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Plant Biology Lecture Notes

Meristems

  • Definition: Meristems are regions within plants that are actively undergoing relatively high rates of cell division (originally stated as "___ __").

  • Function: These regions are where primary growth is initiated, allowing plants to grow in length and develop new organs.

Guard Cells

  • Function: Guard cells are responsible for controlling the intake of molecules of carbon dioxide (originally stated as ""), which are required for the photosynthetic reactions to occur (originally stated as "_").

  • Water Evaporation: The activities of guard cells also affect the evaporation of water from the plant through a process known as transpiration (originally stated as "").

Photosynthesis

  • Definition: Photosynthesis involves a series of chemical reactions that provides the chemical energy that powers the Earth’s biosphere.

    • Structures Involved:

    • a. Photosynthesis reactions occur in the structures known as chloroplasts within plant cells.

    • Basic Inputs Required:

    • b. The three basic inputs required by these reactions are:

      1. Carbon dioxide (CO₂)

      2. Water (H₂O)

      3. Sunlight (light energy)

    • Products of Photosynthesis:

    • c. The two ultimate products of these reactions are:

      1. Glucose (C₆H₁₂O₆)

      2. Oxygen (O₂)

Unique Plant Structures

  • Comparison with Non-Plant Organisms: The three structures that occur within the cells of plants that do not occur in the cells of non-plant organisms are:

    1. Chloroplasts (for photosynthesis)

    2. Cell wall (providing structure and support)

    3. Large central vacuole (for storage and maintaining turgor pressure)

Plant Classification: Monocots vs Eudicots

  • Organs for Examination: To determine whether a particular plant species is a monocot or eudicot, examine the following four organs:

    1. Leaves: Leaf shape and venation pattern differ between monocots and eudicots.

    2. Roots: Root systems exhibit different arrangements (

      • Monocots have fibrous root systems.

      • Eudicots have taproot systems).

    3. Stems: Vascular arrangement in stems

      • Monocots have scattered vascular bundles.

      • Eudicots have vascular bundles arranged in a ring.

    4. Flowers: Flower structures and parts (e.g., number of petals)

      • Monocots typically have floral parts in multiples of three.

      • Eudicots typically have floral parts in multiples of four or five.