BCH 1.08 Lipids (EDIT LATER WHEN REVIEWING)

These flashcards cover essential concepts regarding fatty acids, triglycerides, and isoprenoids based on the lecture notes provided.

What are the two main structural classes of lipids?

Those based on fatty acid structure and those based on isoprenoid structure.

What are the two common naming conventions for fatty acids?

1) Δ (delta) notation and 2) ω (omega) notation.

What does the term 'cis' refer to in unsaturated fatty acids?

Cis refers to double bonds that create a bend in the structure, affecting membrane fluidity.

What is the significance of essential fatty acids?

Essential fatty acids, such as ω-3 and ω-6, are crucial for cardiovascular, immune, reproductive, and nervous systems.

What is the role of acetyl CoA in fatty acid synthesis?

Acetyl CoA serves as the substrate for fatty acid chains, combining with malonyl CoA during synthesis.

What effect do glucagon and insulin have on fatty acid synthesis?

Glucagon inhibits and insulin promotes fatty acid synthesis.

How are trans fats primarily formed?

Trans fats are primarily formed as a by-product of partial hydrogenation of vegetable oils.

What is the mechanism involved in cis and trans double-bonds in fatty acids?

Cis bonds create bends in fatty acid chains, while trans bonds lead to straighter chains which pack more tightly.

What is the basic structure of triglycerides?

Triglycerides consist of three fatty acids attached to a glycerol backbone.

What are eicosanoids derived from?

Eicosanoids are derived from arachidonic acid (20:4) or similar fatty acids.

What type of enzyme is HMG-CoA reductase, and what is its role in cholesterol synthesis?

HMG-CoA reductase is the rate-limiting enzyme that catalyzes the conversion of HMG-CoA to mevalonate, a crucial step in cholesterol synthesis.

What effect does high intracellular cholesterol have on HMG-CoA reductase?

High intracellular cholesterol inhibits the transcription of the HMG-CoA reductase gene, reducing cholesterol synthesis.

What are the three categories of terpenes identified in the lecture?

1) Monoterpenes, 2) Diterpenes, and 3) Triterpenes.

What can be a consequence of excess trans fat consumption?

Increased risk of coronary heart disease.

How does insulin affect fat synthesis?

Insulin promotes fatty acid synthesis by activating acetyl CoA carboxylase.

What is the property of phosphatidyl phospholipids in cellular membranes?

They have a glycerol backbone and two fatty acid chains or ceramines with a phosphate-alcohol head group.

What role do plant sterols play in human health?

Plant sterols compete with cholesterol for absorption in the intestines, potentially lowering LDL cholesterol levels.

What hormones regulate the activity of hormone-sensitive lipase (HSL)?

Glucagon and epinephrine activate HSL, while insulin inhibits it.

What is lipogenesis?

The process of synthesizing fatty acids and storing them as triglycerides.

What are glycosphingolipids, and where can they be found?

Glycosphingolipids are sphingolipids with carbohydrate head groups, commonly found in neuronal cell membranes.