As a tutor, I’ve noticed that many students read the entire passage in the physical sciences and biology section. While this may seem like a good idea, reading the entire passage and understanding all of its complexities before attacking the questions just wastes time.*
Instead of reading the entire passage in the science sections, use it to orient yourself as to what kinds of questions will be asked. Think of a the MCAT as a library: if you pick a book off a shelf and start reading about “Victoria,” you'd need to know what section of the library you were in to tell whether the the book refers to the frumpish queen or the African lake. The passage introduction serves the same function. Like an abstract of a scientific paper, the first paragraph of a passage tells what kinds of questions are going to be asked and orients you in a specific field of knowledge. For example, an opening paragraph about rocketry probably leads to questions about kinematics and energy while a discussion of titration will most likely accompany questions about stoichiometry, equilibrium, and acid/base chemistry. Get used to priming your brain with relevant examples using the first paragraph before answering questions The MCAT presents most questions as linked to passages so many students think they must read the entire passage to answer the accompanying questions. In fact, many of the questions on the MCAT can be answered without any reference to the passage, so for those questions, a test-taker doesn’t need the passage at all.
Sometimes, the MCAT will ask about specific pieces of the passage. If it does, just locate that part, jump a few lines above to see what is going on, and then find the needed information. If a passage talks about the 10-step synthesis of a molecule, but a question only asks about step 3 in the synthesis, just read steps 2, 3, and 4, then answer the question
Focus on Just the Important Part
To summarize: Skim the first Paragraph- Think for a few seconds as to what topics the passage will treat. Does it sound like anything you’ve heard discussed before or make you think about a familiar topic? Then, start answering questions using your own knowledge. If you come to one that requires knowledge you don’t know off the top of your head or asking about a specific part of some experiment, find the answer or the system in the passage and then come back to the question. Refer to the passage often, but know that most of it simply wastes your time.
** This advice applies best to the physical sciences section and the organic chemistry components of the biology section. The anatomy questions often require constant referral back to the passages. Read every word of the Verbal section because careful reading helps understand the main idea of the passage of a whole.