Purine
2 rings of carbon+nitrogen
Pyrimidine
1 ring of carbon
Introns
The intervening sequences, and are “blank”
Exons
The sequences that code for proteins and are “expressed”
Double Helix
Two DNA strands that are bound together and then are twisted
Nucleotide
1 phos
1 deoxyribose
1 nitrogen base
Monomer of nucleic acids
Replication
Before a cell can divide in two to make daughter cells, first the cell’s DNA must copy itself
Helicase
Enzymes that unwind the DNA and break the hydrogen bonds between strands.
Replication fork
A “Y” shaped DNA that appears at many places along the length of the DNA molecule and speeds up replication.
Polymerase
Enzymes that add new nucleotides to the single strands of DNA and proofread the DNA molecule and remove incorrect nucleotides
Transcription
The info from the DNA sequence is rewritten as messenger RNA
Translation
The process of using mRNA to assemble a sequence of amino acids into a protein
Codon
3 mRNA nucleotides that code for a specific amino acid
Mutation
Any change in the nucleotide sequence of DNA
Insertion
An excess base is inserted
Deletion
A base is accidentally deleted
Substitution
Replaces one base with another
DNA
A long, thin molecule that stores heredity information