Bioinorganic Chemistry MCQs for CSIR NET, GATE - Download PDF

Bioinorganic Chemistry
Chapterwise Assignment-1

         

Q1 The ligand system present in vitamin B12 is

[NET June 2011]

(a) porphyrin
(b) corrin
(c) phthalocyanine
(d) crown ether

Q2 Carboxypeptidases contains

[NET June 2011]

(a) Zn(II) and hydrolysis CO₂
(b) Zn(II) and hydrolysis peptide bonds
(c) Mg(II) and hydrolysis CO₂
(d) Mg(II) and hydrolysis peptide bonds

Q3 Superoxide dismutase contains the metal ions

[NET Dec 2011]

(a) Zn(II) and Ni(II)
(b) Cu(II) and Zn(II)
(c) Ni(II) and Co(III)
(d) Cu(II) and Fe(III)

Q4 The reduction of nitrogen to ammonia carried out by enzyme nitrogenase needs

[NET Dec 2011]

(a) 2 electrons
(b) 4 electrons
(c) 6 electrons
(d) 8 electrons

Q5 In bacterial rubredoxin, the number of iron atoms, sulfur bridges and cystine ligands respectively are

[NET Dec 2011]

(a) 4, 4, 4
(b) 2, 2, 4
(c) 2, 2, 2
(d) 1, 0, 4

Q6 The oxidation state of iron in met-hemoglobin is

[NET June 2012]

(a) Three
(b) Two
(c) Four
(d) Zero

Q7 The changes (from A-D given below) which occur when O₂ binds to hemerythrin are

[NET June 2012]

A. One iron atom is oxidized
B. Both the iron atoms are oxidized
C. O₂ binds to one iron atom and is also hydrogen bonded
D. O₂ binds to both the iron atoms and is also hydrogen bonded
(a) B and C
(b) B and D
(c) A and D
(d) A and C

Q8 The correct set of biologically essential elements is

[NET Dec 2012]

(a) Fe, Mo, Cu, Zn
(b) Fe, Cu, Co, Ru
(c) Cu, Mn, Zn, Ag
(d) Fe, Ru, Zn, Mg

Q9 Based on the behavior of metalloenzymes, consider the following statements
A. In the enzymes, zinc activates O₂ to form peroxide species.
B. In the enzymes, zinc activates H₂O and provides a zinc bond hydroxide.
C. In the oxidases, iron activates O₂ to break the bonding between the two oxygens.
D. Zinc ion acts as a nucleophile and attacks the peptide carbonyl.

[NET Dec 2012]

(a) A and B
(b) B and C
(c) C and D
(d) A and D

Q10 Fe²⁺porphyrins fail to exhibit reversible oxygen transport and cannot differentiate CO from O₂. However, the hemoglobin is free from both these pit falls.
Choose the correct statements among the following.

[NET Dec 2012]

A. Fe²⁺ porphyrins undergo μ-oxo dimer formation and the same is prevented in case of the hemoglobin.
B. Fe-CO bond strength is much low in case of hemoglobin when compared to the Fe²⁺ porphyrins.
C. While Fe-CO is linear, Fe-O₂ is bent and is recognized by hemoglobin.
D. The interlinked four monomeric units in the hemoglobin are responsible to overcome the pitfalls.
(a) A and B
(b) A and C
(c) C and D
(d) B and D

Ans Key:

1.b 2.b 3.b 4.d 5.d 6.a 7.a 8.a 9.b 10.b

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