W11 L1 - Lipids

Flashcards about lipids and cell membranes.

What are the three major types of lipids that will be discussed?

Glycerophospholipids, Sphingolipids, and Sterols.

What are carbohydrates such as glycogen and starch made of?

A whole bunch of sugars

Why are fatty acids better storage molecules than carbohydrates?

Their potential for oxidation is very high

What defines lipids?

Insolubility in water

Name three examples of lipids.

Oils, fats, and waxes.

Describe the basic structure of a fatty acid.

It has a polar head group (carbonyl group) and a long hydrocarbon aliphatic chain.

What determines the saturation of a fatty acid?

The single and double bond character of the hydrocarbon chain.

In naturally occurring fatty acids, are double bonds usually in cis or trans configuration?

Cis, which introduces a bend in the structure.

How does the presence of kinks in unsaturated fatty acids affect their packing?

Kinks prevent the molecules from packing together as easily.

What does '18:0' signify in the nomenclature of fatty acids?

18 carbons in the chain and 0 double bonds.

How do you designate the position of double bonds in fatty acid nomenclature?

Count from the carboxyl end (carbon number one) and indicate the position of the first carbon in the double bond.

How are omega-3 and omega-6 fatty acids named?

Based on the position of the double bond from the omega carbon (the bottom carbon).

How does increasing the length of the hydrocarbon chain affect the melting temperature of a fatty acid?

The melting temperature increases.

How does increasing the number of double bonds in the aliphatic chain affect the melting temperature?

The melting temperature decreases.

Why are trans fatty acids considered unhealthy?

They increase the chances of cardiovascular disease.

What is the structure of a triacylglycerol?

Glycerol with three fatty acids attached through ester linkages.

Why do triglycerides store more energy and weigh less than carbohydrates?

They store more energy because there are multiple fatty acids together and they weigh less because they exclude more water.

What three components make up glycerophospholipids?

Glycerol, two fatty acids, phosphate with a head group attached.

How are phosphoglycerides named?

Based on the head group. For example, phosphatidylserine when there's a serine there, phosphatidylcholine when there's a choline there.

What is unique about cardiolipin?

It has a repeat of the phosphoglyceride structure, resulting in four fatty acid chains.

Instead of a glycerol bridge, what acts as the bridge in sphingolipids?

Sphingosine

What role do oligosaccharides play when attached to lipids (gangliosides)?

Cell recognition, ABO blood groups.

What is the basic structure of sterols?

Four fused rings

Name the major sterol in animals.

Cholesterol

What functions do sterols perform?

Act as hormones, play roles in pigmentation, vision, communication and pheromones.