Biology Study Guide: Bacteria, Archaea, Protists, Fungi, and Plant Diversity

Chapter 27: Bacteria and Archaea

Overview of Prokaryotes

Prokaryotes are divided into two domains: Bacteria and Archaea. These organisms are unicellular and lack a membrane-bound nucleus. They play essential roles in ecosystems and have diverse metabolic capabilities.

• Bacteria: Characterized by cell wall structure, metabolic diversity, and ecological roles.

• Archaea: Often extremophiles, living in harsh environments.

Bacterial Cell Structure and Function

• Gram-positive vs. Gram-negative: Classification based on cell wall composition. Gram-positive bacteria have thick peptidoglycan layers; Gram-negative have thin layers and an outer membrane.

• Capsule: A polysaccharide layer outside the cell wall that protects against desiccation and immune attack.

• Endospore: Dormant, tough, non-reproductive structure for survival in harsh conditions.

• Fimbriae and Pili: Hair-like appendages for attachment (fimbriae) and DNA transfer (pili).

• Flagella: Structures for motility.

Reproduction and Genetic Diversity

• Binary Fission: Asexual reproduction by cell division.

• Genetic Diversity Mechanisms: Transformation (uptake of DNA), Transduction (virus-mediated DNA transfer), Conjugation (direct transfer via pili).

Nutritional Modes and Role of Oxygen/Nitrogen

• Photoautotrophs: Use light and CO2 for energy and carbon.

• Chemolithoautotrophs: Use inorganic chemicals and CO2.

• Photoheterotrophs: Use light and organic compounds.

• Chemoheterotrophs: Use organic compounds for energy and carbon.

• Oxygen: Obligate aerobes require O2; obligate anaerobes are poisoned by O2; facultative anaerobes can use either.

• Nitrogen: Nitrogen fixation converts atmospheric N2 to ammonia (NH3).

Major Types of Bacteria

• Proteobacteria: Diverse group, includes E. coli.

• Chlamydias: Parasitic bacteria, cause diseases.

• Spirochetes: Spiral-shaped, includes pathogens like Borrelia.

• Cyanobacteria: Photosynthetic, oxygen-producing.

• Gram-positive bacteria: Includes Streptococcus, Bacillus.

Archaea and Extremophiles

• Extremophiles: Live in extreme conditions (high temperature, salinity, acidity).

Ecological Roles and Impact

• Ecological Roles: Decomposers, nitrogen fixers, symbionts.

• Useful vs. Harmful: Some bacteria are beneficial (e.g., gut flora), others cause disease.

Chapter 28: Protists

Overview of Protists

Protists are mostly unicellular eukaryotes with diverse forms and functions. They occupy various ecological niches and have complex life cycles.

• Nutritional Modes: Photoautotrophs, heterotrophs, mixotrophs.

• Reproduction: Asexual and sexual; some exhibit alternation of generations.

Supergroups of Protists

• Excavata: Includes Euglena, characterized by feeding grooves.

• SAR: Stramenopiles (e.g., diatoms), Alveolates (e.g., Paramecium), Rhizarians.

• Archaeplastida: Includes red and green algae.

• Unikonta: Includes amoebas and slime molds.

Ecological Role of Protists

• Primary Producers: Algae contribute to aquatic food webs.

• Pathogens: Some cause diseases (e.g., malaria).

Chapter 31: Fungi

Overview of Fungi

Fungi are heterotrophs that absorb nutrients from their environment. They exist as multicellular filaments or single-celled yeasts and play vital roles in ecosystems.

• Lifestyles: Decomposers, parasites, mutualists.

• Body Structure: Hyphae form mycelium; yeasts are unicellular.

• Reproduction: Sexual and asexual via spores.

Role of Fungi in Ecosystems

• Decomposers: Break down organic matter.

• Mutualists: Mycorrhizae with plants, lichens with algae/cyanobacteria.

• Parasites: Cause diseases in plants and animals.

Chapters 29 & 30: Plant Diversity

Key Traits Defining Plants

• Multicellular, eukaryotic, photosynthetic autotrophs

• Cell walls made of cellulose

• Chloroplasts with chlorophyll a and b

• Alternation of generations

• Embryophytes: Multicellular dependent embryos

Phyla and Plant Groups

• Nonvascular Plants: Mosses, liverworts, hornworts; lack vascular tissue.

• Vascular Plants: Have xylem and phloem.

• Seedless Plants: Ferns and relatives; reproduce via spores.

• Seed Plants: Gymnosperms (naked seeds, e.g., pines) and Angiosperms (flowering plants).

• Monocots vs. Dicots: Monocots have one seed leaf, parallel veins; dicots have two seed leaves, net-like veins.

Main Structural Components of Plants

• Roots: Anchor plant, absorb water and minerals.

• Stems: Support, transport fluids, store nutrients.

