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MDCAT notes

MDCAT notes are chapter-level revision notes: a definition, the way the chapter is examined, the traps that cost marks, and a worked example. Every MDCAT chapter has a note, across Biology, Chemistry, Physics, English and Logical Reasoning.

What one note contains

Four parts, in the order a student needs them. The definition is not the whole note.

A definition, in one paragraph

What the idea means, in the words the paper uses. Not a list of headings to memorise.

How the chapter is examined

The framing the questions use, measured from the papers: which detail is asked, and how many times.

The traps

The wrong option students choose, and why it looks right. A good note names the trap.

A worked example

One solved question with the arithmetic shown, so the method is visible rather than asserted.

One real excerpt

From the Acellular Life note. The wording is the published note, not a sample written for this page.

Biology: Acellular Life

1. The particle: genome, capsid, envelope, virion

Definition

A virus is a piece of genetic material wrapped in protein. The genetic material is the genome, either DNA or RNA, and the protein coat around it is the capsid. The capsid is built from repeated protein subunits called capsomeres, which are proteins and nothing else. Some viruses add a layer outside that coat, the envelope, and the whole assembled particle in its complete, mature, infectious form is the virion, the phrase the papers also use as "complete virus". Four words, four levels of description, and almost every structure question in this chapter turns on picking the right one.

On the exam

Viral Structure and Classification is the largest topic in this chapter at 106 distinct questions, 2006 to 2026. The phrasing of the correct answer is itself a clue to the syllabus: "capsid" and "virion" are both common correct options, so the examiner wants the level of the term named, not described.

The trap

"Capsomere" and "Capsid" collapse for most students because the words look like the same word. What separates them is scale: the capsid is the whole coat, a capsomere is one protein subunit of that coat, and the virion is the entire particle including coat, genome and, where present, envelope. Asked for the complete mature infectious particle against capsomere, genome and capsid, three of the four options are parts of it, which is the standard construction.

Worked example

A diagram shows a core of nucleic acid surrounded by protein subunits, with a lipoprotein layer bearing glycoprotein spikes outside it. Ask in order. Is there a protein coat? yes, so this is a virus, not a viroid, which is naked RNA, and not a prion, which has no nucleic acid to be in the core. Is there a layer outside the coat? yes, so the particle is enveloped, and that layer came from the host membrane, not from the virus. Is the whole assembly infectious on its own? then it is the virion. The step students get wrong is the first, because a diagram with spikes on a membrane looks like a bacterium to anyone whose last diagram was a bacterial cell.
Read the full Acellular Life note

Notes by subject

Notes for every MDCAT subject. The other subjects link to chapter practice.

Every published chapter note

80 notes, grouped by subject. Each link opens the public note.

Biology

Chemistry

Physics

English

Logical Reasoning

How to use a note

Read the definition, then the exam framing, then the traps. Stop before the worked example and try it yourself; a worked example you read is a demonstration, not practice. Then answer the chapter in chapter practice so the note becomes a question you can actually do.

The notes use the same chapter taxonomy as practice, so a note and its questions sit under the same chapter. The syllabus page shows which chapters the MDCAT paper carries, and spaced repetition is how you keep the definitions after the first read.

Read the note, then answer the chapter.

A free account includes 500 practice attempts with worked explanations, and the notes stay readable.

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