RIO BIO 202 EXAM 3 STUDY GUIDE 2026 –
COMPLETE CONCEPT REVIEW & PRACTICE
MATERIALS (LATEST EDITION)
1. What is the primary function of DNA polymerase III in E. coli?
a) Sealing nicks between Okazaki fragments
b) Unwinding the DNA double helix ✓
c) Adding nucleotides to the 3' end of a growing DNA strand
d) Removing RNA primers and replacing them with DNA
2. A silent mutation is most likely a result of:
a) A change in the promoter sequence
b) A frameshift deletion
c) A substitution in the third base of a codon ✓
d) A nonsense mutation in the first exon
3. In a dihybrid cross (AaBb x AaBb), what proportion of offspring are expected to be
homozygous recessive for both traits?
a) 1/16 ✓
b) 3/16
c) 9/16
d) 1/4
4. Which process is directly responsible for the segregation of alleles during gamete
formation?
a) Independent assortment
b) Fertilization
c) Crossing over
d) Meiosis I ✓
5. The lac operon in E. coli is an example of:
a) Constitutive gene expression
b) Positive and negative inducible control ✓
c) Repressible control only
d) Eukaryotic transcriptional regulation
, 6. During translation, the growing polypeptide chain is attached to which site on the
ribosome?
a) E site
b) P site ✓
c) A site
d) T site
7. A woman is a carrier for an X-linked recessive disorder (X^NX^n). What is the probability
her son will inherit the disorder?
a) 0%
b) 25%
c) 50% ✓
d) 100%
8. What is the role of tRNA synthetase?
a) Synthesizes tRNA from a DNA template
b) Binds the ribosome to mRNA
c) Attaches the correct amino acid to its corresponding tRNA ✓
d) Facilitates peptide bond formation
9. In a DNA molecule, if 30% of the bases are Thymine, what percentage are Guanine?
a) 20% ✓
b) 30%
c) 40%
d) 60%
10. Which technique would be most appropriate to amplify a specific DNA sequence for
analysis?
a) Gel electrophoresis
b) Polymerase Chain Reaction (PCR) ✓
c) Southern blotting
d) Sanger sequencing
Category 2: Cell Structure & Function
11. Which organelle is primarily responsible for the synthesis of phospholipids and
detoxification of drugs?
a) Rough ER
b) Smooth ER ✓
, c) Golgi apparatus
d) Lysosome
12. The movement of water across a selectively permeable membrane from an area of low
solute concentration to high solute concentration is called:
a) Active transport
b) Osmosis ✓
c) Facilitated diffusion
d) Endocytosis
13. Which component of the cytoskeleton is involved in cell shape, organelle movement,
and forms the mitotic spindle?
a) Microfilaments (Actin)
b) Intermediate filaments
c) Microtubules ✓
d) Centrioles
14. During which phase of the cell cycle is DNA replicated?
a) G1
b) S ✓
c) G2
d) M
15. The proton gradient generated across the thylakoid membrane during the light reactions
is used to:
a) Oxidize water
b) Reduce NADP+
c) Synthesize ATP via chemiosmosis ✓
d) Fix carbon dioxide
16. Which of the following is a feature unique to prokaryotic cells?
a) Ribosomes
b) A cell membrane
c) A nucleoid region ✓
d) Cytoplasm
17. In mitochondria, the Krebs (Citric Acid) cycle occurs in the:
a) Intermembrane space
b) Outer membrane
, c) Matrix ✓
d) Cristae
18. What is the primary role of the Golgi apparatus?
a) Protein synthesis
b) ATP production
c) Modification, sorting, and packaging of proteins and lipids ✓
d) Breakdown of macromolecules
19. A cell placed in a hypertonic solution will:
a) Swell and potentially lyse
b) Shrivel (crenate) ✓
c) Remain unchanged
d) Divide rapidly
20. Which junction forms a watertight seal between animal cells, such as those in the lining
of the intestine?
