Mnemonics

Dr Ashish Anjankar

Cell membrane and Transport

1. Components of Cell Membrane (Fluid Mosaic Model)

Mnemonic: “Phat People Can Make Fun Friends”

P – Phospholipids
P – Proteins (Integral & Peripheral)
C – Cholesterol
M – Membrane carbohydrates (Glycolipids, Glycoproteins)
F – Fluid mosaic
F – Flexibility

2. Functions of Cell Membrane

Mnemonic: “PETERS”

P – Protection
E – Endocytosis & Exocytosis
T – Transport (Selective permeability)
E – Enzymatic activity
R – Receptor for signaling
S – Structural support

3. Types of Membrane Transport

Mnemonic: “P-FATE” (Passive and Facilitated transport are FATE-ful)

P – Passive transport
F – Facilitated diffusion
A – Active transport
T – Transcytosis (Endo- & Exocytosis)
E – Endocytosis (Pinocytosis, Phagocytosis)

 4. Types of Membrane Proteins

Mnemonic: “TRICE”

T – Transport proteins
R – Receptor proteins
I – Integral proteins
C – Cell recognition proteins
E – Enzymatic proteins

 5. Differences: Active vs Passive Transport

Mnemonic for Active: “NEEDS ATP”

  • N – Needs Energy (ATP)

  • A – Against gradient

  • T – Transport proteins needed

  • P – Pumps (Na+/K+ pump)

Mnemonic for Passive: “HIGH to LOW, No ATP Flow”

 6. Types of Endocytosis

Mnemonic: “PPR” – Please Pick Right
P – Phagocytosis (“cell eating”)
P – Pinocytosis (“cell drinking”)
R – Receptor-mediated endocytosis

 7. Amphipathic Nature of Phospholipids

Mnemonic: “HAIL”
H – Hydrophilic head
A – Amphipathic molecule
I – Insoluble in water overall
L – Lipophilic tail

Enzymes 

Six Classes of Enzymes (IUBMB Classification)
Mnemonic: OTH LIL

    • Oxidoreductase
    • Transferase
    • Hydrolase
    • Lyase
    • Isomerase
    • Ligase

OR

Mnemonic: “Over The HILL”

  • O – Oxidoreductases (oxidation-reduction reactions)

  • T – Transferases (transfer functional groups)

  • H – Hydrolases (hydrolysis reactions)

  • I – Isomerases (isomerization changes)

  • L – Ligases (joining molecules with ATP)

  • L – Lyases (break bonds without water)

Tip: Remember “HILL” as enzymes help you climb the hill of metabolism.

2. Features/Properties of Enzymes

Mnemonic: “SPEEED”

  • S – Specificity

  • P – Protein in nature (mostly)

  • E – Efficient (high catalytic power)

  • E – Environment-sensitive (pH & temp)

  • E – Enzyme-substrate complex formation

  • D – Denaturation (by heat or extreme pH)

3. Factors Affecting Enzyme Action

Mnemonic: “PLET PSAT”

  • P- pH

  • L- Light & radiation

  • E – Enzyme concentration

  • T – Temperature

  • P  – Product Concentration
  • S – Substrate concentration
  • A – Activators

  • T – Time

Enzyme Kinetics – Michaelis-Menten Constants

Mnemonic: “KM = Half the Max”

  • Km: Substrate concentration at which V = ½ Vmax

 This helps you remember that Km reflects the enzyme’s affinity for its substrate (lower Km = higher affinity).

5. Enzyme Inhibition Types

Mnemonic: “CUN” – Competitive, Uncompetitive, Non-competitive

Competitive Inhibition

Mnemonic: “Competes & Increases Km, No Vmax Change”

Non-Competitive Inhibition

Mnemonic: “No Competition, No Km Change, Lowers Vmax”

Uncompetitive Inhibition

Mnemonic: “UNique – Both Km & Vmax Decrease”

6. Coenzymes vs Cofactors

Mnemonic: “Coenzyme = Organic, Cofactor = For all (metal or organic)”

  • Coenzyme – Organic (e.g., NAD⁺, FAD)

  • Cofactor – May be metal ions (e.g., Zn²⁺, Mg²⁺) or coenzymes

 

7. Isoenzymes: Mnemonic – “Let Cool Kids Always Party”

This mnemonic helps remember the main isoenzymes of Lactate Dehydrogenase (LDH):

L – LDH-1 → C – Cardiac muscle (Heart)
L – LDH-2 → K – Kidney
L – LDH-3 → A – Alveolar (Lung)
L – LDH-4 → P – Pancreas
L – LDH-5 → L – Liver & Skeletal muscle

Mnemonic Breakdown:
Let Cool Kids Always Party = LDH 1 (Cardiac), 2 (Kidney), 3 (Alveoli), 4 (Pancreas), 5 (Liver)

Clinical Pearl:
LDH-1 > LDH-2 = Myocardial infarction
(Normally, LDH-2 > LDH-1, so a “flip” indicates MI)

8. Enzymes in Myocardial Infarction (MI): Mnemonic – “Clever Lab Test”

Use this to recall the key cardiac enzymes released in MI:

C – CK-MB
L – LDH (especially LDH-1)
T – Troponin I & T

Timing Clue (Another Mnemonic):
“Troops Come Late”

