Gene Expression 2: RNA Translation

The primary role of mRNA is to carry the genetic information from DNA and serve as a template for synthesizing proteins.

The genetic code is the relationship between nucleotide sequences in mRNA and the corresponding amino acids in a polypeptide chain, crucial for accurate protein synthesis.

The start codon AUG signals the initiation of protein synthesis and codes for the amino acid methionine.

<p>Degenerate genetic code means that multiple codons can specify the same amino acid, with exceptions for tryptophan and methionine.</p> Signup and view all the answers

<p>Wobble theory suggests that the third nucleotide in a codon is less critical for amino acid specificity, allowing flexibility in base pairing.</p> Signup and view all the answers

<p>tRNA acts as an adapter molecule that recognizes specific codons on mRNA and carries the corresponding amino acids.</p> Signup and view all the answers

<p>The directionality of mRNA, which is read from 5' to 3', ensures proper translation and synthesis of proteins in the correct sequence.</p> Signup and view all the answers

<p>The three stop codons are UAA, UAG, and UGA; they signal the termination of protein synthesis.</p> Signup and view all the answers

<p>It specifies the insertion of methionine in the growing peptide sequence.</p> Signup and view all the answers

<p>The genetic code is unambiguous because each codon corresponds to only one specific amino acid.</p> Signup and view all the answers

<p>The components required for translation include mRNA, tRNA, ribosomes, and various protein factors.</p> Signup and view all the answers

<p>The alpha amino group of the amino acid in the A site attacks the carboxylic group of the peptidyl-tRNA in the P site, facilitated by peptidyl transferase.</p> Signup and view all the answers

<p>Translocation is the movement of the newly formed peptidyl-tRNA from the A site to the P site, enabling the A site to receive a new aminoacyl-tRNA.</p> Signup and view all the answers

<p>The appearance of a stop codon (UAA, UAG, or UGA) in the A site signals termination.</p> Signup and view all the answers

<p>They recognize the stop codons in the A site and promote the hydrolysis of the bond between the peptide chain and tRNA at the P site.</p> Signup and view all the answers

<p>Four high-energy phosphate bonds are required.</p> Signup and view all the answers

<p>Molecular chaperones assist in the folding of proteins into their three-dimensional structures.</p> Signup and view all the answers

<p>Faulty proteins produced can be targeted for degradation or may function abnormally.</p> Signup and view all the answers

<p>The 80S ribosomal subunit, tRNA, mRNA, GDP, and inorganic phosphate (Pi) are released.</p> Signup and view all the answers

<p>ATP is hydrolyzed to AMP, resulting in the charging of tRNA with the amino acyl moiety.</p> Signup and view all the answers

<p>It ensures that each codon is read as a distinct triplet, preventing confusion between overlapping sequences.</p> Signup and view all the answers

<p>tRNA, rRNA, mRNA, eukaryotic initiation factors (eIFs), GTP, ATP, and specific amino acids.</p> Signup and view all the answers

<p>It specifically binds to the initiation codon AUG to start the protein synthesis process.</p> Signup and view all the answers

<p>It involves the attachment of a specific amino acid to the 3' hydroxyl group of tRNA in an ester linkage.</p> Signup and view all the answers

<p>The anticodon pairs with a specific codon on mRNA, ensuring the correct amino acid is added during protein synthesis.</p> Signup and view all the answers

<p>eukaryotic elongation factor-1 (eEF-1) and GTP activate the aminoacyl-tRNA, allowing it to bind to the A site.</p> Signup and view all the answers

<p>It allows for the transfer of genes between different organisms, facilitating advancements in genetic engineering.</p> Signup and view all the answers

<p>eIFs assist in the assembly of the initiation complex by binding to the ribosomal subunits and mRNA.</p> Signup and view all the answers

<p>It is the assembly of mRNA, initiator tRNA, and ribosomal subunits that begins the translation process.</p> Signup and view all the answers

<p>The A, P, and E sites accommodate the different stages of tRNA interaction during protein synthesis.</p> Signup and view all the answers

<p>The main purpose of proteolysis is to remove specific amino acid sequences, such as amino terminal and carboxy terminal residues, that are not needed for the protein's final functional form.</p> Signup and view all the answers

<p>Hydroxylation of proline and lysine is essential for the stability and proper formation of collagen, as it allows for the formation of hydrogen bonds between collagen molecules.</p> Signup and view all the answers

<p>Phosphorylation of serine, threonine, or tyrosine residues in proteins serves as a key regulatory mechanism in cell signaling pathways, altering protein activity and communication.</p> Signup and view all the answers

<p>Glycosylation is the attachment of carbohydrate (CHO) side chains to proteins, which stabilizes them against degradation and aids in proper folding for functional activity.</p> Signup and view all the answers

<p>Acylation involves adding fatty acids to protein side chains, which helps anchor proteins to cellular membranes and influences their functional roles.</p> Signup and view all the answers

<p>Bacterial protein synthesis inhibitors are antibiotics that disrupt the translation process in bacteria; examples include Tetracyclines and Macrolides like Erythromycin.</p> Signup and view all the answers

<p>Shiga toxin inhibits eukaryotic translation by acting on the 60S ribosomal subunit, preventing tRNA binding and disrupting protein synthesis.</p> Signup and view all the answers

<p>Diphtheria toxin poses severe health risks by inhibiting translocation in protein synthesis, potentially leading to breathing difficulties, heart failure, paralysis, and death.</p> Signup and view all the answers

<p>Signal peptides direct the translocation of newly synthesized proteins to their final destinations and are removed after the transport process.</p> Signup and view all the answers

<p>γ-Carboxylation of glutamic acid is a modification that enhances calcium binding in proteins like prothrombin and osteocalcin, which is vital for blood clotting and bone health.</p> Signup and view all the answers