Biology Kai

Characteristics of Plants 🌱

• Multicellular organisms with eukaryotic plant cells.

• Possess autotrophic nutrition through photosynthesis.

• Belong to the plant kingdom and have differentiated tissues.

• Typical size: ranges from 10–150 µm.

• Genetic material is enclosed by the cell membrane.

• Cytoplasm contains cellular organelles that perform specific functions.

Autotrophic Nutrition 🌞

• Organisms such as plants, algae, and some bacteria obtain inorganic substances from the environment.

• These organisms convert inorganic substances into organic material through photosynthesis.

Plant Tissues 🧬

Tissue Types and Primary Functions

• Chlorophyll Tissue: Conducts photosynthesis.

• Supporting Tissue: Keeps the plant upright.

• Protective Tissue (Epidermis & Cuticle): Prevents desiccation.

• Conducting Tissue (Xylem & Phloem): Transports water, minerals, and sugars.

Classification of Plants 📊

Seedless Plants (Non-Vascular & Simple/Complex Vascular)

• Bryophytes:
    - Examples: Mosses, Hepaticas (liverworts).
    - No true vascular system.

• Pteridophytes:
    - Examples: Ferns, horsetails, club mosses.
    - Contains a simple vascular system.

Seed-bearing Plants (Complex Vascular System)

• Gymnosperms:
    - Produce seeds but no fruits.

• Angiosperms:
    - Produce both seeds and fruits.

Approximate Species Numbers

• Bryophytes: ~24,000

• Pteridophytes: ~12,000

• Gymnosperms: ~850

• Angiosperms: ~255,000

Bryophytes 🌿

• Characteristics:
    - Non-vascular, lack conductive vessels and seeds.

• Main Groups:
    - Mosses:
      - Very simple conductive structures; no true roots or leaves.
      - Absorb water and nutrients directly from the environment.
      - Example Genera: Sphagnum (peat moss), Polytrichum (haircap moss), Funaria (cord moss).
      - Key Structures:
        - Capsule: Site of spore formation.
        - Stem-like Structures: Provide support.
        - Leaf-like Structures: Carry out photosynthesis.
        - Rhizoids: Anchor the plant.
  
    - Hepaticas (Liverworts):
      - Lack conductive vessels.
      - Representative species: Marchantia polymorpha (common liverwort), Porella platyphylla.

Pteridophytes 🌾

• Characteristics:
    - Vascular plants without flowers or seeds.

• Representative Genera:
    - Pteridium (bracken fern), Adiantum (maidenhair fern), Naphrolepis (Boston fern), Dryopteris (male fern), Equisetum (horsetail), Lycopodium (club moss).

• Typical Morphology:
    - Fronds: Large leaves divided into leaflets or pinnae; underside bears sori containing sporangia for spore production.
    - Rhizome: Underground stem.
    - Roots: Anchor plant and absorb water/minerals.

Spermatophytes (Seed Plants) 🌳

• Vascular plants that produce seeds:
    - Gymnosperms: Seeds without fruits.
    - Angiosperms: Seeds enclosed in fruits; possess structural organs (stems, leaves, roots) and reproductive organs (flowers, cones).

Roots 🌿

• Grow opposite to stem direction from a growth zone; protected by a root cap.

• Functions:
    - Absorb nutrients via root hairs.
    - Stabilize the plant.
    - Store nutrients.

• Parts of the Root:
    - Neck: Connects the root to the stem.
    - Primary Root: Main downward-growing root.
    - Secondary Roots: Smaller branches growing from the primary root.
    - Root Hairs: Tiny structures increasing surface area for absorption.
    - Growth Zone: Region where cells divide to lengthen the root.
    - Root Cap: Protective cover at the tip of the root.

Stem 🌾

• Provides mechanical support and straightness.

• Functions:
    - Transports water, minerals, and photosynthates.
    - Grows from buds that can develop into branches.

• Parts of the Stem:
    - Terminal Bud: Located at the top for vertical growth.
    - Axillary Bud: Found at leaf-stem junction; develops into new branches or flowers.
    - Node: Point on the stem where leaves or branches grow.
    - Internode: Section between two nodes.

Reproductive Organs of Gymnosperms

• Cones (Strobili): Gymnosperms produce cones instead of flowers.

• Male cones produce pollen; female cones contain exposed ovules that become seeds post-fertilization.

• Seed Distribution: The seeds are grouped within cones and are "naked" (not enclosed in an ovary), thus relying on wind for pollen transfer.

• Diagram Labels:
    - Male Cone: Smaller structure on the branch.
    - Female Cone: Larger, more complex structure.

Reproductive Organs of Angiosperms

• Characterized by flowers.

• Ovules are contained in an ovary, which develops into fruit post-fertilization.

• Flowers:
    - Have stamens (male organs) and carpels (female organs).

