AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA REPLICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What does primase do?
A
add DNA to the new strand
B
add RNA primers for DNA polymerase to work from
C
close the gap between nucleotides
D
relieve strain ahead of the replication fork
Explanation: 

Detailed explanation-1: -Primase is the enzyme that synthesizes RNA primers. Primers are oligonucleotides that are complementarily bound to a DNA template and from which DNA polymerases elongate. Special proteins are responsible for loading primase at the origin of replication so that leading strand DNA synthesis can commence.

Detailed explanation-2: -Primase synthesizes RNA primers complementary to the DNA strand. DNA polymerase III extends the primers, adding on to the 3’ end, to make the bulk of the new DNA. RNA primers are removed and replaced with DNA by DNA polymerase I. The gaps between DNA fragments are sealed by DNA ligase.

Detailed explanation-3: -Since primase produces RNA molecules, the enzyme is a type of RNA polymerase. Primase functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA, which serves as its template. It is critical that primers are synthesized by primase before DNA replication can occur.

Detailed explanation-4: -Posted October 28, 2021. RNA primase is a type of enzyme that synthesizes primer for replication to start. Primase is an enzyme that synthesizes short RNA sequences known as primers. The primers that are synthesized are complementary to a single-stranded piece of DNA and serve as its template.

Detailed explanation-5: -The primase generates short strands of RNA that bind to the single-stranded DNA to initiate DNA synthesis by the DNA polymerase. This enzyme can work only in the 5’ to 3’ direction, so it replicates the leading strand continuously.

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