🏥 MDCAT Pakistan
MDCAT Key Points Cheatsheet
Biology, Chemistry, Physics and English — all essential concepts for Pakistan MDCAT exam.
📖 10 sections
⏱ 30 min read
✅ Quizzes included
🌙 Dark mode
01 Biology — Cell ▼
Cell Biology Essentials
Prokaryotic cells
No nucleus, no membrane-bound organelles. 70S ribosomes. Examples: bacteria.
Eukaryotic cells
True nucleus, 80S ribosomes. Plants, animals, fungi.
Cell membrane
Phospholipid bilayer + proteins. Fluid mosaic model (Singer-Nicolson 1972).
Mitochondria
Double membrane. Cristae = inner folds. Site of aerobic respiration (ATP production).
Chloroplast
Double membrane + thylakoids. Granum = stack of thylakoids. Site of photosynthesis.
Cell wall
Cellulose (plant), chitin (fungi), peptidoglycan (bacteria). Provides rigidity.
Cell Division
Mitosis
PMAT: Prophase, Metaphase, Anaphase, Telophase. 2 diploid daughter cells.
Meiosis
2 divisions: Meiosis I (homologs separate) + Meiosis II (chromatids separate). 4 haploid cells.
Crossing over
Prophase I: chiasmata form between homologous chromosomes. Creates genetic variation.
Karyotype
Human: 46 chromosomes = 23 pairs. Autosomes: 1-22. Sex chromosomes: XX or XY.
Cancer
Mutations in tumour suppressor genes (p53, BRCA1) or proto-oncogenes → uncontrolled division.
💡
MDCAT frequently tests: cell organelle functions, mitosis vs meiosis stages, DNA replication, and cell membrane transport.
02 Biology — Genetics ▼
Mendelian Genetics
Law of segregation
Allele pairs separate during gamete formation.
Law of independent assortment
Genes on different chromosomes assort independently.
Dominant-recessive
Dominant (B) masks recessive (b). Heterozygous (Bb) = dominant phenotype.
Incomplete dominance
Neither allele dominant: RR=red, Rr=pink, rr=white. Blending.
Codominance
Both alleles expressed: IA IB = blood type AB.
ABO blood groups
I^A I^A or I^A i = A. I^B I^B or I^B i = B. I^A I^B = AB. ii = O.
Sex-linked traits
On X chromosome. Males (XY) hemizygous. Colour blindness, haemophilia.
Test cross
Cross dominant phenotype × recessive (aa) to find genotype.
Molecular Biology
DNA replication
Semi-conservative: each new DNA has 1 old + 1 new strand. DNA polymerase needs primer.
Transcription
DNA → mRNA. RNA polymerase. Occurs in nucleus.
Translation
mRNA → protein at ribosome. tRNA brings amino acids. 3 bases = 1 codon = 1 amino acid.
Mutation types
Substitution, insertion, deletion (frameshift). Point mutation, nonsense, missense.
PCR
Polymerase Chain Reaction. Amplifies DNA. Denaturation 95°C → Annealing → Extension 72°C.
💡
MDCAT tests blood group genetics extensively. Practice Punnett squares for ABO and sex-linked traits.
03 Biology — Human Physiology ▼
Digestive System
Enzymes
Mouth: salivary amylase (starch). Stomach: pepsin (protein), HCl pH 1-2. Pancreas: lipase, protease, amylase.
Villi
Finger-like projections in small intestine. Microvilli = brush border. Increase surface area.
Liver functions
Bile production (emulsification), glycogen storage, detoxification, protein synthesis, coagulation factors.
Large intestine
Absorbs water + minerals. Houses gut microbiome. Produces vitamin K and B12.
Circulatory System
Heart anatomy
4 chambers: RA, RV, LA, LV. Right side: deoxygenated blood. Left side: oxygenated.
Cardiac cycle
Systole (contraction) + Diastole (relaxation). Normal BP: 120/80 mmHg.
Blood components
Plasma (55%), RBCs (haemoglobin, no nucleus, biconcave), WBCs (immune), Platelets (clotting).
Double circulation
Pulmonary (heart↔lungs) + Systemic (heart↔body). Efficient: high pressure to body.
Arteries vs veins
Arteries: thick, elastic, high pressure. Veins: thin, valves, low pressure.
Haemoglobin
4 globin chains + haem groups. Carries O2 and CO2 (as HCO3-).
Respiratory System
Gas exchange
Alveoli: thin wall, large surface area, rich blood supply, moist surface.
Breathing
Inspiration: diaphragm contracts (down), external intercostals contract → ribs rise → volume ↑ → pressure ↓.
Bohr effect
High CO2/low pH → haemoglobin releases O2 more readily to active tissues.
💡
Heart and blood circulation is heavily tested. Learn: heart chambers, valves, blood flow pathway, and cardiac cycle events.
04 Biology — Ecology ▼
Ecology Essentials
Food chain
Producer (plant) → Primary consumer → Secondary → Tertiary. Energy decreases each level (~10% transferred).
Ecosystem
All organisms (biotic) + environment (abiotic) in an area interacting.
Niche
Role/position of organism in ecosystem — what it eats, where it lives, when active.
Succession
Pioneer species → intermediate species → climax community. Primary (bare rock) vs secondary (after disturbance).
Carbon cycle
Photosynthesis removes CO2. Respiration, decomposition, combustion release CO2.
Nitrogen cycle
Fixation → Nitrification → Assimilation → Ammonification → Denitrification.
Population growth
J-curve (exponential: unlimited resources). S-curve (logistic: with carrying capacity).
Biomes
Tropical rainforest, savanna, desert, temperate forest, taiga, tundra, aquatic.
💡
MDCAT ecology questions focus on: food chains/webs, energy flow, nutrient cycles, and human impact on ecosystems.
05 Chemistry — Organic ▼
CHEMOrganic chemistry essentials
Homologous series — each differs by CH2:
Alkanes: CnH2n+2  (methane CH4, ethane C2H6)
Alkenes: CnH2n    (ethene C2H4) — C=C double bond
Alkynes: CnH2n-2  (ethyne C2H2) — C≡C triple bond
Alcohols: CnH2n+1OH (ethanol C2H5OH)
Carboxylic acids: -COOH (ethanoic acid CH3COOH)

