AP BIOLOGY

Detailed explanation-1: -The process of breaking the hydrogen bonds between the nucleotide base pairs in double-stranded DNA requires energy. To break the bonds, helicases use the energy stored in a molecule called ATP, which serves as the energy currency of cells.

Detailed explanation-2: -Hydrogen bonds between the DNA strands are broken by enzyme helicase, which unwinds the strands that terminate at the replication fork.

Detailed explanation-3: -DNA helicases are molecular motors. Through conformational changes caused by ATP hydrolysis and binding, they move along the template double helix, break the hydrogen bonds between the two strands and separate the template chains, so that the genetic information can be accessed.

Detailed explanation-4: -In the laboratory, exposing the two DNA strands of the double helix to high temperatures or to certain chemicals can break the hydrogen bonds between complementary bases, thus separating the strands into two separate single strands of DNA (single-stranded DNA [ssDNA]).

Detailed explanation-5: -The main function of DNA helicase is to separate two strands of DNA for replication. Helicase is the enzyme, which unzips the DNA strands by breaking the hydrogen bonds between them.