Chromosome
Single, long piece of DNA that is associated with proteins in a condensed structure
Chromatin
DNA and protein complex
Histones
Any group of basic proteins found in chromatin
Nucleosome
First level of chromosomal organization
Euchromatin
Portions of chromosomes that exist in extended state
Heterochromatin
Highly condensed region of chromosome
Epigenetics
the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself
DNA Replication
Process of copying DNA during cell division
Replication Origins
Specific DNA sequence recognized by initiator proteins
Initiator Protein
Break hydrogen bonds between bases of two DNA strands
DNA Polymerase
Enzyme that catalyzes addition of new base pairs to template strand of DNA
RNA Primers
Short (10 nucleotides long) sequence of RNA added to DNA
Telomeres
Long, repetitive nucleotide sequences at the ends of chromosomes
Telomerase
Enzyme that contains RNA sequence to add repetitive DNA segments to lagging strand
Mutation
Alteration of DNA structure that influences protein expression
Depurination
Removal of a purine base from DNA
Deamination
Spontaneous loss of amino group from cytosine to create uracil
Thymine Dimers
UV radiation causes two thymine molecules in close proximity to bond together
Transcription
Conversion of DNA to RNA
Promoter
Specific sequence of DNA that lies immediately upstream of the starting point for RNA synthesis and requires activation to bind RNA polymerase
tRNA
Carries amino acids to ribosomes and recognizes codons of mRNA
Wobble
Flexible base pairing of anticodon on tRNA to mRNA codon
Initiator tRNA
Specialized tRNA that recognizes the AUG codon
Polyribosomes
Multiple ribosomes translate the same mRNA at one time
Genes
Segment of DNA that holds a nucleotide sequence that codes for a particular protein