a) Gap junction
b) Tight junction ✓
c) Desmosome
d) Plasmodesmata
Category 3: Cellular Energetics & Metabolism
21. The final electron acceptor in the mitochondrial electron transport chain is:
a) NAD+
b) FAD
c) Oxygen ✓
d) Water
22. In glycolysis, for one molecule of glucose, what is the net yield of ATP?
a) 2 ATP ✓
b) 4 ATP
c) 30 ATP
d) 36 ATP
23. An enzyme's active site binds to its substrate to form a(n):
a) Enzyme-product complex
b) Enzyme-inhibitor complex
c) Enzyme-substrate complex ✓
d) Allosteric complex
COMPLETE CONCEPT REVIEW & PRACTICE
MATERIALS (LATEST EDITION)
1. What is the primary function of DNA polymerase III in E. coli?
a) Sealing nicks between Okazaki fragments
b) Unwinding the DNA double helix ✓
c) Adding nucleotides to the 3' end of a growing DNA strand
d) Removing RNA primers and replacing them with DNA
2. A silent mutation is most likely a result of:
a) A change in the promoter sequence
b) A frameshift deletion
c) A substitution in the third base of a codon ✓
d) A nonsense mutation in the first exon
3. In a dihybrid cross (AaBb x AaBb), what proportion of offspring are expected to be
homozygous recessive for both traits?
a) 1/16 ✓
b) 3/16
c) 9/16
d) 1/4
4. Which process is directly responsible for the segregation of alleles during gamete
formation?
a) Independent assortment
b) Fertilization
c) Crossing over
d) Meiosis I ✓
5. The lac operon in E. coli is an example of:
a) Constitutive gene expression
b) Positive and negative inducible control ✓
c) Repressible control only
d) Eukaryotic transcriptional regulation
, 6. During translation, the growing polypeptide chain is attached to which site on the
ribosome?
a) E site
b) P site ✓
c) A site
d) T site
7. A woman is a carrier for an X-linked recessive disorder (X^NX^n). What is the probability
her son will inherit the disorder?
a) 0%
b) 25%
c) 50% ✓
d) 100%
8. What is the role of tRNA synthetase?
a) Synthesizes tRNA from a DNA template
b) Binds the ribosome to mRNA
c) Attaches the correct amino acid to its corresponding tRNA ✓
d) Facilitates peptide bond formation
9. In a DNA molecule, if 30% of the bases are Thymine, what percentage are Guanine?
a) 20% ✓
b) 30%
c) 40%
d) 60%
10. Which technique would be most appropriate to amplify a specific DNA sequence for
analysis?
a) Gel electrophoresis
b) Polymerase Chain Reaction (PCR) ✓
c) Southern blotting
d) Sanger sequencing
Category 2: Cell Structure & Function
11. Which organelle is primarily responsible for the synthesis of phospholipids and
detoxification of drugs?
a) Rough ER
b) Smooth ER ✓
, c) Golgi apparatus
d) Lysosome
12. The movement of water across a selectively permeable membrane from an area of low
solute concentration to high solute concentration is called:
a) Active transport
b) Osmosis ✓
c) Facilitated diffusion
d) Endocytosis
13. Which component of the cytoskeleton is involved in cell shape, organelle movement,
and forms the mitotic spindle?
a) Microfilaments (Actin)
b) Intermediate filaments
c) Microtubules ✓
d) Centrioles
14. During which phase of the cell cycle is DNA replicated?
a) G1
b) S ✓
c) G2
d) M
15. The proton gradient generated across the thylakoid membrane during the light reactions
is used to:
a) Oxidize water
b) Reduce NADP+
c) Synthesize ATP via chemiosmosis ✓
d) Fix carbon dioxide
16. Which of the following is a feature unique to prokaryotic cells?
a) Ribosomes
b) A cell membrane
c) A nucleoid region ✓
d) Cytoplasm
17. In mitochondria, the Krebs (Citric Acid) cycle occurs in the:
a) Intermembrane space
b) Outer membrane
, c) Matrix ✓
d) Cristae
18. What is the primary role of the Golgi apparatus?
a) Protein synthesis
b) ATP production
c) Modification, sorting, and packaging of proteins and lipids ✓
d) Breakdown of macromolecules
19. A cell placed in a hypertonic solution will:
a) Swell and potentially lyse
b) Shrivel (crenate) ✓
c) Remain unchanged
d) Divide rapidly
20. Which junction forms a watertight seal between animal cells, such as those in the lining
of the intestine?
a) Gap junction
b) Tight junction ✓
c) Desmosome
d) Plasmodesmata
Category 3: Cellular Energetics & Metabolism
21. The final electron acceptor in the mitochondrial electron transport chain is:
a) NAD+
b) FAD
c) Oxygen ✓
d) Water
22. In glycolysis, for one molecule of glucose, what is the net yield of ATP?
a) 2 ATP ✓
b) 4 ATP
c) 30 ATP
d) 36 ATP
23. An enzyme's active site binds to its substrate to form a(n):
a) Enzyme-product complex
b) Enzyme-inhibitor complex
c) Enzyme-substrate complex ✓
d) Allosteric complex
