Plant Cell Structure and Photosynthesis

Plant Cell Structure

• The basic unit of every living organism, with the ability to grow and reproduce.
• Composed of three main parts: cell wall, cytoplasm, and nucleus.
• Cell wall provides protection and tensile strength, surrounding the plasma membrane.
• Cytoplasm holds the cell's components, protects them, stores molecules for cellular processes, and gives the cell its shape.
• Nucleus controls cell activities like growth and metabolism, carries genes containing hereditary information.

Photosynthesis

• The process by which plants create food using sunlight, carbon dioxide, and water.
• Occurs in the chloroplasts of the plant cell.

Plant Cell Parts

• Plasmalemma/Plasma Membrane plays a crucial role in solute transport into and out of the cell and sensory transduction.
• Mitochondria are membrane-bound organelles where energy production occurs.
• Plastid is a general term for organelles involved in various processes like photosynthesis and storage.

Plant Structures and Tissue Systems

• Stem provides support for the plant, facilitates transport of water, nutrients, and photosynthetic products.
• Root anchors the plant in the soil and absorbs water and minerals.

Angiosperms

• Dominate Earth's vegetation, with approximately 250,000 species.
• Seeds contain an embryo and cotyledons, nourished by the endosperm and protected by a seed coat.
• Examples: Fruit trees like mango, apple, banana, peach, cherry, orange, and pear.
• Grains like rice, corn, and wheat.

Seed Germination and Growth

• Germination occurs under favorable conditions: moisture, temperature, oxygen, and sometimes light.
• Radicle (root) and plumule (shoot) emerge from the embryo during germination.
• Seedling growth is driven by cell division in meristematic tissues.

Plant Development

• Seedling matures through the juvenile stage.
• Produces flowers and fruits following pollination and fertilization.
• Fruits develop from fertilized flowers and contain seeds, completing the plant's life cycle.

Plant Tissues

• Simple tissues contain one type of cell. Examples include parenchyma, collenchyma, and sclerenchyma.
• Complex tissues contain multiple cell types. Examples include xylem and phloem.
• Meristematic tissues are actively dividing cells responsible for plant growth.
• Permanent tissues have lost the ability to divide and are specialized for specific functions.

Types of Permanent Tissues

• Simple Permanent Tissues:
  • Parenchyma - living cells with thin cell walls involved in storage, photosynthesis, and wound repair.
  • Collenchyma - thicker cell walls, providing flexible support to growing parts of the plant.
  • Sclerenchyma - thick lignified cell walls providing rigid support and strength.
• Complex Permanent Tissues:
  • Xylem - transports water and minerals from roots to the rest of the plant.
  • Phloem - transports photosynthetic products (sugars) from leaves to other parts of the plant.

Plant Organs

• Structures composed of several tissues that perform distinct functions.
• Examples include leaves, stems, and roots.

Plant Systems

• Groups of interacting organs working together as a functional unit.
• Vascular system includes xylem and phloem, responsible for transporting water, nutrients, and food.

Roots

• Root cap protects the tender apex.
• Region of cell division contains small cells with thin walls undergoing repeated cell division.
• Region of elongation undergoes rapid elongation and enlargement, responsible for root length growth.
• Region of maturation produces root hairs.

Types of Roots

• Tap root system has a primary root growing vertically downward with branches extending horizontally or downwards.
• Adventitious root system grows from any part of the plant other than the radicle.
• Fibrous root system is found in monocots, with all adventitious roots.
• Foliar root system grows from leaves, mainly petiole or vein.

Types of Stems

• Bulb - short, erect underground stem.
• Culm - flowering stem of grasses and sedges.
• Offset - a thickened branch growing from the leaf axil, away from the mother plant.
• Rhizome - horizontal underground stem.
• Runner or Stolon - indeterminate aboveground stem with internodes and a new plantlet at the tip.
• Sucker - shoot arising from the old stem below ground.
• Tendril - slender coiling branch for climbing.

Fruits

• Dry Fruits:
  • Indehiscent Fruits:
    • Achene - one-seeded fruit with the seed attached at one point to the fruit wall.
    • Nut - thick, hard fruit wall.
    • Samara - fruit wall grows into a wing.
    • Grain - one-seeded fruit where the fruit wall and seed coat are fused.
    • Schizocarp - several carpels separating into distinct indehiscent fruits.
• Pericarp:
  • The entire fruit wall, composed of the exocarp, mesocarp, and endocarp.
  • Exocarp: outermost layer.
  • Mesocarp: middle layer, often the edible part.
  • Endocarp: innermost layer, often containing the seed(s).

Explore the fascinating world of plant cells with this quiz, focusing on their structure and the process of photosynthesis. Learn about the different parts of the plant cell, including the cell wall, cytoplasm, and nucleus, as well as the role of chloroplasts in food production. Test your knowledge and understanding of these essential biological concepts.