  • Troponins ↑ in 3–6 hrs, peak in 12–24 hrs, stay ↑ for 7–10 days

  • CK-MB ↑ in 3–6 hrs, peak 12–24 hrs, normal in 48–72 hrs

  • LDH ↑ later but remains longer

 9. Liver Enzymes: Mnemonic – “A Liver’s Secret Guard”

Helps remember liver-related enzymes:

A – ALT (Alanine transaminase)
L – LDH
S – AST (Aspartate transaminase)
G – GGT (Gamma-glutamyl transferase)
Also: ALP (Alkaline phosphatase)

 Clinical Tip:

  • ALT > AST → Viral hepatitis

  • AST > ALT → Alcoholic liver disease
    (“S for Spirits“)

10. Pancreatic Enzymes: Mnemonic – “PALE”

Used in diagnosis of acute pancreatitis:

P – Pancreatic lipase
A – Amylase
L – Low calcium (hypocalcemia may occur)
E – Elevated glucose (due to islet damage)

11. Bone Disorders: Mnemonic – “ALP Builds Bones”

ALP (Alkaline Phosphatase) is raised in:

  • Bone diseases (e.g., Paget’s disease, rickets, osteomalacia)

  • Liver diseases (especially obstructive)

  • Growing children (physiological)

 Remember:
High ALP + Normal GGT → Bone origin
High ALP + High GGT → Liver origin

Chemistry of Amino Acids & Proteins

  • 1. Essential Amino Acids

    These cannot be synthesized by the body and must be obtained from diet.

    Mnemonic: “PVT TIM HALL”

    • P – Phenylalanine

    • V – Valine

    • T – Threonine

    • T – Tryptophan

    • I – Isoleucine

    • M – Methionine

    • H – Histidine (semi-essential)

    • A – Arginine (semi-essential)

    • L – Leucine

    • L – Lysine

    Tip: Arginine & Histidine is essential in children (growth phase), hence semi-essential.

     2. Classification Based on Side Chain (R-group)

     Mnemonic: “GAVLIMP” loves “PASTA” but hates “A SHET”

    Non-polar (Hydrophobic) – “GAVLIMP”

    • G – Glycine

    • A – Alanine

    • V – Valine

    • L – Leucine

    • I – Isoleucine

    • M – Methionine

    • P – Proline

    Polar Uncharged – “PASTA”

    • P – Phenylalanine (Actually aromatic, but can show mixed behavior)

    • A – Asparagine

    • S – Serine

    • T – Threonine

    • A – Tyrosine (can be classified here or with aromatics)

    Charged Polar (Hydrophilic)

    Acidic – “A SHET”

    • A – Aspartic acid

    • S – Succinic acid (Not an AA, just a sound-alike for Aspartate!)

    • H – Histidine

    • E – Glutamic acid

    • T – Technically wrong – but use for “GlutaTamic”

    (You can revise this to: “DE” = Aspartic, Glutamic acid → Acidic)

     Basic – “HAL”

    • H – Histidine

    • A – Arginine

    • L – Lysine

     3. Aromatic Amino Acids

    Mnemonic: “Try Tripping on a Tyre”

    • Try – Tryptophan

    • Tripping – Phenylalanine

    • Tyre – Tyrosine

    These absorb UV light at ~280 nm (used in protein quantification)

    4. Acidic and Basic Amino Acids

    Mnemonic for Acidic: “Acid is Negative – DE”

    • D – Aspartic acid (Aspartate)

    • E – Glutamic acid (Glutamate)

    Mnemonic for Basic: “HAL is positive”

    • H – Histidine

    • A – Arginine

    • L – Lysine

    Remember: Acidic = Negatively charged at physiological pH;
    Basic = Positively charged.

    5. Protein Structure Levels

     Mnemonic: “1° Beads, 2° Coils, 3° Folds, 4° Friends”

    • 1° – Primary: Sequence of amino acids (peptide bonds)

    • 2° – Secondary: α-helix, β-sheet (H-bonds)

    • 3° – Tertiary: 3D folding (Disulfide bonds, H-bonds, hydrophobic interactions)

    • 4° – Quaternary: Multiple polypeptides joining (e.g., Hemoglobin)

     6. Bonds in Protein Structure

    Mnemonic: “PHI-DH”

    • P – Peptide bond – Primary

    • H – Hydrogen bond – Secondary

    • I – Ionic bond – Tertiary

    • D – Disulfide bond – Tertiary/Quaternary

    • H – Hydrophobic interactions – Tertiary

    7. Tests for Proteins & AAs

    Mnemonic: “BINCP” – Basic Individual Needs Can Pass”

    • B – Biuret test → Peptide bonds (protein presence)

    • I – Xanthoproteic test → Aromatic AAs (yellow color)

    • N – Ninhydrin test → Free amino group (used in chromatography)

    • C – Millon’s test → Tyrosine (red color)

    • P – Pauly’s test → Histidine & Tyrosine

Metabolism of Amino Acids and Proteins

  1. Digestion of Proteins

Mnemonic: “Some People Try Eating Chips”

  • S – Stomach → Pepsin (activated from pepsinogen by HCl)

  • P – Pancreas → Enzymes like Trypsin, Chymotrypsin, Carboxypeptidase

  • T – Trypsin → Activates other zymogens

  • E – Enteropeptidase → Converts trypsinogen to trypsin

  • C – Small intestine → Final digestion by peptidases

Proteins → Peptides → Amino Acids

 2. Urea Cycle

 Mnemonic: “Ordinarily, Careless Crappers Are Also Furious  About Urination “

  • O – Ornithine

  • C – Carbamoyl phosphate

  • C – Citrulline

  • A – Aspartate

  • A – Argininosuccinate

  • F – Fumarate

  • A – Arginine

  • U-  Urea

 Occurs mainly in the liver
 Clinical link: Deficiency of enzymes → Hyperammonemia

