Review Worksheet for Exam 1
Chem 103, Winter 2006
1. Circle and label all of the functional groups (besides alkanes) in hirsutic acid (an
antibiotic metabolite from a fungus):
O
HO
C
CH2
H H 3C
OH
H 3C
H
O
2. Circle all of the chiral carbons in hirsutic acid:
O
HO
C
CH2
H H 3C
OH
H 3C
H
O
3. Glucose has the molecular formula C6H12O6.
a) What is the molar mass of glucose (mass of one mole of glucose in grams/mol)?
b) How many glucose molecules are in 0.100 g of glucose?
c) How many moles of glucose are in 10.0 L of a 0.100 M glucose solution?
d) How many grams of glucose are in 5.00 L of a 5.00% glucose solution?
4. Give an example (draw the Fischer projection and write the name) of each of the
following classes of monosaccharides:
a) a D aldohexose
b) an L aldotriose
c) an L ketohexose
d) a D ketotetrose
5. Which saccharide is the main energy source for cells of the central nervous system?
6. Galactose is an important component of the cell membranes of the nervous system.
a) What is our main dietary source of galactose (what type of food)?
b) Do we obtain the galactose directly from the food? If not, how do we get it?
c) How else might we obtain galactose besides through food?
6. Give the structure and the name of the product (or products) for each of the
following reactions:
CH2 OH
O
HO
H
a)
H
OH
H
OH
Benedict's
reagent
CH2 OH
CHO
H
OH
HO
H
H2
HO
H
Pt
b)
H
OH
CH2 OH
CH2 OH
O
H
CH3OH
H
OH
Acid Cat.
H
OH
HO
c)
CH2 OH
d)
Sucrose
e)
Fructose
Invertase
Yeast
7. D-Glucose in solution in mainly found in the pyranose form. However, a small
amount is also present in the furanose form. Draw the Haworth structure for the
furanose form of -D-glucose.
8. Many adults experience an intolerance to lactose.
a) Draw the Haworth structure for -lactose.
b) What type of glycosidic bond does -lactose have? Label it on your structure.
c) Is lactose a reducing sugar? Explain your answer.
d) What are the two methods for hydrolyzing lactose (give the specific reagents needed
for each)?
e) Write the products (Haworth structures and names) of the hydrolysis products of
lactose.
f) Pure -lactose has a specific rotation of +92.6 at 20C. However, when it is
dissolved in water, the optical rotation decreases over time until it reaches +52.3.
Explain why this occurs.
10.
Amylose, amylopectin, glycogen and cellulose are all polymers of what
monosaccharide?
11. What is the main difference in the chemical structures of amylose and cellulose?
12. The iodine test is used to detect the presence of starch. Explain why iodine
complexes strongly with starch, but not with glycogen or cellulose.
13. What characterizes a biomolecule as being a lipid?
14. Why are unsaturated fatty acids liquid at room temperature, while saturated fatty
acids are solid at room temperature?
15. Write the structure for a cis monounsaturated fatty acid with 12 carbons.
16. What is the main function of triacylglycerols in animals?
17. What is the difference between a fat and an oil?
18. Give the products (structures) for each of the following reactions:
O
H 2C
O
C
O
(CH2)7 C
CH(CH2) 7CH3
a)
CH
H 2C
O
O
C
O
C
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
H2
Ni
O
H 2C
O
C
O
3KOH
b)
CH
H 2C
O
O
C
O
C
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
O
H 2C
O
C
O
lipase
c)
CH
H 2C
O
O
C
O
C
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
(CH2)7 C
CH(CH2) 7CH3
O
H 2C
O
C
O
O2
d)
CH
H 2C
O
O
C
O
C
(CH2)7 C
(CH2)7 C
CH(CH2) 7CH3
CH(CH2) 7CH3
19. Why do oils and fats turn rancid over time if left out at room temperature in an
open container? Explain in terms of chemical reactions that take place.
20. What are the main structural differences between glycerophospholipids and
sphingolipids? Draw a schematic of the structure for each.
21. Where are cerebrosides and gangliosides mainly found? What are their main
functions?
22. Draw the chemical structure of the steroid nucleus.
23. Can your body synthesize cholesterol? If so, where is it made?
24. Name three important biological functions of cholesterol:
25. You will often hear people speak about “good cholesterol” and “bad cholesterol”.
Are these terms accurate? Explain.
26. From what lipid are bile salts biosynthesized? What is the main function of bile
salts?
27. What is a steroid hormone?
28. What are the roles of aldosterone and cortisone (two corticosteroids produced in the
adrenal glands)?
29. Why are cell membranes made up mainly of phospholipids?
30. Does adding cholesterol make cell membranes more rigid or less rigid? Explain.
31. Explain the difference between active transport and facilitated transport.