Chorismate, Phenylalanine, Tyrosine Biosynthesis

The video tutorial discusses the synthesis of aromatic amino acids, focusing on phenylalanine, tyrosine, and tryptophan, which share a common precursor, chorismate. The synthesis of chorismate involves high-energy molecules from glycolysis and the pentose phosphate pathway. The video also covers the biosynthesis pathways of tyrosine and phenylalanine, highlighting the essential nature of these amino acids for humans, as they cannot be synthesized de novo. The tutorial emphasizes the energy-intensive nature of these biosynthetic processes and the role of specific enzymes in the pathways.

Which amino acid does not share the same precursor as phenylalanine, tyrosine, and tryptophan?

• Histidine

• Lysine

• Methionine

• Valine

What are the two molecules used in the synthesis of chorismate?

• Pyruvate and lactate

• Acetyl-CoA and oxaloacetate

• Phosphoenolpyruvate and erythrose 4-phosphate

• Glucose and fructose

Which pathway provides erythrose 4-phosphate for chorismate synthesis?

• Glycolysis

• Citric Acid Cycle

• Pentose Phosphate Pathway

• Urea Cycle

What enzyme is involved in the conversion of chorismate to prephenate?

• Prephenate dehydrogenase

• Tyrosine aminotransferase

• Prephenate synthase

• Phenylalanine hydroxylase

Which molecule is formed when prephenate is converted towards tyrosine synthesis?

• 4-Hydroxyphenylpyruvate

• Phenylpyruvate

• Acetyl-CoA

• Oxaloacetate

Why is tyrosine considered essential despite being listed as non-essential?

• It is synthesized from phenylalanine, which must be obtained from the diet

• It is synthesized from histidine

• Humans can synthesize it from glucose

• It is produced in large amounts in the liver

What is the role of phenylalanine hydroxylase in humans?

• Synthesizes chorismate

• Degrades tryptophan

• Converts tyrosine to phenylalanine

• Converts phenylalanine to tyrosine