Class 10 Computer Science Chapter 1: Office Tools (Notes & Online Test) - PSEB

BIOMOLECULES

NCERT Masterclass & NEET Biology Study Module

1. How to Analyse Chemical Composition?

To analyze organic compounds, living tissue is ground in Trichloroacetic acid ($CCl_3COOH$) using a mortar and pestle. This yields a thick slurry which is filtered to obtain two fractions:

• Filtrate (Acid-soluble pool): Contains small, low molecular weight biomolecules (Micromolecules) like amino acids, sugars, and nucleotides.
• Retentate (Acid-insoluble pool): Contains Biomacromolecules like Proteins, Nucleic Acids, Polysaccharides. Exception: Lipids are micromolecules but are found in the acid-insoluble pool because they form vesicles during grinding.

Ash Analysis for Inorganic Elements: Burning tissue removes all carbon compounds as $CO_2$ and water vapour. The remaining "ash" contains inorganic elements like Calcium, Magnesium, Sulphates, and Phosphates.

2. Primary and Secondary Metabolites

🔥 NEET Must-Know Secondary Metabolites:

• Pigments: Carotenoids, Anthocyanins.
• Alkaloids: Morphine, Codeine.
• Terpenoides: Monoterpenes, Diterpenes.
• Essential Oils: Lemon grass oil.
• Toxins: Abrin, Ricin.
• Lectins: Concanavalin A.
• Drugs: Vinblastin, Curcumin.
• Polymeric substances: Rubber, Gums, Cellulose.

3. Proteins & Amino Acids

Proteins are heteropolymers made of amino acids linked by Peptide bonds. There are 20 types of amino acids. Collagen is the most abundant protein in the animal world, and RuBisCO is the most abundant protein in the whole biosphere.

Amino acids have an amino group, acidic carboxyl group, hydrogen, and a variable R group on the same alpha-carbon. They can form Zwitterions (molecules with both positive and negative charges) at specific pH.

4. Polysaccharides & Nucleic Acids

• Polysaccharides: Long chains of sugars joined by Glycosidic bonds.
  Cellulose (polymer of glucose, does not hold $I_2$, no blue color).
  Starch (plant energy storage, forms helical secondary structure, holds $I_2$, gives blue color).
  Glycogen (animal energy storage, highly branched).
  Inulin (polymer of fructose).
  Chitin (complex structural homopolymer of N-acetyl glucosamine found in fungal cell walls/arthropod exoskeletons).
• Nucleic Acids: Polymers of nucleotides joined by Phosphodiester bonds. A nucleotide consists of a heterocyclic nitrogenous base, a monosaccharide (ribose/deoxyribose), and a phosphate group.
  B-DNA: Double helix (Watson & Crick). A pairs with T (2 H-bonds), G pairs with C (3 H-bonds). One full turn (pitch) is $34\text{ \AA}$ and contains 10 base pairs. Rise per base pair is $3.4\text{ \AA}$.

5. Enzymes and Concept of Activation Energy

Enzymes are mostly proteins (exceptions: Ribozymes are catalytic RNA). They act as biological catalysts by lowering the activation energy required for a reaction, thereby speeding it up tremendously.

Factors Affecting Enzyme Activity: Temperature, pH, Substrate Concentration.
Michaelis-Menten Constant ($K_m$): The substrate concentration at which the reaction velocity is half of its maximum ($V_{max}/2$). High $K_m$ means low affinity.

6. Enzyme Inhibition and Co-factors

Competitive Inhibition: Inhibitor closely resembles the substrate and competes for the active site. E.g., Malonate inhibits Succinate dehydrogenase. $V_{max}$ remains the same, but $K_m$ increases.

Co-factors: Non-protein constituents required to make the enzyme catalytically active. The protein portion is called Apoenzyme. (Holoenzyme = Apoenzyme + Co-factor).
1. Prosthetic groups: Tightly bound organic compounds (e.g., Haem in peroxidase).
2. Co-enzymes: Transiently bound organic compounds, often vitamins (e.g., NAD/NADP contain Niacin).
3. Metal Ions: Form coordination bonds (e.g., Zinc is a co-factor for Carboxypeptidase).

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🚀 NEET BIOMOLECULES MEGA QUIZ (100 MCQ)

Solve the 5 parts below to master Proteins, Nucleic Acids, Carbohydrates, and Enzymes.

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