When to Take Each Prerequisite: A Sequenced Course Map for Pre‑Meds

The biggest mistake pre‑meds make with prerequisites is not what they take, but when they take them.

You can earn A’s and still sabotage your MCAT timing, your GPA trend, or your application year if the sequence is off by even a semester. A smart pre‑med course plan is a timeline problem, not a bravery test.

Below is a sequenced, time‑anchored course map: what to take each year, by semester, with clear checkpoints. At each point you will know:

• Which prerequisites to prioritize
• How the classes feed into the MCAT
• What to avoid doubling up (and when it is safe to do so)

(See also: Freshman Year Pre‑Med Timeline for what to do each month to stay on track.)

Assumptions:

• You plan to apply after junior year for immediate matriculation after senior year (traditional path).
• Your school runs on semesters.
• You are aiming for a strong MCAT taken spring of junior year.

Adjustments for non‑traditional, community college, or post‑bacc students are noted along the way.

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Year 0: Before College – Laying the Foundation

At this point you should not be choosing specific courses yet. You should be deciding on trajectory.

Your goals before freshman fall:

1. Determine your math starting point
2. Understand your AP/IB/dual enrollment credits
3. Identify likely major and its overlap with pre‑med requirements

Summer Before Freshman Year

Action checklist:

• Pull up your university’s pre‑health advising page and degree requirements for:

  • Biology B.S.
  • Chemistry or Biochemistry B.S.
  • A non‑science major you are curious about (e.g., Psychology, Philosophy)

• List core med school prerequisites:

  • 1 year General Chemistry with lab
  • 1 year Organic Chemistry with lab
  • 1 year General Biology with lab
  • 1 year Physics with lab (algebra‑ or calculus‑based)
  • 1–2 semesters of Math (often including statistics)
  • 1 year English / Writing
  • 1–2 semesters of Biochemistry (increasingly expected)
  • Psychology and Sociology (high‑yield for MCAT)

• Check how your AP/IB/dual enrollment credits apply:

  • Do they place you into higher‑level courses?
  • Do they replace a requirement or just give elective credit?
  • Many med schools do not accept AP to fully substitute core science sequences. Plan to take equivalent college‑level work even if you have credit.

Decision point: Math placement

At this point you should know: Will you start in:

• Pre‑calculus
• Calculus I
• Statistics

Your math start affects:

• When you can start Physics (if calculus‑based)
• How heavy your first‑year STEM load is

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Year 1: Freshman Year – Building the Core Base

Year 1 is your foundation year. Your primary objectives:

• Establish a strong science GPA
• Knock out introductory sequences that unlock later prerequisites
• Keep MCAT‑relevant content spaced, not stacked, to avoid burnout

Freshman Fall (Semester 1)

At this point you should keep the schedule challenging but controlled.

Typical optimal lineup:

1. General Chemistry I + Lab
   • Sets up Gen Chem II → Organic Chemistry I
   • High‑yield for MCAT general chemistry
2. Introductory Biology I + Lab
   • If your major requires it and you are ready
   • If worried about overload, some students delay Bio I to spring
3. Math Course
   • Pre‑Calc or Calc I, depending on placement
   • If you are already in Calc II, that is fine; just do not overload with every hard course at once
4. English / Writing or General Education course
   • Start fulfilling 1 year of English / writing‑intensive coursework

Guiding rule for this semester:
No more than two lab‑heavy science courses unless you have strong evidence you can handle it (e.g., rigorous high school, prior college coursework).

If you are underprepared in science or math:

• Consider:
  • One lab science (Gen Chem I)
  • A non‑lab science or lighter biology course (e.g., “Cells and Molecules” without lab)
  • Math at your appropriate level
  • Writing/Gen Ed

Your priority is a strong GPA trajectory. MCAT and application timing can be shifted a year; a poor freshman science GPA is much harder to undo.

Freshman Spring (Semester 2)

Now you connect sequences and prepare for sophomore‑level coursework.

Target schedule:

1. General Chemistry II + Lab
   • Must be completed to start Organic Chemistry I in sophomore fall
2. Introductory Biology II + Lab
   • If you took Bio I in fall; if not, start Bio I now and shift Bio II to sophomore fall
3. Math or Statistics
   • If you did Calc I in fall, consider:
     • Calc II, or
     • A statistics course (high‑yield for both med school and MCAT)
4. English / Writing or Social Science (Psych or Soc)
   • Ideal time to take Introductory Psychology or Introductory Sociology
   • Both are MCAT content areas and easier to digest now than crammed later

Checkpoint at end of Year 1:

By this point you should have:

• Completed:
  • Gen Chem I–II + labs
  • 0–2 semesters of Intro Biology + labs
  • 1–2 math courses
  • 1 semester of English / writing
• A science GPA trend that supports moving into Organic Chemistry

If Organic Chemistry feels intimidating based on your Year 1 performance, you might start planning for:

• A lighter semester when you take Organic I
• Possibly a delayed MCAT/application timeline (apply after senior year → one glide year)

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Year 2: Sophomore Year – The Heavy Sciences and MCAT Spine

Sophomore year defines your timeline. Organic Chemistry, second‑year Biology, and Physics form the backbone of MCAT science content.

