CBSE Class 12 (Science) Molecular Basis of Inheritance — practice questions
98 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 12 (Science) Molecular Basis of Inheritance in the app →In a DNA double helix, adenine pairs with thymine throughThe two strands of a DNA double helix areA nucleosome consists ofThe Hershey-Chase experiment used radioactive isotopes to labelThe Meselson-Stahl experiment proved that DNA replication isDNA polymerase synthesises a new DNA strand in which direction?The central dogma of molecular biology states the flow of information asDuring transcription, the strand of DNA actually read by RNA polymerase isIntrons are best described asWhich eukaryotic RNA polymerase synthesises the mRNA precursor (hnRNA)?The total number of possible codons in the genetic code isWhich of the following is the universal start codon?Approximately how much of the human genome codes for proteins?In DNA, Adenine (A) pairs with Thymine (T) via:The Hershey-Chase experiment (1952) proved that:The Central Dogma of molecular biology states that genetic information flows:Okazaki fragments are produced during DNA replication on which strand?The START codon in eukaryotic mRNA translation is:Translation of mRNA into protein occurs on which cellular structure?The Lac Operon in E. coli is INDUCED (turned ON) by the presence of:The Human Genome Project (HGP) ran from 1990 to:During transcription, the enzyme that synthesises mRNA from DNA is:Which sugar is present in the nucleotides of DNA?Which nitrogenous base takes the place of thymine in RNA?Who first identified DNA as an acidic substance in the nucleus in 1869?In which year did Watson and Crick propose the double helix model of DNA?What did Erwin Chargaff observe about double-stranded DNA?What is the polarity relation between the two strands of the DNA double helix?How many hydrogen bonds join adenine and thymine in DNA?Which base pair is held together by three hydrogen bonds in DNA?What is the pitch of the right-handed DNA double helix?Roughly how many base pairs are there in each turn of the DNA helix?According to the central dogma, how does genetic information flow?About how long is the DNA helix in a typical mammalian cell?Histones are rich in which basic amino acids?About how many base pairs of DNA does a typical nucleosome contain?Which type of chromatin is loosely packed and transcriptionally active?Griffith's 1928 transformation experiments used which bacterium?What gives S strain pneumococcus its smooth, shiny colonies?What happened to mice injected with heat-killed S plus live R bacteria?Which biochemical from heat-killed S cells alone transformed R bacteria?Hershey and Chase worked with which kind of virus?Which radioactive element labelled the DNA of the viruses in the Hershey-Chase experiment?Radioactive sulfur labelled which part of the bacteriophage?In which year did Hershey and Chase publish their blender experiment?Which virus has RNA as its genetic material?What makes RNA less stable than DNA?Which nucleic acid is preferred for storing genetic information?Which molecule is believed to have been the first genetic material?What does each daughter DNA contain in semiconservative replication?Meselson and Stahl grew E. coli on which heavy isotope?One generation after shifting E. coli to 14N medium, DNA density was?After 40 minutes in 14N medium, how was the E. coli DNA composed?Which is the main enzyme of DNA replication?Which enzyme joins the discontinuously synthesised DNA fragments?What is the small opening of the helix where replication occurs called?During transcription, adenine of the DNA template pairs with which RNA base?Which three regions define a transcription unit?Which DNA sequence provides the binding site for RNA polymerase?Which region of a transcription unit usually ends transcription?Which sequences appear in mature or processed RNA?Which sequences are removed from hnRNA during splicing?Which processing step adds methyl guanosine triphosphate to the 5-prime end of hnRNA?How many adenylate residues are added to hnRNA during tailing?How many nucleotides make up one codon?How many of the 64 codons code for amino acids?A code where several codons specify one amino acid is described as?Which codon codes for methionine and also acts as the initiator?Which codon does not code for any amino acid?From bacteria to humans, which amino acid does UUU code for?Which physicist argued that the genetic code must use combinations of bases?Whose chemical method made RNA with defined base combinations?Whose cell-free protein synthesis system helped decipher the genetic code?Insertion or deletion of one or two bases causes which kind of mutation?A single base change in the beta globin gene replaces glutamate with which amino acid?There are no tRNAs for which type of codon?What is the actual three-dimensional shape of a tRNA molecule?Amino acids in a polypeptide are joined by which bond?Which molecule supplies energy to activate amino acids before they bind tRNA?Which bacterial rRNA acts as a ribozyme in peptide bond formation?Which molecule alone recognises the start codon AUG during initiation?Which factor binds the stop codon and ends translation?The repressor of the lac operon is encoded by which gene?Which lac operon gene codes for beta-galactosidase?Which lac operon product increases permeability to beta-galactosides?Which two scientists elucidated the lac operon?Regulation of the lac operon by its repressor is called?Which human chromosome has the most genes?Which is the largest known human gene, at 2.4 million bases?What percentage of nucleotide bases is identical in all humans?What does SNP stand for in human genetics?Automated DNA sequencers in HGP used a method developed by whom?In HGP, which vectors cloned DNA fragments in bacterial hosts?Identifying all genes expressed as RNA in HGP was called?HGP was closely linked to the rapid growth of which new area of biology?Who initially developed the DNA fingerprinting technique?A person's DNA fingerprint pattern matches whose?Which technique made DNA fingerprinting sensitive enough for a single cell?