UIUC MCB 450 EXAM 2 UPDATED ACTUAL QUESTIONS AND CORRECT ANSWERS

UIUC MCB 450 EXAM 2 UPDATED ACTUAL QUESTIONS
AND CORRECT ANSWERS

Question:
1. systematic name for 12:0 laurate
Answer:
n-dodecanoate

Question:
2. systematic name for 16:0 palmitic acid
Answer:
n-hexadecanoate

Question:
3. systematic name for 18:1(delta9) oleate
Answer:
cis-delta9-octadecenoate

Question:
4. systematic name for 18:2(delta9,12) linoleate
Answer:
cis,cis-delta9,delta12-octadienoate

Question:
5. How does hydrocarbon solubility change with increase in length?
Answer:
Decreases

Question:
6. How does hydrocarbon solubility change with increased saturation?
Answer:
Decreases

Question:
7. How does hydrocarbon melting temperature change with increase in chain length?
Answer:
Increases

Question:
8. How does hydrocarbon melting temperature change with increased saturation?
Answer:
Increases

Question:
9. Why does the absence of double bonds increase melting temperature in hydrocarbons?

,Answer:
There is free rotation about the C-C bonds so the chains can be fully extended and pack tightly together,
stabilized by VdW and hydrophobic interactions

Question:
10. Why are interactions between unsaturated hydrocarbon chains weaker than between saturated ones?
Answer:
The unsaturated fatty acids cannot pack as tightly together due to restricted rotation about the C=C bonds
so there are fewer interactions between molecules

Question:
11. Why do unsaturated fatty acids have a lower melting point?
Answer:
The reduced number of interactions between unsaturated FA means it takes less thermal energy to disorder
arrays containing them

Question:
12. What is the general structure of triacylglycerols?
Answer:
3 fatty acids ester-linked to a glycerol molecule

Question:
13. In what form at fatty acids stored?
Answer:
In molecules of triacylglycerol, which accumulate as liquid droplets in adipocytes

Question:
14. Why are triacylglycerols richer in energy than carbohydrates?
Answer:
Complete oxidation of Tg yields 38kJ/g compared to 17kJ/g for carbohydrates?

Question:
15. Why are triacylglycerols a better energy reserve than carbohydrates?
Answer:
Tg are hydrophobic and stored anhydrously whereas glycogen is hydrated

Question:
16. How much more energy does fat store than an equal amount of hydrated glycogen?
Answer:
6x

Question:
17. What is the process called in which a base is added to Tg and the ester linkages break?
Answer:
Saponification/alkaline hydrolysis

, Question:
18. What are the products of saponification?
Answer:
1 glycerol, 3 soap molecules

Question:
19. What are the two classes of phospholipids?
Answer:
Phosphoglycerides and sphingolipids

Question:
20. What is the basic structure of a phospholipid?
Answer:
A scaffold with fatty acids and a charged phosphoryl group attached

Question:
21. Where on glycerol are phosphoglyceride components attached?
Answer:
Hydroxyls at C-1 and C-2 esterified to carboxyls of fatty acids; C-3 hydroxyl esterified to phosphoric acid

Question:
22. What is the simplest phosphoglyceride?
Answer:
Phosphatidate

Question:
23. What is the structure of sphingosine?
Answer:
Amino alcohol with long, unsaturated hydrocarbon chain

Question:
24. What is the structure of sphingomyelin?
Answer:
Fatty acid linked to sphingosine amino group via amide bond; primary sphingosine hydroxyl ester-linked
to phosphorylcholine

Question:
25. Where in the body is sphingomyelin most prevalent?
Answer:
In the myelin sheaths of nerve cells

Question:
26. What is the general structure of cholesterol?
Answer:
Hydrocarbon tail at cyclopentane end, hydroxyl at opposite end