
[C] Paralogs
[D] Syllogs
Answer: Homologs
(18) All the statements regarding peptide bond are true except
[A] Peptide bond is a co-valent bond
[B] Peptide bond is rigid and planar
[C] Peptide bond has partial double bond character
[D] Peptide bond is formed by non-condensation reaction
Answer: Peptide bond is formed by non-condensation reaction
(19) Αlpha-helix has
[A] 3.6 residues/turn and is a right handed helix
[B] 3.8 residues/turn and is a right handed helix
[C] 3.6 residues/turn and is a left handed helix
[D] 3.8 residues/turn and is a left handed helix
Answer: 3.6 residues/turn and is a right handed helix
(20) Which of the following amino acids are rarely present in alpha helix
[A] Glycine and proline
[B] Proline and tryptophan
[C] Tryptophan and glycine
[D] Proline only
Answer: Glycine and proline

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