BIOLOGY 189 - ZAVEN O'BRYANT
FINAL EXAM STUDY GUIDE
QUESTIONS WITH CORRECT
ANSWERS GRADED A+ 2026
ASSURED EXCEL!!
1. How do isotopes of carbon (like Carbon-12 and Carbon-14) differ from one another?
• Answer: They have different numbers of neutrons (6 vs. 8), giving them different atomic
masses, but the same number of protons (6).
• Rationale: An element's identity is strictly defined by its proton count. Changing the
number of neutrons creates an isotope, altering atomic mass without changing chemical
identity.
2. Why do nonpolar molecules fail to mix well with water?
• Answer: Nonpolar molecules share electrons equally and lack partial charges, meaning
they cannot form hydrogen bonds with water molecules.
• Rationale: Water is highly polar and strongly attracts other charged or polar substances
(hydrophilic). Nonpolar substances (hydrophobic) are repelled because water prefers to
bond with itself rather than interact with uncharged molecules.
Unit 2: Macromolecules & Biological Building Blocks
Core Concepts Summary
Monomer (Building
Macromolecule Polymer / Structure Primary Function
Block)
Monosaccharide Disaccharides, Short-term energy
Carbohydrates
(e.g., glucose) Polysaccharides storage, structure
, Monomer (Building
Macromolecule Polymer / Structure Primary Function
Block)
Enzymes, structural
Proteins Amino acids Polypeptide chains
support, transport
Genetic information
Nucleic Acids Nucleotide DNA & RNA
storage & transfer
Long-term energy
Phospholipids,
Lipids No true monomer storage, cell
Triglycerides
membranes
Key Rule: Proteins do NOT store or pass on hereditary information (that is the job of nucleic
acids), nor do they form the primary barrier of cell membranes.
Unit 2 Review Questions
3. What three components make up a nucleotide monomer?
• Answer: A 5-carbon sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous
base.
• Rationale: These three components form the basic repeat unit that polymerizes into
DNA or RNA chains. Catalase is an enzyme (protein), not a component of a nucleotide.
4. Why are lipids not considered true polymers like proteins or nucleic acids?
• Answer: Lipids are not made of repeating identical monomer subunits bonded into long
chains.
• Rationale: Macromolecules like proteins and nucleic acids form through repeated
covalent bonds between identical or structurally similar monomer units. Lipids (such as
phospholipids or triglycerides) are assemblies of distinct molecules (like glycerol and
fatty acids) held together primarily by hydrophobic interactions.
Unit 3: Cell Biology & Membrane Transport
Core Concepts Summary
• Cell Types:
FINAL EXAM STUDY GUIDE
QUESTIONS WITH CORRECT
ANSWERS GRADED A+ 2026
ASSURED EXCEL!!
1. How do isotopes of carbon (like Carbon-12 and Carbon-14) differ from one another?
• Answer: They have different numbers of neutrons (6 vs. 8), giving them different atomic
masses, but the same number of protons (6).
• Rationale: An element's identity is strictly defined by its proton count. Changing the
number of neutrons creates an isotope, altering atomic mass without changing chemical
identity.
2. Why do nonpolar molecules fail to mix well with water?
• Answer: Nonpolar molecules share electrons equally and lack partial charges, meaning
they cannot form hydrogen bonds with water molecules.
• Rationale: Water is highly polar and strongly attracts other charged or polar substances
(hydrophilic). Nonpolar substances (hydrophobic) are repelled because water prefers to
bond with itself rather than interact with uncharged molecules.
Unit 2: Macromolecules & Biological Building Blocks
Core Concepts Summary
Monomer (Building
Macromolecule Polymer / Structure Primary Function
Block)
Monosaccharide Disaccharides, Short-term energy
Carbohydrates
(e.g., glucose) Polysaccharides storage, structure
, Monomer (Building
Macromolecule Polymer / Structure Primary Function
Block)
Enzymes, structural
Proteins Amino acids Polypeptide chains
support, transport
Genetic information
Nucleic Acids Nucleotide DNA & RNA
storage & transfer
Long-term energy
Phospholipids,
Lipids No true monomer storage, cell
Triglycerides
membranes
Key Rule: Proteins do NOT store or pass on hereditary information (that is the job of nucleic
acids), nor do they form the primary barrier of cell membranes.
Unit 2 Review Questions
3. What three components make up a nucleotide monomer?
• Answer: A 5-carbon sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous
base.
• Rationale: These three components form the basic repeat unit that polymerizes into
DNA or RNA chains. Catalase is an enzyme (protein), not a component of a nucleotide.
4. Why are lipids not considered true polymers like proteins or nucleic acids?
• Answer: Lipids are not made of repeating identical monomer subunits bonded into long
chains.
• Rationale: Macromolecules like proteins and nucleic acids form through repeated
covalent bonds between identical or structurally similar monomer units. Lipids (such as
phospholipids or triglycerides) are assemblies of distinct molecules (like glycerol and
fatty acids) held together primarily by hydrophobic interactions.
Unit 3: Cell Biology & Membrane Transport
Core Concepts Summary
• Cell Types:
