nucleotide

a molecule made of a phosphate group a pentose sugar and a nitrogenous base

purine

a large double ring nitrogen base such as adenine or guanine

pyrimidine

a small single-ring nitrogen base such as cytosine (C), thymine (T), or uracil (U)

complementary bases

bases that pair together in dna adenine with thymine and guanine with cytosine

double helix

the twisted ladder shape of dna made of two strands of nucleotides

transformation

the process where a cell absorbs external dna and changes genotype and phenotype

griffith experiment

an experiment showing harmless bacteria became harmful by absorbing dna from heat killed pathogenic bacteria

avery mccarty macleod experiment

an experiment proving dna is the transforming agent that changes bacteria

hershey chase experiment

an experiment using bacteriophages showing that dna enters bacteria not protein

chargaff rule

the rule that adenine equals thymine and guanine equals cytosine in dna

helicase

the enzyme that unzips and untwists dna by breaking hydrogen bonds

dna polymerase

the enzyme that builds new dna nucleotides using a dna template

leading strand

the dna strand that is built continuously in the five to three direction

lagging strand

the dna strand built discontinuously in fragments because it runs three to five

okazaki fragments

short dna pieces made on the lagging strand during replication

dna ligase

the enzyme that connects okazaki fragments into a continuous strand

nuclease

the enzyme that removes damaged dna during repair

transcription

the process of making rna from a dna template in the nucleus

rna polymerase

the enzyme that builds rna nucleotides from a dna template

tata box

a promoter region of dna where transcription begins

terminator sequence

a dna sequence that stops transcription

mRNA

messenger rna that carries genetic code to the ribosome

tRNA

transfer rna that carries amino acids and has an anticodon

rRNA

ribosomal rna that forms the structure of ribosomes

codon

a three base sequence on mrna that codes for an amino acid

anticodon

a three base sequence on trna that pairs with an mrna codon

translation

the process of building a protein from an mrna sequence at a ribosome

ribosome A site

the site where a new trna enters with an amino acid

ribosome P site

the site holding the trna with the growing amino acid chain

ribosome E site

the exit site where used trna molecules leave

start codon

the first mRNA codon AUG that begins translation

stop codon

a codon such as uga uag or uaa that ends translation

genetic code

the dictionary showing which amino acid each mrna codon codes for

polyribosome

a chain of ribosomes translating the same mrna at once

point mutation

a mutation where one base is substituted for another

silent mutation

a point mutation that does not change the amino acid

missense mutation

a point mutation that changes the amino acid

nonsense mutation

a point mutation that changes a codon to a stop codon

frameshift mutation

a mutation caused by base addition or deletion that shifts the reading frame

AUG is

Methionine