Topics
Diversity in the Living World
The Living World
Biological Classification
- History of Classification
- Five Kingdom Classification
- Kingdom Monera
- Bacteria
- Classification of Bacteria
- Structure of Bacteria
- Division of Kingdom Monera
- Examples of Kingdom Monera
- Kingdom Protista
- Protozoa
- Kingdom Protista
- Kingdom Fungi
- Fungi
- Structure of Fungi
- Life Processes in Fungi: Nutrition
- Reproduction in Fungi
- Division of Kingdom Fungi
- Kingdom Plantae
- Kingdom Plantae
- Life Cycle Patterns in Plants
- Kingdom Animalia
- Viruses
- Structure and Function of Viruses
- Viroids
- Prions
- Lichens
Structural Organisation in Plants and Animals
Cell: Structure and Function
Plant Kingdom
Plant Physiology
Animal Kingdom
Morphology of Flowering Plants
Human Physiology
Anatomy of Flowering Plants
- Anatomy and Functions of Different Parts of Flowering Plants
- Tissues - “The Teams of Workers”
- Plant and Animals Tissue
- Meristems or Meristematic Tissues
- Permanent Tissue
- Simple Permanent Tissues (Supporting Tissue)
- Complex Permanent Tissues
- Complex Permanent Tissue: Xylem Structure and Function (Conducting Tissue)
- Complex Permanent Tissue: Phloem Structure and Function (Conducting Tissue)
- Epidermal Tissue System
- Ground Tissue System
- Vascular Tissue System
- Dicotyledonous Root
- Monocotyledonous Root
- Dicotyledonous Stem
- Monocotyledonous Stem
- Isobilateral (Monocotyledonous) Leaf
- Dorsiventral (Dicotyledonous) Leaf
- Vascular Cambium
- Cork Cambium
- Secondary Growth in Roots
Structural Organisation in Animals
Cell : the Unit of Life
- Cell: Structural and Functional Unit of Life
- The Invention of the Microscope and the Discovery of Cell
- Cell Theory
- Organisms Show Variety in Cell Number, Shape and Size
- Prokaryotic Cells
- Cell Envelope and Its Modifications
- Ribosomes and Inclusion Bodies
- Structure of Prokaryotic and Eukaryotic Cells
- Structure of the Cell > Plasma Membrane / Cell Membrane
- Structure of the Cell > Cell Wall: “Supporter and Protector”
- Endomembrane System
- Mitochondria - “Power House of the Cell”
- Plastids
- Ribosomes - "The sites of protein synthesis"
- Cilia and Flagella
- Centrosome and Centrioles
- Cytoskeleton
- Structure of the Cell > Nucleus: “Brain” of the Cell
- Microbodies
- Plant Cell Vs Animal Cell
Biomolecules
- Analysis of Chemical Composition
- Primary and Secondary Metabolites
- Biomacromolecules
- Polysaccharides
- Biomolecules in the Cell > Proteins
- Biomolecules in the Cell > Nucleic Acids
- Structure of Proteins
- Nature of Bond Linking Monomers in a Polymer
- Dynamic State of Body Constituents – Concept of Metabolism
- Metabolic Basis for Living
- The Living State
- Biomolecules in the Cell > Enzymes
- Enzymes - Chemical Reactions
- Enzyme- High Rates Chemical Conversion
- Nature of Enzyme Action
- Factors Affecting Enzyme Activity
- Classification and Nomenclature of Enzymes
- Enzymes - Co-factors
- Biomolecules in Living System
- Chemical Constituents of Living Cells
- Biomolecules in the Cell > Carbohydrates
- Structure and Function of Lipids
Cell Cycle and Cell Division
Transport in Plants
- Introduction of Transport in Plants
- Movement of Water, Gases and Nutrients
- Cell to Cell Transport
- Comparison of Different Transport Processes
- Concept of Plant-water Relations
- Osmosis
- Introduction of Long Distance Transport of Water
- Plants Absorb Water
- Water Movement up a Plant
- Transpiration - Transpiration and Photosynthesis – a Compromise
- Uptake of Mineral Ions
- Phloem Transport - Flow from Source to Sink
- Phloem Transport - Pressure Flow Or Mass Flow Hypothesis
- Diffusion of Gases
- Transport in Plants (Numericals)
Photosynthesis in Higher Plants
- Experiments on Photosynthesis
- Site of Photosynthesis
- Pigments in Photosynthesis
- Light Reaction
- Electron Transport
- Splitting of Water
- Cyclic and Non-cyclic Photo-phosphorylation
- Chemiosmotic Hypothesis
- Primary Acceptor of CO2
- The Calvin Cycle
- The C4 Pathway
- Photorespiration
- Factors Affecting Photosynthesis
- Photosynthesis as a Mean of Autotrophic Nutrition
