Friday, 29 January 2021

CBSE Class 12 Biology - MCQ and Online Tests - Unit 6 - Molecular Basis of Inheritance

CBSE Class 12 Biology – MCQ and Online Tests – Unit 6 – Molecular Basis of Inheritance

Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.


 

CBSE Class 12 Biology – MCQ and Online Tests – Unit 6 – Molecular Basis of Inheritance

Question 1.
The ratio constant for a species is :
(a) T+C/G + A
(b) A+C/T + G
(c) G + G/A + T
(d) A + C/C + T

Answer

Answer: (b) A+C/T + G


Question 2.
DNA repairing is done by:
(a) By DNA polymerase I
(b) By DNA Polymerase II
(c) Both (a) and (b)
(d) By Ligase

Answer

Answer: (b) By DNA Polymerase II


Question 3.
Represser Lac-Operon protein attached to:
(a) Operator
(b) Inducer
(c) Regulator
(d) β-Glacto sidase

Answer

Answer: (b) Inducer


Question 4.
A ribotide is made up of:
(a) Ribose + Phosphate + Uracil
(b) Deoxribose + Uracil + Phosphate
(c) Thymine + Ribose + Phosphate
(d) Deoxyribpse + Phosphate + Adenine

Answer

Answer: (a) Ribose + Phosphate + Uracil


Question 5.
DNA fragments are joined in a correct sequence by :
(a) DNA ligase
(b) RNA polymerase
(c) Helicase
(d) DNA polymerase

Answer

Answer: (b) RNA polymerase


Question 6.
the enzyme involved in transcription is:
(a) DNA Polymerase I
(b) DNA Polymerase II
(c) RNA Polymerase
(d) DNA Polymerase

Answer

Answer: (d) DNA Polymerase


Question 7.
Antiparallel strands of a DNA molecule means that:
(a) One strand turns clockwise
(b) One strand turns anticlockwise
(c) The phosphate groups at the start of two DNA strands are in opposite position
(d) The phosphate groups at the start of two DNA strands, at their ends, share the same position

Answer

Answer: (c) The phosphate groups at the start of two DNA strands are in opposite position


Question 8.
Following is important in Ïranscription:
(a) DNA Methylase
(b) CAAT Box
(c) Promotar
(d) DNA Polymerase

Answer

Answer: (a) DNA Methylase


Question 9.
One turn of the helix in p-from DNA is approximately:
(a) 20 Å
(b) 2 nm
(c) 20 nm
(d) 34 nm

Answer

Answer: (d) 34 nm


Question 10.
Which one is mainly transcribed:
(a) Only RNA sequence
(b) Middle repetitive DNA sequence
(c) Highly repetitive DNA sequence
(d) Single copy of DNA sequence

Answer

Answer: (c) Highly repetitive DNA sequence


Question 11.
Amino acid sequence, in protein synthesis is decided by the sequence of?
(a) c-DNA
(b) r-RNA
(c) f-RNA
(d) m-RNA

Answer

Answer: (b) r-RNA


Question 12.
DNA multiplication is also called:
(a) Replication
(b) Transduction
(c) Translation
(d) Transcription

Answer

Answer: (b) Transduction


Question 13.
One of these is not prepared directly from DNA
(a) m-RNA
(b) f-RNA
(c) r-RNA
(d) Protein

Answer

Answer: (d) Protein


Question 14.
During Protein synthesis, atone point the process comes to a halt. Select the group of the three codons from the following, from which any one of the three could bring about this halt:
(a) UUC, UUA, UAC
(b) UAG, UGA, UAA
(c) UUE, UCA, UCG
(d) UUU, UCC, UAU

Answer

Answer: (b) UAG, UGA, UAA


Question 15.
During splicing axon attached and inducer enzyme for reaction:
(a) RNA Ligase
(b) RNA Catalase
(c) RNA permease
(d) RNA poloymerase

Answer

Answer: (b) RNA Catalase


Question 16.
Which is not component of lac operon:
(a) Primer gene
(b) Promoter gene
(c) constructive gene
(d) Regulator gene

Answer

Answer: (c) constructive gene


Question 17.
Okazaki fregments is:
(a) RNA primer
(b) small segments of DNA on leading stand
(c) Small segments of DNA on lagging stand
(d) None of these

Answer

Answer: (c) Small segments of DNA on lagging stand


Question 18.
Transposons occur in:
(a) In Eukaryotes
(b) In Prokaryotes
(c) In both (a) and (b)
(d) None of these

Answer

Answer: (c) In both (a) and (b)


Question 19.
Anticodon found in:
(a) On DNA
(b) On t-RNA
(c) On r-RNA
(d) On m-RNA

Answer

Answer: (b) On t-RNA


Question 20.
In DNA helix:
(a) Quadrate structure
(b) Polarity
(c) Antiparallel Polarity
(d) Disuiphide bond

Answer

Answer: (c) Antiparallel Polarity


Question 21.
Coiling of DNA duplex is:
(a) Left-handed
(b) Right-handed
(c) Parallel
(d) All of these

Answer

Answer: (c) Parallel


Question 22.
Inprokaryotic translation, GTP molecule required in at:
(a) Formation of formyl-met-f-RNA
(b) Joining of 30S sub-unit of ribosome with n-RNA
(c) Joining of 30S m-RNA on Formyl-met-f-RNA
(d) Joining of 50S subunit of ribosome with initiation complex

Answer

Answer: (b) Joining of 30S sub-unit of ribosome with n-RNA


Question 23.
During DNA synthesis formed segment is:
(a) Polymerase fragment
(b) RNA fragment
(c) Okazaki fragment
(d) RNA Primer

Answer

Answer: (c) Okazaki fragment


Question 24.
DNA double helix model was given by:
(a) Knoll and Ruska
(b) Khorana
(c) Watson and Crick
(d) Priestley

Answer

Answer: (c) Watson and Crick


Question 25.
In a give DNA segment ATC ACC AGG ACC CCA ACA, the first base gets mutated. The effect of this on coding by the DNA segment will result in :
(a) One amino acid less in protein
(b) No change in the sequence
(c) Complete change in the type and sequence of amino acid
(d) Change in first amino acid only

Answer

Answer: (b) No change in the sequence


 

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