Ch 17 From Gene to Protein: The Central Dogma of Biology

Central Dogma

Flow of genetic information: DNA to RNA to protein.

Gene Expression

Process of producing proteins from genes.

Transcription

Synthesis of mRNA from DNA template.

Translation

Synthesis of polypeptide from mRNA.

Metabolic Studies

Research linking genes to enzyme production.

One Gene-One Enzyme Hypothesis

Each gene encodes a specific enzyme.

One Gene-One Polypeptide Hypothesis

Each gene encodes a specific polypeptide.

Template Strand

DNA strand used for mRNA synthesis.

mRNA

Messenger RNA, carries genetic information.

Codons

Triplets of nucleotides coding for amino acids.

Reading Frame

Correct grouping of codons during translation.

RNA Polymerase

Enzyme that synthesizes RNA from DNA.

Promoter

DNA sequence where RNA polymerase binds.

Terminator

Sequence signaling end of transcription.

5' Cap

Modified guanine added to mRNA for stability.

3' Poly-A Tail

String of adenines added for mRNA protection.

RNA Splicing

Process of removing introns and joining exons.

snRNPs

Small nuclear ribonucleoproteins involved in splicing.

Spliceosome

Complex that catalyzes RNA splicing.

Chaperonin

Protein assisting in proper polypeptide folding.

Aminoacyl-tRNA Synthetase

Enzyme linking tRNA to its specific amino acid.

Ribosome

Site of protein synthesis, composed of rRNA.

Polyribosomes

Multiple ribosomes translating a single mRNA.

Signal Peptide

Sequence directing protein to its cellular destination.

Mutations

Changes in genetic material affecting protein function.

Point Mutations

Alterations in a single nucleotide pair.

Base-Pair Substitution

Replacement of one nucleotide pair with another.

Missense Mutation

Mutation resulting in a different amino acid.

Nonsense Mutation

Mutation creating a premature stop codon.

Frameshift Mutation

Insertion or deletion altering reading frame.

Mutagens

Agents causing genetic mutations.

Eukaryotic Transcription

Occurs in nucleus, involves RNA processing.

Prokaryotic Transcription

Occurs in cytoplasm, no RNA processing.