Sophomore Fall (Semester 3)

At this point you should be ready to step into rigorous, MCAT‑central coursework.

Core schedule pattern:

1. Organic Chemistry I + Lab
   • Non‑negotiable for staying on a traditional MCAT/application path
2. Biology (if not completed)
   • Bio II + Lab if you finished Bio I in freshman year
   • If you are a biology major, this might be Genetics, Cell Biology, or Physiology instead
3. Statistics or Psychology/Sociology (if not done)
   • Having Psych and/or Soc finished by end of sophomore year boosts MCAT readiness
4. General Education or lighter major elective

Do you start Physics now?

• Starting Physics I + Lab here is possible if:
  • You have finished the required math (often through Calc I or equivalent)
  • You managed freshman science well (A/A‑ range in Gen Chem and Bio)

However, Organic I + Physics I + a major biology course is a very heavy STEM load. Many students stagger Physics:

• Plan A (traditional, aggressive):

  • Physics I in Sophomore Fall
  • Physics II in Sophomore Spring
  • MCAT in late spring/early summer of junior year

• Plan B (more conservative):

  • Physics I in Sophomore Spring
  • Physics II in Junior Fall
  • MCAT in winter or early spring of junior year after Physics II content

If you struggled in Gen Chem or Bio, avoid stacking Org I + Physics I in same term.

Sophomore Spring (Semester 4)

Now you complete critical sequences and prepare directly for upper‑level and MCAT studies.

Key courses:

1. Organic Chemistry II + Lab
   • Finishes the organic sequence
   • Sets up Biochemistry (often requires at least Organic I, sometimes both)
2. Physics I or II + Lab
   • Choose based on what you did in fall:
     • If you took Physics I in fall → Physics II now
     • If you held off → Physics I now, Physics II in junior fall
3. Upper‑Level Biology (if major requires)
   • Common: Genetics, Cell Biology, Microbiology, or Physiology
   • Genetics and Cell Bio are especially MCAT‑relevant
4. Psychology or Sociology (whichever you still need)
   • Completing both by end of sophomore year is ideal

End of Sophomore Year checkpoint: absolute minimum for spring junior MCAT

By this point you should have completed, or have a clear plan to complete before MCAT:

• General Chemistry I–II with labs
• Organic Chemistry I–II with labs
• Biology I–II with labs (plus at least one upper‑level is ideal)
• Physics I–II with labs (or Physics II scheduled for junior fall)
• At least 1 semester of Biochemistry (can be taken junior fall if applying after junior year)
• Intro Psychology and Sociology
• At least 1 semester of Statistics or equivalent

If you are missing multiple core subjects or feel conceptually weak (e.g., B‑ or below in several prerequisites), this is the time to consider:

• Pushing MCAT to late junior year or early senior year
• Applying after senior year with a glide year

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Year 3: Junior Year – MCAT Alignment and Final Prerequisites

Junior year is where timing mistakes show up. You need to line up Biochemistry, remaining Physics, and MCAT preparation without overwhelming yourself.

Junior Fall (Semester 5)

At this point you should treat your schedule as “MCAT sync.”

High‑yield junior fall schedule:

1. Biochemistry
   • Often requires Organic I (sometimes Organic II)
   • Central to MCAT: metabolism, protein structure, enzymes, molecular pathways
2. Physics II + Lab (if not yet completed)
   • Important for torque, circuits, optics content
3. Upper‑Level Biology Course
   • Good options:
     • Physiology
     • Molecular Biology
     • Microbiology
     • Immunology
   • Choose one that aligns with your interests but also supports MCAT topics
4. Light, writing‑intensive or humanities course
   • Essays and reading, not problem sets, pair better with MCAT prep

MCAT prep starts now

• By mid‑semester, you should:
  • Decide on an MCAT test window (March–June of junior year for traditional timeline)
  • Build a week‑by‑week content review plan that draws on your coursework
  • Begin low‑intensity review (e.g., Anki for Biochemistry pathways, Psych/Soc terms)

If you still lack Psych, Soc, or Statistics, use junior fall to finish at least one of these. They are lower‑intensity compared with core sciences but high-yield for the exam.

Junior Spring (Semester 6)

This semester is your launchpad: MCAT, letters of recommendation, and AMCAS preparation.

Course load strategy depends on MCAT timing:

If taking MCAT March–April of junior year:

At this point you should lighten your course load:

1. 1–2 moderate‑rigor science/major courses
2. 1–2 lighter humanities or electives
3. No more than 12–14 credits if possible

Avoid adding new heavy prerequisites. You want content review, not brand‑new conceptual overload.

