Plant Biology: Cell Structure, Physiology, Anatomy, and Development

Vocabulary practice flashcards covering cell chemistry, physiology, respiration, photosynthesis, tissues, shoot and root systems, floral development, and secondary growth based on lecture notes.

Primary metabolite

Molecules essential for basic cell growth, development, and survival, including carbohydrates, lipids, proteins, and nucleic acids.

Dehydration synthesis

A chemical reaction in which monomers are joined together by covalent bonds with the elimination of a water molecule.

Hydrolysis

A cleavage reaction that breaks covalent bonds in polymers by adding a water molecule.

Endosymbiont theory

The evolutionary concept stating that eukaryotic organelles such as mitochondria and chloroplasts originated from free-living prokaryotes internalized by ancient host cells.

Middle lamella

A pectin-rich layer cementing together the primary cell walls of adjacent plant cells.

Plasmodesmata

Cytoplasmic channels passing through cell walls that connect the protoplasts of adjacent plant cells.

Symplast

The interconnected network of protoplasts and their plasmodesmata within a plant.

Apoplast

The non-living continuum of cell walls, intercellular spaces, and water-filled lumen outside the plasma membrane.

Tonoplast

The single membrane surrounding the central vacuole in plant cells.

Secondary metabolites

Plant chemical compounds not directly required for basic metabolic survival, functioning in defense, ecological interaction, and attraction (such as alkaloids, terpenoids, and phenolics).

Oxidative phosphorylation

The production of ATP using energy derived from the redox reactions of the mitochondrial electron transport chain.

Resonance energy transfer

The physical process by which excitation energy is passed directly from one photosynthetic pigment molecule to another without emitting a photon.

Rubisco

Ribulose 1,5-bisphosphate carboxylase/oxygenase; the key enzyme catalyzing initial carbon fixation in the Calvin cycle.

Kranz anatomy

A specialized leaf architecture in C4 plants featuring prominent bundle-sheath cells surrounded by ring-like mesophyll cells.

Apical meristem

Meristematic tissue located at the tips of roots and shoots responsible for primary growth and lengthening.

Protoderm

The primary meristem that gives rise to dermal tissue (epidermis).

Procambium

The primary meristem that gives rise to primary vascular tissues, including primary xylem and primary phloem.

Ground meristem

The primary meristem that gives rise to ground tissue, including parenchyma, collenchyma, and sclerenchyma.

Casparian strips

Band-like cell wall thickenings impregnated with suberin in root endodermal cells that regulate entry of water and solutes into the vascular cylinder.

Eustele

A stele type typical of eudicot stems in which discrete vascular bundles are arranged in a ring around a central pith.

Atactostele

A stele type typical of monocot stems in which vascular bundles are scattered throughout the ground tissue.

Cladophyll

A modified photosynthetic stem that resembles and functions as a leaf.

Phyllotaxy

The arrangement pattern of leaves on a plant stem (such as alternate, opposite, whorled, decussate, or spiral).

Connation

The floral fusion of like organ parts, such as petal to petal.

Adnation

The floral fusion of unlike organ parts, such as stamen to petal.

Vascular cambium

A lateral meristem that produces secondary xylem inwardly and secondary phloem outwardly in woody plant tissue.

Cork cambium

A lateral meristem (phellogen) that produces periderm, forming phellem (cork) to the outside and phelloderm to the inside.

Double fertilization

An angiosperm fertilization event where one sperm fuses with the egg cell to form a zygote, while the second sperm fuses with two polar nuclei to form triploid endosperm.

Epigeous

A seed germination type where the cotyledons are carried above the soil surface by hypocotyl elongation.

Hypogeous

A seed germination type where cotyledons remain below the soil surface while the epicotyl elongates.

Phototropin

A specialized flavoprotein photoreceptor mediating plant phototropism in response to blue light.

Amyloplast (statolith)

A dense, starch-storing plastic organelle that functions as a gravity sensor by settling in response to gravitational orientation.

