NCERT Class 12 Biology Optional Questions with Answers

NCERT Class 12 Biology Multiple Choice Questions(MCQs) & Answers NCERT Class 12 Biology QUESTIONS

NCERT Class 12 Biology Optional Questions with Answers

41 Eukaryotic RNA polymerase III catalyses the synthesis of
A tRNA
B hnRNA
C mRNA
D rRNA

Answer: tRNA
42 The sequence of nitrogen bases in a # segment of a coding strand of DNA is ’ AATGCTTAGGCA. What will be the sequence of nitrogen bases in the wRNA transcribed by it?
A UUA CGA AUC CGU
B AAU GCU UAG GCA
C AAU GCU AAC CGA
D AAU GCA AUC CGU

Answer: AAU GCU UAG GCA
43 Which one of the following impurities is easiest to remove from wastewater?
A Suspended solids
B Dissolved solids
C Bacteria
D Colloids

Answer: Suspended solids
44 Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentrations of
A phosphorus
B calcium
C carbon
D sulphur

Answer: phosphorus
45 The reservoir for the gaseous type of biogeochemical cycle exists in
A stratosphere
B atmosphere
C ionosphere
D lithosphere

Answer: atmosphere
46 The sequence of communities of primary succession in water is
A phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees.
B free-floating hydrophytes, sedges, phytoplankton, rooted hydrophytes, grasses and trees.
C phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees.
D phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses and trees.

Answer: phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees.
47 Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unbumt hydrocarbons into
A carbon dioxide and water
B methane
C carbon mono oxide
D carbon dioxide and methane.

Answer: carbon dioxide and water
48 Which of the following sets of codons contains only termination codons?
A UAA, UGA, UAG
B UUU, UCC, UGG
C UAA, UUU, UGG
D UAA, UAG, UAC

Answer: UAA, UGA, UAG
49 The central dogma of molecular biology (genetic information flow) was modified by the discovery of
A RNA polymerase
B DNA ligase
C Reverse transcriptase
D DNA polymerase

Answer: Reverse transcriptase
50 The human chromosome with the highest and least number of genes in them are respectively
A Chromosome 21 and Y
B Chromosome 1 and Y
C Chromosome X and Y
D Chromosome 1 and X

Answer: Chromosome 1 and Y

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