AP Biology-Ch 16 The Molecular Basis of Inheretance

The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape.

Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.

A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, topoisomerase helps to relieve strain in the double helix ahead of the replication fork.

Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5′ → 3′ directions).

an enzyme that catalyzes the elongation of new DNA at a replication fork by the addition of nucleotides to the existing chain

A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of one DNA fragment (such as an Okazaki fragment) to the 5' end of another DNA fragment (such as a growing DNA chain).

The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.

A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are growing.

A short stretch of RNA with a free 3' end, bound by complementary base pairing to the template strand, that is elongated with DNA nucleotides during DNA replication.

An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.

The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5'?3' direction.

The tandemly repetitive DNA at the end of a eukaryotic chromosome's DNA molecule that protects the organism's genes from being eroded during successive rounds of replication. See also repetitive DNA.

The DNA strand that provides the pattern, or template, for ordering the sequence of nucleotides in an RNA transcript.

An enzyme that untwists the double helix of DNA at the replication forks, separating the two strands and making them available as template strands.

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5'3' direction away from the replication fork.

A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication, many of which are joined together to make up the lagging strand of newly synthesized DNA.

A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA.

An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.

Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand.

A dense region of DNA in a prokaryotic cell.

5' to 3' exonuclease activity, removal of RNA primers.

5' to 3' polymerase activity, 3' to 5' exonuclease activity (delete key)

oads DNA polymerase on the DNA and keeps DNA polymerase from falling. Increase processivity.