Translation and Genetic Code

These flashcards cover key terms related to the process of translation and the genetic code in protein synthesis.

Translation

The process of converting information stored in nucleic acid sequences into proteins.

Genetic Code

The set of rules by which information encoded in genetic material is translated into proteins.

Codon

A sequence of three nucleotides in mRNA that specifies a particular amino acid.

Triplet Code

The genetic code is read in groups of three nucleotides, called codons.

AUG

The start codon that codes for Methionine and initiates translation.

Stop Codons

Codons that signal the end of translation; UAA, UAG, UGA.

tRNA (transfer RNA)

Molecules that carry amino acids to the ribosome during protein synthesis.

Peptidyl transferase

An enzymatic activity of the ribosome that forms peptide bonds between amino acids.

Initiation Factors

Proteins that assist in the assembly of the ribosome and initiation of translation.

Elongation Factors

Proteins that facilitate the elongation of the peptide chain during translation.

Wobble Hypothesis

The assumption that the correspondence between the 3rd base of a codon and an anti-codon can be less specific.

Degeneracy of the Code

The phenomenon where most amino acids are coded by more than one codon.

Exons

Coding segments of a gene that are expressed.

Introns

Non-coding segments of a gene that are spliced out during RNA processing.

Aminoacyl-tRNA Synthetase

Enzymes that attach the correct amino acid to its corresponding tRNA.

Hydrolysis of GTP

A process that provides energy for the translation process and is crucial for the binding of elongation factors.

70S Ribosome Initiation Complex

The assembled complex of mRNA, initiator tRNA, and ribosomal subunits ready for translation to begin.

What is cellular translation?

Cellular translation is the process by which ribosomes synthesize proteins using messenger RNA (mRNA) as a template.

What is mRNA?

mRNA, or messenger RNA, is a type of RNA that carries genetic information from DNA to the ribosome, where it serves as a template for protein synthesis.

What are ribosomes?

Ribosomes are molecular machines in the cell that facilitate the translation of mRNA into proteins.

What is tRNA?

tRNA, or transfer RNA, is a type of RNA that transports amino acids to the ribosome during protein synthesis, matching them to the coded mRNA sequence.

What is an amino acid?

Amino acids are the building blocks of proteins, and they are linked together by peptide bonds during the translation process.

What role does the start codon play in translation?

The start codon, typically AUG, signals the beginning of protein synthesis and the starting point for reading the mRNA sequence.

What is a stop codon?

A stop codon is a nucleotide sequence in mRNA that signals the end of protein synthesis, instructing the ribosome to release the newly formed protein.

What is the significance of the genetic code?

The genetic code is a set of rules that translates nucleotide sequences in mRNA into a sequence of amino acids, determining the structure and function of proteins.

How does post-translational modification affect proteins?

Post-translational modifications are chemical alterations that occur to proteins after translation, influencing their function, activity, and location within the cell.

What is the difference between transcription and translation?

Transcription is the process where DNA is copied into mRNA, whereas translation is the process where mRNA is used to synthesize proteins.

What is the role of the small ribosomal subunit in translation?

The small ribosomal subunit binds to mRNA and reads the codons to determine the correct tRNA and amino acids to be added.

What is the role of the large ribosomal subunit in translation?

The large ribosomal subunit catalyzes the formation of peptide bonds between amino acids, facilitating protein synthesis.

What is elongation in translation?

Elongation is the phase of translation where tRNAs bring amino acids to the ribosome, and the polypeptide chain is formed.

What is initiation in translation?

Initiation is the first step of translation, where the ribosome assembles around the start codon of the mRNA.

What happens during termination in translation?

Termination occurs when a stop codon is reached, prompting the release factors to prompt the ribosome to release the completed polypeptide.

What is a polypeptide chain?

A polypeptide chain is a sequence of amino acids linked by peptide bonds, which folds into a functional protein.

What role do initiation factors play in translation?

Initiation factors are proteins that assist in the assembly of the ribosome and the initiation of translation at the start codon.

What are release factors?

Release factors are proteins that recognize stop codons during termination and promote the release of the newly formed polypeptide from the ribosome.

What is the importance of codon-anticodon pairing?

Codon-anticodon pairing ensures that the correct tRNA delivers the appropriate amino acid to match the mRNA sequence during translation.

How does the cytosol relate to translation?

The cytosol is the fluid component of the cytoplasm where ribosomes and translation processes occur, facilitating protein synthesis.

What are translation inhibitors?

Translation inhibitors are substances that prevent protein synthesis by interfering with the ribosomes or the translation process.

What is elongation factor Tu (EF-Tu)?

Elongation factor Tu (EF-Tu) is a protein that helps bring the correct aminoacyl-tRNA to the ribosome during the elongation phase.

What is the difference between free and bound ribosomes?

Free ribosomes are suspended in the cytosol and synthesize proteins that function within the cytoplasm, while bound ribosomes are attached to the endoplasmic reticulum and produce proteins for export or for use in membranes.

What is the role of chaperones in protein folding?

Chaperones are proteins that assist in the proper folding of polypeptides, ensuring they achieve the correct three-dimensional structure.

What is the significance of protein domains?

Protein domains are distinct functional and structural units within a protein, each responsible for different activities or interactions.

What are post-translational modifications?

Post-translational modifications are chemical changes to a protein after synthesis, such as phosphorylation or glycosylation, that can affect its activity and stability.

What is the purpose of signal peptides?

Signal peptides are short amino acid sequences that direct the transport of a protein to specific locations within or outside the cell.

What is a polysome?

A polysome is a cluster of ribosomes translating the same mRNA strand simultaneously, allowing for efficient protein synthesis.

What are molecular chaperones?

Molecular chaperones are proteins that assist other proteins in folding correctly without being part of the final structure.

What is the role of nucleotides in translation?

Nucleotides provide the building blocks for RNA and also serve as energy carriers (e.g., GTP) during the translation process.