3. Products of Glycine, Tyrosine, Tryptophan

Glycine → “He Creatively Purifies Collagen”

  • Heme (with Succinyl-CoA)

  • Creatine (with arginine)

  • Purines (nucleotides)

  • Collagen (component of triple helix)

Tyrosine → “Do Not Make My Thyroid Hormones”

  • Dopa → Dopamine

  • Norepinephrine

  • Melanin

  • MAO degrades Catecholamines

  • Thyroxine (T₄)

  • Hormones of adrenal medulla

  • Tryptophan → “Sister Makes Nice Protein”

  • Serotonin

  • Melatonin

  • Niacin → Needed for NAD⁺/NADP⁺

  • Protein synthesis

Deficiency in B6 or iron can affect these pathways
Hartnup disease → ↓ tryptophan absorption → ↓ niacin → Pellagra-like symptoms

Chemistry of Carbohydrates

Classification of Carbohydrates

Based on number of sugar units and derivatives.

1. Based on Number of Units

Mnemonic:  “My Dear Old Papa”

  • M – Monosaccharides (single unit)
  • D – Disaccharides (2 units)
  • O – Oligosaccharides (3–10 units)
  • P – Polysaccharides (>10 units)

2. Based on Functionality

  • Aldoses – contain aldehyde group (e.g., glucose)
  • Ketoses – contain ketone group (e.g., fructose)

 Mnemonic: “Aldo Glows, Keto Fruits”

2. Functions of Carbohydrates

Mnemonic:  “SHE BIDS”

  1. S – Structural (cellulose in plants, ribose in RNA)
  2. H – Helps in fat metabolism
  3. E – Energy source (main role)
  4. B – Building blocks (e.g., ribose in DNA/RNA)
  5. I – Immediate energy via glycolysis
  6. D – Dietary fiber – helps bowel movement
  7. S – Storage form as glycogen (animals), starch (plants)

 

3. Glycosaminoglycans (GAGs)

 “He Please Kindly Help Drive Car”

GAG Mnemonic
He – Heparin Anticoagulant in mast cells, blood
P – Heparan sulfate Basement membrane, cell surfaces
K – Keratan sulfate Cornea, cartilage
H – Hyaluronic acid Synovial fluid, vitreous humor
D – Dermatan sulfate Skin, blood vessels
C – Chondroitin sulfate Cartilage, tendons

4. Functions of GAGs

Mnemonic:  “GLUE”

  • G – Ground substance in ECM
  • L – Lubrication in joints (e.g., hyaluronic acid)
  • U – Unusual anticoagulant (heparin)
  • E – Elasticity and support (cartilage, skin)

5. Disaccharides

Mnemonic:  “Some Like More Red Sugar”

  • Lactose – Reducing
  • Maltose – Reducing
  • Sucrose – Non-reducing (because of its glycosidic bond involving both anomeric carbons)

Metabolism of Carbohydrates

  • 1. Digestion of Carbohydrates

    Mnemonic:
    “Saliva, Small, Sweet Simplicity”

    • Saliva – Salivary amylase (in mouth)

    • Small intestine – Pancreatic amylase

    • Sweet – Disaccharides → Monosaccharides

    • Simplicity – Absorbed in simple form (glucose, galactose, fructose)

    2. Glycolysis (Embden-Meyerhof Pathway)

    Mnemonic:
     “Hungry Peter Pan And The Great Mighty Pirate Picked Pumpkin Pie To Prepare”

    Each capitalized word stands for one step/enzyme in glycolysis:

    1. H – Hexokinase

    2. P – Phosphoglucose isomerase

    3. P – Phosphofructokinase-1 (PFK-1)

    4. A – Aldolase

    5. T – Triose phosphate isomerase

    6. G – Glyceraldehyde-3-phosphate dehydrogenase

    7. M – Phosphoglycerate kinase

    8. P – Phosphoglycerate mutase

    9. P – Enolase

    10. T – Pyruvate kinase

     Rate-Limiting Enzyme: PFK-1
    Mnemonic: “PFK is the King of Glycolysis”

     3. Kreb’s Cycle (TCA Cycle)

    Mnemonic:
     “Can I Keep Selling Sex For Money, Officer?”

    1. C – Citrate

    2. I – Isocitrate

    3. K – α-Ketoglutarate

    4. S – Succinyl-CoA

    5. S – Succinate

    6. F – Fumarate

    7. M – Malate

    8. O – Oxaloacetate

     Rate-Limiting Enzyme:
     Isocitrate dehydrogenase

     4. Gluconeogenesis

    Mnemonic:
     “Pathway Produces Fresh Glucose”

    1. P – Pyruvate carboxylase

    2. P – PEP carboxykinase

    3. F – Fructose-1,6-bisphosphatase

    4. G – Glucose-6-phosphatase

     Mnemonic to remember it’s the reverse of glycolysis with bypasses:
     “Gluconeogenesis Bypasses Three Irreversible Steps of Glycolysis”

     5. Glycogen Metabolism

    (A) Glycogenesis

    Mnemonic:
     “G6 Makes Great Branches”

