Transcription, RNA processing, and translation; mutations

Promoter

DNA sequence where RNA polymerase binds to begin transcription

Transcription initiation

Beginning stage of transcription where RNA polymerase binds DNA

Transcription elongation

Stage where RNA polymerase adds RNA nucleotides

Transcription termination

Stage where transcription stops and RNA is released

Primary transcript

Initial RNA molecule produced during transcription

Mature RNA

Processed mRNA ready for translation.

Transcription Unit

DNA region transcribed into RNA

Regulatory element

DNA sequence that controls gene expression

Nuclear envelope

Double membrane surrounding the nucleus

Inner and outer nuclear membranes

Two membranes forming the nuclear envelope

RNA processing

Modifications made to RNA before it functions

Nuclear pore

Opening in the nuclear envelope allowing transport between nucleus and cytoplasm

5’ Cap

Modified guanine nucleotide added to the beginning of eukaryotic mRNA

Polyadenylation

Addition of adenine nucleotides to the 3’ end of mRNA

Poly A tail

String of adenines added to mRNA for stability and export.

RNA splicing

Removal of introns and joining of exons.

Intron

Noncoding sequence removed from RNA

Exon

Coding sequence retained in mature mRNA.

5’ and 3’ splice sites

Boundaries where introns are cut out.

Alternative splicing

Process where different combinations of exons produce different proteins.

Transfer RNA (tRNA)

RNA molecule that carries amino acids to the ribosome

Anticodon

Three-base sequence on tRNA complementary to an mRNA codon

Aminoacyl tRNA synthetase

Enzyme that attaches the correct amino acid to a tRNA

tRNA charging

Attachment of an amino acid to its tRNA

Ribosomal RNA (rRNA)

RNA component of the ribosome.

Ribosomal protein

Protein component of the ribosome.

Small and large ribosomal subunits

Two ribosome parts that work together during translation.

Aminoacyl tRNA

tRNA carrying an amino acid.

Peptidyl tRNA

tRNA holding the growing polypeptide chain

E, P, and A sites

Ribosome binding sites for tRNAs during translation

Translation initiation

Beginning stage of translation

Translation elongation

Stage where amino acids are added to the growing protein

Translation termination

End of translation when the protein is released

Peptidyl transferase

Ribosomal activity that forms peptide bonds

Translocation

Ribosome movement along mRNA during translation

Release factor

Protein that recognizes stop codons and ends translation

Insertion

Mutation adding one or more nucleotides.

Deletion

Mutation removing one or more nucleotides

Silent mutation

Mutation that does not change the amino acid sequence

Missense mutation

Mutation that changes one amino acid

Nonsense mutation

Mutation that creates a stop codon prematurely

Frameshift mutation

Mutation that shifts the reading frame by insertion or deletion