Plant Physiology and Biochemistry Overview

Study Notes

Cell Structure and Function

Cell membrane consists of a phospholipid bilayer, crucial for defining cell boundaries.
Cytoplasm contains organelles suspended in cytosol, a semi-fluid substance facilitating cellular processes.

Organelles

Endoplasmic Reticulum (ER):
- Smooth ER involved in lipid synthesis, detoxification, and calcium storage.
- Rough ER specializes in protein synthesis due to ribosomes and acts as a membrane factory.
Ribosomes:
- Protein synthesis sites composed of rRNA and proteins; exist as free or bound ribosomes.
Vacuoles:
- Occupy 95% of cell volume; maintain turgor pressure by storing salts and degrading macromolecules.
Mitochondria:
- Known as the "powerhouse" of the cell, they produce ATP through cellular respiration using oxygen.
Plastids:
- Unique to plant cells; includes chloroplasts (photosynthesis), chromoplasts (pigmentation), and periderm (protection).

Plant Tissues

Ground Tissues:
- Parenchyma: Flexible walls storing starches and proteins.
- Collenchyma: Thickened walls providing structural support.
- Sclerenchyma: Thick, lignified walls ensuring long-term support and aiding in water conduction.
Vascular Tissues:
- Xylem transports water and nutrients upwards from roots to shoots.
- Phloem distributes photosynthetic products from leaves to other parts.

Plant Organs

Roots: Anchor plants, absorb water and nutrients, and store carbohydrates.
- Primary root (radicle) is the first to emerge; secondary roots enhance acquisition.
- Two systems: Taproot (single main root) and fibrous (dense network).
Stems: Support leaves and flowers, facilitating light exposure and pollination.
- Features include nodes from which lateral shoots arise and modifications like rhizomes and bulbs.
Leaves: Composed of a flat blade (lamina) and petiole; primary sites for photosynthesis and gas exchange.
Flowers: Reproductive structures in angiosperms, featuring petals, sepals, and reproductive organs (pistil and stamen).
Fruits: Mature ovaries post-fertilization containing seeds; consist of exocarp, mesocarp, and endocarp.

Flower Classification

Complete flowers have all parts; perfect flowers contain both male (stamen) and female (pistil) structures.
Types include monoecious (both sexual parts on one plant) and dioecious (sexual parts on separate plants).

Fruit Types

Simple Fruits: Developed from a single pistil; classified as fleshy or dry.
- Fleshy types include drupe, berry, and pome.
- Dry types include legume, follicle, capsule, and achene.
Aggregate Fruits: Formed from multiple pistils of a single flower (e.g., strawberry).
Multiple Fruits: Derived from many clustered flowers (e.g., pineapple).

Seeds

Ripened ovules consist of an embryo, seed coat, and sometimes an endosperm.
Dicotyledons have two cotyledons; monocotyledons possess one with an endosperm.
Seed structure includes embryo, seed coat, hilum (attachment scar), micropyle (pores), radicle (future root), and plumule (future shoot).

Description

Explore the fundamental concepts of plant physiology and biochemistry, including the composition of cells and the role of cytoplasm. This quiz covers key topics from the works of Taiz et al. and Heldt et al., focusing on plant cell structures and functions.