    1. G6 – Glucose-6-phosphate

    2. M – Mutase (G6P → G1P)

    3. G – Glycogen synthase (adds glucose units)

    4. B – Branching enzyme (creates branches)

    (B) Glycogenolysis

    Mnemonic:
     “Pretty Dumb Guys Dismantle”

    1. P – Phosphorylase (breaks α-1,4 bonds)

    2. D – Debranching enzyme (removes branches)

    3. G – Glucose-1-phosphate

    4. D – Converted to G6P → then to glucose in liver

     6. Glycogen Storage Disorders

    Mnemonic:
     “Very Poor Cori Anderson Made Herself Hers”

    Disease Mnemonic Word Enzyme Deficiency
    Von Gierke’s Very Glucose-6-phosphatase
    Pompe’s Poor Lysosomal α-1,4-glucosidase
    Cori’s Cori Debranching enzyme
    Andersen’s Anderson Branching enzyme
    McArdle’s Made Muscle glycogen phosphorylase
    Hers’ Herself Hepatic glycogen phosphorylase

     7. HMP Shunt (Pentose Phosphate Pathway)

    Mnemonic:
     “Hand Me Power”

    • H – HMP shunt

    • M – Makes NADPH

    • P – Produces Pentoses for nucleotide synthesis

     Key Enzyme: Glucose-6-phosphate dehydrogenase (G6PD)

     8. G6PD Deficiency & Hemolytic Anemia

    Mnemonic:
     “G6PD: No NADPH, No Defense!”

    • G6PD deficiency → ↓ NADPH

    • No NADPH → No reduced glutathione

    • Leads to oxidative damage → hemolysis

    • Triggered by: fava beans, infections, sulfa drugs

     Mnemonic for triggers: “FIS”

    • F – Fava beans

    • I – Infections

    • S – Sulfa drugs

     9. Regulation of Blood Sugar

    Mnemonic:
     “High Glucose Insulin Goes, Low Glucose Glucagon Grows”

    • High glucose → ↑ Insulin → ↓ blood sugar

    • Low glucose → ↑ Glucagon → ↑ blood sugar

     10. Diabetes Mellitus (DM)

    Mnemonic:
     “3 Ps of Diabetes”

    • Polyuria – Excess urination

    • Polydipsia – Excess thirst

    • Polyphagia – Excess hunger

    Type 1 vs Type 2 Mnemonic:
     “Type 1: T-cell Attack, Type 2: Too much sugar”

    • Type 1: Autoimmune destruction of β-cells

    • Type 2: Insulin resistance ± deficiency

Chemistry of Lipids 

    • Bile acids are the main fate of cholesterol

    • Others excreted in feces

      Fatty Acids – Saturated vs Unsaturated

      Mnemonic:
       “Saturated = Straight; Unsaturated = Unsure (Kinks)”

      • Saturated FA – No double bonds (e.g. palmitic acid)

      • Unsaturated FA – One or more double bonds (e.g. oleic acid)

      Think: “Sat = Solid” (at room temp)
      “Unsat = Unstable” → liquid

      2. Essential Fatty Acids (EFAs)

      Mnemonic:
      👉 “Lino Likes Alpha”

      • Linoleic acid

      • Linolenic acid (α-linolenic)

      • Both are polyunsaturated and cannot be synthesized by the body

       “Essential to Eat” – must come from diet.

      3. Omega Fatty Acids

      Mnemonic:
      “3-6-9 Are Prime Omegas”

      • Omega-3 – α-linolenic acid

      • Omega-6 – Linoleic acid

      • Omega-9 – Oleic acid

       Remember: “Omega-3 is anti-inflammatory”

       

      4. Lipoproteins (Order of lipoproteins by increasing density)

      Mnemonic:
       “Chylos Love Very Low Hormones”

      • Chylomicrons – lowest density, highest TG

      • LDL – Low-density lipoprotein

      • VLDL – Very low-density lipoprotein

      • HDL – High-density lipoprotein (good cholesterol)

       “LDL = Lousy, HDL = Healthy”

      5. Functions of Lipids

      Mnemonic:
       “SHE Fights Cold Water”

      • S – Storage of energy

      • H – Hormone synthesis

      • E – Enzyme co-factors (e.g. vitamins)

      • F – Formation of membranes (phospholipids)

      • C – Cell signaling (e.g. prostaglandins)

      • W – Waterproofing (sebum, waxes)

      6. Lipid-Soluble Vitamins

      Mnemonic:
      👉 “KADE in Fat”

      • K, A, D, E – fat-soluble vitamins

      • Absorbed along with dietary fat

      • Deficiency seen in fat malabsorption (e.g. cystic fibrosis)

      Metabolism of Lipids

      1. Digestion of Lipids

      Mnemonic:
       “Lingual, Gastric, Pancreatic – Bile Brings Breakup”

      • Lingual lipase – Acts in mouth/stomach

      • Gastric lipase – Acts in stomach

      • Pancreatic lipase – Acts in intestine (main enzyme)

      • Bile salts – Emulsify fats → micelle formation

      • Final products: FFA, monoacylglycerol, cholesterol, lysophospholipids

      2. Lipolysis (Breakdown of Stored Fat)

      Mnemonic:
       “HSL is the Hero”

      • HSL = Hormone Sensitive Lipase

      • Activated by: Glucagon, Epinephrine

      • Inhibited by: Insulin

       Tip: “When hungry (low insulin), fat breaks down.”

