01. Enzymes
Definition
-
Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed.
-
Mostly proteins, though some RNA molecules (ribozymes) can also act as enzymes.
Characteristics
-
Specificity: Each enzyme works on a specific substrate.
-
Efficiency: Speeds up reactions millions of times faster than without enzymes.
-
Regulation: Activity can be regulated by temperature, pH, and inhibitors.
-
Reusability: Not consumed in the reaction; can be used repeatedly.
Mechanism of Action
-
Substrate binds to the enzyme at the active site.
-
Enzyme-substrate complex is formed.
-
Reaction occurs, forming product.
-
Product released, enzyme is free to act again.
Types of Enzymes (Based on Function)
| Type | Function | Example Concept |
|---|---|---|
| Oxidoreductases | Catalyze oxidation-reduction reactions | Catalase |
| Transferases | Transfer functional groups | Aminotransferase |
| Hydrolases | Break bonds using water | Amylase, Lipase |
| Lyases | Add or remove groups without water | Decarboxylases |
| Isomerases | Catalyze rearrangement of atoms | Glucose isomerase |
| Ligases | Join two molecules | DNA ligase |
Functions in Biology
-
Speed up metabolic reactions.
-
Assist in digestion (amylase, lipase, protease).
-
Involved in DNA replication and repair.
-
Regulate cellular processes efficiently.
2. Nucleic Acids
Definition
-
Nucleic acids are biopolymers of nucleotides, storing and transmitting genetic information.
-
Two main types: DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid).
Structure
-
Nucleotide: Basic unit, consisting of
-
Sugar (deoxyribose in DNA, ribose in RNA)
-
Phosphate group
-
Nitrogenous base (A, T/U, G, C)
-
Types and Functions
| Type | Structure Concept | Function |
|---|---|---|
| DNA | Double-stranded, stores genetic info | Stores hereditary information; guides protein synthesis |
| RNA | Single-stranded, several types | mRNA: Carries code from DNA to ribosome tRNA: Brings amino acids rRNA: Ribosome structure and function |
Importance
-
Inheritance: DNA stores and transfers genetic material.
-
Protein synthesis: RNA helps in translating genetic code into proteins.
-
Regulation: RNA molecules regulate gene expression (e.g., miRNA).
3. Key Points to Remember
-
Enzymes: Biological catalysts, highly specific, speed up reactions, reusable, and essential for metabolism.
-
Nucleic acids: DNA and RNA are information-carrying molecules; DNA stores information, RNA helps in protein synthesis.
-
Nucleotides are the building blocks of nucleic acids.
-
Enzymes and nucleic acids together control, regulate, and sustain life processes.