Reactions:
• Addition: alkene + X2 → disubstituted alkane
• Combustion: CnH2n+2 + O2 → CO2 + H2O
• Fermentation: C6H12O6 → 2C2H5OH + 2CO2
• Saponification: ester + NaOH → alcohol + sodium salt
• Esterification: acid + alcohol → ester + water

Functional groups:
-OH (alcohol), -COOH (acid), -CHO (aldehyde)
-CO- (ketone), -NH2 (amine), -X (halide)

Isomers:
Structural: same formula, different connectivity
Stereoisomers: same connectivity, different spatial arrangement
Geometric (cis/trans): around C=C double bond
💡
Remember: alkanes end in -ane, alkenes in -ene, alkynes in -yne. Count carbons: meth(1) eth(2) prop(3) but(4) pent(5) hex(6).
06 Chemistry — Physical ▼
Mole
Amount of substance. 1 mole = 6.022×10²³ particles (Avogadro's number).
Molarity
Moles of solute per litre of solution: M = moles/L. Units: mol/dm³.
Mole calculations
moles = mass/Mr. moles = M×V(L). moles = vol/22.4 (at STP).
pH
pH = -log[H⁺]. pH 7=neutral. Below 7=acid. Above 7=alkali.
Buffer
Resists pH change. Weak acid + conjugate base (e.g., CH3COOH + CH3COO⁻).
Le Chatelier's principle
System disturbed → equilibrium shifts to oppose the change.
Kc
Equilibrium constant. Products over reactants (raised to stoichiometric powers).
Oxidation state
Hypothetical charge. Increases = oxidised. Decreases = reduced. OIL RIG.
CHEMKey equations
moles = mass / Molar mass
moles = Molarity × Volume(L)
moles = Volume(L) / 22.4   [STP: 0°C, 1 atm]

pH = -log[H+]   →   [H+] = 10^-pH
pKa = -log(Ka)