      3. Beta-Oxidation of Fatty Acids

      Mnemonic for Steps:
       “OHOT” – Oxidation, Hydration, Oxidation, Thiolysis

      Each cycle removes 2C as acetyl-CoA.

      • O – Acyl-CoA dehydrogenase

      • H – Enoyl-CoA hydratase

      • O – Hydroxyacyl-CoA dehydrogenase

      • T – Thiolase

       Tip: Occurs in mitochondria.

      4.  Disorders of Beta-Oxidation

      Mnemonic:
      “MCAD is Most Common”

      • MCAD Deficiency – Medium-Chain Acyl-CoA Dehydrogenase

        • Symptoms: Hypoglycemia, vomiting, sudden infant death

        • Treatment: Avoid fasting

       Remember: Beta-oxidation fuels fasting. If defective → hypoglycemia

      5. Fatty Acid Biosynthesis

      Mnemonic:
       “ACC FAS”

      • ACC = Acetyl-CoA carboxylase (Rate-limiting)

      • FAS = Fatty Acid Synthase (multienzyme complex)

       Cofactor: Biotin
       Occurs in cytoplasm, uses NADPH from HMP shunt

      6. Ketone Body Metabolism

      Mnemonic:
       “HAA” for Ketone Bodies

      • H – Hydroxybutyrate

      • A – Acetoacetate

      • A – Acetone (exhaled → fruity breath)

      Produced in liver, used by muscles, brain (during starvation)

       7. Ketosis

      Mnemonic:
       “No Sugar → Liver Makes Ketones”

      Seen in:

      • Starvation

      • Uncontrolled Diabetes Mellitus

      • Low-carb diets

       Excess ketones → ketoacidosis → fruity breath, low pH

      8. Cholesterol Synthesis

      Mnemonic:
       “HMG-CoA is Key”

      • Rate-limiting enzyme: HMG-CoA reductase

      • Precursor: Acetyl-CoA

      • Statins inhibit HMG-CoA reductase

      Occurs in liver cytoplasm, needs NADPH

      9. Cholesterol Degradation

      Mnemonic:
       “BAKE” – Bile Acids, Kidneys Excrete”

    10. Atherosclerosis

    Mnemonic:
     “Fatty LDL = Arterial Damage”

    • LDL gets oxidized → taken up by macrophages → foam cells

    • Leads to plaque formation

     HDL removes cholesterol from plaques

    11. Fatty Liver (Hepatic Steatosis)

    Mnemonic:
     “ALCOHOL = Accumulated Lipids”

    Causes:

    • A – Alcohol

    • L – Liver disease

    • C – Carbohydrate overload

    • O – Obesity

    • H – Hepatitis

    • O – Other drugs

    • L – Lipid metabolism defects

    12. Lipotropic Factors

    Mnemonic:
     “Be Cool”

    • B – Vitamin B12

    • C – Choline

    • Others: Methionine, folate
      🧠 Help prevent fatty liver by exporting lipids

    13. Eicosanoids (Prostaglandins, Thromboxanes, Leukotrienes)

    Mnemonic:
     “AA Makes PETL”

    • Derived from Arachidonic Acid

    • Forms:

      • P – Prostaglandins

      • E – Epoxides

      • T – Thromboxanes

      • L – Leukotrienes

     Key enzymes: COX, LOX

    14. Obesity

    Mnemonic:
     “CAMP” – Causes of Obesity

    • C – Calories > burned

    • A – Activity low

    • M – Metabolic disorders (hypothyroidism)

    • P – Psychological/genetic causes

      15. Important Lipid-related Disorders

      Mnemonic:
      “Some Guys Try Having Nice Looks”

      Disease Enzyme Deficiency Mnemonic Word
      S – Sandhoff β-Hexosaminidase A & B Some
      G – Gaucher Glucocerebrosidase Guys
      T – Tay-Sachs Hexosaminidase A Try
      H – Niemann-Pick Sphingomyelinase Having
      N – Fabry α-Galactosidase A Nice
      L – Krabbe Galactocerebrosidase Looks

      All are lysosomal storage disorders

      16. Lipid Peroxidation (Free Radical Damage)

      Mnemonic:
       “I-I-T”

      1. Initiation – free radical formation

      2. Propagation – chain reaction

      3. Termination – neutralization by antioxidants (e.g. Vit E)

Biological Oxidation

ELECTRON TRANSPORT CHAIN (ETC)

Complexes & Their Functions:

Mnemonic: “Nice Suave Cats Play Around”

Complex Name Function Mnemonic Hint
I NADH Dehydrogenase Transfers e⁻ from NADH → CoQ Nice
II Succinate Dehydrogenase Transfers e⁻ from FADH₂ → CoQ Suave
III Cytochrome bc₁ complex Transfers e⁻ from CoQ → Cyt c Cats
IV Cytochrome c oxidase Transfers e⁻ from Cyt c → O₂ Play
V ATP synthase Synthesizes ATP Around

 INHIBITORS OF ETC

Mnemonic: “Rats And Ants Can Bite Our Cat”

Site Inhibitor Action Mnemonic
Complex I Rotenone, Amytal, Piericidin A Block e⁻ from NADH to CoQ Rats (Rotenone), And (Amytal)
Complex II Thenoyltrifluoroacetone (TTFA) Inhibits succinate → fumarate (optional)
Complex III Antimycin A Blocks CoQ → Cyt b Ants (Antimycin)
Complex IV Cyanide, Carbon monoxide, Sodium azide, Hydrogen sulfide Block Cyt oxidase (O₂ can’t accept e⁻) Can Bite Our Cat (Cyanide, CO, Azide, H₂S)

 Memory trick:
 “When the chain is poisoned, ATP can’t be gained.”