The 4 Main Groups of Angiosperms (Ordered from Evolutionarily Simple to Complex)

1. Basal Angiosperms

2. Magnoliids

3. Monocots

4. Eudicots

Gymnosperms

• Have conducting vessels, seeds, and cone-like structures but do not produce fruit.

• Examples of Gymnosperms:
    - Pinus: Pines
    - Abies: Fir
    - Cycas: Cycad
    - Ginkgo biloba: Ginkgo
    - Cedrus: Cedar
    - Ephedra: Ephedra

Leaves

• Grow from stems and branches; contain many chloroplasts for photosynthesis and have stomata for gas exchange.

Parts of a Leaf

• Top: Upper surface of the leaf.

• Underside: Lower surface.

• Edge (Margin): Outer boundary of the leaf.

• Veins: Transport vessels throughout the blade.

• Midrib: Central, main vein.

• Petiole: Stalk attaching leaf to stem.

Primary Functions

• Photosynthesize: Produce energy for the plant.

• Gas Exchange: Allow plant to breathe via stomata.

Eudicots (Groups)

• Asterales: Sunflower, daisy, lettuce.

• Rosales: Rose, apple tree, strawberry.

• Fabales (Legumes): Pea, bean, peanuts.

• Lamiales (Aromatic): Lavender, mint, sage.

• Solanales: Potato, tomato, pepper, eggplant.

• Brassicales: Broccoli, cabbage.

• Fagales: Oak, walnut.

Monocots

• Poales: Rice, corn, wheat, sugarcane, oat, rye.

• Asparagales: Orchids, asparagus, onion, garlic.

• Liliales: Lily, tulip.

• Arecales: Palms, coconuts.

Magnoliids

• Magnoliales: Magnolia.

• Piperales: Black pepper.

Basal Angiosperms

• Nymphaeales: Water lilies.

• Examples include: Water lily, sacred lotus.

3 Vital Functions

1. Nutrition

• Global process of photosynthesis:
    - Chemical Equation:
      - Photosynthesis equation involves the modification of atomic balance with components of Oxygen, Hydrogen, and Carbon.
      - Chloroplast structure includes an inner membrane and thylakoids (tilacoides).

Stages of Nutrition

a) Absorption of Water and Minerals

• Plants use absorbent hairs on the roots.

• The mixture of water and minerals is known as xylem sap.

• Xylem sap reaches the leaves to be transformed into phloem sap.

b) Photosynthesis and Gas Exchange

• Plants perform gas exchange via leaves (especially through stomata).

• Plants take in carbon dioxide (CO₂) and release oxygen (O₂).

c) Phloem Sap

• Phloem sap is transported in vessels called phloem.

• Contains sugars and reaches all cells; often mnemonic is "phood" to signify that phloem carries food.

d) Cellular Respiration

• Plants derive energy through cellular respiration occurring in mitochondria.

• Use the products of photosynthesis for respiration.

• Cellular Respiration Equation: Glucose + Oxygen → Water + Carbon Dioxide + Energy

• Photosynthesis Equation: Water + Carbon Dioxide + Energy → Glucose + Oxygen

Plant Interactions

Reacting to the Environment

• Plants react to environmental stimuli and can either move or secrete hormones to respond.

• Hormones act as internal stimuli to generate responses such as growth, leaf drop, or fruit ripening.

Two Types of Movements

a) Tropism

• Growth responses to external stimuli:
    - Phototropism: Growth response to light.
    - Geotropism (Gravitropism): Response to gravity.
    - Hydrotropism: Response to water.

b) Nastic Movements

• Temporary movements in parts of a plant; faster than tropisms and reversible:
    - Photonasty: Plants adjusting leaf positions in response to light.
    - Thermonasty: Tulips changing position due to temperature.
    - Thigmonasty: Carnivorous plants closing when touched by insects.

Phytohormones

Vegetative Propagation

Table of Features

Cuttings (Esquejes)

• Definition: Fragment of a plant cut and placed in a rooting medium to produce a new plant.

• Types include: Stem cuttings, semi-ripe cuttings, hardwood cuttings, leaf cuttings, root cuttings.

• Steps to Grow Plants from Cuttings:
    - Select a healthy parent plant.
    - Make the cut.
    - Prepare the cutting.
    - Use rooting hormone.
    - Plant the cutting.
    - Create humidity.
    - Maintenance.

Chemical Equation Adjustment

• Balancing the reaction between Barium Oxide and Hydrochloric Acid:

• Corrected Balanced Equation:

Unbalanced:

Balanced:

• Correction Summary:
    - Barium (Ba): 1 on both sides.
    - Oxygen (O): 1 on both sides.
    - Hydrogen (H): Needs to be 2 to match.
    - Chlorine (Cl): Needs to be 2 to match.