DAT - Dental Admission Reading Comprehension: Scientific Passages Questions and Answers

Question 1

What is the primary purpose of the passage?

Accepted Answer

To describe the molecular adaptations of psychrophiles and their biotechnological applications.

Answer

The passage provides a comprehensive overview of psychrophiles, dedicating the first three paragraphs to their specific molecular adaptations (membrane composition, enzyme structure, and protective proteins) and the final paragraph to the practical and biotechnological uses of these adaptations. While it does compare enzymes (Choice C) and discuss ice recrystallization (Choice D), these are supporting details, not the main purpose. There is no argument for funding (Choice A).

Question 2

According to the passage, how do psychrophiles maintain cell membrane fluidity at low temperatures?

Accepted Answer

By incorporating a higher percentage of unsaturated and short-chain fatty acids.

Answer

The first paragraph explicitly states that a primary challenge is reduced membrane fluidity and that 'Psychrophilic bacteria counteract this by incorporating a higher proportion of unsaturated and short-chain fatty acids into their membrane phospholipids.' This directly answers the question.

Question 3

The passage suggests that a cold-adapted enzyme from a psychrophile would most likely:

Accepted Answer

lose its catalytic function if heated to 50 °C.

Answer

Paragraph 2 describes the 'thermolability trade-off,' stating that the flexibility that allows psychrophilic enzymes to work in the cold 'makes them more susceptible to denaturation at even moderate temperatures.' Since 50 °C is a moderate temperature where a mesophilic enzyme might be stable, the less stable psychrophilic enzyme would likely denature and lose its function.

Question 4

A biotechnology company wants to develop a laundry detergent that effectively removes protein-based stains in cold water washes. Based on the passage, which of the following would be the most promising component to include?

Accepted Answer

A protease isolated from a psychrophilic organism.

Answer

The final paragraph states that 'enzymes like proteases...from these organisms are used in...cold-water laundry detergents.' A protease is an enzyme that breaks down proteins, making it ideal for protein-based stains. The enzyme must come from a psychrophilic (cold-adapted) organism to be effective in cold water.

Question 5

In the context of the third paragraph, what is the best definition for the word 'adsorbing'?

Accepted Answer

Accumulating on the surface of the ice crystals.

Answer

The sentence reads, 'By adsorbing to the surface of ice, they inhibit the growth of these crystals...' The phrase 'to the surface' provides direct context, indicating that adsorption is a surface phenomenon where molecules adhere to the exterior of a substance, as opposed to absorption, which involves permeating the interior.

DAT Practice Test

DAT Practice Test

DAT - Dental Admission Reading Comprehension: Scientific Passages Questions and Answers