Chapter 16, Problem 61P

Interpretation Introduction

Interpretation:

The process in which DNA unzips and makes a stand of mRNA should be determined.

Concept Introduction:

The sequence of the amino acids in the protein is determined by the sequence of bases in DNA, and the relationship between these two sequences is called the genetic code.

The DNA molecules which occurs in the chromosomes found in the cell nucleus, usually exists as double helices. RNAs are usually single strands, but one RNA and one DNA can also form a double helix, which is known as hybridisation of RNA and DNA.

In this way a given DNA determines the base sequence in its complementary RNA. When the RNA strand is synthesised, the DNA-RNA double helix splits. Three types of RNAs are synthesised in this way, each performing one type of function in protein biosynthesis. One RNA acts as messenger or informational RNA; this is mRNA. The second type of RNA is the transfer RNA, tRNA and the third type of RNA is the ribosomal RNA i.e. rRNA. The base composition of different mRNAs and different tRNAs vary, rRNAs show little bit variation. The variations are possible because RNA molecules are very much smaller than the DNA molecules and so a number of RNAs can be synthesised from a DNA, each particular RNA being synthesised on a specified part of DNA molecule.

Correct answer:

Option (c), the process in which the DNA molecule unzips to form mRNA is called transcription.