Eicosanoid Biosynthesis [Part 2] | Leukotrienes

The video tutorial by Kevin Tolkoff covers the biosynthesis of leukotrienes, a class of eicosanoids. It begins with a review of eicosanoids, including prostaglandins and thromboxanes, and introduces arachidonic acid as a precursor. The tutorial explains the role of leukotrienes in allergic reactions, such as asthma, and details the enzymatic pathways involved in their synthesis, focusing on lipoxygenase enzymes. The video concludes with a comprehensive overview of the leukotriene synthesis pathway, highlighting key enzymes and intermediates.

What is the precursor molecule for eicosanoids like prostaglandins, thromboxanes, and leukotrienes?

• Linoleic acid

• Arachidonic acid

• Palmitic acid

• Stearic acid

Which enzyme is activated in response to an inflammatory stimulus to release arachidonic acid?

• Thromboxane synthase

• Phospholipase A2

• Lipoxygenase

• Cyclooxygenase

What is the role of leukotrienes in asthma?

• Dilate blood vessels

• Constrict airways

• Increase heart rate

• Reduce inflammation

Which enzyme catalyzes the conversion of arachidonic acid to 5-HPETE in leukotriene synthesis?

• Thromboxane synthase

• Cyclooxygenase

• Phospholipase C

• 5-Lipoxygenase

What is the first true leukotriene formed in the biosynthesis pathway?

• Leukotriene B4

• Leukotriene C4

• Leukotriene D4

• Leukotriene A4

Which compound is conjugated to leukotriene A4 to form leukotriene C4?

• Glutamate

• Glutathione

• Cysteine

• Glycine

What is the role of peptidases in the conversion of leukotriene C4?

• Convert to hydroxyl group

• Add amino acids

• Remove amino acids

• Form double bonds

Which enzyme is involved in the committed step of leukotriene synthesis?

• 5-Lipoxygenase

• Cyclooxygenase

• Thromboxane synthase

• Phospholipase A2

How do leukotrienes differ from prostaglandins in their synthesis?

• Leukotrienes use cyclooxygenase

• Leukotrienes use lipoxygenase

• Leukotrienes are not derived from arachidonic acid

• Leukotrienes are synthesized in the nucleus

What is the function of lipoxins in the immune response?

• Induce fever

• Stimulate antibody production

• Resolve inflammation

• Enhance inflammation