LET
General EducationProfessional EducationMajorship (Sec)
Practice Exams

Science Majorship Reviewer 🔬

The Science majorship in the LET is a "general science" challenge, requiring mastery over four distinct fields. This module focuses on the high-yield concepts that bridge these disciplines.

1. Biology: Life at Every Level

Cell Biology & Genetics

  • Mitosis vs. Meiosis:
    • Mitosis: Results in 2 identical daughter cells (2n → 2n). Used for growth and repair.
    • Meiosis: Results in 4 unique daughter cells (2n → n). Used for gamete production.
  • Central Dogma: DNA → RNA → Protein.
    • Transcription: DNA to mRNA (happens in the Nucleus).
    • Translation: mRNA to Protein (happens in the Ribosomes).
  • Mendelian Genetics: Know the difference between Genotype (genetic makeup) and Phenotype (physical appearance). A Punnett Square is a must-know tool!

2. Chemistry: Matter and its Changes

Atomic Structure & Bonding

  • Quantum Numbers:
    1. Principal (n): Size and energy.
    2. Angular Momentum (l): Shape (s, p, d, f).
    3. Magnetic (ml): Orientation.
    4. Spin (ms): Direction of electron spin (+1/2 or -1/2).
  • Chemical Bonds:
    • Ionic: Transfer of electrons (Metal + Non-metal).
    • Covalent: Sharing of electrons (Non-metal + Non-metal).
    • Metallic: "Sea of electrons" (Metal + Metal).

Visual Breakdown: The Water Molecule (Covalent) 💧

Polar Covalent Bond (Bent Shape)

3. Physics: Motion and Energy

Mechanics: Newton’s Laws

  1. Inertia: An object at rest stays at rest unless acted upon by a force.
  2. Acceleration (F=maF = ma): Force equals mass times acceleration.
  3. Action-Reaction: For every action, there is an equal and opposite reaction.

Thermodynamics

  • First Law: Energy cannot be created or destroyed, only transformed.
  • Second Law (Entropy): The universe tends toward disorder. Heat always flows from hot to cold.

4. Earth and Space Science

  • Plate Tectonics: Convergent (crashing), Divergent (spreading), and Transform (sliding) boundaries.
  • Rock Cycle: Igneous (cooled lava), Sedimentary (compressed layers), and Metamorphic (heat/pressure).
  • Astronomy: The "Goldilocks Zone" refers to the distance from a star where liquid water can exist.

💡 LET Strategy: Science Specifics

  1. The "Extreme" Rule: In science, options that use words like "Always" or "Never" are often incorrect because nature usually has exceptions.
  2. Units Matter: If a problem gives you mass in grams but the formula requires kilograms, you must convert first!
  3. Process over Content: The LET often asks about the Scientific Method. Remember that a hypothesis must be testable and falsifiable.
  4. The "Longest Option" pattern in Science:
    • Correct answers in Science often include the specific conditions under which a law applies (e.g., "At constant temperature and pressure...").
    • Strategy: Check if the long answer includes the "if/then" or "given" conditions that make a scientific statement true.

🔗 Related Topics

Practice Quiz

Test your scientific inquiry: Try the Science Majorship Quiz.