Ans.1.
The enzymes that break the hydrogen bonds present between the DNA base pairs are known as DNA helicases. These enzymes are vital enzymes as they are responsible for unwinding of double-stranded DNA, which is required for DNA replication.
DNA helicases break hydrogen bonds and separate the DNA by using energy through breakdown of ATP molecules. In given diagram, DNA helicase is represented by blue figure (2).
Thus, the correct answer is option). 'DNA helicase.'
Ans.2.
The enzymes that attach the free nucleotides to the template or parent DNA strand, during DNA replication are called DNA-dependent DNA polymerases or simply DNA polymerases. These enzymes are also vital enzymes as each cell replicates it genetic material prior to cell division.
DNA polymerase forms two identical, daughter DNA strands from an original, parent DNA molecule. In given diagram, DNA polymerases are represented by yellow figures (6 and 8).
Thus, the correct answer is option). 'DNA polymerase.'