Botany set

Primary Metabolites

Molecules essential for basic cellular growth and reproduction (Carbohydrates, Lipids, Proteins, Nucleic Acids)

Secondary Metabolites

Non-essential plant compounds synthesized for defense, communication, and environmental stress response

Terpenoids

Secondary metabolites made of isoprene units; examples include essential oils, rubber, and toxic cardiac glycosides

Phenolics

Secondary metabolites containing benzene rings; examples include colorful flavonoids, antiherbivory tannins, and structural lignin

Prokaryotic Cells

Small cells lacking a defined nucleus, membrane-bound organelles, and a cytoskeleton

Eukaryotic Cells

Large, complex cells that possess a nucleus, specialized organelles, and an internal cytoskeleton

Shared Eukaryotic Organelles

Cell structures plants share with animals, including the nucleus, mitochondria, endoplasmic reticulum, and ribosomes

Differing Plant Organelles

Structures unique to plant cells, including chloroplasts, a large central vacuole, and a rigid cell wall

Plasmodesmata

Microscopic cytoplasm channels bridging adjacent plant cell walls to facilitate communication and transport

Primary Cell Wall

Flexible cellulose wall deposited on the outside of the plasma membrane during active cell growth

Secondary Cell Wall

Rigid cell wall layer deposited inside the primary wall composed of cellulose and waterproof lignin once growth stops

Vacuole Function

Maintains cell shape and internal pressure (turgor), stores secondary defensive compounds, and expands cell surface area

Plastids

Double-membrane organelles including clear leucoplasts (storage), colorful chromoplasts, and photosynthetic chloroplasts

Lecture 3: Flowers and PollinatorsFour Floral Whorls

Calyx (sepals), Corolla (petals), Stamens, and Carpels

Sterile Whorls

The protective outer parts of a flower that do not produce gametes (Calyx/sepals and Corolla/petals)

Fertile Whorls

The reproductive organs of a flower (Stamens produce male pollen; Carpels house female parts)

Complete Flower

A flower that possesses all four structural whorls

Incomplete Flower

A flower that is physically missing one or more of the four whorls

Perfect Flower

A bisexual flower containing both functioning male (stamens) and female (carpels) structures

Imperfect Flower

A unisexual flower missing either functioning stamens or functioning carpels

Darwin's Abominable Mystery

Darwin's frustration over the sudden, rapid explosion and diversification of flowering plants in the mid-Cretaceous fossil record

Angiosperm Diversification Cause

Coevolutionary interactions and mutual relationships established between plants and flower-frequenting insect pollinators

Wind Pollination Features

Tiny or absent petals, no odor, and unisexual/imperfect flowers often grouped together on trees or grasses

Beetle Pollination Features

Wide, open bowl-shaped flowers with a relatively weak odor

Fly Pollination Features

Brownish or reddish bowl-shaped flowers that emit a strong foul, rotting odor

Bee Pollination Features

Showy, brightly colored flowers containing specific visual pigments that fluoresce under UV light

Butterfly Pollination Features

Brightly colored, tubular flowers that emit a sweet, enticing smell

Moth Pollination Features

White or pale-colored flowers that open at night and emit heavy, sweet scents

Bird Pollination Features

Bright red, odorless tubular flowers that continuously secrete lots of nectar slowly

Bat Pollination Features

Large, dull white or green flowers hanging down with lots of nectar in tropical or desert spaces

Lecture 4: Tissues and Tissue SystemsPlant Growth vs Morphogenesis

Growth is an irreversible size increase; morphogenesis is the taking of a specific physical shape

Plant Differentiation

The process where unspecialized cells shift in structure to become specialized for distinct functional roles

Apical Meristem

Regions of active cell division found at tips of roots and shoots responsible for elongating primary growth

Three Primary Meristems

Protoderm (forms epidermis), Procambium (forms vascular tissue), and Ground Meristem (forms ground tissue)

Meristem Initials vs Derivatives

Initials are stem cells that stay in the meristem; derivatives are daughter cells pushed out to specialize

Simple vs Complex Tissues

Simple tissues contain only one cell type (like parenchyma); complex tissues contain multiple cell types (like xylem)

Parenchyma

Living ground tissue derived from ground meristem; handles photosynthesis and storage in the cortex, pith, and mesophyll

Collenchyma

Living ground tissue derived from ground meristem with unevenly thickened primary walls; supports young growing organs

Sclerenchyma

Dead ground tissue derived from ground meristem with thick, lignified secondary walls; supports non-growing tissues

Two Tracheary Elements

Tracheids (small diameter water conductors) and Vessel Elements (wide, short cells linked end-to-end in angiosperms)

