OBJECTIVE LIFE SCIENCE
MOLECULAR BIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
DNA polymerase separates the two DNA strands.
|
|
|
DNA molecules containing nucleotides from the original molecule are produced.
|
|
|
Adenine forms a base pair with either thymine or uracil.
|
|
|
New bases attach to the original sugar-phosphate backbone.
|
Detailed explanation-1: -The initiation of DNA replication occurs in two steps. First, a so-called initiator protein unwinds a short stretch of the DNA double helix. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.
Detailed explanation-2: -The replication of DNA occurs during the synthesis phase, or S phase, of the cell cycle, before the cell enters mitosis or meiosis. The elucidation of the structure of the double helix provided a hint as to how DNA is copied. Recall that adenine nucleotides pair with thymine nucleotides, and cytosine with guanine.
Detailed explanation-3: -During DNA replication, one new strand (the leading strand) is made as a continuous piece. The other (the lagging strand) is made in small pieces. DNA replication requires other enzymes in addition to DNA polymerase, including DNA primase, DNA helicase, DNA ligase, and topoisomerase.