11.11: End of Chapter Problems
Fatty Acids
1. In terms of structure what distinguishes:
a. fatty acids from carboxylic acids
b. saturated fatty acid from unsaturated fatty acid.
2. Which has lower melting point? Explain.
a. lauric acid or myristic acid.
b. linoleic acid or oleic acid
Waxes
1. List the biological functions of waxes.
2. What property of waxes allows them to fulfill their primary biological functions?
Triglycerides
1. Construct a triglyceride from myristic acid, palmitic acid, oleic acid, and glycerol. Would you expect the triglyceride to be a liquid or a solid at room temperature? Explain.
2. List biological functions of triglycerides.
3. Why are triglycerides not found in cell membranes?
4. Explain with IMF's why butter is a fat (solid) at room temperature?
5. Explain with IMF's why canola oil is a liquid at room temperature?
6. True or False
a. Triglycerides are carboxylic acids
b. Saturated fats contain only saturated fatty acids.
c. Unsaturated fats contain only unsaturated fatty acids.
Reactions of Lipids
1. Vegetable oils tend to become rancid more quickly than animal fats. Why?
2. Vegetable oils are easier to digest than animal fats. Why?
3. List four different ways to slow the spoilage (rancidity) of vegetable oil.
4. What does it mean to partially hydrogenate vegetable oil?
5. What are trans fats? How are they produced? Why do restaurants ban the use of trans fats in Ca?
6. Why do food companies partially hydrogenate vegetable oils? Why do they not fully hydrogenate vegetable oils?
7. Which is likely to have most trans-fats: vegetable oil, margarine, or butter? Explain.
8. Draw the products formed when the triglyceride below is saponified. Label each compound in the reaction based on the solubility classification.
9. Draw a picture of a soap micelle and clearly label the parts that interact with water and grease. Explain how soap works to clean grease in your hands.
10. What is hard water? Explain what happens when a soap interacts with a hard water ion.
Steroids
1. How is cholesterol used in the human body?
2. What are the biological functions of HDL and LDL?
3. What are the signs of heart disease in terms of HDL and LDL?
4. A person whose diet contains no cholesterol can still have high cholesterol levels. Explain.
5. What is the role of bile salts in digestion?
Membranes & Transport
1. Draw a sketch of the lipid bilayer. Name the kinds of lipids that make up membrane structure? Why are these lipids used to make up membrane structure?
2. What is the role of cholesterol in membranes?
3. Plant membranes contain a higher proportion of unsaturated fatty acids than do animal membranes. Which type of membrane would you expect to be more fluid (flexible), plant or animal?
4. The phospholipid known as Lecithin is an emulsifying agent but triglycerides are not. Account for the difference.
5. The lipids present in the cell membranes of fish, especially fish that live in cold water, contain more unsaturated fatty acid residues than do lipids found in the membranes of land animals. Explain why.
6. To function properly, membranes must flexible or fluid. In light of this fact, propose an explanation of why cell membranes in the feet and legs of reindeer contain a higher percentage of unsaturated fatty acids than do the cell membranes in the interior of its body.
7. Compare diffusion and facilitated diffusion. How are they similar and different?
8. Compare facilitated diffusion and active transport. How are they similar and different?
Digestion of Triglycerides
1. What part of the digestive system is involved in the digestion of triglycerides?
2. Name the functional group hydrolyzed when a triglyceride undergoes digestion.
3. Name an enzyme that catalyzes the digestion of triglycerides.
4. What products are formed when a triglyceride undergoes digestion?
5. Explain the role of bile salts in lipid digestion?
Fatty Acid Catabolism
1. Answer the following question based on a spiral of fatty acid catabolism:
a. What is the function of FAD in step 1 of the spiral?
b. Identify the type of reaction in step 2 of the spiral?
c. What is the function of NAD + in step 3 of the spiral?
d. What is the harvest of each spiral? (note: last spiral is different)
e. What is different about the harvest in the last spiral?
2. Calculate the net number of ATP’s produced when a myristic acid is activated, undergoes oxidation via adequate number of spirals, acetyl-CoA's pass through the correct number of citric acid cycles, and all the reduced coenzymes (NADH & FADH 2 ) pass through the electron transport chain.
3. Calculate the net number of ATP’s produced when one 10-carbon fatty acid is activated, undergoes oxidation via adequate number of spiral, acetyl-CoA's pass through the correct number of citric acid cycles, and all the reduced coenzymes (NADH & FADH 2 ) pass through the electron transport chain.
4. Where in a cell does fatty acid oxidation take place?
5. a. What are ketone bodies?
b. Why is acidosis (low blood pH) associated with the overproduction of ketone bodies?
c. In 2004 a low carb diet craze swept the US. People on the diet had very bad breath. What molecule is the reason for the bad breath?