Do this exam if your social/id # ends with an ODD number. If
you’re your social ends in a zero or an even # do exam A. I will
not grade exam if you don’t follow instructions.
TAKE HOME EXAM B:
1. DHA is added to baby formula. Answer the following questions regarding this molecule: 18pts
a. Draw the chemical structure of DHA
b. Is this molecule a lipid, hormone or a sugar?
c. Why do you think this molecule is essential to have in baby formula? Give at least two reasons to substantiate your answer
2. Why can humans digest starch but not cellulose when both contain D-glucose?
3. Give the name of a carbohydrate for each of the following descriptions:
a.
a disaccharide that is not a reducing sugar
b.
a disaccharide that occurs as a breakdown product of starch
c.
A a disaccharide composed of two glucose units
d.
A carbohydrate that is not digestible by humans
e.
Another name for the linear form of glucopyranose
10pts
15pts
4.
Give the structure of a sphingomyelin that contains stearic acid
5.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
True or False. Rewrite each incorrect statement to make it correct: 20pts
alpha D-glucose and beta-D-glucose are enantiomers
Cells that need cholesterol are able to absorb the low density lipoprotein
The carbon of a secondary alchohol is more reduced than the carbon of a primary alcohol
D-glyceraldehyde and L-glyceraldehyde are epimers
Cholesterol is often found in membranes
A lipid bilayer has a hydrophilic interior
The disaccharide found in mammalian milk is galactose
Lipids are often small molecules
Invert sugar is sweeter than fructose
Hormones are steroidal
6.
Draw the Hayworth projection of beta-D-galactose
7.
Consider the following data to answer the questions:
Molecule
Melting point, C
Arachidonic acid
-50
Stearic acid
70
Linoleic acid
-5
Oleic Acid
16
a.
b.
10pts
10pts
16
Density
0.878
0.789
0.911
0.887
Explain the trend shown with respect to melting points.
Explain the data shown with respect to density as compared to water.
g/ml