AP BIOLOGY

Previous
Next

THE MOLECULAR BASIS OF INHERITANCE

DNA REPLICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Nucleotides are the monomer units of nucleic acids. When they undergo condensation reactions, they form polynucleotides (strands of DNA or RNA). Polymerization is an endothermic process. Where do the enzymes that carry out the condensation reactions to build polynucleotides get the energy for this process?
A
By converting ATP into ADP and using the energy of the phosphate bonds.
B
by breaking down glucose
C
by converting nucleoside triphosphates into nucleotides and using the energy from the high energy phosphate bonds.
D
From complementary base pairing.
Explanation: 

Detailed explanation-1: -The monomers of DNA are called nucleotides. Nucleotides have three components: a base, a sugar (deoxyribose) and a phosphate residue. The four bases are adenine (A), cytosine (C), guanine (G) and thymine (T). The sugar and phosphate create a backbone down either side of the double helix.

Detailed explanation-2: -The hydroxyl group of a phosphate on one nucleotide undergoes a condensation reaction with the hydroxyl group on the carbohydrate ring of another nucleotide. The process may continue, building up nucleic acid molecules. These are polymers called polynucleotides.

Detailed explanation-3: -When two nucleotides join by a condensation reaction, the phosphate group of one molecule will bind to the sugar (not the nitrogenous base) of the second nucleotide. This is called a phosphodiester bond.

Detailed explanation-4: -Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are polymers composed of monomers called nucleotides. An RNA nucleotide consists of a five-carbon sugar phosphate linked to one of four nucleic acid bases: guanine (G), cytosine (C), adenine (A) and uracil (U).

There is 1 question to complete.
Previous
Next