Genetik 2_DNA Structure and Replication
Genetik 2_DNA Structure and Replication
Genetik 2_DNA Structure and Replication
-
- 1 / 33
-
Lernkarten
complementary base pairs
Refers to specific pairing between adenine and thymine and between guanine and cytosine.
conservative replication
a disproved model of DNA synthesis suggesting that one-half of the daughter DNA molecules should have both strands composed of newly polymerized nucleotides.
daughter molecule
One of the 2 products of DNA replication composed of one template strand and one newly synthesized strand.
deoxyribose
The pentose sugar in the DNA backbone.
distributive enzyme
An enzyme that can add only a limited number of nucleotides before falling off the DNA template.
DNA ligase
An important enzyme in DNA replication and repair that seals the DNA backbone by catalyzing the formation of phosphodiester bonds.
double helix
The structure of DNA first proposed by James Watson and Francis Crick, with 2 interlocking helices joined by hydrogen bonds between paired bases.
enol = tautomeric shift = tautomerization
Spontaneous isomerization of a nitrogen base from its normal keto form to an alternative hydrogen-bonding enol/imino form.
genetic code
A set of correspondences between nucleotide triplets in RNA and AS in protein.
helicase
An enzyme that breaks hydrogen bonds in DNA and unwinds DNA during movement of the replication fork.
lagging strand
In DNA replication, the strand that is synthesized apparently in the 3'-to-5' direction by the ligation of short fragments synthesized individually in the 5'-to-3' direction.
leading strand
In DNA replication, the strand that is made in the 5'-to-3' direction by continous polymerization at the 3' growing tip.
major groove
The larger of the 2 grooves in the DNA double helix.
minor groove
The smaller of the 2 grooves in the DNA double helix.
nucleotide
A molecule composed of a nitrogen base, a sugar, and a phosphate group. The basic building block of nucleic acids.
Okazaki fragment
A small segment of single-stranded DNA synthesized as part of the lagging strand in DNA replication.
origin
The point of a specific sequence at which DNA replication is initiated
phosphate
An ion formed of 4 oxygen atoms attached to a phosphorus atom or the chemical group formed by the attachment of a phosphate ion to another chemical species by an ester bond.
polymerase III holoenzyme
In E.coli, the large multisubunit complex at the replication fork consisting of 2 catalytic cores and many accessory proteins.
primase
An enzyme that makes RNA primers in DNA replication.
primer
An RNA / DNA oligonucleotide that can serve as a template for DNA synthesis by DNA polymerase when annealed to a longer DNA molecule.
primosome
A protein complex at the replication fork whose central component is primase.
processive enzyme
Describes the behavior of DNA polymerase III, which can perform thousands of rounds of catalysis without dissociating from ist substrate.
purine
A type of nitrogen base, the purine bases in DNA are adenine and guanine.
pyrimidine
A type of nitrogen base, the pyrimide bases in DNA are cytosine and thymine.
replication fork
The point at which the 2 strands of DNA are separated to allow te replication of each strand.
replisome
The molecular machine at the replication fork that coordinates the numerous reactions necessary for the rapid and accure replication of DNA .
semiconservative replication
The established model of DNA replication in which each double-stranded molecule is composed of one parental strand and one newly polymerized strand.
single-strand-binding protein (SSB)
A protein that binds to DNA single strands and prevents the duplex from re-forming before replication.
telomerase
An enzyme that, with the use of a special small RNA as a template, adds repetitive units to the ends of linear chromosomes to prevent shortening after replication.
telomere
The tip/end of a chromosome
template
A molecular "mold" that shapes the structure or sequence of another molecule, for example, the nucleotide sequence of DNA acts as a template to control the nucleotide sequence of RNA during transcription.
topoisomerase
An enzyme that can cut and re-form polynucleotide backbones in DNA to allow it to assume a more relaxed configuration.
