Methionine Metabolism and Activated Methyl Cycle | Pathway and Purpose

The video tutorial explains methionine metabolism, highlighting its role as an essential amino acid obtained from dietary sources. It details the methionine metabolism pathway, emphasizing the production of succinyl COA and its utilization in the TCA cycle for ATP generation. The tutorial covers the activated methyl cycle, the role of S-Adenosyl Methionine as a methyl donor, and the importance of vitamin B12-dependent enzymes. It also discusses the energy generation pathway from methionine, involving cystathionine and the TCA cycle.

What is the primary source of methionine for humans?

• Synthesis in the kidneys

• Synthesis in the pancreas

• Dietary intake

• Synthesis in the liver

Which cycle is methionine involved in for ATP production?

• Pentose phosphate pathway

• Urea cycle

• TCA cycle

• Glycolysis

What is the role of S-adenosylmethionine (SAM) in the body?

• Acts as a glucose donor

• Acts as a sulfate donor

• Acts as a phosphate donor

• Acts as a methyl donor

Which vitamin is crucial for the methionine metabolism pathway?

• Vitamin B12

• Vitamin D

• Vitamin C

• Vitamin K

What is the function of methionine synthase in the activated methyl cycle?

• Converts methionine to homocysteine

• Converts homocysteine to methionine

• Converts SAM to homocysteine

• Converts SAM to methionine

Which enzyme requires vitamin B6 in the methionine metabolism pathway?

• Cystathionine beta synthase

• Methylmalonyl CoA mutase

• Methionine synthase

• Adenosyl homocysteine hydrolase

What is the end product of methionine metabolism that enters the TCA cycle?

• Succinyl CoA

• Cystathionine

• Methylmalonyl CoA

• Propionyl CoA

Which enzyme is responsible for converting Methylmalonyl CoA to Succinyl CoA?

• Methylmalonyl CoA mutase

• Propionyl CoA carboxylase

• Cystathionine gamma lyase

• Methionine synthase

What is the role of cystathionine beta synthase in methionine metabolism?

• Converts homocysteine to cystathionine

• Converts cystathionine to homocysteine

• Converts SAM to cystathionine

• Converts methionine to homocysteine

Which two enzymes in humans require vitamin B12?

• Cystathionine beta synthase and propionyl CoA carboxylase

• Methylmalonyl CoA mutase and cystathionine gamma lyase

• Methionine synthase and cystathionine beta synthase

• Methionine synthase and methylmalonyl CoA mutase