Protoxylem vs Metaxylem

Protoxylem forms early from the procambium during elongation; metaxylem matures later after elongation stops

Vascular System Complexity

Considered complex because it contains diverse cell types working together, including tracheary elements, parenchyma, and fibers

Two Phloem Cells

Sieve elements (living conducting cells derived from procambium) and companion cells (supportive metabolic helpers)

Sieve Tubes vs Tracheary Elements

Sieve tubes are living cells under positive pressure; tracheary elements are dead hollow tubes under negative tension

Epidermis Function

Dermal tissue system derived from protoderm; regulates gas exchange above ground and water/nutrient uptake below ground

Guard Cells

Specialized pairs of dermal cells from the protoderm flanking stomata that swell and shrink to regulate gas exchange

Trichomes

Hair-like specialized dermal cells from the protoderm used for light reflection, water absorption, and insect protection

Lecture 5: RootsMain Root Functions

Anchorage, water/nutrient absorption, nutrient storage, conduction, and hormone synthesis

Taproot vs Lateral Root

A taproot is a single dominant central primary root; lateral roots are branch roots emerging horizontally

Root Cap

A layer of living parenchyma cells that protects the root apical meristem and secretes lubricating mucigel

Three Regions of Root Growth

Region of division (apical meristem), region of elongation (stretching cells), and region of maturation (root hairs form)

Monocot vs Dicot Plant Seeds

Monocots contain a single embryonic seed leaf (cotyledon); dicots contain two embryonic seed leaves

Root Hairs

Extensions of the root epidermal layer (protoderm origin) in the region of maturation that maximize absorption surface area

Rhizosphere

The highly active layer of soil directly surrounding and influenced by a plant's living roots

Exodermis

A protective, suberized layer of ground tissue (ground meristem origin) that develops to replace the root epidermis

Root Cortex

Ground tissue derived from the ground meristem made mostly of parenchyma cells used primarily to store starches

Apopoplastic vs Symplastic Transport

Apoplast moves water passively through intercellular gaps and cell walls; symplast moves water actively through cytoplasm via plasmodesmata

Endodermis

The innermost layer of the root cortex (ground tissue system) that acts as a selective filter for entering water and minerals

Casparian Strip

A waterproof band of suberin in endodermal walls blocking apoplastic flow, forcing water into the living cytoplasm

Vascular Cylinder (Stele)

The central core of the root containing vascular tissues (procambium origin) situated entirely inside the endodermis

Pericycle

A layer of ground tissue inside the endodermis that produces lateral roots and aids secondary growth

Dicot Root Vascular Pattern

Xylem (procambium origin) forms a solid star/cross shape in the center with phloem tucked between rays; no pith

Monocot Root Vascular Pattern

Ring of alternating xylem and phloem bundles enclosing a large central core of ground tissue called a pith

Root Pith Composition

A central core of parenchyma cells belonging functionally to the ground tissue system

Lecture 6: ShootsShoot Organs & Functions

Stems (provide physical support and conduction) and Leaves (act as the primary site of photosynthesis)

Phytomere

The repeating structural unit of a shoot consisting of a node, its attached leaf, an axillary bud, and an internode

Three Stem Tissue Arrangements

1. Continuous cylinder (woody plants), 2. Ring of discrete vascular bundles (herbaceous dicots), 3. Scattered bundles (monocots)

Stem Vascular Orientation

Primary xylem is oriented internally toward the pith; primary phloem is oriented externally toward the cortex

Phloem Fibers

Sclerenchyma cells providing structural support; part of the vascular tissue system (procambium origin)

Anatomical Monocot vs Dicot Stems

Monocots feature scattered vascular bundles resembling monkey faces; dicots have bundles arranged in a neat ring

Hydrophytes

Plants adapted to wet/submerged spaces with stomata on the upper surface, low vascular tissue, and massive air spaces

Xerophytes

Arid-adapted plants featuring stomata tucked into sunken cavities on the lower surface alongside thick protective trichomes

Palisade vs Spongy Mesophyll

Palisade is upper elongated parenchyma dense with chloroplasts; spongy is lower parenchyma with large air spaces for gas diffusion

Leaf Bundle Sheath Cells

A protective ring of ground tissue cells enclosing vascular veins to regulate materials and isolate airflow

Bulliform Cells

Large, specialized grass-exclusive epidermal cells (protoderm origin) that deflate to curl the leaf during droughts

Kranz Anatomy

A specialized arrangement in C4 grasses where concentric rings of mesophyll surround oversized bundle sheath cells