Question

If a nucleotide lacking a hydroxyl group at the 3’ end is added to a PCR, what would be the outcome?
A. No additional nucleotides would be added to a growing strand containing that nucleotide.
B. Strand elongation would proceed as usual.
C. Nucleotides would only be added at the 5’ end.
D. T. aquaticus DNA polymerase would be denatured.

Answer 1

Hint: PCR is a laboratory technique for producing millions of copies of a specific section of DNA. A nucleotide is a compound that forms the basis of DNA and RNA. A nucleotide is made up of three parts: a nitrogenous base, a 5-carbon sugar, and a phosphate group.


Complete step by step solution:
The basic units of a DNA molecule are nucleotides. Our genetic material, deoxyribonucleic acid (DNA), comprises subunits known as monomers. The monomers in DNA are known as nucleotides, and they are connected to form a polynucleotide chain that could be hundreds, thousands, or millions of nucleotides long.
The nucleotide is a complex molecule composed of three different parts. A sugar, a nitrogenous base, and a phosphate group are all present.

Sugar+Nitrogenous base+Phosphate group = Nucleotide

When a polynucleotide is formed, the incoming nucleotide's 5′ phosphate connects to the 3′ hydroxyl group at the end of the growing chain. The 3′ carbon of the sugar deoxyribose is connected to a hydroxyl (OH) group in DNA nucleotides.
PCR, also renowned as "molecular photocopying," is a low-cost method for "amplifying" - or duplicating - small segments of DNA. Studies of isolated segments of DNA are practically impossible without PCR amplification because significant amounts of a DNA sample are needed for molecular and genetic analyses.

Hence, the correct option is A.

Note:
A hydroxyl group at a nucleotide's 3' position is required for the binding of any additional nucleotides. Other nucleotides could not be added to a growing strand if this hydroxyl group was missing.