IB DNA-PROTEIN HL

Histone

Composed of a set of 8 proteins clustered together

Nucleosome

Composed of a set of 8 proteins clustered together, with 2 loops of DNA

Chromatin

Loosely packed DNA

Chromosome

Tightly packed DNA

Deoxyribose

Sugar of DNA

Ribose

Sugar in RNA

Helicase

Enzyme that breaks H-bonds between Nitrogen bases in DNA

Gyrase

Eases tension during DNA Replication

Semi-conservative

Describes how DNA replication occcurs - the two original strands separate and are used as templates for building more DNA

DNA Polymerase III

Delivers free DNA nucleotides to the broken helix

RNA Primase

Delivers RNA primer to get replication started, provides a 3' end for DNA nucleotides to attach

DNA Polymerase I

Proofreads DNA, replaces RNA primer with DNA nucleotides

Ligase

Forms phosphodiester bonds between Okazaki fragments of DNA

Leading strand

DNA Built towards the replication fork continuously

Lagging strand

DNA built away from the replication fork discontinuously

Okazaki fragments

Small pieces of DNA created away from the replication fork during DNA replication

Phosphodiester bond

Forms between the Phosphate of one nucleotide and the 3' carbon of the previous nucleotide

Transcription

creates mRNA by reading the DNA code

Translation

process of creating a protein by delivering amino acids to the ribosome as dictated by the mRNA

RNA Polymerase

Delivers free mRNA nucleotides to the DNA in order to elongate mRNA

Promotor region

TATAA box that signals the beginning of a transcription unit

Terminator region

ATAAA box that signals the end of a transcription unit

pre-mRNA

Introns and exons that were transcribed from the DNA

mature RNA

RNA that has been processed before leaving the nucleus

Introns

Junk RNA sequences that will not be translated into a protein

Exons

RNA sequences that will be translated into a protein at the ribosome

Spicesosome

composed of snrps that re used to remove introns from pre-mRNA

E-site

holds the naked t-RNA molecules before they leave the ribosome

P-site

Holds the growing polypeptide at the ribosome

A-site

Site of codon recognition

mutation

error in DNA or RNA

frameshift mutation

error caused by the addition or deletion of a DNA or mRNA base

base substitution / point mutation

error caused by a single base being exchanged for a different base

aminoacyl t-RNA synthetase

enzyme that ensures that amino acids are connected to the correct tRNA molecules

codon

sequence of 3 mRNA bases that codes for 1 amino acid

sense/coding strand

Strand of DNA that is not used during transcription (5'-3')

template/antisense strand

Strand of DNA that is used during transcription (3'-5')

DNA Replication

process of making copies of DNA

anticodon

sequence of 3 tRNA bases

triplet

sequence of 3 bases on DNA that will code for 1 amino acid after being transcribed and translated

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Initiation

First step of transcription or translation

Elongation

Process of adding on more mRNA during transcription, or adding more amino acids during translation

termination

process of stopping transcription or translation