BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The size of RNA molecules depends on the type. tRNA molecules range from 60 to 95 nucleotides, some rRNA molecules in E. coli have polynucleotide strands of   120,  1500, and  2900 nucleotide units, while mRNA ranges from hundreds to thousands of nucleotides.

Detailed explanation-2: -A DNA molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits. Each of these chains is known as a DNA chain, or a DNA strand. Hydrogen bonds between the base portions of the nucleotides hold the two chains together (Figure 4-3).

Detailed explanation-3: -Modern transfer RNAs (tRNAs) are composed of  76 nucleotides and play an important role as “adaptor” molecules that mediate the translation of information from messenger RNAs (mRNAs).

Detailed explanation-4: -anticodon – a sequence of three nucleotides on a tRNA molecule that bond to a complementary sequence on an mRNA molecule. The anticodon sequence determines the amino acid that the tRNA carries.

Detailed explanation-5: -A tRNA, like the one modeled below, is made from a single strand of RNA (just like an mRNA is). However, the strand takes on a complex 3D structure because base pairs form between nucleotides in different parts of the molecule. This makes double-stranded regions and loops, folding the tRNA into an L shape.