10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The DAT exam has 280 questions and runs 5 hours 15 minutes.
These 10 free DAT questions are organized by exam domain, so you can see how each part of the Dental Admission Test blueprint is tested. Reveal the answer and explanation under each question.
During the repolarization phase of a neuronal action potential, the return of the membrane potential toward its resting value is caused primarily by:
Correct answer: A - Efflux of potassium ions through voltage-gated channels
A molecule has a central atom surrounded by three bonding domains and one lone pair. What are its molecular geometry and approximate bond angle?
Correct answer: C - Trigonal pyramidal, approximately 107°
Which compound reacts most rapidly with sodium iodide in acetone by an SN2 mechanism?
Correct answer: D - 1-Bromobutane
A competitive inhibitor is added to an enzyme-catalyzed reaction. Compared with the uninhibited reaction, what happens to the apparent Km and to Vmax?
Correct answer: A - Km increases and Vmax is unchanged
A weak monoprotic acid is titrated with a strong base. At the equivalence point, the pH of the resulting solution is:
Correct answer: D - Greater than 7.00
Which of the following species is aromatic?
Correct answer: D - Cyclopentadienyl anion
In the Cube Counting subtest, a stack of cubes is cemented together and painted on all exposed surfaces. If the stack consists of a single cube resting on a flat surface, how many of that cube's faces are painted?
Correct answer: C - Five
A square sheet of paper is folded exactly in half three times, and then a single hole is punched through all of the resulting layers. How many holes are present when the sheet is completely unfolded?
Correct answer: C - Eight
Tooth enamel is composed largely of hydroxyapatite, a crystalline calcium phosphate mineral. In the mouth, enamel exists in continuous exchange with the surrounding saliva: mineral ions dissolve from the crystal surface when the local pH falls, and redeposit when the pH recovers. Bacterial fermentation of dietary carbohydrates produces organic acids that can drive the pH in plaque below roughly 5.5, the threshold at which hydroxyapatite becomes undersaturated in plaque fluid and net demineralization begins. Fluoride alters this equilibrium in two distinct ways. When fluoride ions are present during remineralization, they are incorporated into the reforming crystal lattice in place of hydroxyl groups, producing fluorapatite. Fluorapatite has a lower critical pH, roughly 4.5, and therefore withstands acid conditions that would dissolve hydroxyapatite. Separately, fluoride adsorbed to the crystal surface slows dissolution even when it is not incorporated into the lattice, and at higher concentrations it suppresses the bacterial enzyme enolase, reducing acid production. For decades the caries-preventive effect of fluoride was attributed mainly to pre-eruptive incorporation during enamel formation. Contemporary evidence has reversed that view: the dominant benefit is now understood to be post-eruptive and topical, arising from the sustained presence of low concentrations of fluoride in saliva and plaque rather than from the fluoride content of the enamel itself. According to the passage, fluorapatite withstands acid dissolution better than hydroxyapatite primarily because:
Correct answer: A - It has a lower critical pH than hydroxyapatite
A car travels 120 miles at an average speed of 40 miles per hour and then returns along the same 120-mile route at an average speed of 60 miles per hour. What is the average speed for the entire round trip?
Correct answer: B - 48 miles per hour
The full bank has 1,020 more DAT questions with explanations.
Continue in the free practice test →
View plans