Plant Biology and Photosynthesis Flashcards

Vocabulary flashcards covering plant anatomy, tissue systems, biological molecules, and photosynthesis based on the lecture transcript.

Osmosis

Diffusion of water from higher water concentration to lower water concentration, or higher water potential to lower water potential.

Chemiosmosis

Diffusion of $H^+$ from higher $H^+$ concentration to lower $H^+$ concentration.

Dermal tissue system

Tissue system originating from protoderm.

Vascular tissue system

Tissue system originating from procambium.

Ground tissue system

Tissue system originating from ground meristem.

Xylem

Vascular tissue composed of vessels, vessel elements, and tracheids.

Phloem

Vascular tissue composed of sieve tubes, sieve tube elements, sieve plates, and companion cells.

SAM

Shoot apical meristem.

RAM

Root apical meristem.

HONCP

Acronym representing the 1, 2, 3, 4, and 5 bonds in Hydrogen, Oxygen, Nitrogen, Carbon, and Phosphorus, respectively.

Amino acid components

Consists of an amino group ($-NH_2$), carboxyl group ($-COOH$), central carbon, and side group.

Primary protein structure

The sequence of amino acids in a polypeptide from amino terminus to carboxy terminus.

Secondary protein structure

The location of alpha helices and beta sheets in a polypeptide.

Tertiary protein structure

Structure created by disulfide bridges between cysteines that tie together different parts of a protein.

Quaternary protein structure

The number of polypeptide subunits that compose a protein.

Enzymes

Proteins that catalyze chemical reactions and lower activation energy, with names typically ending in -ase.

NADPH synthesis

Formed from $NADP^+$ plus $H^+$ plus $2\,e^-$ via reduction.

Visible light range

Wavelengths from $400\,nm$ to $700\,nm$, where light energy is higher for shorter wavelengths.

Granum

A stack of thylakoids within a chloroplast.

Light-dependent reactions

Photosynthetic reactions taking light and water in, and producing oxygen, ATP, and NADPH out.

Light-independent reactions

Photosynthetic reactions taking ATP, NADPH, and $CO_2$ in, and producing sugar out.

Calvin-Benson cycle components

Light-independent reactions involving RuBP (5 carbons), $CO_2$ (1 carbon), PGA (3 carbons), and PGAL (3 carbons).

PEPC

Abbreviation for PEP carboxylase.

Plasmodesmata

Microscopic channels through plant cell walls that allow transport and communication between adjacent cells.

Chloroplast

A double-membrane plastid containing chlorophyll where photosynthesis occurs.

Amyloplast

A non-pigmented plastid specialized for the synthesis and storage of starch granules.

Chromoplast

A plastid that synthesizes and stores carotenoid pigments, giving color to flowers, fruits, and autumn leaves.

Primary cell wall

A relatively thin, flexible wall layer secreted by young, growing plant cells.

Secondary cell wall

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

Suberin

A waxy, hydrophobic substance found in cork cell walls and the Casparian strip that acts as a water barrier.

Lignin

A complex polymer that stiffens and reinforces the secondary cell walls of vascular plant tissues.

Dermal tissue system

The outer protective covering of plants, originating from the protoderm.

Vascular tissue system

The transport tissue system consisting of xylem and phloem, originating from the procambium.

Ground tissue system

Tissue system originating from ground meristem that functions in storage, photosynthesis, support, and secretion.

Parenchyma

Versatile plant tissue composed of thin-walled, living cells involved in photosynthesis, storage, and tissue repair.

Collenchyma

Support tissue composed of elongated living cells with unevenly thickened primary cell walls, providing flexible support to growing shoots.

Sclerenchyma

Rigid plant tissue with thick, lignified secondary walls that provides structural support, typically dead at maturity.

Sclereid

A short, irregularly shaped sclerenchyma cell with thick, lignified secondary walls.

Fiber

A long, slender sclerenchyma cell that occurs in strands or bundles to provide flexible strength.

Xylem

Vascular tissue responsible for conducting water and dissolved minerals upward from roots to the rest of the plant.

Phloem

Vascular tissue responsible for conducting organic nutrients, particularly sugars, throughout the plant body.

Tracheid

A tapered, water-conducting xylem cell found in all vascular plants that lacks open perforations.

Vessel element

A wide, tube-like xylem cell aligned end-to-end with perforated end plates, characteristic of angiosperms.

Sieve tube element

An elongated phloem cell lacking a nucleus at maturity that forms continuous tubes for sugar transport.

Companion cell

A specialized parenchyma cell connected to a sieve-tube element that manages its metabolic functions and loading/unloading.

Axillary bud

A structure located in the axil of a leaf that has the potential to form a lateral branch or flower.

Terminal bud

The bud located at the tip of a stem, responsible for primary stem elongation.

Node

The point on a plant stem where leaves, buds, or branches originate.

Internode

The region of a stem located between two successive nodes.

Petiole

The stalk that attaches a leaf blade to the stem node.

Alternate leaf arrangement

A phyllotaxy pattern where only one leaf is attached at each stem node.

Opposite leaf arrangement

A phyllotaxy pattern where two leaves arise directly across from each other at the same stem node.

Whorled leaf arrangement

A phyllotaxy pattern where three or more leaves are attached at a single stem node.

Simple leaf

A leaf with an undivided blade attached to a single petiole.

Compound leaf

A leaf whose blade is completely divided into distinct leaflets.

Palisade mesophyll

Upper layer of leaf mesophyll consisting of column-like cells specialized for light absorption during photosynthesis.

Spongy mesophyll

Lower layer of leaf mesophyll containing loosely packed, irregularly shaped cells with air spaces for gas exchange.

Guard cells

Pairs of specialized epidermal cells that control the opening and closing of stomata.

Cuticle

A waxy layer secreted on the outer surface of the epidermis that reduces water loss.

Trichome

A hair-like outgrowth on the plant epidermis that deters herbivores, regulates heat, or secretes compounds.

Tendril

A modified slender leaf or stem structure used by climbing plants to cling to support structures.

Spine

A modified, sharp leaf structure that protects the plant from herbivory and reduces surface area for water transpiration.

Cotyledon

An embryonic leaf present within a seed that often stores or absorbs food reserves for seedling growth.

Monocot stem vascular arrangement

Cross-sectional arrangement where vascular bundles are scattered randomly throughout the ground tissue.

Eudicot stem vascular arrangement

Cross-sectional arrangement where vascular bundles are arranged in a distinct outer ring separating cortex and pith.

Cortex

The outer region of stem or root ground tissue located between the epidermis and the vascular cylinder.

Pith

The central core of ground tissue in stems or roots, internal to the vascular tissue.

SAM

Shoot apical meristem; a region of dividing undifferentiated cells located at shoot tips responsible for primary stem growth.

RAM

Root apical meristem; a region of dividing undifferentiated cells located at root tips responsible for primary root elongation.

Thorn

A modified, sharp branch or stem structure that acts as a physical defense mechanism.

Tuber

A swollen underground modified stem used for nutrient storage and vegetative propagation.

Root cap

A protective structure covering the tip of a root that shields the root apical meristem and secretes mucilage.

Root hair

A tubular outgrowth of a root epidermal cell that increases surface area for water and mineral absorption.

Endodermis

The innermost cell layer of the root cortex surrounding the vascular cylinder that regulates entry of substances into xylem.

Pericycle

The cell layer located inside the endodermis from which lateral roots originate.

Casparian strip

A suberin-containing waterproof band surrounding endodermal cell walls that forces water through the symplast.

Apoplast route

Water and solute movement through non-living spaces such as cell walls and extracellular spaces.

Symplast route

Water and solute movement through the continuous cytoplasm of adjacent cells linked via plasmodesmata.

Vascular cambium

A lateral meristem that produces secondary xylem (wood) inward and secondary phloem outward.

Bark

All tissues external to the vascular cambium in woody stems, comprising secondary phloem and periderm.

Heartwood

Older, non-functional inner secondary xylem that accumulates resins and provides structural support.

Sapwood

Active, functional outer secondary xylem that conducts water and dissolved nutrients.

Periderm

The protective outer covering of woody plants replacing epidermis, composed of cork cambium, phelloderm, and cork.

Osmosis

Diffusion of water from a higher water potential to a lower water potential across a selectively permeable membrane.

Chemiosmosis

Diffusion of $H^+$ ions down an electrochemical gradient across a membrane to generate ATP via ATP synthase.

Water potential

The physical property predicting the direction water flows, measured in megapascals ($MPa$).

Turgid

The firm, swollen condition of a plant cell when water enters by osmosis and creates internal hydrostatic pressure.

Plasmolysis

The shrinking of the plant cell membrane away from its cell wall when placed in a hypertonic solution.

Role of $K^+$ in guard cells

Influx of $K^+$ lowers solute potential, prompting osmotic water movement into guard cells to open the stoma.

Pressure flow model

Mechanism of phloem transport driven by osmotic pressure differences created between sugar sources and sugar sinks.

HONCP

Acronym for the common valences in biomolecules: 1 bond for H, 2 for O, 3 for N, 4 for C, and 5 for P.

Primary protein structure

The linear sequence of amino acids in a polypeptide chain from the amino terminus to the carboxy terminus.

Secondary protein structure

Localized folding patterns within a polypeptide chain, specifically alpha helices and beta sheets.

Tertiary protein structure

The three-dimensional conformation of a single polypeptide created by side-chain interactions and covalent disulfide bridges between cysteines.

Quaternary protein structure

The overall protein structure formed by the assembly of multiple individual polypeptide subunits.

Enzymes

Biological catalysts made of protein that lower the activation energy required for chemical reactions.

Visible light range

Light wavelengths between $400\,nm$ and $700\,nm$ that drive photosynthetic processes.

Granum

A stack of disc-shaped thylakoid membranes within a chloroplast.

Stroma

The fluid-filled interior space of a chloroplast surrounding the thylakoid system where light-independent reactions occur.

Light-dependent reactions

Photosynthetic processes occurring in thylakoid membranes that absorb light energy and water to produce oxygen, ATP, and NADPH.