AP BIOLOGY

LABORATORY REVIEW

MOLECULAR BIOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which enzyme adds base pairs to the DNA strand during DNA replication?
A
ligase
B
primase
C
helicase
D
DNA polymerase
Explanation: 

Detailed explanation-1: -The central enzyme involved is DNA polymerase, which catalyzes the joining of deoxyribonucleoside 5′-triphosphates (dNTPs) to form the growing DNA chain. However, DNA replication is much more complex than a single enzymatic reaction.

Detailed explanation-2: -One of the key molecules in DNA replication is the enzyme DNA polymerase. DNA polymerases are responsible for synthesizing DNA: they add nucleotides one by one to the growing DNA chain, incorporating only those that are complementary to the template.

Detailed explanation-3: -DNA polymerase enzymes cannot begin a new polynucleotide chain by linking two nucleoside triphosphates together. Instead, they absolutely require a base-paired 3′-OH end of a primer strand on which to add further nucleotides (see Figure 5-4).

Detailed explanation-4: -DNA polymerase is responsible for the process of DNA replication, during which a double-stranded DNA molecule is copied into two identical DNA molecules. Scientists have taken advantage of the power of DNA polymerase molecules to copy DNA molecules in test tubes via polymerase chain reaction, also known as PCR.

Detailed explanation-5: -DNA polymerase can only add DNA bases in one direction, from the 5’ end to the 3’ end. One of the new strands of DNA, the leading strand, is made continuously, the DNA polymerase adding bases one by one in the 5’ to 3’ direction.

There is 1 question to complete.