If taking MCAT May–June:

You can carry a slightly heavier spring load but still:

• Avoid three simultaneous lab sciences
• Prioritize sleep and consistent weekly study hours over maximal credit count

Courses that fit well in junior spring:

• Completing any remaining:
  • Upper‑level Biology elective
  • Psychology or Sociology
  • English / Writing requirement
• A seminar‑style course that improves:
  • Critical reading
  • Argumentation
  • Scientific writing

You should also be:

• Requesting letters of recommendation from professors who taught your prerequisite sciences (Gen Chem, Org Chem, Physics, Bio, Biochem)
• Finalizing your school list with attention to specific course expectations—some schools strongly prefer or require:
  • 2 semesters of English
  • 2 semesters of Math
  • Specific Biology subfields (e.g., Anatomy & Physiology)

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Year 4: Senior Year – Plugging Gaps and Strengthening Your File

If you followed the traditional timeline, your core prerequisites will be done before senior year. Senior year becomes your opportunity to:

• Deepen science background with advanced electives
• Strengthen GPA with courses aligned to your strengths
• Address any missing or school‑specific requirements

Senior Fall (Semester 7)

At this point you should be in one of two situations:

1. Already applied (traditional path) – you are interviewing this year.
2. Planning to apply after senior year (glide year) – you are finishing prerequisites and studying for MCAT.

For students who already applied:

• Focus on:
  • Maintaining or slightly improving GPA
  • Taking advanced biology electives (e.g., Neurobiology, Advanced Physiology)
  • Continuing clinical exposure and research

For glide‑year planners (later MCAT and application):

This semester is critical:

• Finish any remaining core prerequisites:
  • Biochemistry (must be done before MCAT)
  • Physics II (if outstanding)
  • Statistics (if missing and required by your target schools)
• Use your lighter schedule in the spring (Semester 8) for focused MCAT study and test in late spring or early summer of senior year.

Senior Spring (Semester 8)

This is consolidation. No new prerequisites should be starting here if you plan to apply in the following cycle.

You should:

• Take at most one moderate science course
• Fill the rest of the schedule with:
  • Humanities
  • Social science electives
  • Capstone or thesis work (if applicable)

This keeps bandwidth open for:

• MCAT retake (if needed)
• Additional hours in clinical, shadowing, or research roles
• Application polishing: personal statement, secondaries, interview prep

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Adjustments for Non‑Traditional, Community College, and Post‑Bacc Students

Not everyone follows the 4‑year on‑campus timeline. The sequencing priorities remain the same; only the calendar shifts.

For community college students planning to transfer

At this point you should prioritize:

• Completing:
  • General Chemistry I–II with labs
  • Intro Biology I–II with labs
  • At least one math course and statistics
  • English / Writing
• Beginning Organic Chemistry I (if offered and accepted by your target 4‑year and med schools)

After transfer, sequence:

• Finish Organic Chemistry (if needed) immediately
• Complete Physics I–II
• Take Biochemistry at the 4‑year institution
• Add upper‑level Biology (Genetics, Physiology, Cell Biology)

For post‑bacc or career‑changer students

You should shorten the calendar but maintain order:

Year 1 (post‑bacc):

• Fall:
  • Gen Chem I + Lab
  • Bio I + Lab
  • Math or Statistics
• Spring:
  • Gen Chem II + Lab
  • Bio II + Lab
  • Psychology or Sociology

Year 2 (post‑bacc):

• Fall:
  • Organic I + Lab
  • Physics I + Lab
  • Upper‑level Biology
• Spring:
  • Organic II + Lab
  • Physics II + Lab
  • Biochemistry (if prerequisites allow)

Then schedule MCAT for late spring or early summer of Year 2, or early Year 3 if you want more prep time.

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Quick Sequence Summary by Content Area

For fast reference, here is when to take each major prerequisite relative to the MCAT:

• General Chemistry:

  • Year 1 (both semesters) → foundational for Organic and MCAT

• Biology (Intro sequence):

  • Year 1–2 → finish by end of sophomore year

• Organic Chemistry:

  • Year 2 → both semesters, completed at least 1 year before MCAT if possible

• Physics:

  • Year 2–3 → complete both semesters before MCAT; do not push both into the year of your test if you can avoid it

• Biochemistry:

  • Year 3 fall → take before MCAT; content is central to exam

• Math/Statistics:

  • Year 1–2 → statistics done by end of sophomore or early junior year

• English/Writing:

  • Spread Year 1–3 → complete 2 semesters whenever they best fit

• Psychology/Sociology:

  • Year 1–2 (or early Year 3) → earlier completion strengthens MCAT prep

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Final Takeaways

1. The “right” sequence is about alignment with MCAT timing, not sheer speed; rushing prerequisites into the wrong semesters costs more than it gains.
2. At every transition point (end of freshman, sophomore, and junior years), reassess: grades, confidence in core sciences, and whether your current timeline still serves you.
3. When in doubt, prioritize strong performance in fewer simultaneous hard sciences and accept a slightly delayed application over a rushed, weaker academic record.