Name:_______________________
Date:_____________ Per #:____
Homework
3.8
– Biological Molecules
Multiple Choice Practice: Answer the following questions by writing the letter of the best answer in the space
provided.
_______1. Glucose and fructose are both examples of
a.
lipids
b. monosaccharides
c.
disaccharides
d. proteins
_______2. Carbohydrates are made of long chains of
glucose units and are called
a. monosaccharides
b. disaccharides
c. polysaccharides
d. simple sugars
_______3. The dissacharide commonly known as
table sugar is
a.
lactose
b. fructose
c.
sucrose
d. maltose
_______4. Proteins are polymers (long chains) made
of many
a. lipids
b. carbohydrates
c. starches
d. amino acids
_______5. When three fatty acids are connected by a
glycerol molecule, they create
a. cholesterol
b. a triglyceride
c. testosterone
d. a protein
_______6. The polysaccharide that plants use for
storing energy (and that we get as energy when we
eat plants) is
a. starch
b. glycerol
c. cellulose
d. glycogen
_______7. What class of biomolecules includes fats,
oils, waxes, steroids, and cholesterol?
a. starches
b. monosaccharides
c. disaccharides
d. lipids
_______8. Which of the following is not a part of a
basic amino acid?
a. An amino group
b. A carboxylic acid group
c. An alcohol group
d. An “R” side chain
_______9. A DNA molecule has a structure called
a. Double helix
b. -helix
c. polypeptide chain
d. cellulose
_______10. Which of the following is not a nucleotide
in human DNA?
a. adenine
b. guanine
c. cytosine
d. heptosine
Lewis Structure Practice: Read over the Steps for Happy Lewis Structure Time and the hints below. Read them
TWICE! Shoot, read them THREE TIMES and copy them down on a separate sheet of paper. MEMORIZE THEM.
Then go to the back and answer the following questions, come back to this side if you forget what to do.
1) Count the total number of valence electrons (# of “A” group) for each atom of the molecule.
 Add electrons if it’s a negative (-) anion.
 Subtract electrons if it’s a positive (+) cation.
2) Draw the skeleton structure with lines for shared electrons.
3) Add dots by pairs, starting with the terminal (outer) atoms until each is used and each atom is surrounded
by 8 electrons (Octet Rule), except hydrogen.
*4) If any atom does not have an octet, erase a lone pair (two dots) from an atom next to it, and draw a
double bond between them.
Hints: Hydrogen always make 1 bond and no dots. The halogens (group 7A) always make one bond and 6 dots.
Carbon always makes 4 bonds. The first atom of a formula is always the central atom, unless it’s hydrogen.
Name:_______________________
Date:_____________ Per #:____
Steve, a new student in your class, drew the following Lewis structures incorrectly. Kindly explain to Steve the
mistake he made and then draw or circle the correct Lewis structure.
11) the molecule: CO2
Steve’s Lewis Structure:
Correct Lewis Structure:
Explanation:
12) the molecule: H2O
Steve’s Lewis Structure:
Correct Lewis Structure:
Explanation:
13) the molecule: HCO
Steve’s Lewis Structure:
Correct Lewis Structure:
Explanation:
14) the molecule: PCl3
Steve’s Lewis Structure:
Correct Lewis Structure:
Explanation:
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