Plant Cells and Tissues — Vocabulary

A set of vocabulary flashcards covering plant cell structure, function, and plant tissues.

Cell

The basic unit of life; the smallest unit that carries out life processes, bounded by a plasma membrane and containing cytoplasm and genetic material.

Cell Theory

Principle that all organisms are made of cells, the cell is the fundamental unit of life, and new cells arise from pre-existing cells.

Prokaryote

Organism lacking a nucleus and other membrane-bound organelles (e.g., bacteria and archaea).

Eukaryote

Organism with a nucleus and membrane-bound organelles; includes plants, animals, fungi, and protists.

Nucleus

Membrane-bound organelle containing DNA; site of transcription; contains a nucleolus and nuclear pores.

Endomembrane system

Interconnected membranes (ER, Golgi, vesicles) that exchange and modify materials inside the cell.

Rough Endoplasmic Reticulum (RER)

ER region studded with ribosomes; synthesizes proteins destined for secretion or membranes.

Smooth Endoplasmic Reticulum (SER)

ER region lacking ribosomes; synthesizes lipids and other non-protein molecules.

Ribosome

Molecular machine that synthesizes proteins using information from RNA; can be free-floating or attached to the ER.

Golgi apparatus

Organelle that modifies, sorts, and packages proteins and lipids; adds carbohydrates to molecules.

Plasma membrane

Phospholipid bilayer with embedded proteins; acts as a barrier and regulates material transport.

Cytoplasm

Interior of the cell (cytosol) containing organelles; provides structural support.

DNA/Genetic material

Genetic blueprint that directs synthesis of RNA and proteins; carries hereditary information.

Central Dogma

Flow of genetic information: DNA → RNA → Protein; DNA replication; reverse transcription occurs in some cases.

Chloroplast

Plastid containing chlorophyll; site of photosynthesis; contains its own DNA and ribosomes.

Plastids

Group of plant organelles including chloroplasts, chromoplasts, and amyloplasts; vary by function.

Cell wall

Rigid layer outside the plasma membrane in plants; mainly cellulose; primary is thin/elastic, secondary is lignified.

Primary cell wall

Thin, flexible cellulose-based layer formed during growth.

Secondary cell wall

Rigid, lignified layer deposited inside the primary wall; adds structural support and rigidity.

Central vacuole

Large membrane-bound organelle for storing water, ions, and nutrients; maintains turgor pressure.

Plasmodesmata

Channels through cell walls that connect plant cells and enable transport and communication.

Parenchyma

Most common plant cell type with thin walls and large central vacuole; metabolic roles and wound healing (totipotent).

Collenchyma

Supportive tissue with unevenly thickened primary walls; alive at maturity; flexible support for growing tissue.

Sclerenchyma

Rigid supportive tissue with thick lignified secondary walls; often dead at maturity; includes fibers and sclereids.

Xylem

Vascular tissue for water transport; composed of vessels, tracheids, and supporting fibers; often contains dead cells at maturity.

Phloem

Vascular tissue for transport of sugars and nutrients; includes sieve tubes and companion cells.

Epidermis

Outermost protective tissue layer; regulates gas exchange and protects against pathogens; includes guard cells and root hairs.

Guard cells

Specialized epidermal cells that regulate stomatal opening for gas exchange.

Mesophyll

Ground tissue in leaves specialized for photosynthesis; includes palisade and spongey forms.

Meristem

Region of actively dividing cells that produces new tissues and organs; sources of growth.

Apical meristem

Meristem at tips of roots and shoots; enables primary (length) growth.

Lateral meristem

Meristem responsible for secondary growth and girth increase (e.g., cambium).

Ground tissue

Plant tissue system that functions in metabolism, storage, and support; includes parenchyma, collenchyma, sclerenchyma.

Vascular tissue

Tissue system for transport; includes xylem (water) and phloem (sugars).

Dermal tissue

Outer protective tissue system; includes epidermis and associated structures.

Pith

Central region of many stems; part of ground tissue.