BIO 114: Plant and Animal Form and Function – Comprehensive Study Guide

Plant Form and Function

General Characteristics of Plants

• Plants are multicellular, primarily photosynthetic organisms belonging to the kingdom Plantae.

• They exhibit indeterminate growth, meaning they can grow throughout their lifetime.

• Key features include cell walls made of cellulose, chloroplasts for photosynthesis, and alternation of generations in their life cycle.

Root and Shoot Systems

• The root system anchors the plant and absorbs water and minerals from the soil.

• The shoot system consists of stems and leaves, responsible for photosynthesis and reproduction.

• Nodes are points on the stem where leaves or branches originate; internodes are stem segments between nodes.

Permanent Tissues in Vascular Plants

• Dermal tissue: Outer protective covering (e.g., epidermis, guard cells, trichomes).

• Ground tissue: Functions in photosynthesis, storage, and support (e.g., parenchyma, collenchyma, sclerenchyma).

• Vascular tissue: Conducts water, minerals, and nutrients (xylem and phloem).

Meristems

• Meristems are regions of undifferentiated cells that divide and generate new tissues.

• Types include apical meristems (growth in length), lateral meristems (growth in thickness), and intercalary meristems (growth at internodes or base of leaves).

Dermal Tissue Adaptations

• Epidermis protects against water loss and pathogens.

• Cuticle (waxy layer) reduces water loss.

• Trichomes (hair-like structures) can reduce herbivory and reflect excess light.

Ground Tissue Cell Types

• Parenchyma: Thin-walled, living cells; function in photosynthesis and storage.

• Collenchyma: Unevenly thickened walls; provide flexible support.

• Sclerenchyma: Thick, lignified walls; provide rigid support (e.g., fibers, sclereids).

Xylem vs. Phloem

• Xylem: Transports water and minerals from roots to shoots; composed of tracheids and vessel elements.

• Phloem: Transports sugars and organic compounds; composed of sieve elements and companion cells.

Root Structure and Modified Roots

• Four regions: root cap, zone of cell division, zone of elongation, zone of maturation.

• Modified roots include storage roots (e.g., carrots), prop roots (support), and pneumatophores (gas exchange).

Dicot vs. Monocot Stems

• Dicots: Vascular bundles arranged in a ring; presence of pith and cortex.

• Monocots: Vascular bundles scattered throughout the stem.

Leaf Structure and Types

• Simple leaf: Single, undivided blade.

• Compound leaf: Blade divided into leaflets.

• Modified leaves include tendrils, spines, and storage leaves.

Evolutionary and Taxonomic Context

• Plants evolved from green algae; major groups include bryophytes, ferns, gymnosperms, and angiosperms.

• Eudicots and monocots are two major groups of angiosperms.

Plant Functioning

Water Potential and Movement

• Water potential (\( \Psi \)) predicts the direction of water movement; water moves from high to low potential.

• Components: Pressure potential (turgor), solute potential (osmotic), and matric potential (adhesion to surfaces).

• Equation: $\Psi = \Psi_s + \Psi_p$

Pathways of Water Movement

• Apoplast: Through cell walls and intercellular spaces.

• Symplast: Through cytoplasm via plasmodesmata.

• Transmembrane: Across cell membranes and cytoplasm.

Casparian Strip and Root Pressure

• Casparian strip: Waxy barrier in endodermis forcing water through cell membranes, controlling entry to xylem.

• Root pressure: Positive pressure in roots, occurs when soil moisture is high and transpiration is low.

Stomatal Regulation and Water Loss

• Guard cells regulate stomatal opening, controlling gas exchange and water loss.

• Plants limit water loss via cuticle, sunken stomata, and leaf modifications.

Translocation and Pressure-Flow Model

• Translocation: Movement of sugars from source (leaves) to sink (roots, fruits) via phloem.

• Pressure-flow model: High pressure at source drives sap to sink where pressure is lower.

Plant Nutrition

• Essential nutrient: Required for plant growth and reproduction; absence prevents completion of life cycle.

• Macronutrients: Needed in large amounts (e.g., N, P, K); micronutrients: Needed in trace amounts (e.g., Fe, Zn).

• Uptake via roots, often aided by mycorrhizae (fungal symbionts).

Plant Hormones

• Auxin: Promotes cell elongation, apical dominance, and phototropism.

• Cytokinins: Stimulate cell division, counteract auxin effects.

• Gibberellins: Stimulate stem elongation, seed germination.

• Ethylene: Promotes fruit ripening, leaf abscission.

• Abscisic acid (ABA): Induces dormancy, closes stomata during stress.

• Phytochromes: Light receptors influencing growth responses.

Phototropism and Gravitropism

• Phototropism: Growth toward light, mediated by auxin redistribution.

• Gravitropism: Growth in response to gravity, perceived by statoliths in root cap cells.

Flowering Plant Reproduction

Flower Structure and Function

• Flowers consist of four whorls: calyx (sepals), corolla (petals), androecium (stamens), gynoecium (carpels/pistil).

• Stamens produce pollen; carpels contain ovules.

Pollination and Fertilization

• Pollination: Transfer of pollen to stigma; can be by wind, water, or animals.

• Self-pollination: Pollen from same plant; cross-pollination: Pollen from different plant.

• Strategies to promote outcrossing: dichogamy, self-incompatibility, spatial separation of sex organs.

• Double fertilization: One sperm fertilizes egg (zygote), another fuses with polar nuclei (endosperm).

Seed and Fruit Development

• Ovule develops into seed; ovary develops into fruit (pericarp forms fruit wall).

• Seeds ensure survival via dormancy and dispersal mechanisms.

