RNA Synthesis and Processing & Translation

Study essential vocabulary related to RNA synthesis, processing, and translation for a comprehensive understanding of gene expression.

Transcription

Process of making RNA from a DNA template.

Template Strand

The single DNA strand that serves as a template for RNA synthesis.

Nontemplate Strand

DNA strand whose sequence corresponds to the RNA transcript, with T instead of U.

RNA Polymerase (RNAP)

Enzyme that synthesizes RNA by reading the template DNA strand.

Promoter

DNA sequence where transcription proteins assemble.

Transcription Factors

Proteins that bind to promoters to direct RNA synthesis.

Terminator

Sequence of DNA where transcription ends.

Elongation

Phase of transcription where RNA is synthesized.

Termination

Phase of transcription where RNA synthesis ends.

Rho-Independent Termination

Termination of transcription that relies solely on features of the RNA transcript.

Rho-Dependent Termination

Termination requiring the rho protein to terminate transcription.

mRNA

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

Cap Structure

7-methylguanosine added to the 5’ end of mRNA for stability and protection.

Poly(A) Tail

A sequence of adenine nucleotides added to the 3’ end of mRNA for stability.

Splicing

Process of removing introns and joining exons in mRNA.

Introns

Non-coding sequences in a primary transcript that are removed during splicing.

Exons

Coding sequences in mRNA that are retained after splicing.

Ribozymes

Catalytic RNA molecules that can act as enzymes.

Group I Slicing

Self-splicing mechanism involving ribozymes in bacteria and some eukaryotes.

Alternative Splicing

Process that generates multiple mRNA transcripts from a single gene.

Translation

Process of synthesizing proteins based on the sequence of mRNA.

Codon

A three-nucleotide sequence on mRNA that encodes for a specific amino acid.

Degeneracy of Codons

Multiple codons can encode the same amino acid, reducing the effects of mutations.

Wobble Hypothesis

The first base of an anticodon can base pair loosely with multiple codons.

Point Mutation

A mutation that involves a single base change in DNA.

Missense Mutation

A mutation that changes one amino acid in a protein sequence.

Nonsense Mutation

A mutation that introduces a premature stop codon in the protein sequence.

Frameshift Mutation

A mutation caused by insertions or deletions that alters the reading frame.

Ribosome

The cellular structure where protein synthesis occurs.

Small Subunit of Ribosome

Component of the ribosome that binds mRNA and initiates translation.

Large Subunit of Ribosome

Component of the ribosome that forms peptide bonds between amino acids.

Initiation Factors (IFs)

Proteins that aid the initiation of translation in prokaryotes.

Elongation Factors (EFs)

Proteins that assist in the elongation phase of translation.

Release Factor (RF)

Protein that recognizes stop codons and ends translation.

Peptidyl Transferase

The ribosomal enzymatic activity that forms peptide bonds between amino acids.

Chaperones

Proteins that assist in the proper folding of other proteins.

Signal Sequence

A short amino acid sequence that directs the transport of proteins to their cellular destination.

Nuclear Localization Signal (NLS)

A sequence that directs proteins to the nucleus.

Post-translational Modification

Chemical changes to a protein after synthesis that allow it to function properly.

Ubiquitin

A small protein that tags other proteins for degradation.

Proteasome

A complex that degrades ubiquitinated proteins in eukaryotes.

Aminoacyl-tRNA

Transfer RNA that is linked to a specific amino acid.

tRNA Synthetase

Enzyme that attaches an amino acid to its corresponding tRNA.

5' Cap

Modification added to the 5' end of mRNA that protects it from degradation.

3' Poly(A) Tail

Modification added to the 3' end of mRNA that assists in stability and export.

Transcription Bubble

Region of unwound DNA where RNA synthesis occurs.

Spliceosome

Complex of snRNPs and snRNA that facilitates splicing.

N-terminal

The start of a protein, corresponding to the amino end.

C-terminal

The end of a protein, corresponding to the carboxyl end.

Codon Recognition

The pairing of codon bases on mRNA with their corresponding anticodon bases on tRNA.

Silencer

Region of DNA that represses gene transcription.

Enhancer

Region of DNA that increases rates of transcription.

Operon

A cluster of genes under the control of a single promoter in prokaryotes.

Genes per Transcript

Refers to the monocistronic nature of eukaryotic mRNAs as opposed to polycistronic prokaryotic mRNAs.

mRNA Processing

The modifications mRNA undergoes before it is translated.

RNA-Induced Silencing Complex (RISC)

Complex that mediates the effect of microRNA on mRNA.

Anticodon

Sequence of three nucleotides on tRNA complementary to a specific mRNA codon.

Ribosomal RNA (rRNA)

Constituent of ribosomes essential for protein synthesis.

Nucleolus

The cellular structure where rRNA synthesis and ribosome assembly occurs.

Ribosome Recycling

The process of disassembling ribosomes after translation termination.

A Site

Location on the ribosome where the incoming aminoacyl-tRNA binds.

P Site

Location on the ribosome where the peptidyl-tRNA is located.

E Site

Location on the ribosome where empty tRNA exits.

Clp Protease

A protease complex involved in degrading proteins in bacteria.

Signal Recognition Particle (SRP)

A ribonucleoprotein that targets proteins to the endoplasmic reticulum.

mRNA Scanning

The process by which ribosomes locate the start codon on mRNA.

Aminoacyl-AMP

Intermediate formed during the activation of amino acids for tRNA.

Peptide Bond

The bond formed between amino acids during protein synthesis.

Signal Receptor Particle

Complex that recognizes and binds to signal sequences on proteins.

RNA Cleavage

The cutting of RNA molecules that occurs during processing.

Nuclear Export Signals

Sequences that direct the transport of proteins from the nucleus to the cytoplasm.

Translocation

Process that moves tRNAs and mRNA through the ribosome.

RISC

RNA-induced silencing complex that regulates gene expression.

Hydrolysis

The reaction involving the breakdown of a compound due to the addition of water.

Translation Initiation Complex

The assembly of the ribosomal subunits and starts tRNA at the start codon.

Guanosine Triphosphate (GTP)

Energy molecule used in protein synthesis and other cellular processes.

C-terminal Domain (CTD)

Region of eukaryotic RNA polymerase II that plays a role in transcription regulation.