Survey of Natural Sciences

In this section of the OAT, you'll have 90 minutes to answer 40 questions on Biology, 30 questions on General Chemistry, and 30 questions on Organic Chemistry for a total of 100 stand-alone, multiple-choice questions.

Essentially you have a little under a minute per question (54 sections to be exact). The key to remember is that some questions require more time whereas others don't take as much time. Begin with your strengths and answer all the questions that you are comfortable with. Mark the tough ones and come back to them at the end.

Sample OAT Natural Sciences Question

Which enzyme breaks down starch into disaccharides?

A. Amylase
B. Gastrin
C. Secretin
D. Pepsin
E. Maltase

Answer & Explanation:

The answer is A.

Amylase (pancreatic or salivary) breaks down complex carbohydrates into disaccharides (pancreatic or salivary).

B is incorrect because gastrin is a hormone secreted by the stomach wall of mammals when food makes contact with the wall; it stimulates other parts of the wall to secrete gastric juice. C is incorrect because secretin is secreted by the small intestine and stimulates the pancreas to secrete pancreatic juice containing bicarbonate ions to buffer the chyme. D is incorrect because pepsin breaks down proteins into amino acids, and E is incorrect because maltase breaks down maltose into glucose.