Primary cell wall

A flexible, extensible layer laid down by growing plant cells, composed mainly of cellulose microfibrils, hemicellulose, and pectin.

Secondary cell wall

A rigid layer deposited inside the primary wall after cell expansion has ceased, often reinforced with lignin.

Lignin

A complex phenolic polymer that stiffens and waterproofs secondary cell walls in vascular plant tissues.

Thylakoid

A membrane-bound sac inside chloroplasts where the light-dependent reactions of photosynthesis take place.

Stroma

The fluid-filled matrix surrounding thylakoid membranes in chloroplasts where carbon fixation reactions occur.

Glycolysis

The initial metabolic pathway in cellular respiration that breaks down glucose into pyruvate in the cytoplasm.

Citric acid cycle

A series of mitochondrial reactions that oxidize acetyl CoA derived from carbohydrates, fats, and proteins into carbon dioxide.

Photosystem II

A protein-pigment complex in thylakoid membranes that uses light energy to oxidize water and generate oxygen and protons.

Photosystem I

A protein-pigment complex in thylakoid membranes that absorbs light energy to drive the reduction of NADP+ to NADPH.

CAM plants

Vegetation that fixes carbon dioxide at night using PEP carboxylase to conserve water in arid environments.

Parenchyma

A versatile ground tissue consisting of thin-walled, living cells involved in photosynthesis, storage, and tissue repair.

Collenchyma

A living ground tissue with unevenly thickened primary cell walls that provides flexible structural support to growing stems and leaves.

Sclerenchyma

A plant ground tissue with thick, lignified secondary walls that provides rigid support, typically dead at maturity.

Xylem

A complex vascular tissue responsible for conducting water and dissolved mineral ions upward from roots to shoots.

Phloem

A complex vascular tissue responsible for transporting dissolved sugars and organic solutes throughout the plant body.

Tracheids

Elongated, tapering water-conducting cells in xylem with pitted walls, lacking open perforations.

Vessel elements

Short, wide conducting cells in xylem with perforated end plates aligned end-to-end to form continuous vessels.

Sieve-tube elements

Specialized phloem cells lacking nuclei at maturity that align end-to-end to form sugar-conducting tubes.

Companion cells

Specialized parenchyma cells closely linked to sieve-tube elements that support their metabolic operations.

Pericycle

A layer of meristematic cells situated just inside the endodermis from which lateral root formation originates.

Rhizome

A horizontally oriented underground stem involved in carbohydrate storage and vegetative propagation.

Tuber

A swollen, underground stem modified for starch storage, featuring nodes called eyes.

Bulb

A short, vertical underground stem surrounded by thick, fleshy modified leaves that store food reserves.

Corm

A solid, vertical, swollen underground stem tissue covered by thin, papery modified leaf scales.

Calyx

The outermost whorl of a flower composed of sepals that enclose and protect the developing bud.

Corolla

The floral whorl consisting of all petals, often brightly colored to attract pollinators.

Androecium

The collective term for all the male reproductive organs (stamens) within a flower.

Gynoecium

The collective term for all the female reproductive organs (carpels or pistils) within a flower.

Monoecious

A plant species that produces separate male and female flowers on the same individual plant.

Dioecious

A plant species that produces male and female flowers on separate individual plants.

Superior ovary

An ovary positioned above the points of attachment of the sepals, petals, and stamens.

Inferior ovary

An ovary located completely below the attachment points of other floral organs.

Auxin

A class of plant hormones that promotes cell elongation, apical dominance, and adventitious root growth.

Cytokinin

A class of plant hormones that stimulates cell division, shoot initiation, and delays senescence.

Ethylene

A gaseous plant hormone that promotes fruit ripening, leaf abscission, and triple responses in seedlings.

Abscisic acid

A plant hormone that inhibits growth, induces seed dormancy, and triggers stomatal closure during water stress.

Gibberellins

A class of plant hormones that promotes stem elongation, seed germination, and flowering growth.