- Chloroplast Structure
- Site of Photosynthesis
- Light Reaction
- Photosynthesis Reaction
- Photochemical and Biosynthetic Phases of Photosynthesis
- Photosynthesis in Higher Plants (Questions)
Mineral Nutrition
- Methods to Study the Mineral Requirements of Plants
- Elementary Idea of Hydroponics
- Criteria for Essentiality
- Macro and Micro Nutrients and Their Role
- Deficiency Symptoms of Essential Elements
- Toxicity of Micronutrients
- Translocation of Solutes
- Nitrogen Metabolism
- Soil as Reservoir of Essential Elements
- Biological Nitrogen Fixation
- Nitrogen to Ammonia Conversion and Nitrogenase
- Mineral Nutrition (Questions)
Respiration in Plants
- Respiration in Plant
- Breathing in Plants
- Glycolysis
- Fermentation
- Oxidation of Pyruvate
- Tricarboxylic Acid Cycle (Citric Acid Cycle or Kreb’s Cycle)
- Electron Transport System (Ets) and Oxidative Phosphorylation
- Respiratory Balance Sheet
- Amphibolic Pathways
- Respiratory Quotient
- Exchange of Gases - in Plants
- Energy Relations - Number of ATP Molecules Generated
- Respiration in Plant
Plant Growth and Development
- Introduction of Plant Growth and Development
- Plant Growth Generally is Indeterminate
- Differentiation, De-differentiation, Re- Differentiation
- Concept of Development
- Characteristics of Growth Regulators
- Plant Growth Regulators
- Physiological Effects of Plant Growth Regulators
- Vernalisation
- Tropic Movements in Plants
- Plant Growth and Development (Questions)
Breathing and Exchange of Gases
Body Fluids and Circulation
Excretory Products and Their Elimination
- Human Excretory System
- Function of the Kidney - “Production of Urine”
- Function of the Tubules
- Mechanism of Concentration of the Filtrate
- Regulation of Kidney Function
- Micturition
- The Excretory Organs
- Common Disorders of the Urinary System
- Modes of Excretion: Ammonotelism, Ureotelism, and Uricotelism
- Modes of Excretion: Ammonotelism, Ureotelism, and Uricotelism
- Modes of Excretion: Ammonotelism, Ureotelism, and Uricotelism
- Osmoregulation
- Dialysis and Artificial Kidney
- Introduction of Excretory Products and Their Elimination
Digestion and Absorption
- Introduction of Digestion and Absorption
- Alimentary Canal
- Digestive Glands
- Digestion of Food
- Absorption of Digested Products
- Nutritional and Digestive Tract Disorders
- Role of Digestive Enzymes and Gastrointestinal Hormones
- Peristalsis, Digestion, Absorption and Assimilation of Proteins, Carbohydrates and Fats
- Digestion and Absorption Questions
- Calorific Values of Proteins
- Calorific Values of Carbohydrates
- Calorific Values of Fats
- Egestion of Food
Locomotion and Movement
Neural Control and Coordination
Chemical Coordination and Integration
- Introduction of Chemical Coordination and Integration
- Testis
- Ovary
- Hormones of Heart, Kidney and Gastrointestinal Tract
- Role of Hormones as Messengers and Regulators
- Hypo and Hyperactivity and Related Disorders
- Chemical Coordination and Integration (Questions)
Estimated time: 3 minutes
- Proximal Convoluted Tubule (PCT)
- Henle’s Loop, Distal Convoluted Tubule (DCT)
CBSE: Class 12
Key Points: Function of the Tubules
- PCT (Proximal Convoluted Tubule) reabsorbs all nutrients and 70–80% of water and electrolytes, and helps maintain pH balance by secretion of H⁺, NH₃, and K⁺.
- Loop of Henle maintains medullary osmolarity.
- Descending limb: permeable to water only
- Ascending limb: permeable to electrolytes, not water
- DCT (Distal Convoluted Tubule) shows selective reabsorption of Na⁺, water, and HCO₃⁻ and secretion of H⁺, K⁺, NH₃ to maintain ionic balance.
- Collecting duct reabsorbs large amounts of water and some urea, helping in urine concentration and osmolarity maintenance.
- Counter-current mechanism (Henle’s loop + vasa recta) creates an osmotic gradient (300 → 1200 mOsm/L) in the medulla.
- This gradient allows maximum water reabsorption from the collecting duct, resulting in concentrated urine.
Shaalaa.com | Excretory Products and Elimination part 8 (Nephron : Renal tubule, Cortical)
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