Polypeptides
the name for a long chain of amino acids
Genetic Code
collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis; the bases in RNA that form a "language" from four letters A, C, G, U
Codon
a group of three consecutive nucleotide bases in messenger RNA that specifies a particular amino acid to be incorporated onto a protein, read by tRNA
Translation
the decoding process of the sequence of bases in mRNA message into a sequence of amino acids making up a protein, ribosomes using the sequence of codons in mRNA to assemble amino acids into polypeptide chains
Steps of translation
1) ribosome attaches to an mRNA molecule in cytoplasm
2) each codon passes through ribosome, tRNAs bring proper amino acids (anticodons) into ribosome
3) ribosome attaches amino acids into a growing chain
4) ribosome has second binding sit for next tRNA m
Anticodon
Three unpaired bases on tRNA molecule, complementary to one mRNA codon
Central Dogma of Molecular Biology
Information is transferred from DNA to RNA to protein (many exceptions, such as viruses transferring in opposite direction from RNA to DNA), useful generalization
Gene Expression
Process by which a gene produces its product and the product carries out its function
Start Codon
Methionine codon AUG, initiates protein synthesis
Stop Codon
Ends translation, 3 stop codons exist
Sequence of nucleotide bases in an mRNA Molecule
Set of instructions that gives the order in which amino acids should be joined to produce a polypeptide
In translation, ribosomes...
Use the sequence of codons in mRNA to assemble amino acids into polypeptide chains
Roles of tRNA, rRNA and mRNA in translation
mRNA- carries coded message that directs the process
tRNA- delivers exactly the right amino acid called for by each codon on the mRNA (adaptors that enable the ribosome to 'read' mRNA messages and get them right)
rRNA- ribosomes are composed of 3 or 4 of