DAT Dental Admission Test Practice Exam
ADA Prometric Actual Exam 2026/2027 with
Detailed Rationales | Complete Exam-Style
Questions | Pass Guaranteed – A+ Graded
Survey of Natural Sciences – Biology (Questions 1–20)
Q1: A red blood cell maintains its normal shape in a 0.9% NaCl solution but shrivels when placed in
a 5% NaCl solution. Which term best describes the 5% NaCl solution relative to the cell?
A. Hypotonic
B. Isotonic
C. Hypertonic [CORRECT]
D. Osmotic
Correct Answer: C
Rationale: The best answer is hypertonic. When a cell shrivels, water is leaving by osmosis toward
the higher solute concentration outside. The DAT expects you to know that water always moves
from low solute to high solute concentration, so the 5% NaCl solution draws water out of the cell.
,Q2: Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?
A. Mitochondrion
B. Lysosome
C. Golgi apparatus [CORRECT]
D. Smooth endoplasmic reticulum
Correct Answer: C
Rationale: The best answer is the Golgi apparatus. It receives proteins from the rough ER and
processes them for delivery to their final destinations. Remember that on the DAT, you need to
distinguish synthesis (rough ER) from modification and packaging (Golgi).
Q3: During which phase of mitosis do sister chromatids separate and move toward opposite poles?
A. Prophase
B. Metaphase
C. Anaphase [CORRECT]
D. Telophase
Correct Answer: C
Rationale: The best answer is anaphase. The spindle fibers shorten and pull sister chromatids
apart toward opposite poles. The DAT frequently tests the order of mitotic events, and anaphase is
the phase where genetic material actually divides.
,Q4: A dihybrid cross between two heterozygous pea plants (AaBb × AaBb) follows Mendelian
inheritance with genes on different chromosomes. What is the expected phenotypic ratio in the
offspring?
A. 1:2:1
B. 9:3:3:1 [CORRECT]
C. 3:1
D. 1:1:1:1
Correct Answer: B
Rationale: The best answer is 9:3:3:1. For independent assortment, 9/16 show both dominant
traits, 3/16 show each combination of one dominant and one recessive, and 1/16 show both
recessive. The DAT expects you to know this ratio cold or be able to derive it quickly from a
Punnett square.
Q5: An enzyme has a Vmax of 100 μmol/min and a Km of 5 mM. A competitive inhibitor is added.
Which statement is true?
A. Vmax decreases and Km decreases
B. Vmax remains the same and Km increases [CORRECT]
C. Vmax decreases and Km remains the same
D. Vmax remains the same and Km decreases
Correct Answer: B
, Rationale: The best answer is that Vmax remains the same and Km increases. Competitive
inhibitors bind reversibly to the active site, so adding more substrate can eventually outcompete
the inhibitor to reach the same Vmax, but it takes higher substrate concentration to reach half of
Vmax. On the DAT, remember competitive affects Km but not Vmax, while noncompetitive affects
Vmax but not Km.
Q6: In a population of 1000 individuals, 160 express a recessive phenotype. Assuming
Hardy-Weinberg equilibrium, what is the frequency of heterozygotes?
A. 0.16
B. 0.36
C. 0.48 [CORRECT]
D. 0.60
Correct Answer: C
Rationale: The best answer is 0.48. If q² = 160/1000 = 0.16, then q = 0.4 and p = 0.6. The
heterozygote frequency is 2pq = 2(0.6)(0.4) = 0.48. The DAT expects you to identify q² from the
recessive phenotype first, then solve for the remaining values.
Q7: Which statement correctly describes DNA replication in eukaryotes?
A. It is conservative and bidirectional
B. It is semiconservative and bidirectional [CORRECT]
C. It is dispersive and unidirectional
ADA Prometric Actual Exam 2026/2027 with
Detailed Rationales | Complete Exam-Style
Questions | Pass Guaranteed – A+ Graded
Survey of Natural Sciences – Biology (Questions 1–20)
Q1: A red blood cell maintains its normal shape in a 0.9% NaCl solution but shrivels when placed in
a 5% NaCl solution. Which term best describes the 5% NaCl solution relative to the cell?
A. Hypotonic
B. Isotonic
C. Hypertonic [CORRECT]
D. Osmotic
Correct Answer: C
Rationale: The best answer is hypertonic. When a cell shrivels, water is leaving by osmosis toward
the higher solute concentration outside. The DAT expects you to know that water always moves
from low solute to high solute concentration, so the 5% NaCl solution draws water out of the cell.
,Q2: Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?
A. Mitochondrion
B. Lysosome
C. Golgi apparatus [CORRECT]
D. Smooth endoplasmic reticulum
Correct Answer: C
Rationale: The best answer is the Golgi apparatus. It receives proteins from the rough ER and
processes them for delivery to their final destinations. Remember that on the DAT, you need to
distinguish synthesis (rough ER) from modification and packaging (Golgi).
Q3: During which phase of mitosis do sister chromatids separate and move toward opposite poles?
A. Prophase
B. Metaphase
C. Anaphase [CORRECT]
D. Telophase
Correct Answer: C
Rationale: The best answer is anaphase. The spindle fibers shorten and pull sister chromatids
apart toward opposite poles. The DAT frequently tests the order of mitotic events, and anaphase is
the phase where genetic material actually divides.
,Q4: A dihybrid cross between two heterozygous pea plants (AaBb × AaBb) follows Mendelian
inheritance with genes on different chromosomes. What is the expected phenotypic ratio in the
offspring?
A. 1:2:1
B. 9:3:3:1 [CORRECT]
C. 3:1
D. 1:1:1:1
Correct Answer: B
Rationale: The best answer is 9:3:3:1. For independent assortment, 9/16 show both dominant
traits, 3/16 show each combination of one dominant and one recessive, and 1/16 show both
recessive. The DAT expects you to know this ratio cold or be able to derive it quickly from a
Punnett square.
Q5: An enzyme has a Vmax of 100 μmol/min and a Km of 5 mM. A competitive inhibitor is added.
Which statement is true?
A. Vmax decreases and Km decreases
B. Vmax remains the same and Km increases [CORRECT]
C. Vmax decreases and Km remains the same
D. Vmax remains the same and Km decreases
Correct Answer: B
, Rationale: The best answer is that Vmax remains the same and Km increases. Competitive
inhibitors bind reversibly to the active site, so adding more substrate can eventually outcompete
the inhibitor to reach the same Vmax, but it takes higher substrate concentration to reach half of
Vmax. On the DAT, remember competitive affects Km but not Vmax, while noncompetitive affects
Vmax but not Km.
Q6: In a population of 1000 individuals, 160 express a recessive phenotype. Assuming
Hardy-Weinberg equilibrium, what is the frequency of heterozygotes?
A. 0.16
B. 0.36
C. 0.48 [CORRECT]
D. 0.60
Correct Answer: C
Rationale: The best answer is 0.48. If q² = 160/1000 = 0.16, then q = 0.4 and p = 0.6. The
heterozygote frequency is 2pq = 2(0.6)(0.4) = 0.48. The DAT expects you to identify q² from the
recessive phenotype first, then solve for the remaining values.
Q7: Which statement correctly describes DNA replication in eukaryotes?
A. It is conservative and bidirectional
B. It is semiconservative and bidirectional [CORRECT]
C. It is dispersive and unidirectional
