Cholesterol Biosynthesis Stage 4 Conversion of Lanosterol to Cholesterol

The video tutorial explains the process of cholesterol synthesis, starting from the generation of mevalonic acid to the conversion of lanosterol into mature cholesterol. It highlights the differences between lanosterol and cholesterol, focusing on the removal of methyl groups and the repositioning of double bonds. The tutorial also covers the generation of xima sterile and the role of various enzymes, such as 24 reductase and isomerase, in the pathway. Additionally, it discusses the significance of 7-dehydrocholesterol in vitamin D synthesis and the various functions of cholesterol, including its role in bile acid and steroid production, as well as membrane stabilization.

What is the first molecule in the cholesterol synthesis pathway that resembles cholesterol?

• Squalene

• Lanosterol

• Isoprene

• Mevalonic acid

Which structural feature of lanosterol is NOT present in cholesterol?

• A double bond in the tail

• A six-membered ring

• A methyl group sticking down

• A five-membered ring

Which enzyme is responsible for reducing the double bond on the tail of lanosterol?

• Isomerase

• Squalene monooxygenase

• 24 reductase

• Lanosterol oxidase

What is the role of 24 reductase in cholesterol synthesis?

• It reduces the double bond on the tail of lanosterol.

• It converts lanosterol to squalene.

• It removes methyl groups from lanosterol.

• It adds a double bond to lanosterol.

Which molecule can be converted into vitamin D during cholesterol synthesis?

• Lanosterol

• 7-dehydrocholesterol

• Mevalonic acid

• Squalene

What is one of the functions of cholesterol in the body?

• It is a primary energy source.

• It forms the backbone of DNA.

• It is used to synthesize glucose.

• It acts as a precursor for bile acids.

Which enzyme catalyzes the conversion of 7-dehydrocholesterol to cholesterol?

• Squalene monooxygenase

• 24 reductase

• 7-dehydrocholesterol reductase

• Lanosterol oxidase