OXIDATIVE PHOSPHORYLATION

Coupling of ETC & ATP synthesis:

ETC pumps protons → creates proton gradient → drives ATP synthase (Complex V).

Mnemonic for process:
“Electrons Excite, Protons Pump, ATP Pops.”

 UNCOUPLERS OF OXIDATIVE PHOSPHORYLATION

They collapse the proton gradient → ETC runs but ATP synthesis stops, energy released as heat.

Mnemonic: “DNP Makes Fever High”

Uncoupler Action Mnemonic
2,4-Dinitrophenol (DNP) Dissipates proton gradient DNP
Malate/Arsenate Indirectly uncouple Makes
FCCP (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone) Protonophore Fever
High dose aspirin Inhibits coupling High

🧠 Extra memory tip:
Natural uncoupler: Thermogenin (UCP1) in brown fat → generates heat (non-shivering thermogenesis).

Vitamins 

  • Vitamins Classification

    Mnemonic:
     “Fat Babies Killed And Drowned, Rest Can Be Washed Away”

    Type Vitamins Solubility Mnemonic
    Fat-soluble A, D, E, K Fat Babies Killed And Drowned
    Water-soluble B-complex + C Rest Can Be Washed Away

     FAT-SOLUBLE VITAMINS

    VITAMIN A (Retinol)

    Mnemonic Summary:

     “A for Appearance, Adaptation, and Antioxidant.”

    Aspect Details
    Sources Animal: Liver, butter, egg yolk 🥚
    Plant: Carrots, mango, papaya, spinach 🥕
    RDA ~600–900 µg/day
    Functions 1️⃣ Vision (retinal in rhodopsin cycle)
    2️⃣ Epithelial cell integrity
    3️⃣ Growth, reproduction, antioxidant
    Deficiency Mnemonic: “3 D’s of Vitamin A” → Dry eyes, Dark vision, Damaged epithelium
    Night blindness, xerophthalmia, keratomalacia
    Toxicity Headache, vomiting, hepatomegaly, teratogenicity

     VITAMIN D (Calciferol)

    Mnemonic Summary:
     “D for D-bone: Development, Deposition, Density.”

    Aspect Details
    Sources Sunlight ☀️, egg yolk, butter, fish liver oil
    RDA 400 IU/day (≈10 µg)
    Functions ↑ Ca²⁺, PO₄³⁻ absorption; bone mineralization
    Deficiency Rickets (children), Osteomalacia (adults)
    Toxicity Hypercalcemia, kidney stones

    VITAMIN E (Tocopherol)

    Mnemonic Summary:
    “E for Egg-cellent Antioxidant.”

    Aspect Details
    Sources Vegetable oils, nuts, wheat germ 🌾
    RDA 10 mg/day
    Functions Antioxidant, protects RBC membranes
    Deficiency Hemolytic anemia, neuropathy
    Toxicity Rare; may interfere with vitamin K function

    VITAMIN K (Phylloquinone, Menaquinone)

    Mnemonic Summary:
    “K for Koagulation.”

    Aspect Details
    Sources Green leafy vegetables, gut flora 
    RDA 70–120 µg/day
    Functions Coenzyme for γ-carboxylation of clotting factors II, VII, IX, X
    Deficiency Bleeding, ↑ PT time, in newborns (Hemorrhagic disease)
    Toxicity Rare; jaundice in newborns (menadione form)

    WATER-SOLUBLE VITAMINS

     VITAMIN B₁ (Thiamine)

    Mnemonic Summary:
     “Thiamine Makes Tissues Thrive.”

    Aspect Details
    Sources Whole grains, pulses, pork, liver
    RDA 1.2 mg/day
    Functions Coenzyme (TPP) for decarboxylation: PDH, α-KGDH, transketolase
    Deficiency Mnemonic: “3 B’s” → Beriberi, Brain (Wernicke), Balance
    Toxicity None reported

    VITAMIN B₂ (Riboflavin)

    Mnemonic Summary:  “Ribo is for Redox Reactions.”

    Aspect Details
    Sources Milk, eggs, liver
    RDA 1.3 mg/day
    Functions FAD, FMN coenzymes in redox reactions
    Deficiency “Cheilosis and Corneal Cracks” (Angular stomatitis, glossitis, photophobia)
    Toxicity None

     VITAMIN B₃ (Niacin)

    Mnemonic Summary:
     “Niacin Needs tryptophan; Deficiency → 3 D’s.”

    Aspect Details
    Sources Meat, fish, peanuts
    RDA 16 mg/day
    Functions NAD⁺/NADP⁺ coenzyme in oxidation-reduction
    Deficiency Pellagra – 3 D’s: Dermatitis, Diarrhea, Dementia
    Toxicity Flushing, itching, hyperglycemia, hyperuricemia

     VITAMIN B₅ (Pantothenic acid)

    Mnemonic Summary:
     “P for Part of CoA.”

