Name: _____________________________________ Period: __________
Study Guide: The Chemical Basis for Life
Part I: Water, Acids, and Bases
1. Vocabulary to know:
A. Acid
B. Adhesion
C. Base
D. Capillarity (CAPILLARY ACTION)
E. Cohesion
F. pH
G. Polarity
H. Solute
I.
Solution
J.
Solvent
2. What gives a water molecule polarity? Draw a water molecule below showing the properties
that make a water molecule polar.
3. Which of the following effects is produced by the high surface tension of water?
A. Lakes do not freeze solid in winter despite low temperatures.
B. A water strider can walk across the surface of a small pond.
C. Water can act as a solvent.
D. The pH of water remains exactly neutral.
4. If you mix sugar into water until it is totally dissolved, what is the solute? ___________________
The solvent? ______________________________ The solution? __________________________
REFRESHER: Know and understand the pH scale!!!!
In pure water there are an equal number of H+ ions and OH- ions. The amount or
number of H+ ions to OH- ions determines the pH of a substance or whether the substance
is acid, base or neutral. This brings us to the pH scale. The pH scale ranges from 0 to 14,
where 0 is the pH of very strong acids and 14 is the pH of very strong bases. Pure water
has a pH of 7 and is a neutral solution, which means it is neither acidic nor basic. The lower
the pH of a solution the more acidic it is and the higher the pH of a solution the more basic
it is.
A solution of lemon juice or Coca-cola that has a pH of 2 is more acidic than Sevenup which has a pH of 4. However, lemon juice is not twice as acidic as Coca-Cola! The
lemon juice with a pH of 2 is actually one hundred times more acidic than the Seven-up with
a pH of 4 and has one hundred times more H+ ions! The pH scale is based on an increase or
decrease by a power of ten. Root beer is ten times more acidic than pure water! Pure water
has a pH of 7 and root beer has a pH of 6, the one unit difference from 7 to 6 means that
there is a ten times difference in strength and 10 times the number of H+ ions. A solution of
pH 5 has a 2 unit change with water (from 7 to 5), so it is 10x10 or one hundred times as
acidic as water.
pH Scale
Pure
Water
1. Draw an arrow showing the direction in which substances become more acidic.
2. Draw an arrow showing the direction in which substances become more basic.
3. Complete the following problems, show your work.
a. Look at Orange juice and Coffee on the pH scale above. Which substance is more
acidic? How much more acidic is this substance than Pure Water?
b. Look at Bleach and Sea Water on the pH scale above. Which substance is more basic?
c.
How much more basic is Sea Water than Pure Water?
Part II: Matter and Organic Compounds
1. Vocabulary to know:
K. Chemical bond
L. Chemical formula
M. Chemical reaction
N. Disaccharide
O. Element
P. Energy
Q. Isomers
R. Organic compound
S. Saturated fatty acids
T. States of matter
U. Unsaturated fatty acids
2. Where is energy stored in chemical compounds?
3. List all four types of organic compounds and their monomers.
4. What elements are found in all of the biological macromolecules shown above?
A. Carbon, Hydrogen, Phosphorous
B. Carbon, Hydrogen, Oxygen
C. Carbon, Hydrogen, Nitrogen
D. Carbon, Nitrogen, Sulfur
5. Which statement correctly describes how carbon’s ability to form four bonds makes it uniquely
suited to form macromolecules?
A. It forms short, simple carbon chains.
B. It forms large, complex, diverse molecules.
C. It forms covalent bonds with other carbon atoms.
D. It forms covalent bonds that can exist in a single plane.
6. List the main function of each organic compound.
7. What are the three parts of an amino acid? Label them on the drawing below. What organic
compound is this a monomer for? ______________________
O
O
8. What are the three parts of a nucleotide? Label them on the drawing below. What organic
compound is this a monomer for? ______________________
9. What are the differences between a saturated fatty acid and an unsaturated fatty acid?
10. What are ‘essential’ amino acids?
HO—1—2—3—H + HO—4—H
HO—1—2—3—4—H + H2O
11. The diagram above shows a reaction that forms a polymer from two monomers. What is this
type of reaction called?
A. Glycolysis
B. Hydrolysis
C. Photosynthesis
D. Dehydration synthesis
Part III: Biochemical Reactions: Enzymes
1. Vocabulary to know:
V. Activation energy
W. Catalysts
X. Endothermic reaction
Y. Enzyme
Z. Exothermic reaction
AA. Metabolism
BB. Product
CC. Reactant
DD. Substrates
2. What happens to the enzyme-substrate complex when it is denatured?
3. Explain what is happening in the graph below; which reaction is catalyzed, which reaction is not
catalyzed, which reaction needs more energy to get started, and which reaction needs less
energy to get started?
Reaction A
Reaction B
4. List the characteristics of an enzyme.
5. How do enzymes help in metabolic processes?