Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
218 Ch. 10
Replication of DNA and Chromosomes
| Question | Answer |
|---|---|
| Semiconservative Replication | the mechanism of DNA replication where the parental molecule is half conserved |
| Equilibrium density-gradient centrifugation | a procedure used to separate macromolecules based on their density (mass per unit volume) |
| Replication fork | the Y-shaped structure where the two parental strands of a DNA double helix are unwound and are being used as templates for the synthesis of new complementary strands |
| Origin of replication | the site of initiation; the site or nucleotide sequence on a chromosome or DNA molecule at which replication is initiated |
| replication bubble | the localized region of complementary strand separation that occurs at the origin of replication during the initiation of DNA replication |
| Autonomously Replicating Sequences (ARS) | segments of chromosomal DNA that allow a fragment of circularized DNA to replicate as an independent unit; extrachromosomal self-replicating unit found in yeast |
| DNA polymerase I | repairs defects in DNA |
| Primer DNA | a short nucleotide sequence with a reactive 3'OH that can initiate DNA synthesis along a template |
| Template DNA | pattern or mold; DNA stores coded information and acts as a model or template from which information is copied into complementary strands of DNA or transcribed into mRNA |
| Endonuclease | an enzyme that breaks strands of DNA at internal positions; some are involved in recombination of DNA |
| Exonuclease | an enzyme that digests DNA or RNA, beginning at the ends of the strands |
| 5' to 3' exonuclease activity | cuts DNA strands starting at 5' termini |
| 3' to 5' exonuclease activity | cleaves nucleotides from the 3' termini of DNA strands |
| DNA polymerase II | |
| DNA polymerase III | in E.coli this enzyme catalyzes the semiconservative replication. catalyzes the addition of deoxyribonucleotides to RNA primers, either continously or discontinuously (via synthesis of okazaki fragments-terminates the o. frag. when hit RNA primer) |
| Holoenzyme | the form of a multimeric enzyme in which all of he component polypeptides are present |
| Proofreading | the enzymatic scanning of NDa for structural defects such as mismatched basepairs |
| Continuous synthesis | the synthesis of nascent strand of DNA by the sequential addition of nucleotides to the 3'OH terminous of the strand. Characteristic of the synthesis of the leading strand. |
| Discontinuous synthesis | the synthesis of a nascent strand of DNA by the formation of short segments of DNA (okazaki fragments) that are subsequentially joined by DNA ligase. Characteristic of the synthesis of the lagging strand (3'-5') |
| Leading strand | 5'-3' (continuous) |
| Lagging strand | 3'-5' (discontinuous) |
| Okazaki fragment | short fragments (100-200 nucleotides) found to be true intermediated of DNA replicaton by pulse-chase experiments |
| DNA ligase | Required for all organisms' replication. Catalyzes covalent closure of nicks in DNA double helices (missing phosphodiester links) AMP intermediate forms phosphoester linkage w 5' nick, then nucleophilic attack from 3'OH |
| RNA Primer | short (10-60 nucleotides) segment of RNA that is used to nitiate the synthesis of a new strand of DNA; synthesized by the enzyme DNA primase |
| DNA primase | an enzyme that catalyzes the synthesis of short strands of RNA that initiate the synthesis of DNA strands |
| DNA helicase | an enzyme that catalyzes the unwinding of the complementary strands of DNA double helix |
| Single-stranded DNA binding protein (SSB protein) | a protein that coats DNA single strands, keeping them in an extended state (prevents them from reattaching to themselves.) |
| DNA topoisomerase | an enzyme that catalyzes the introduction or removal of supercoils from DNA; gives the swivel axis |
| DNA gyrase | an enzyme in bacteria that catalyzes the formation of negative supercoils in DNA (typeII topoisomerase) |
| oriC | single origin of replication in E.coli; 245 nucleotide pairs long and contains 2 different conserved repeat sequences |
| prepriming proteins | form replication bubble with oriC |
| DnaA protein | first step of prepriming binds 4 molecules of 9bp repeats of oriC forms core of 20-40 polypeptides with oriC |
| DnaC protein | 6 molecules that, with dnaB forms the 2 replication forks |
| Primosome | a protein replication complex that catalyzes the initiation of the okazaki fragments during discontinuous DNA synthesis. It contains DNA primase and DNA helicase activities |
| Replisome | the complete replication apparatus- present at replication fork- that carries out the semiconservative replication of DNA |
| Replicon | a unit of DNA whose replication is controlled by a specific origin of replication |
| DNA polymerase a (alpha) | required for initiation at origins and priming of okazaki fragments; found complexed to DNA primase (eukaryotes) |
| DNA polymerase d (delta) | completes okazaki fragment synthesis responsible for processive synthesis of chromosomal DNA Must interact with PCNA and replication factor C (Rf-C) to be active Contain 3’ to 5’ exonuclease activity (important for proof reading) |
| telomerase | an enzyme that adds telomere sequences to the ends of eukaryotic chromosomes |
| DNA synthesis | -chain initiation -chain extension or elongation -chain termination |
| Conservative replication | potential mechanism of replication where parental double helix is conserved and a new progeny double helix would be synthesized |
| dispersive replication | segments of both strands of the parental molecule would be conserved and used as templates for the synthesis of complementary segments that would subsequently be joined to produce progeny DNA strands. |
| Meselsohn and Stahl | used E.coli to demonstrate that DNA replicates semiconservitively. Used density gradients and CsCl with heavy and light isotopes. The DNA would separate into two bands; first generation was hybrid, second was hybrid and light. |
| Taylor, Woods, Hughes | Semiconservative replication in eukaryotes |
| bidirectional | direction DNA is replicated in |
| Denaturation mapping | Schnos and Inman: used AT rich clusters as physical markers to demonstrate that replication is initiated as a unique origin and proceeds bidirectionally |
| sticky ends | single stranded 12 nucleotides long that are complimentary to each other at the 5' ends |
| DNA polymerases | an enzyme that catalyzes the synthesis of DNA; absolute requirement of free 3'OH because it only moves in a 5' to 3' direction |
| polA | DNA can still replicate without this gene, however, it is key in repairing DNA defects; polA1 mutant was extremely sensitive to UV light |
| de novo | has to do with the synthesis of a new DNA strand. "With absolute req. for free 3'OH on the primer strand, the polymerases and enzymes cannot begin the synthesis of a new strand _________" |
Created by:
ktl34
Popular Biology sets