    Aspect Details
    Sources Egg yolk, liver, whole grains
    RDA 5 mg/day
    Functions Component of CoA for acyl group transfer
    Deficiency Rare; “burning feet syndrome”
    Toxicity None

    VITAMIN B₆ (Pyridoxine)

    Mnemonic Summary:
     “B6 Builds Brain & Blood.”

    Aspect Details
    Sources Meat, cereals, banana
    RDA 2 mg/day
    Functions Coenzyme (PLP) in transamination, decarboxylation, heme synthesis
    Deficiency Peripheral neuropathy, anemia, convulsions (esp. with isoniazid)
    Toxicity Sensory neuropathy (high dose)

     VITAMIN B₇ (Biotin)

    Mnemonic Summary:
     “Biotin Binds CO₂.”

    Aspect Details
    Sources Egg yolk, liver, gut flora
    RDA 30 µg/day
    Functions Coenzyme for carboxylase reactions
    Deficiency Dermatitis, alopecia, from raw egg (avidin binds biotin)
    Toxicity None

     VITAMIN B₉ (Folic acid)

    Mnemonic Summary:
     “Folate For Fetus & Forming Cells.”

    Aspect Details
    Sources Green leafy vegetables, liver
    RDA 400 µg/day (↑ in pregnancy)
    Functions Transfer of 1-C units in DNA synthesis
    Deficiency Megaloblastic anemia, neural tube defects
    Toxicity High dose may mask B₁₂ deficiency

     VITAMIN B₁₂ (Cobalamin)

    Mnemonic Summary:
     “B12 Builds Blood & Brain.”

    Aspect Details
    Sources Animal foods (meat, fish, milk) 
    RDA 2–3 µg/day
    Functions Methylmalonyl-CoA → succinyl-CoA; homocysteine → methionine
    Deficiency Megaloblastic anemia, neuropathy, glossitis
    Toxicity None

    VITAMIN C (Ascorbic acid)

    Mnemonic Summary:
     “C for Collagen, Cold, and Cure.”

    Aspect Details
    Sources Citrus fruits , amla, guava
    RDA 75–90 mg/day
    Functions Hydroxylation of proline & lysine in collagen, antioxidant, iron absorption
    Deficiency Scurvy: Bleeding gums, poor wound healing
    Toxicity Diarrhea, oxalate stones

    Minerals

    Mnemonic for Major Minerals:
    “Can People Make Cells Strong?”
    Calcium, Phosphorus, Magnesium, Chloride, Sodium, Potassium

    Mnemonic for Trace (Minor) Minerals:
    “I See Zinc in My Copper-Chromed Mo’Bike.”
    Iodine, Selenium, Zn, Mn, Cu, Cr, Mo, Fe

    Macrominerals

    CALCIUM (Ca)

    Mnemonic Summary:

    “Calcium for Clotting, Contraction, and Construction.”

    Aspect Details
    Sources Milk 🥛, cheese, ragi, green leafy vegetables
    RDA ~1000 mg/day
    Functions Bone & teeth structure, muscle contraction, nerve transmission, blood clotting (Factor IV)
    Deficiency Rickets, osteomalacia, tetany, osteoporosis
    Hormonal control PTH ↑, Calcitonin ↓ Ca²⁺

    PHOSPHORUS (P)

    Mnemonic Summary:

    “Phosphorus Powers Phosphorylation.”

    Aspect Details
    Sources Meat, fish, milk, nuts
    RDA ~700 mg/day
    Functions ATP, nucleic acids, phospholipids, bone & teeth formation
    Deficiency Weak bones, muscle weakness, growth retardation

    MAGNESIUM (Mg)

    Mnemonic Summary:

    “Magnesium Makes Muscles Move and Metabolism Go.”

    Aspect Details
    Sources Nuts, green leafy vegetables, whole grains
    RDA ~400 mg/day
    Functions Cofactor for >300 enzymes (especially kinases), neuromuscular transmission
    Deficiency Muscle cramps, cardiac arrhythmia, hypocalcemia

    SODIUM (Na)

    Mnemonic Summary:

    “Na for Nerve Activity.”

    Aspect Details
    Sources Common salt, processed foods
    RDA < 2.3 g/day (as NaCl)
    Functions Osmotic balance, nerve impulse transmission
    Deficiency Hyponatremia → weakness, confusion, hypotension

    POTASSIUM (K)

    Mnemonic Summary:

    “K Keeps heart OK.”

    Aspect Details
    Sources Fruits (banana 🍌, orange), vegetables, meat
    RDA ~3500 mg/day
    Functions Nerve conduction, muscle contraction (heart rhythm), osmotic balance
    Deficiency Hypokalemia → muscle weakness, cardiac arrhythmia

    CHLORIDE (Cl)

    Mnemonic Summary:

    “Chloride for Charge and Stomach Acid.”

    Aspect Details
    Sources Table salt, seaweed
    RDA ~2300 mg/day
    Functions Osmotic pressure, HCl formation in stomach
    Deficiency Hypochloremia → metabolic alkalosis, muscle cramps

     TRACE ELEMENTS (Microminerals)

    IRON (Fe)

    Mnemonic Summary:

    “Iron for Intense Hemoglobin.”

    Aspect Details
    Sources Liver, meat, spinach, jaggery 
    RDA 17 mg/day (men), 21 mg/day (women)
    Functions Hemoglobin, myoglobin, cytochromes
    Deficiency Microcytic hypochromic anemia, fatigue, pallor

    IODINE (I)

    Mnemonic Summary:

    “Iodine for I.D. of Thyroid.”

