Free MCQs & Online Quiz Practice for Exams

Q: The most important hormone in initiating and maintaining lactation after birth is

A) Estrogen

B) FSH

C) Prolactin

D) Oxytocin

Q: A chromosome with unequal length of its arms is called

A) Metacentric

B) Sub metacentric

C) Acrocentric

D) Telocentric

Q: In Meselson & Stahl experiment, DNA sample at 20 minutes after centrifugation made sediments at

A) Top

B) Bottom

C) Intermediate

D) Top & intermediate

Q: Which of the following acts as a stop codon?

A) UGG

B) UGC

C) UAG

D) UGU

Q: In mitochondria UGA codon acts to specify instead of stop codon

A) Arginine

B) Valine

C) Glutamic acid

D) Tryptophan

Q: If an mRNA is synthesized with all different codons, what is the minimum number of amino acids in the protein formed?

A) 64 amino acids

B) 62 amino acids

C) 60 amino acids

D) None of them

Q: In eukaryotic mRNA with 90 nucleotides involved in translation, the protein formed will have

A) 29 amino acids

B) 30 amino acids

C) 45 amino acids

D) 90 amino acids

Q: In Griffith experiment, mice developed pneumonia when injected with

A) R-type bacteria

B) Heat killed S-type bacteria

C) Heat killed R-type bacteria

D) Heat killed S-type bacteria along with live R-type bacteria

Q: If the codon consisted of only two nucleotides, possible codons would be

A) 4

B) 8

C) 20

D) 16

Q: The reaction of CH₃MgI with acetone followed by hydrolysis gives:

A) tert-butyl alcohol

B) sec-butyl alcohol

C) n-butyl alcohol

D) none of these

Q: Which one of the following halides is most reactive towards nucleophilic substitution reaction?

A) C₂H₅Br

B) C₂H₅I

C) C₂H₅F

D) C₂H₅Cl

Q: An electron-deficient species is:

A) Electrophile

B) Nucleophile

C) Both (a) and (b)

D) None of these

Q: R–CH₂–X is an example of:

A) Primary alkyl halide

B) Secondary alkyl halide

C) Tertiary alkyl halide

D) None of these

Q: The carbon atom carrying positive charge and attached to three other atoms or groups is called:

A) Carbocation

B) Carbanion

C) Oxonium ion

D) Carbene

Q: Grignard reagent can be represented by general formula:

A) R–Mg–NH₂

B) R–Mg–OR

C) R–Mg–OH

D) R–Mg–X

Q: The end product of reaction of a Grignard reagent with ethyl acetate is:

A) Primary alcohol

B) Secondary alcohol

C) Tertiary alcohol

D) Methyl alcohol

Q: An electron-pair donor is:

A) Lewis acid

B) Electrophile

C) Nucleophile

D) Free radical

Q: In secondary alkyl halides the carbon atom to which the halo group is attached is in turn bonded directly to:

A) One other carbon

B) Two other carbons

C) Three other carbons

D) Four other carbons

Q: Characteristic of SN1 reaction is:

A) 100% inversion

B) 100% retention

C) Partial racemization

D) None of these

Q: Which of the following solvent is aprotic?

A) Acetone

B) Ethyl alcohol

C) Water

D) Formic acid