Chapter 13 Flashcards
(26 cards)
The process by which a DNA molecule is copied; also called DNA synthesis
DNA Replication
One of two chemical compounds that cells use to make the building blocks of DNA and RNA. Examples are adenine and guanine.
Purine
One of two chemical compounds that cells use to make the building blocks of DNA and RNA. Examples are cytosine, thymine, uracil.
Pyrimidine
Two complementary DNA nucleotide bases that pair together to form a “rung of a DNA ladder”
Base Pair
Either of the two chains that make up a double helix of DNA, with corresponding positions on the two chains being composed of a pair of complementary bases.
Complementary Strand
The DNA sequence that can duplicate itself during mRNA synthesis
Template Strand
Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5’ and 3’ directions)
Antiparallel
DNA from any cell of all organisms should have a 1:1 ratio of pyrimidine and purine bases.
Chargaff’s Rule
The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape.
Double Helix
Type of DNA replication in which the replicated double helix consists of one old strand, derived from the parental molecule, and one newly made strand.
Semiconservative Model
Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.
Origin of Replication
A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized.
Replication Fork
An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands.
DNA Helicase
A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, this helps to relieve strain in the double helix ahead of the replication fork.
Topoisomerase
An enzyme that joins RNA nucleotides to make a primer during DNA replication, using the parental DNA strand as a template
Primase
An enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3’ end of an existing chain.
DNA Polymerase
The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5’S 3’ direction.
Leading Strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5’ S 3’ direction away from the replication fork.
Lagging Strand
A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. Many are joined together to make up the lagging strand of newly synthesized DNA.
Okazaki Fragment
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of one DNA fragment to the 5’ end of another DNA fragment.
DNA Ligase
The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides.
Mismatch Repair
A repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide.
Nucleotide Excision Repair
An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides
Nuclease
The complex of DNA and proteins that makes up eukaryotic chromosomes.
Chromatin
