Thursday, April 2, 2026

Development and growth of the tooth

Initiation Stage (Dental Lamina Stage)

Primitive oral cavity lined by stratified squamous epithelium

Formation of Primary Epithelial Band

Divides into:

Dental lamina → forms teeth

Vestibular lamina → forms oral vestibule

Dental Lamina

Appears at 6th week of intrauterine life

Forms tooth buds of all primary teeth

Gives rise to:

Successional lamina → permanent successors

Accessional lamina → permanent molars

Remnants of dental lamina = Rests of Serres

2. 🔹 Role of Ectomesenchyme

Derived from neural crest cells

Responsible for:

Formation of dentin, pulp, cementum

3. 🔹 Morphological Stages of Tooth Development

1. 🟢 Bud Stage

First sign of tooth development

Proliferation of dental lamina into ectomesenchyme

Structures:

Enamel organ (early)

Ectomesenchymal condensation

Cells:

Peripheral cuboidal cells

Central polygonal cells

2. 🟡 Cap Stage

Enamel organ becomes cap-shaped

Components formed:

Enamel organ

Dental papilla → dentin + pulp

Dental sac (follicle) → cementum, PDL

Layers in enamel organ:

Outer enamel epithelium (OEE)

Inner enamel epithelium (IEE)

Stellate reticulum ⭐

3. 🟠 Early Bell Stage

Histodifferentiation & morphodifferentiation begin

New layer:

Stratum intermedium

Important changes:

IEE → differentiates into ameloblasts

Dental papilla → forms odontoblasts

Nuclear polarity reversal

4. 🔴 Advanced Bell Stage (Apposition Stage)

Hard tissue formation begins

Sequence:

Odontoblasts form dentin first

Then ameloblasts form enamel

👉 Key Point: Dentin formation precedes enamel formation

Other features:

Stellate reticulum collapses

Enamel and dentin deposition continues

4. 🔹 Root Formation (Hertwig’s Epithelial Root Sheath - HERS)

Forms after crown formation

Function:

Shapes root

Induces dentin formation in root

Breakdown leads to:

Cementum formation

👉 Remnants of HERS = Rests of Malassez

Thursday, March 26, 2026

Development of oral cavity mind map

Thursday, March 19, 2026

Protein metabolism mind map

PROTEIN METABOLISM – COMPLETE REVISION NOTES

1. METABOLISM OF AMINO ACIDS

🔹 A. Transamination

Transfer of amino group from amino acid → keto acid

Enzymes: Transaminases

⭐ Salient Features:

Requires coenzyme: Pyridoxal phosphate (PLP)

Occurs in pairs:

Alanine transaminase (ALT)

Aspartate transaminase (AST)

No free NH₃ released

Reversible process

Helps in:

Synthesis of non-essential amino acids

Gluconeogenesis

🔹 B. Deamination

Removal of amino group → helps in urea formation

Types:

1. Oxidative Deamination

Substrate: Glutamate

Enzyme: Glutamate dehydrogenase

Products:

α-ketoglutarate

NH₃

Site: Liver mitochondria

Coenzyme: NAD⁺

2. Reductive Deamination

Removal of amino group by reduction

Substrate: Keto acids / Imino acids

Enzyme: Reductase

Product: NH₃ released

Coenzyme: NADPH

2. TRYPTOPHAN METABOLISM

🔹 Features:

Essential amino acid

Contains β-indole ring

🔹 Pathways:

1. Kynurenine Pathway

Steps: Tryptophan

→ N-formylkynurenine

→ Kynurenine

→ 3-hydroxykynurenine

→ 3-hydroxyanthranilic acid

Clinical:

Pellagra → 3 D’s:

Dermatitis

Diarrhea

Dementia

Products:

Melatonin (sleep regulation)

2. Serotonin Pathway

Steps: Tryptophan

→ 5-hydroxytryptophan

→ Serotonin

Functions:

Mood regulation

Depression link

3. PHENYLALANINE & TYROSINE METABOLISM

🔹 Characteristics:

Aromatic amino acids

🔹 Conversion:

Phenylalanine

→ Tyrosine

Enzyme: Phenylalanine hydroxylase

Converts essential → non-essential amino acid

🔹 Functions of Tyrosine:

Melanin synthesis

Thyroid hormone synthesis

Catecholamine synthesis

🔹 Tyrosine Degradation Pathway:

Tyrosine

→ p-Hydroxyphenylpyruvate

→ Homogentisate

→ Maleylacetoacetate

→ Fumarylacetoacetate

→ Fumarate + Acetoacetate

Final Fate:

Fumarate → TCA cycle → Glucose

Acetoacetate → Fat

4. UREA CYCLE

🔹 Key Points:

End product of protein metabolism

80–90% nitrogen excreted via urine

🔹 Steps:

CO₂ + NH₄⁺

→ Carbamoyl phosphate

(Enzyme: Carbamoyl phosphate synthetase)

