From Genotype to Phenotype: The Mechanisms of Gene Expression

Central Dogma

The framework in biology that explains the flow of genetic information: DNA -> RNA -> Protein.

Gene Expression

The process by which DNA directs the synthesis of proteins or RNAs.

Transcription

The synthesis of an RNA molecule from a DNA template.

Template Strand

The DNA strand that is read by RNA Polymerase to synthesize RNA.

Coding Strand

The DNA strand that matches the sequence of RNA, except for uracil in RNA.

RNA Polymerase

The enzyme that synthesizes RNA from a DNA template.

Promoter

A specific DNA sequence where RNA Polymerase binds to initiate transcription.

TATA box

A crucial promoter sequence in eukaryotes.

Transcription Factors

Proteins that help RNA Polymerase bind to the promoter in eukaryotes.

Elongation

The stage in transcription where RNA Polymerase adds RNA nucleotides complementary to the template.

Terminator Sequence

A specific sequence in DNA that signals the end of transcription.

5' GTP Cap

A modified Guanine added to the 5' end of pre-mRNA for protection and ribosome attachment.

3' Poly-A Tail

A chain of adenine nucleotides added to the 3' end of pre-mRNA for stability and export.

RNA Splicing

The process of removing introns and joining exons in pre-mRNA.

Introns

Non-coding segments of RNA that are removed during splicing.

Exons

Coding sequences that are retained and joined together during RNA splicing.

Spliceosome

The complex of proteins and RNA that carries out RNA splicing.

Translation

The synthesis of a polypeptide directed by mRNA.

Codons

Sequences of three bases in mRNA that correspond to specific amino acids.

mRNA

Messenger RNA that carries genetic information from DNA to the ribosome.

tRNA

Transfer RNA that brings amino acids to the ribosome during translation.

rRNA

Ribosomal RNA that makes up the ribosome and catalyzes peptide bond formation.

A site

The ribosomal site where the tRNA carrying the next amino acid enters.

P site

The ribosomal site that holds the tRNA with the growing polypeptide chain.

E site

The ribosomal exit site where discharged tRNAs leave the ribosome.

Release Factor

A protein that binds to the stop codon and releases the polypeptide during termination.

Stop Codon

A codon that signals the end of translation.

Retroviruses

Viruses like HIV that copy RNA into DNA using reverse transcriptase.