Answers to the MCQ:
Q21) amount of DNA in telophase
Ans: c) 4C. The amount of DNA double at the S phase by replication.
Q22) Sister chromatid separation.
Ans: b) Meiosis II. In meiosis in the meiosis I only the bivalents get separated from the tetrads (a couple of two homozygous bivalents), but in the meiosis II, the chromatids from each bivalent get separated.
Q23) Meiosis II of meiosis
Ans: E) V During meiosis II the two chromatids get separated and during this process, the nuclear membrane does not disintegrate.
Q24) Prophase I of meiosis
Ans:D) IV The diagram is depicting the crossing over the stage where two homologous chromosomes pair and exchange their DNA arms.
Q50) Attachment site for RNA polymerase
Ans: b) Promoter region
The region of DNA where the DNA dependent RNA polymerase binds for transcription is called a promoter region.
Q51) frameshift mutation
Ans: e) a base substitution
The Code is a triplet and they are degenerate, continuous in a reading frame. Thus, in a sequence of DNA, we can have three reading frames. If we delete either one or two or insert either one or two nucleotides, then the reading frame downstream to these gets changed. If we delete three consecutive nucleotides, then the reading frame will not change except that it is possible that the two of these three bases may be of one amino acid changing it and the subsequent or next amino acid may also change because of the first base change in the codon. Thus at the most three bases, deletion or insertion may lead to two amino acid mutations. However, if we just substitute a single base in an ORF, then the reading frame will not change. If may however only cause a single amino acid mutation if the base is first or second in that codon.
Q52)UUU
Ans: d) Phenylalanine
The genetic code is conserved.
Q53) tRNA containing first amino acid binds to…
Ans: None of the alternatives is correct because the tRNA containing the first amino acid binds to the start codon of mRNA bound to the smaller subunit of the ribosome. After this, only the larger subunit of the ribosome comes and binds to form the initiation complex.
Q54) chain elongation continues till.
Ans: d) chain termination codon occurs.
In the mRNA, there are the termination codons that do not code for any amino acid. When the translation continues and reaches till that termination codon then there is no tRNA for them that have any amino acid attached. Hence, translation terminates.

2. Base stacking between base pairs in double-stranded DNA is enth...