🔸 Uses 2 ATP

Carbamoyl phosphate + Ornithine

→ Citrulline

(Ornithine transcarbamoylase)

Citrulline

→ Argininosuccinate

(Argininosuccinate synthetase)

🔸 Uses 1 ATP

Argininosuccinate

→ Arginine + Fumarate

(Argininosuccinase)

Arginine

→ Urea + Ornithine

(Arginase)

🔹 Important Points:

Total energy: 4 ATP used

Fumarate enters:

TCA cycle

Gluconeogenesis

Ornithine is regenerated (cycle continues)

🔥 QUICK SUMMARY (EXAM REVISION)

Transamination → No NH₃, reversible

Deamination → NH₃ released → Urea

Tryptophan → Serotonin + Kynurenine → Pellagra

Phenylalanine → Tyrosine → Hormones & pigments

Urea cycle → Detoxifies ammonia → Uses 4 ATP

Sunday, March 8, 2026

🧠 LIPID METABOLISM – Colorful Handwritten Mind Map

🧠 LIPID METABOLISM

🔴 1. Fatty Acid Oxidation (β-Oxidation)

Occurs in mitochondria

Steps

1️⃣ Activation

Fatty acid + CoA + ATP

→ Fatty acyl-CoA

(enzyme: Acyl-CoA synthetase)

2️⃣ Transport

Carnitine carrier system

3️⃣ β-Oxidation Cycle

• Dehydrogenation → FADH₂ formed

• Hydration

• Oxidation → NADH formed

• Cleavage → Acetyl-CoA

Energetics (Palmitate)

7 FADH₂ → 10.5 ATP

7 NADH → 17.5 ATP

8 Acetyl-CoA → 80 ATP

✔ Total = 108 ATP

✔ Net = 106 ATP

🟠 2. Cholesterol Biosynthesis

Location: Cytosol of liver cells

Pathway

Acetyl-CoA

⬇

HMG-CoA

⬇

Mevalonate

⬇

Isoprene units (IPP + DPP)

⬇

Squalene

⬇

Cholesterol

Requirements

18 Acetyl-CoA

36 ATP

16 NADPH

Uses

✔ Bile acids

✔ Steroid hormones

✔ Vitamin D

🟡 3. Lipoproteins

Lipoprotein = Lipid + Protein

Types

Chylomicrons

Transport dietary fat

VLDL

Transport endogenous triglycerides

LDL

Transport cholesterol to tissues

HDL

Reverse cholesterol transport

Lipoprotein Degradation

1️⃣ Lipoprotein + LPL enzyme

2️⃣ Triglyceride hydrolysis

3️⃣ Fatty acid uptake

4️⃣ Chylomicron remnant formation

5️⃣ Uptake by liver

🟢 4. Ketone Bodies

Types

Acetoacetate

β-Hydroxybutyrate

Acetone

✔ Water soluble

✔ Alternative energy source

Ketogenesis (Liver)

2 Acetyl-CoA

⬇

Acetoacetyl-CoA

⬇

HMG-CoA

⬇

Acetoacetate

⬇

Acetone + β-Hydroxybutyrate

Use

During fasting/starvation

Overproduction

Ketonuria / Ketoacidosis

🔵 5. Fatty Liver

Normal liver lipid ≈ 5%

Cause

Excess triglyceride accumulation

Reasons

Increased TG synthesis

Decreased lipoprotein formation

Alcohol / metabolic disorders

🟣 6. Atherosclerosis

✔ Thickening and hardening of arteries

✔ Due to lipid deposition

Result

⬆ Risk of

Coronary heart disease

Heart attack

✅ Memory Trick for Lipid Metabolism Topics

"F C L K F A"

F → Fatty acid oxidation

C → Cholesterol synthesis

L → Lipoproteins

K → Ketone bodies

F → Fatty liver

A → Atherosclerosis

Thursday, March 5, 2026

Mind map of carbohydrates metabolism

For TCA cycle menomic is used

C citrate

I isocitrate

Alpha. Ketoglutarate

S. Succinnyal coa

S. Succinate

F. Fumarate

M. Malate

O. Oxyloacetate

For glycolysis

Good Glucose

Girls Glucose-6-phosphate

Find Fructose-6-phosphate

Friends Fructose-1,6-bisphosphate

Don't Dihydroxyacetone phosphate

Get Glyceraldehyde-3-phosphate

Big 1,3-Bisphosphoglycerate

Problems 3-Phosphoglycerate

Please 2-Phosphoglycerate

Please Phosphoenolpyruvate

Please Pyruvate

Tuesday, March 3, 2026

Mind map of protein

Essential amino acid menmonic

PVT TIM HALL

P – Phenylalanine

V – Valine

T – Tryptophan

T – Threonine

I – Isoleucine

M – Methionine

H – Histidine

L – Leucine

L – Lysine

Sunday, February 1, 2026

Ploysaccharide mind map for medical student

Friday, January 30, 2026

Disaccharides mind map for medical student

Sunday, January 25, 2026

ENZYMES

Mind ma

ENZYMES — SHORT NOTE (Exam Oriented)

Reference: Satyanarayan

Definition-Enzymes are biological catalysts, mostly proteins, that speed up biochemical reactions without being consumed.

