Structural Organisation in Animals and Plants

Definition

The underground part of the plant that anchors it and absorbs water and minerals.

Key Types

• Tap Root: One main thick root with smaller branches (e.g., Dicots like Carrot).
• Fibrous Root: A cluster of thin roots from the base of the stem (e.g., Monocots like Wheat).
• Adventitious Root: Roots growing from unusual places like stems or leaves.

Real-Life Application

Root Grafting: Farmers join hardy wild roots with high-quality fruit trees to increase pest resistance and survival.

Definition

The main axis of the plant that supports leaves and flowers, acting as a transport system.

Key Features

• Contains Nodes (leaf attachment points) and Internodes (space between nodes).
• Modifications: Tubers for food storage (Potato) or tendrils for climbing (Money Plant).

Real-Life Application

Eco-Construction: Bamboo's specialized vascular stem structure makes it a sustainable steel alternative in architecture.

Definition

The primary site for photosynthesis; the plant's "solar panels."

Key Concepts

• Venation: Reticulate (Net-like) in dicots; Parallel in monocots (e.g., Banana leaf).
• Phyllotaxy: Arrangement of leaves on the stem (Alternate, Opposite, or Whorled).

Real-Life Application

Pharmacology: Herbalists use leaf venation and shape to accurately identify medicinal plant species.

Definition

Inflorescence is the arrangement of flowers on the floral axis. The flower is the reproductive unit.

Key Types

• Racemose: Indefinite growth, acropetal order (e.g., Mustard).
• Cymose: Limited growth, main axis ends in a flower (e.g., Jasmine).
• Parts: Calyx, Corolla, Androecium, Gynoecium.

Real-Life Application

Apiculture: Bee-keepers use flower morphology (shape/color) to place hives near flowers that attract specific bee species.

Fruit & Seed

• Parthenocarpic fruit: Seedless fruit formed without fertilization.
• Structure: Seed coat, embryo, and endosperm.

Plant Families

• Fabaceae (Pea): Nitrogen-fixing roots, legumes.
• Solanaceae (Potato): Persistent calyx, often medicinal.
• Liliaceae (Lily): Monocots with tepals.

Real-Life Application

Crop Rotation: Planting Fabaceae increases soil nitrogen, reducing the need for chemical fertilizers.

Types of Tissues

• Meristematic: Active dividing cells (Apical, Intercalary, Lateral).
• Permanent: Specialized cells (Parenchyma, Collenchyma, Sclerenchyma).

Real-Life Application

Tissue Culture: Using the totipotency of meristematic cells to clone plants in labs.

Vascular System

• Xylem: Unidirectional transport of water (upward).
• Phloem: Bidirectional transport of food.
• Cambium: Responsible for thickness (Secondary growth).

Dicot vs Monocot

Dicots typically show a "ring" arrangement of vascular bundles, whereas Monocots show "scattered" bundles.

Real-Life Application

Dendrochronology: Using annual rings in secondary xylem to determine the age of a tree and past climate.

Explanation

The increase in girth/thickness of the plant, primarily occurring in dicots via the vascular cambium.

Result: Production of secondary xylem (wood) and secondary phloem.

Industry Use

High-quality timber (e.g., Mahogany) is produced by maximizing this secondary growth for density.

• Epithelial: Covering/Lining (e.g., Skin). Function: Protection/Secretion.
• Connective: Binding organs (e.g., Blood, Bone). Function: Support.
• Muscular: Movement (e.g., Cardiac, Skeletal). Function: Contraction.
• Neural: Signaling (e.g., Brain). Function: Communication.

Real-Life Application

Sports Medicine: Ligament repairs focus on restoring the integrity of connective tissues.

Key Systems

• Digestive: Crop (storage) $\rightarrow$ Gizzard (grinding) $\rightarrow$ Midgut $\rightarrow$ Hindgut.
• Circulatory: Open system with hemolymph and a 13-chambered heart.
• Respiratory: Tracheal system with spiracles.
• Excretory: Malpighian tubules.

Real-Life Application

Pest Control: Chemical baits are designed to target the Malpighian tubules or specific digestive enzymes of insects.

• Confocal Microscopy: 3D high-resolution imaging of tissues.
• CRISPR/Cas9: Modifying structural genes for drought resistance.
• 3D Bioprinting: Printing artificial skin using epithelial/connective tissue knowledge.

1. Which root is modified to store food in a carrot?
   Ans: (c) Tap root
2. The arrangement of leaves on a stem is called:
   Ans: (b) Phyllotaxy
3. Parallel venation is a characteristic of:
   Ans: (b) Monocots
4. Which tissue is responsible for secondary growth in dicots?
   Ans: (c) Vascular cambium
5. Sclerenchyma cells are characterized by walls thickened with:
   Ans: (c) Lignin
6. Which of the following is a "connecting" tissue?
   Ans: (b) Blood
7. The "grinding" organ in a cockroach's gut is the:
   Ans: (b) Gizzard
8. Malpighian tubules are used for:
   Ans: (c) Excretion
9. Which family do peas and beans belong to?
   Ans: (c) Fabaceae
10. Tepals are found in which family?
    Ans: (b) Liliaceae

1. Q: Differentiate between Racemose and Cymose inflorescence.
   Ans: Racemose has an indefinite growth axis with acropetal flowers. Cymose has a limited growth axis ending in a flower with basipetal order.
2. Q: What are Pneumatophores? Give an example.
   Ans: Respiratory roots that grow vertically upwards to get oxygen in swampy areas. Example: Rhizophora.
3. Q: Explain the difference between Heartwood and Sapwood.
   Ans: Heartwood is central, dark, non-functional (support), while Sapwood is outer, light, functional (conduction).
4. Q: Describe the structure of a Neuron.
   Ans: Consists of a Cell Body (Cyton), Dendrites (receive signals), and an Axon (transmits signals).
5. Q: How does the circulatory system of a cockroach differ from humans?
   Ans: Humans have a closed system; Cockroaches have an open system where blood (hemolymph) flows in the hemocoel.
6. Q: What is the role of the Gizzard in a cockroach?
   Ans: It uses chitinous teeth and muscular walls to grind food particles.
7. Q: Define Placentation. Name any two types.
   Ans: Arrangement of ovules within the ovary. Examples: Marginal (Pea) and Axile (Tomato).
8. Q: What are the three types of Meristems?
   Ans: Apical (length), Intercalary (between nodes), and Lateral (thickness).
9. Q: Explain the function of the Casparian strip in roots.
   Ans: A waxy suberin strip that prevents water leakage and forces it into the xylem via living membranes.
10. Q: Compare Simple and Complex tissues in plants.
    Ans: Simple tissues consist of one cell type (e.g., Parenchyma); Complex tissues consist of multiple cell types (e.g., Xylem).

• Photosynthesis Structural Basis: $6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$ (Occurs in Mesophyll).
• Cell Wall: Cellulose + Hemicellulose + Pectin.

Mnemonics:

• Families: Solanaceae (Salt/Spice), Fabaceae (Fabric/Fiber), Liliaceae (Lily/Luxe).
• Animal Tissues: "Every Cat Makes Noise" (Epithelial, Connective, Muscular, Neural).
• Roots: Tap = Thick; Fibrous = Fine.