• Leaves: Photosynthesis, gas exchange.

• Seeds: Protect and nourish embryo.

• Flowers: Reproduction.

• Fruits: Seed dispersal.

Chapter 35: Vascular Plant Structure, Growth, and Development

Plant Organs and Their Functions

• Roots: Absorption, anchorage, storage.

• Stems: Support, transport, growth.

• Leaves: Photosynthesis, transpiration.

Tissue Types

• Dermal Tissue: Protection.

• Vascular Tissue: Transport of water (xylem) and nutrients (phloem).

• Ground Tissue: Photosynthesis, storage, support.

Common Plant Cell Types

• Parenchyma: Thin-walled, photosynthesis, storage.

• Collenchyma: Support in growing regions.

• Sclerenchyma: Thick-walled, structural support.

• Water-conducting cells of xylem: Tracheids and vessel elements.

• Sugar-conducting cells of phloem: Sieve-tube elements.

Growth and Meristems

• Primary Growth: Lengthening via apical meristems.

• Secondary Growth: Thickening via lateral meristems (vascular cambium, cork cambium).

Chapter 36: Resource Acquisition and Transport in Vascular Plants

Water-Loss Compromise and Compensation

• Transpiration: Water loss through leaves; regulated by stomata.

• Adaptations: Waxy cuticle, reduced leaf area, stomatal regulation.

Root Architecture and Water/Mineral Uptake

• Root hairs: Increase surface area for absorption.

• Mycorrhizae: Symbiotic fungi enhance nutrient uptake.

Transport Systems

• Apoplast: Movement through cell walls and intercellular spaces.

• Symplast: Movement through cytoplasm via plasmodesmata.

• Transmembrane: Movement across cell membranes.

Water Potential and Cell States

• Water Potential ($\Psi$): Determines direction of water movement.

• Flaccid: Limp cell due to water loss.

• Plasmolysis: Cell membrane pulls away from wall.

• Turgid: Firm cell due to water uptake.

Bulk Flow and Sap Transport

• Xylem: Transports water and minerals upward.

• Phloem: Transports sugars and organic nutrients.

• Bulk Flow: Movement due to pressure differences.

Chapter 37: Plant Nutrition

Soil Texture and Composition

• Soil Texture: Proportion of sand, silt, clay affects water and nutrient retention.

• Soil Composition: Includes minerals, organic matter, air, water.

Cation Exchange

• Cation Exchange: Process by which plants obtain mineral nutrients from soil particles.

Plant Mineral Requirements

• Essential Elements: Required for growth and development.

• Macronutrients: Needed in large amounts (N, P, K, Ca, Mg, S).

• Micronutrients: Needed in trace amounts (Fe, Mn, Zn, Cu, etc.).

Nitrogen Cycle

• Nitrogen Fixation: Conversion of N2 to NH3 by bacteria.

• Nitrification: NH3 to NO3-.

• Assimilation: Uptake of NO3- by plants.

Nutritional Adaptations in Plants

• Epiphytes: Grow on other plants, absorb moisture from air.

• Parasitic Plants: Obtain nutrients from host plants.

• Carnivorous Plants: Trap and digest insects for nutrients.

Chapter 38: Angiosperm Reproduction and Biotechnology

Angiosperm Life Cycle and Floral Organs

• Life Cycle: Alternation of generations; double fertilization.

• Floral Organs: Sepals, petals, stamens, carpels.

Flower Structure and Reproduction

• Sepals: Protect flower bud.

• Petals: Attract pollinators.

• Stamens: Male organs (anther, filament).

• Carpels: Female organs (stigma, style, ovary).

Types of Flowers and Pollinators

• Complete vs. Incomplete Flowers: Complete have all four organs.

• Pollinators: Bees, birds, wind, bats; plants adapt to attract specific pollinators.

Fruit Types and Seed Dispersal

• Fruit Types: Simple, aggregate, multiple.

• Seed Dispersal: Wind, water, animals.

Asexual Fertilization Mechanisms

• Vegetative Reproduction: New plants from roots, stems, leaves.

• Apomixis: Seeds produced without fertilization.

Biotechnology in Plants

• Genetically Engineered Plants: Modified for traits like pest resistance, improved nutrition.

• Pros: Increased yield, reduced pesticide use.

• Cons: Environmental concerns, potential for gene flow to wild species.

Plant Group	Defining Traits	Examples
Nonvascular	No vascular tissue, dominant gametophyte	Mosses, liverworts
Seedless Vascular	Vascular tissue, spores	Ferns, horsetails
Gymnosperms	Naked seeds, cones	Pines, firs
Angiosperms	Flowers, fruits, enclosed seeds	Roses, grasses

Additional info: Where original notes were brief, academic context was added to clarify definitions, examples, and mechanisms. Equations and cell types were expanded for completeness.