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Exam guide

The MCAT, explained

What does the MCAT look like?

Start MCAT practice See the 4 sections 2,640 questions · free · no account

MCAT at a glance

Medical College Admission Test, for medical school applicants.

230questions on test day
6 h 15of testing time
7 h 30seated, with breaks
472-528total score range

The MCAT takes about seven and a half hours once breaks are counted, and asks 230 questions across four sections. Most questions are based on a passage, so the exam tests what you can do with science under time pressure rather than what you can recite. Each section is scored from 118 to 132, and the four combine into a total between 472 and 528.

The 4 sections

What each one asks of you, and how much practice QuizNucleus has for it.

Chemical and Physical Foundations of Biological Systems

General chemistry, organic chemistry, physics and biochemistry, aimed at the physical basis of how a body works. 59 questions in 95 minutes.

530 to practicePractice

Biological and Biochemical Foundations of Living Systems

Biology and biochemistry, from molecules and metabolism up to organ systems. 59 questions in 95 minutes.

1,885 to practicePractice

Psychological, Social, and Biological Foundations of Behavior

Psychology, sociology and the biology of behavior, including how people respond to illness. 59 questions in 95 minutes.

225 to practicePractice

Critical Analysis and Reasoning Skills

Passages from the humanities and social sciences, testing reasoning rather than knowledge. Nothing to memorize. 53 questions in 90 minutes.

Coming soon

Two questions from the bank

Both formats, as they appear in practice. QuizNucleus accepts an answer typed in your own words.

Fill in the blank

Lactate produced in skeletal muscle or erythrocytes can travel to the ______, where it can be converted back into glucose through the ______ cycle.

Show answer

Answers: (1) liver, (2) Cori

Lactate produced in skeletal muscle or erythrocytes can travel to the liver, where it can be converted back into glucose through the Cori cycle. The liver can convert lactate to glucose by gluconeogenesis, and that glucose can return to peripheral tissues in the Cori cycle.

Multiple choice

An enzyme has a low Km for its substrate. What does this indicate?

  1. That the enzyme is saturated at all substrate concentrations
  2. High affinity because half-maximal velocity needs little substrate
  3. Low affinity, since a great deal of substrate is required to reach half of Vmax
  4. A high maximum reaction velocity once the enzyme is saturated
Show answer

Answer: B. High affinity because half-maximal velocity needs little substrate

Km is the substrate concentration producing half of Vmax, so a small Km means the enzyme reaches half speed with very little substrate around — high affinity. The inverse relationship is the point to hold onto. It has real consequences: hexokinase has a low Km and works in most tissues at ordinary glucose levels, while liver glucokinase has a high Km and engages only after a meal raises glucose substantially.

Practice all 2,640 MCAT questions

How to study for it

  • Learn the content, then practice passages.Recall is useful, but practicing large passages is critical for exam day.
  • Biochemistry appears in two sections.Critical for both science sections, which makes it the best-value subject to know well.
  • Do not leave psych and soc until last.Makes up a quarter of your score and the most learnable section of the four.
  • Build stamina deliberately.Seven and a half hours is an endurance event. Practice in longer blocks as the test date gets closer.

Studying something else?

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