PV = nRT   (Ideal Gas Law)
R = 8.314 J/mol.K

% yield = (actual / theoretical) × 100
% purity = (pure mass / total mass) × 100
💡
MDCAT mole calculations: always convert mass to moles first using Mr, then use ratios from balanced equation.
07 Physics — Mechanics ▼
v = u + at
Velocity = initial + acceleration × time
Kinematics
s = ut + ½at²
Displacement formula
Kinematics
v² = u² + 2as
Without time
Kinematics
F = ma
Newton's 2nd Law
Dynamics
W = mg
Weight formula, g=9.81 m/s²
Gravity
p = mv
Momentum
Conservation
F = mv - mu / t
Force = rate of change of momentum
Impulse
KE = ½mv²
Kinetic energy
Energy
GPE = mgh
Gravitational potential energy
Energy
P = W/t = Fv
Power
Energy
P = F/A
Pressure
Fluid mechanics
ρ = m/V
Density
Properties of matter
Hooke's Law
F = kx
k=spring constant, x=extension
💡
MDCAT physics: most questions involve SUVAT equations or energy conservation. Always list given values before choosing equation.
08 Physics — Waves & Electricity ▼
Waves
v = fλ
Wave speed = frequency × wavelength
T = 1/f
Period = 1/frequency
Speed of light
c = 3×10⁸ m/s
In vacuum
Speed of sound
≈ 340 m/s
In air at 20°C
Snell's Law
n₁sinθ₁ = n₂sinθ₂
Refraction
Electricity
V = IR
Ohm's Law
P = IV = I²R = V²/R
Power
Q = It
Charge = current × time
Series
R_total = R1+R2
Same current, V splits
Parallel
1/R = 1/R1 + 1/R2
Same V, I splits
E = Pt
Energy = power × time
kWh for bills
💡
MDCAT electricity: practice Ohm's Law, series vs parallel circuits, power calculations. These are always on the exam.
09 English — Verbal ▼
Sentence correction
Identify grammatical errors: tense, subject-verb agreement, articles, prepositions.
Word analogies
Identify relationships: Big:Huge :: Small:Tiny (synonyms), Hot:Cold :: Day:Night (antonyms).
Reading comprehension
Main idea, supporting details, inference, author's tone, vocabulary in context.
Vocabulary
Synonyms, antonyms, word meanings. Focus on academic and medical vocabulary.
Fill in the blanks
Context clues, collocations, grammar rules. Read entire sentence first.
Prepositions
At (time/place), in (months/years/cities), on (days/dates/surfaces).
Idioms
At the drop of a hat=immediately. Get cold feet=lose courage. Hit the nail=be exactly right.
Active vs Passive
Active: Subject does action. Passive: Subject receives action (be+past participle).
ENGLISHCommon MDCAT English patterns
Synonym questions: exhausted = tired, verbose = wordy
Antonym questions: benevolent ≠ malevolent

Sentence completion:
'Despite his _____ efforts, he failed.' → strenuous/tireless

Subject-verb agreement:
'The committee (has/have) made its decision.' → has (collective=singular)

Article usage:
'I saw ____ elephant.' → an (vowel sound)
'She is ____ European.' → a (consonant sound 'y')
💡
MDCAT English section: focus on vocabulary and sentence correction. Revise 500 common synonym/antonym pairs and basic grammar rules.
10 Mini Quizzes ▼
❓ Quiz 1
Which organelle is the site of aerobic respiration in eukaryotic cells?
Mitochondria carry out aerobic respiration (Krebs cycle + ETC) producing 36-38 ATP per glucose. Chloroplasts do photosynthesis (glucose production). Ribosomes do protein synthesis.
❓ Quiz 2
In a cross between two parents with blood type AB, what percentage of offspring can have blood type O?
AB × AB: I^A I^B × I^A I^B → offspring: I^A I^A (25%) = type A, I^A I^B (50%) = type AB, I^B I^B (25%) = type B. Type O (ii) = 0% — neither parent carries the i allele.
❓ Quiz 3
What is the value of Avogadro's number?
Avogadro's number = 6.022 × 10²³ particles per mole. 6.63 × 10⁻³⁴ is Planck's constant (not Avogadro's).