BCH 351 EXAM 3 (DR. KUO) UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
Question:
1. What are all fatty acids made up of?
Answer:
1.) carboxylate group at the head (pKa = 4.8 + hydrophilic)
2.) long hydrocarbon tail (hydrophobic, 4-36 C almost always even,
saturated or unsaturated)
Question:
2. What does it mean if something is saturated?
Answer:
no C, C double bonds
Question:
3. What does it mean if something is unsaturated?
Answer:
has double bonds (mono or polyunsaturated) can be cis (naturally
occurring) or trans.
Question:
4. Describe the naming system for fatty acids.
Answer:
Done in numbers
1 = # of Cs in F.A.
2 = # of D.B.
3 = position of D.B.
Question:
5. Draw the following fatty acid:
18:3 (cdelta 9, 12(t), 15)
Answer:
Drawing
Question:
6. How do tail length and double bonds affect fatty acid
melting temperature?
Answer:
1.) increasing hydrophobic tail → increases melting temp.
2.) increasing # of D.B. → decreases melting temp.
,Question:
7. How do cis D.B. affect tail structure?
Answer:
Prevents close packing due to bend →less hydrophobic effect + van der
waal interaction → lower melting temp.
Question:
8. Describe some characteristics and two examples of
triacylglycerols.
Answer:
1.) very hydrophobic
2.) major form of energy storage
3.) long saturated chains → solid
shorter chain w/ D.B. → liquid
Ex) fats and oils
Question:
9. What is unique about Palm Oil?
Answer:
Semi-solid at room temp.
Question:
10. What are some characteristics of glycerolphospholipids?
Answer:
1.) amphipathic (hydrophilic head + hydrophobic tail
2.) most abundant lipids in cell membranes
Question:
11. What are some characteristics of sphingolipids?
Answer:
1.) backbone = sphingosine
2.) second most abundant lipids in animal and plants membranes
3.) important in membranes of nerve cells and myelin sheaths
Question:
12. What are ceramides?
Answer:
1.) Fatty acyl group linked to the C2 amino group of sphingolipids
2.) precursor for all sphingolipids
, Question:
13. What are sphingomyelins?
Answer:
A sphingophospholipids with the addition of phosphocholine to ceramide at
C1
Question:
14. What is a cerebroside?
Answer:
a glycosphigolipid with the addition of a simple sugar to ceramide at C1
Question:
15. What is a ganglioside?
Answer:
A glycosphigolipid with the addition of a complex sugar to the ceramide at
C1
Question:
16. Describe the structure of cholesterol?
Answer:
1.) 4 rings in total (3 6-carbon rings and a single 5-carbon ring)
2.) very hydrophobic
3.) rigid and bulky
Question:
17. What are the functions of cholesterol?
Answer:
1.) component of animal cell membrane and can influence membrane
fluidity
2.) precursor for steroid hormones and vitamin D
Question:
18. What are biological membranes composed primarily of?
How does this affect their function?
Answer:
Lipids and proteins; protein content varies which directly relates to the cell
function
QUESTIONS AND CORRECT ANSWERS
Question:
1. What are all fatty acids made up of?
Answer:
1.) carboxylate group at the head (pKa = 4.8 + hydrophilic)
2.) long hydrocarbon tail (hydrophobic, 4-36 C almost always even,
saturated or unsaturated)
Question:
2. What does it mean if something is saturated?
Answer:
no C, C double bonds
Question:
3. What does it mean if something is unsaturated?
Answer:
has double bonds (mono or polyunsaturated) can be cis (naturally
occurring) or trans.
Question:
4. Describe the naming system for fatty acids.
Answer:
Done in numbers
1 = # of Cs in F.A.
2 = # of D.B.
3 = position of D.B.
Question:
5. Draw the following fatty acid:
18:3 (cdelta 9, 12(t), 15)
Answer:
Drawing
Question:
6. How do tail length and double bonds affect fatty acid
melting temperature?
Answer:
1.) increasing hydrophobic tail → increases melting temp.
2.) increasing # of D.B. → decreases melting temp.
,Question:
7. How do cis D.B. affect tail structure?
Answer:
Prevents close packing due to bend →less hydrophobic effect + van der
waal interaction → lower melting temp.
Question:
8. Describe some characteristics and two examples of
triacylglycerols.
Answer:
1.) very hydrophobic
2.) major form of energy storage
3.) long saturated chains → solid
shorter chain w/ D.B. → liquid
Ex) fats and oils
Question:
9. What is unique about Palm Oil?
Answer:
Semi-solid at room temp.
Question:
10. What are some characteristics of glycerolphospholipids?
Answer:
1.) amphipathic (hydrophilic head + hydrophobic tail
2.) most abundant lipids in cell membranes
Question:
11. What are some characteristics of sphingolipids?
Answer:
1.) backbone = sphingosine
2.) second most abundant lipids in animal and plants membranes
3.) important in membranes of nerve cells and myelin sheaths
Question:
12. What are ceramides?
Answer:
1.) Fatty acyl group linked to the C2 amino group of sphingolipids
2.) precursor for all sphingolipids
, Question:
13. What are sphingomyelins?
Answer:
A sphingophospholipids with the addition of phosphocholine to ceramide at
C1
Question:
14. What is a cerebroside?
Answer:
a glycosphigolipid with the addition of a simple sugar to ceramide at C1
Question:
15. What is a ganglioside?
Answer:
A glycosphigolipid with the addition of a complex sugar to the ceramide at
C1
Question:
16. Describe the structure of cholesterol?
Answer:
1.) 4 rings in total (3 6-carbon rings and a single 5-carbon ring)
2.) very hydrophobic
3.) rigid and bulky
Question:
17. What are the functions of cholesterol?
Answer:
1.) component of animal cell membrane and can influence membrane
fluidity
2.) precursor for steroid hormones and vitamin D
Question:
18. What are biological membranes composed primarily of?
How does this affect their function?
Answer:
Lipids and proteins; protein content varies which directly relates to the cell
function
