Carbohydrates and Lipids

What are the major functions of lipids?

1. Energy storage via triglycerides 2. Providing structural elemnts of cells and organelles 3. Signal transduction in the form of hormone precursors.

What is starch?

Alpha-1,4-linked D-glucose units (storage polysaccharide in plants)

What is Glycogen?

Alpha-1,4-linked D-glucose units with more alpha-1,6 branches than starch.

What are lipopolysaccharides (LPS)?

Bacterial endotoxin which interacts with host TLR4 to initiate inflammatory response.

What is Chitin?

Beta-1,4 linked N-acetylglucosamine units. Cell wall of fungi and exoskeletons of insects.

What is cellulose?

Beta-1,4-linked D-glucose units (found in plant cell wall)

What is common to carbohydrates and lipids?

Both are major sources of energy for the body.

How are carbohydrates stored?

Carbohydrates are stored as glycogen

What is the most abundant of all carbohydrates?

Cellulose

What determines chirality in carbohydrates?

Chirality of carbohydrates is determined by the orientation of the highest numbered asymmetric chiral center (furthest from aldehyde or keto group)

What is the second most abundant carbohydrate?

Chitin

What are unsaturated fatty acids?

Contain one or more double bond in carbon tail.

When the highest numbered asymmetric chiral center points to the right in a fischer projection, the carbohydrate is which type?

D-Family

Carbohydrates in the body are typically found in which configuration?

D-Family.

What polysaccharide is found in dental plaques?

Dextrans

What is the most common storage polysaccharide in animals?

Glycogen

When the highest numbered asymmetric chiral center points to the left in a fischer projection, the carbohydrate is which type?

L-Family

What is cholesterol?

Lipid found only in animal fat. Synthesized and degraded in liver.

How are lipids stored?

Lipids are stored as triglycerides

What are saturdated fatty acids?

Saturated fatty acids do not contain any double bonds in the carbon chain and are very hydrophobic.

What are sphingolipids?

Similar to triacylglycerols but have sphingosine backbone, not glycerol. Found on outer surface of plasma membranes as recognition sites - responsible for blood groups.

What are terpenes?

Simple lipids that lack a fatty acid component. They are responsible for flavors and odors.

What is the most common storage polysaccharide in plants?

Starch

As the fatty acid chain increases in length, what happens to the melting point?

The melting point increases.

As more double bonds are introduced into the carbon chain of fatty acids, what happens to the solubility in water?

The solubility increases with the number of double bonds.

What are dextrans?

alpha-1,4, alpha-1,6, and alpha-1,3-linked glucose units. Found in dental plaques.