Kategorier: Alle - replication - mutations - transcription - proteins

av Erik Buys 10 år siden

319

New Map

The process of DNA replication involves several key proteins, each with specific roles to ensure accurate duplication of the genetic material. Topoisomerase alleviates the strain caused by unwinding the DNA, while helicase unwinds the double helix at the replication forks.

New Map

Semiconservative Replication

DNA replication consits of one old strand, derived from the parental molecule, and one newly made strand

RNA Processing

Modification of RNA primary transcripts, including splicing out of introns, joining of exons, and alteration of the 5' and 3' ends

Translation

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of "language" from nucleotides to amino acids

DNA Replication

Proteins used in Replication

DNA Ligase
Joins 3' end of DNA that replaces primer to rest of leading strand and joins Okazki fragments of lagging strand
DNA Pol 1
Removes RNA necleotides of primer from 5' end and replaces them with DNA necleotides
DNA Pol 3
Using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to the 3' end of a pre-existing DNA strand or RNA primer
Primase
Synthesizes an RNA primer at 5' end of leading stand and of each Okazaki fragment of lagging strand
Topoisomerase
Relieves "overwinding" strain ahead of replication forks by breaking, swiveling and rejoining DNA strands
Single Strand Binding Protein
Binds to and stabilizes single-stranded DNA until it can be used as a template
Helicase
Unwinds parental double helix at replication forks

Replication Bubble

Lagging Strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki Fragments, each synthesized in a 5' -> 3' direction away from the replication fork
Okazaki Fragments

Short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. many such segments are joined together to make up the lagging strand of newly synthesized DNA

Leading Strand
The new complementary DNA strand synthesized continuously along the template stand toward the replication fork in the mandatory 5' -> 3' direction
Replication Fork
A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized
Origin(s) of Replication
Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides

Transcription

The synthesis of RNA using a DNA template

Mutations

Frame-shift Mutation
Deletion

a mutational loss of one or more nucleotide pairs from a gene

Insertion

a mutation involving the addition of one or more nucleotide pairs to a gene

Nucleotide-pair substitutions
Nonsense Mutation

a mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein

Missense Mutation

A nucleotide-pair substitution that results in a codon that codes for a different aminp acid

Silent Mutation

A nucleotide-pair substitution that has no observable effect on the phenotype

Double stranded, completentary base pairng