Mutations are spontaneous and occur at random however there are some mutagenic agents which increase the chance of this happening such as radiation exposure. If it is a point shift mutation then only a few bases on the dna sequence are changed so only changes a few of the amino acids in that chain (such as inversion of a base). If its a frame shift then the base sequence is altered so much so that every amino acid from after that changes (such as deletion of a base) which can create things such as cri-du-chat syndrome which results from a piece of chromosome 5 is missing. Hope this helps:)
The correct matching of enzymes and their role in the process of DNA replication is A- 3, B- 5, C-1, D-2 and E-4.
Replication is the process of synthesis of two indentical copies of DNA from a single DNA molecule. It is catalyzed by a set of enzymes with the following function-
A. RNA primase synthesizes an RNA primer (short sequence of RNA) on the lagging strand complementary to the single stranded DNA which acts as template during DNA replication.
B. Ligase is involved in joining the okazaki fragments on the lagging strand together and sealing the nicks of the DNA strand.
C. Helicase separates the two DNA strands at the replication fork.
D. Polymerase synthesizes the complementary daughter strand by adding nucleotides to DNA.
E. Topoisomerase relaxes the highly coiled DNA by creating nick ahead of the replication fork in the phosphate backbone of DNA strands.
The first three answers are natural changes, while the last three are because of human intervention.