Key Characteristics

Highly specific for substrates

Lower activation energy

Remain unchanged after reaction

Active at optimum pH & temperature

Mostly globu

Some require cofactors

Classification of Enzymes (IUBMB)

Oxidoreductases – Redox reactions

Transferases – Transfer functional groups

Hydrolases – Hydrolysis reactions

Lyases – Add/remove groups without water

Isomerases – Rearrangement reactions

Ligases – Joining molecules using ATP

Mnemonic -OTHLIL

Mechanism of Action

1)Lock and Key Model

2)Induced Fit Model

(Substrate binds to active site → product formed)

Factors Affecting Enzyme Activity

1)Temperature- optimum temprature enzyme activity is high

At low temperature enzyme activity is stop

At high temperature enzyme activity denaturation

2) ph-optimum ph it will be high enzyme activity

3)Substrate concentration-Vmax is low high is the velocity of an enzyme and vise Versa

4)Enzyme concentration-high concentration of enzyme High its velocity

Enzyme Inhibition

1)Competitive – Competes with substrate

2)Non-competitive – Binds elsewhere

3)Irreversible – Permanently inactivates enzyme

Isoenzymes

Definition:

Isoenzymes are different molecular forms of the same enzyme that catalyze the same biochemical reaction but differ in physical, chemical, kinetic properties and tissue distribution.

Characteristics

1)Same substrate specificity

2)Different amino acid composition

3)Different electrophoretic mobility

4)Different optimum pH & Km

5)Tissue specific distribution

Example

1)Lactate Dehydrogenase (LDH)

Tetrameric enzyme made of H & M subunits

5 isoenzymes:

LDH₁ (H₄) – Heart

LDH₂ (H₃M₁) – RBC

LDH₃ (H₂M₂) – Lung

LDH₄ (H₁M₃) – Kidney

LDH₅ (M₄) – Liver & Skeletal muscle

2)Creatine Kinase (CK) – Applications

Creatine kinase catalyzes the reversible transfer of phosphate between creatine and ATP. It exists as isoenzymes, useful in clinical diagnosis.

CK Isoenzymes

CK-BB (CK₁) – Brain, smooth muscle

CK-MB (CK₂) – Cardiac muscle

CK-MM (CK₃) – Skeletal muscle

Clinical Importance

Diagnostic markers (AST, ALT, ALP)

Used in therapy & biotechnology

Metabolic disease detection

Tuesday, January 20, 2026

Fat soluble vitamins

Lipids

Wednesday, November 26, 2025

STERILISATION AND DISINFECTION

STERALISATION

Define -It is a process by which an article,surface or medium is made free of all microorganisms either in the vegetative or spore form

HEAT BASED

A)Moist Heat based

Heat is most relaible method of steralsition the most heat kills the bacteria by denaturation and coagulation of the cytoplasmic proteins

1)TEMP BELOW 100 oC

Vaccine bath -At 56 oC for 1hrs

Pasteurisation of milk -63oC for 30 min

2) TEMP ABOVE 100 oC

Boiling

Steam at atmospheric pressure at 100 oC for 90 min

Autoclave

Principles and procedure

Principle-

1)Water boils when vapour pressure = surrounding atmosphere

2)Pressure inside a closed vessels increase the atmosphere boils also increased to more 100 oC

3)The considered water ensure the moist conditions for killing of the microbes present

Procedure

1)Before beginning to use the autoclave, it should be checked for any items left from the previous cycle.

2)A sufficient amount of water is then put inside the chamber.

Now, the materials to be sterilized are placed inside the chamber.

3)The lid is then closed, and the screws are tightened to ensure an airtight condition, and the electric heater is switched on.

4)The safety valves are adjusted to maintain the required pressure in the chamber.

5)Once the water inside the chamber boils, the air-water mixture is allowed to escape through the discharge tube to let all the air inside to be displaced.

6)The complete displacement can be ensured once the water bubbles cease to come out from the pipe.

7)The drainage pipe is then closed, and the steam inside is allowed to reach the desired levels (15 lbs in most cases).

8)Once the pressure is reached, the whistle blows to remove excess pressure from the chamber.

9)After the whistle, the autoclave is run for a holding period, which is 15 minutes in most cases.

10)Now, the electric heater is switched off, and the autoclave is allowed to cool until the pressure gauge indicates the pressure inside has lowered down to that of the atmospheric pressure.

11)The discharge pipe is then opened to allow the entry of air from the outside into the autoclave.

12)Finally, the lid is opened, and the sterilized materials are taken out of the chamber.