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, splicing, and polyadenylation. The video details tRNA charging, emphasizing the role of aminoacyl-tRNA synthetase, which uses ATP to ligate amino acids to tRNA. Nutrient requirements for protein synthesis, such as ATP and amino acids, are discussed. The mechanism of Type 2 aminoacyl-tRNA synthetase is explored, highlighting its role in protein synthesis.

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 form the structural components of the ribosome

• To transport amino acids to the ribosome

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

• Conversion to DNA

• Addition of a 5' cap

• Splicing of exons

• Formation of a poly-A tail

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

• It is ready to be transcribed

• It is bound to an amino acid

• It has been converted to mRNA

• It has a phosphate group attached

Which nutrient is NOT directly rate-limiting for the charging of tRNA?

• Amino acids

• ATP

• tRNA

• Glucose

What class of enzymes do aminoacyl-tRNA synthetases belong to?

• Oxidoreductases

• Transferases

• Hydrolases

• Ligases

How many amino acids are specifically recognized by Type 2 aminoacyl-tRNA synthetases?

• 15

• 10

• 5

• 20

What is the initial nucleophile in the mechanism of Type 2 aminoacyl-tRNA synthetases?

• Amino group of the amino acid

• Hydroxyl group of the ribose

• Carboxyl group of the amino acid

• Phosphate group of ATP

What is the leaving group in the reaction catalyzed by Type 2 aminoacyl-tRNA synthetases?

• Adenosine monophosphate (AMP)

• Carbon dioxide

• Pyrophosphate

• Water

What type of bond is formed between the amino acid and tRNA in the Type 2 synthetase mechanism?

• Peptide bond

• Ester bond

• Glycosidic bond

• Phosphodiester bond

Why is the ester bond between the amino acid and tRNA important in protein synthesis?

• It is highly stable and prevents degradation

• It is reactive enough for the ribosome to transfer the amino acid

• It allows the tRNA to be recycled

• It provides energy for the ribosome