36 Chapter 2
- Buffers are special substances that act as reservoirs for
hydrogen ions, donating them to a solution when their
concentration falls and taking them from a solution
when their concentration rises. Buffers help maintain
homeostasis within cells in regard to pH levels,
keeping them fairly close to 7.
Review Questions
1.^ Describe the nature and structure of an atom.^
2. List the major chemical elements found in living
systems.^
*3. Compare ionic and covalent bonding, and indicate
which major four elements found in cells bond
covalently.^
*4. Why is it necessary for a cell to have nucleic acids
in its nucleus?^
*5. Explain the roles that water plays in living
systems.^
- What two major roles do carbohydrates play in liv-
ing cells?^
7.^ List three functions of fats in the human body.^
*8. List four functions of proteins necessary for the
function and survival of the human body.^
*9. Compare the differences and similarities between
osmosis and diffusion and how they function in the
body.^
*10. What is the significance of active transport to the
survival of a cell?^
*11. Why is pH important to the maintenance of
-homeostasis in the body?^
- Discuss the pH of an acid, base, and salt.
*Critical Thinking Questions
FILL IN THE BLANK
Fill in the blank with the most appropriate term.
- Molecules that contain carbon, hydrogen, and
-oxygen are known as. Glucose (a sugar) is one
of these molecules.^
Molecules known as are the (^)
building blocks of protein.^
All the carbon in the larger organic compounds found
in living systems comes directly or indirectly^
from^.^
- The smallest particles of elements that enter into
chemical reactions are.
5. An is a substance whose atoms all contain the same
number of protons and the same number of electrons.
6. In the atoms of some elements, the number of
neutrons varies. These different kinds of atoms are^
called. (^)
7. Two kinds of chemical bonds found in living- (^)
(^) matter are and (^)
8.
(^) bonds. (^)
The most abundant molecule found in living cells is (^)
9.
(^).
Carbohydrates have two basic -functions: (^)
and. (^)
10. Nucleotides bonded together between the (^)
phosphate group of one and the sugar of (^)
another- form long-chain molecules called (^)
(^).
MATCHING
Place the most appropriate number in the blank
provided.NH 3 1. Plant carbohydrate (^)
C 6 H 12 O (^6) 2. Hydroxyl group
Glycogen (^) 3. Amino group
Starch (^)
CO 2 4. Ammonia (^)
OH^2 5. Glycerol (^)
COOH (^) 6. Carboxyl group
NH 2
- Inorganic phosphate group^
PO (^42)
C 5 8. Animal carbohydrate (^)
9. Fatty acid (^)
10. Ribose (^)
11. Glucose (^)
12. Carbon dioxide (^)
Search and Explore
● Search the Internet with key words from
the chapter to discover additional in-
formation and interactive exercises. Key
words might include DNA, diffusion, and
osmosis.^
● Visit http://www.acid-base.com for an
acid-base tutorial.