Exam 26: Lipids

What functional group of the protein opsin reacts with retinal to form rhodopsin, a light-sensitive pigment?

The following tetracylic structure is common to steroids, an importnat class of biomolecules that have a number of sterocenters. Modify the structure on the right by placing the hydrogen atoms and methyl groups to accurately depict the structure on the left (including steeochemistry).

Arachidonic acid is a C₂₀ acid that is involved in the biosynthesis of prostaglandins, an important class of biomolecules. Provide the IUPAC name of arachidinic acid.

How many triglycerides (including stereoisomers) are there which contain one molecule of stearic acid, one of myristic acid and one of arachidic acid?

Which of the following is not true?

The main difference between fats and oils is that oils contain a lower percentage of unsaturated alkyl chains.

Circle the hydrophilic part of sodium palmitate, a soap that is the sodium salt of a fatty acid, and put a rectangle around the hydrophobic part.

Explain the formation of "soap scum", formed in areas which have "hard" water. What chemical reaction takes place, and what physical process results?

An example of a cationic detergent is shown below.

The chiral centers in $\alpha$ -santonin are indicated by asterisks in the following.

What is the biological precursor of prostaglandins?

Which of the following is not an intermediate in the biosynthesis of cholesterol?

Salts of long chain fatty acids are called detergents.

Which of the following processes is used to harden an oil to give a fat?

Provide the general structure of a triglyceride.

Consider the following structures. Use these to answer the following questions by placing the appropriate Roman numerical in the blank. -Saponification followed by protonation of structure _____ produces two moles of the salt of stearic acid and one mole of the salt of oleic acid.

Which of the following fatty acids has the highest melting point?

Describe how the structure of a phospholipid differs from that of a trigyceride fat, and what influence this difference has on the interaction of these molecules with water.

Female sex hormones like estrone are called _____________.

Consider the following. Structure ____ would be classified as an synthetic detergent.