    Aspect Details
    Sources Iodized salt, sea fish 🐟
    RDA 150 µg/day
    Functions Thyroid hormone synthesis
    Deficiency Goiter, cretinism (children)

    ZINC (Zn)

    Mnemonic Summary:

    “Zinc for Zygote, Zest, and Zinc Fingers.”

    Aspect Details
    Sources Meat, eggs, whole grains
    RDA 10–15 mg/day
    Functions Enzyme cofactor (carbonic anhydrase, DNA/RNA polymerase), growth, wound healing, taste
    Deficiency Growth retardation, delayed wound healing, hypogonadism, loss of taste (hypogeusia)

    COPPER (Cu)

    Mnemonic Summary:

    “Cu Conducts Collagen & Cytochrome.”

    Aspect Details
    Sources Shellfish, liver, nuts
    RDA 1–2 mg/day
    Functions Enzymes: cytochrome oxidase, lysyl oxidase, ceruloplasmin (Fe metabolism)
    Deficiency Microcytic anemia, bone fragility, Menkes disease (defect in Cu transport)

    SELENIUM (Se)

    Mnemonic Summary:

    “Selenium Saves from Stress (Antioxidant).”

    Aspect Details
    Sources Seafood, meat, cereals
    RDA 55 µg/day
    Functions Component of glutathione peroxidase, antioxidant defense
    Deficiency Cardiomyopathy (Keshan disease), muscle pain, weakness

    MANGANESE (Mn)

    Mnemonic Summary:

    “Manganese Maintains Metabolism.”

    Aspect Details
    Sources Whole grains, nuts, tea
    RDA 2–5 mg/day
    Functions Cofactor for superoxide dismutase, pyruvate carboxylase
    Deficiency Rare – skeletal deformities, impaired growth

    CHROMIUM (Cr)

    Mnemonic Summary:

    “Chromium Controls Carbohydrates.”

    Aspect Details
    Sources Brewer’s yeast, whole grains
    RDA 25–35 µg/day
    Functions Potentiates insulin action (Glucose tolerance factor)
    Deficiency Impaired glucose tolerance, hyperglycemia-like symptoms

    MOLYBDENUM (Mo)

    Mnemonic Summary:

    “Mo for Metalloenzyme.”

    Aspect Details
    Sources Legumes, cereals
    RDA 45 µg/day
    Functions Cofactor for xanthine oxidase, aldehyde oxidase
    Deficiency Rare; neurological abnormalities

    FLUORIDE (F)

    Mnemonic Summary:

    “Fluoride For Firm Teeth.”

    Aspect Details
    Sources Fluoridated water, tea, seafood
    RDA 3–4 mg/day
    Functions Hardens tooth enamel, bone mineralization
    Deficiency Dental caries
    Excess Fluorosis – mottled teeth, skeletal deformities

    Extracellular Matrix

    1. Components of Extracellular Matrix

    The ECM has 3 main components:
    Fibers, Ground substance, and Adhesion proteins

    Mnemonic: “Funny Grand Aunt”

    • F – Fibers (Collagen, Elastin, Reticular)

    • G – Ground substance (Proteoglycans, Glycosaminoglycans)

    • A – Adhesion proteins (Fibronectin, Laminin, Integrins)

    2. Types of Fibers in ECM

    There are three main types of fibers.

    Mnemonic: “CRE” – Collagen, Reticular, Elastic

    • C – Collagen fibers → Strength

    • R – Reticular fibers → Support (delicate framework)

    • E – Elastic fibers → Elasticity

    3. Types of Collagen

    There are many types, but focus on the first four (I–IV).

    Mnemonic: “Be(So) Totally Cool, Read Books”

    • I – Bone, Skin, Tendon → most abundant

    • II – Cartilage (carTWOlage)

    • III – Reticular fibers, Blood vessels

    • IV – Basement membrane (“Floor = IV”)

    4. Ground Substance Components

    Ground substance = GAGs + Proteoglycans + Glycoproteins

    Mnemonic: “Great People Give Support”

    • G – Glycosaminoglycans (GAGs)

    • P – Proteoglycans

    • G – Glycoproteins

    • S – Support + structure

    5. Functions of Extracellular Matrix

    Mnemonic: “SACRED”

    • S – Support to cells & tissues

    • A – Adhesion (helps cells attach)

    • C – Communication between cells

    • R – Regulates cell behavior (growth, differentiation)

    • E – Elasticity & resilience

    • D – Diffusion of nutrients & waste

    6. Basement Membrane Components

    Mnemonic: “LACE”

    • L – Laminin

    • A – Agrin

    • C – Collagen type IV

    • E – Entactin (nidogen)

    7. Cells That Produce ECM

    Mnemonic: “Funny Chubby Cells”

    • F – Fibroblasts (main producers)

    • C – Chondroblasts (cartilage)

    • C – Osteoblasts (bone)

Nucleic Acids

  • Purines:
    Mnemonic: PURe As Gold
    Purines = Adenine, Guanine (2 rings)
  • Pyrimidines:
    Mnemonic: CUT the Py
    Cytosine, Uracil, Thymine (1 ring each)

Acid-base Balance

  • Causes of metabolic acidosis with increased anion gap:
    Mnemonic: MUDPILES
  • Methanol, Uremia, Diabetic ketoacidosis, Propylene glycol, Isoniazid/Iron, Lactic acidosis, Ethylene glycol, Salicylates