Aminoacyl tRNA Synthetase Class II Physiology, Biochemistry, and Mechanism

The video reviews the central dogma of molecular biology, focusing on DNA transcription to RNA and translation to proteins. It explains RNA processing, including mRNA capping and splicing, and the charging of tRNA with amino acids. The role of aminoacyl-tRNA synthetases in protein synthesis is detailed, highlighting the importance of ATP and amino acids as nutrients. The video also covers the mechanism of Type 2 synthetases, emphasizing the ligation of amino acids to tRNA.

What is the primary role of messenger RNA (mRNA) in the cell?

• To catalyze chemical reactions

• To carry genetic information from DNA to the ribosome

• To transport amino acids to the ribosome

• To form the structure of ribosomes

Which of the following is NOT a step in mRNA processing?

• Addition of a 5' cap

• Addition of a poly-A tail

• Splicing of introns

• Formation of peptide bonds

What does it mean when a tRNA is 'charged'?

• It is in the nucleus

• It is bound to an amino acid

• It has a phosphate group attached

• It is ready to be transcribed

Which nutrient is NOT directly rate-limiting for protein synthesis?

• Glucose

• Amino acids

• tRNA

• ATP

What is the main difference between Type 1 and Type 2 aminoacyl-tRNA synthetases?

• Type 1 uses GTP, Type 2 uses ATP

• Type 1 attaches amino acids to the 3' hydroxyl group, Type 2 to the 2' hydroxyl group

• Type 1 attaches amino acids to the 2' hydroxyl group, Type 2 to the 3' hydroxyl group

• Type 1 is found in prokaryotes, Type 2 in eukaryotes

Which of the following amino acids is NOT charged by Type 2 aminoacyl-tRNA synthetases?

• Alanine

• Glycine

• Lysine

• Valine

What is the role of pyrophosphate in the reaction catalyzed by aminoacyl-tRNA synthetases?

• It stabilizes the enzyme

• It inhibits the reaction

• It is a byproduct that drives the reaction forward

• It acts as a substrate

In the mechanism of Type 2 aminoacyl-tRNA synthetases, what type of bond is formed between the amino acid and tRNA?

• Peptide bond

• Phosphodiester bond

• Ester bond

• Glycosidic bond

What is the significance of the ester bond formed in the Type 2 synthetase mechanism?

• It prevents the amino acid from being used

• It is more stable than an amide bond

• It is not involved in the reaction

• It is less stable and allows for easy transfer of the amino acid

Which enzyme class do aminoacyl-tRNA synthetases belong to?

• Oxidoreductases

• Transferases

• Ligases

• Hydrolases