• Germination requires water, oxygen, and suitable temperature.

Life Cycle and Alternation of Generations

• Plants alternate between sporophyte (diploid) and gametophyte (haploid) generations.

• Microgametophyte: pollen grain; megagametophyte: embryo sac.

Animal Form and Function

Tissues, Organs, and Organ Systems

• Tissue: Group of similar cells performing a function.

• Organ: Structure composed of multiple tissues.

• Organ system: Group of organs working together.

• Four tissue types: connective (loose, dense, supportive, fluid), nervous, muscle (smooth, cardiac, skeletal), epithelial.

Epithelial Tissue Structure

• Apical side: Faces lumen or outside; basolateral side: Faces underlying tissue.

• Basal lamina: Thin layer anchoring epithelium to connective tissue.

• Classified as simple (one layer) or stratified (multiple layers); shapes: squamous, cuboidal, columnar.

Surface Area to Volume Ratio

• High surface area/volume ratio enhances exchange of materials (e.g., microvilli in intestines).

• Adaptations include folding, branching, and flattening of surfaces.

Homeostasis

• Homeostasis: Maintenance of stable internal environment.

• Conformational: Internal state varies with environment; regulatory: Maintains constant internal state.

• Mechanism involves sensor, set point, integrator, effector, and negative feedback.

Thermoregulation

• Mechanisms of heat exchange: conduction, convection, radiation, evaporation.

• Endotherms: Generate heat metabolically; ectotherms: Rely on environment.

• Homeotherms: Maintain constant body temperature; heterotherms: Body temperature varies.

• Countercurrent heat exchangers conserve heat in extremities.

Water and Electrolyte Balance in Animals

Osmoregulation

• Osmoconformers: Internal osmolarity matches environment (e.g., marine invertebrates).

• Osmoregulators: Maintain constant internal osmolarity (e.g., vertebrates).

Kidney Structure and Function

• Primary components: cortex, medulla, nephron (functional unit).

• Nephron structure: Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct.

• ADH (antidiuretic hormone) regulates water reabsorption, maintaining osmotic homeostasis.

• Blood osmolarity and pressure are closely linked; kidneys adjust both via filtration and reabsorption.

Animal Nutrition

Nutrition Process and Digestive Systems

• Four steps: ingestion, digestion, absorption, elimination.

• Essential nutrients: Cannot be synthesized by the animal (e.g., amino acids, vitamins).

• Feeding modes: suspension, deposit, fluid, bulk feeding.

• Digestive systems: incomplete (one opening) vs. complete (mouth and anus).

Vertebrate Digestive Tract

• Parts: mouth, esophagus, stomach, small intestine, large intestine, anus.

• Accessory organs: liver, pancreas, gallbladder.

• Food moves via peristalsis; stomach digests proteins; small intestine absorbs nutrients.

• Large intestine reabsorbs water, forms feces.

• Insulin regulates blood sugar; diabetes results from insulin deficiency or resistance.

Gas Exchange and Circulation

Fick's Law of Diffusion

• Describes rate of gas diffusion across membranes:

$Rate = k \times A \times \frac{(P_2 - P_1)}{D}$

• Where k is the diffusion constant, A is surface area, P2 - P1 is partial pressure difference, D is membrane thickness.

• Adaptations increase A or decrease D to enhance exchange.

Respiratory Mechanisms

• Gills use countercurrent flow for efficient O2 uptake.

• Amphibians: positive pressure breathing; mammals: negative pressure via diaphragm; birds: unidirectional airflow.

• Mammalian lungs: alveoli increase surface area; CNS regulates breathing rate.

Circulatory System and Blood

• Hemoglobin: Oxygen-carrying protein; affinity changes with pH, CO2, temperature (Bohr effect).

• CO2 transported as bicarbonate ions in plasma.

• Blood contains red cells, white cells, platelets, plasma.

• Cardiac cycle: sequence of heart contraction and relaxation.

• Arteries withstand high pressure; veins have valves and thinner walls; capillaries allow exchange but cannot withstand high pressure.

• Lymphatic system returns interstitial fluid to circulation.

Key Comparative Table: Dicot vs. Monocot Stems

Feature	Dicot Stem	Monocot Stem
Vascular Bundle Arrangement	Ring	Scattered
Pith and Cortex	Present	Not distinct
Secondary Growth	Possible	Rare

Key Comparative Table: Xylem vs. Phloem

Feature	Xylem	Phloem
Main Function	Water & minerals transport	Sugar & organic transport
Direction	Root to shoot (upward)	Source to sink (varies)
Main Cells	Tracheids, vessels	Sieve elements, companion cells

Glossary of Key Terms

• Node: Point on stem where leaves or branches originate.

• Internode: Stem segment between nodes.

• Blade: Flat part of leaf.

• Petiole: Stalk attaching leaf blade to stem.

• Guard cells: Cells controlling stomatal opening.

• Trichomes: Hair-like epidermal outgrowths.

• Root hairs: Extensions of root epidermal cells, increase surface area.

• Tracheids: Elongated xylem cells for water transport.

• Sieve elements: Phloem cells for sugar transport.

• Parenchyma: Living ground tissue cells.

• Collenchyma: Supportive ground tissue cells.

• Sclerenchyma: Rigid ground tissue cells.

• Cortex: Ground tissue between epidermis and vascular tissue.

• Pith: Central ground tissue in stems.

• Eudicot: True dicots, a major group of angiosperms.

• Monocot: Angiosperms with one seed leaf.

Additional info: This guide expands on the listed objectives and terms, providing academic context and explanations suitable for exam preparation in introductory biology courses.