Stern's Introductory Plant Biology - Ch. 3 - Basic Plant Structure

This vocabulary list covers all the key words in Stern's Introductory Plant Biology Ch. 3. This book is a scientific, reliable source that you can rely on. If you master this deck you will be an expert on the general plant body.

cell theory

a foundational principle in biology that states all plants are composed of one or more cells, the cell is the basic unit of structure, function, and organization in plants, and all cells arise only from pre-existing cells through the process of cell division.

prokaryotic cell

a simple cell type without a true nucleus or membrane-bound organelles, with DNA floating freely in the cytoplasm (example: bacteria).

eukaryotic cell

a complex cell with a true nucleus enclosed by a nuclear membrane and numerous membrane-bound organelles.

cell wall

a rigid outer layer surrounding plant cells, composed primarily of cellulose microfibrils along with pectin and lignin in some cases.

primary cell wall

thin, flexible wall formed first during cell growth, consisting mainly of cellulose and pectin.

secondary cell wall

is a thicker, stronger wall deposited inside the primary cell wall in mature cells, often containing lignin for added rigidity.

middle lamella

a pectin-rich layer that cements adjacent plant cell walls together.

plasma membrane

a semi-permeable phospholipid bilayer located just inside the cell wall that controls the movement of substances into and out of the cell.

cytoplasm

the jelly-like fluid inside the plasma membrane (excluding the nucleus) where most cellular organelles are suspended.

nucleus

the control center of the eukaryotic cell, a membrane-bound organelle containing the cell's DNA.

nucleolus

a dense, non-membrane-bound region inside the nucleus where ribosomal RNA is synthesized.

chromatin

Chromatin consists of DNA and associated proteins that make up chromosomes within the nucleus.

chromosome

a condensed structure of DNA and proteins that carries genetic information.

chloroplast

a green, membrane-bound organelle containing chlorophyll and its own DNA, serving as the site of photosynthesis.

thylakoid

flattened, membrane-bound sacs inside chloroplasts stacked into grana where the light-dependent reactions of photosynthesis occur.

granum

a stack of thylakoids within the chloroplast that increases surface area for light absorption.

stroma

the fluid-filled space surrounding the thylakoids inside the chloroplast where the light-independent reactions take place.

central vacuole

a large, fluid-filled sac that stores water, ions, wastes, pigments, and maintains turgor pressure.

tonoplast

the membrane surrounding the central vacuole that actively transports ions and molecules into or out of the vacuole.

turgor pressure

the outward pressure exerted by water against the cell wall due to water filling the central vacuole.

plasmodesmata

tiny cytoplasmic channels through adjacent cell walls that connect the cytoplasm of neighboring plant cells.

endoplasmic reticulum (ER)

an extensive network of interconnected membranes throughout the cytoplasm involved in the synthesis, folding, and transport of proteins and lipids.

rough ER(endoplasmic reticulum)

the portion of the ER(endoplasmic reticulum) studded with ribosomes on its surface, specializing in the synthesis and modification of proteins.

smooth ER(endoplasmic reticulum)

this organelle lacks ribosomes and functions in the synthesis of lipids, detoxification of harmful substances, and calcium ion storage.

Golgi apparatus

a stack of flattened membrane sacs that modifies, sorts, and packages proteins and lipids received from the ER.

vesicle

a small, membrane-bound sac that buds off from the ER or Golgi apparatus to transport proteins, lipids, or other materials.

mitochondrion

a double-membrane organelle that produces ATP through cellular respiration by breaking down glucose.

ribosome

a small organelle composed of RNA and proteins that serves as the site of protein synthesis.

cytoskeleton

an internal framework of microtubules, microfilaments, and intermediate filaments that provides structural support.

microtubule

a hollow, tube-like protein filament in the cytoskeleton that helps maintain cell shape and moves organelles.

microfilament

a thin, solid protein fiber in the cytoskeleton responsible for cell movement and changes in cell shape.

cytoplasmic streaming (cyclosis)

the continuous flowing movement of cytoplasm and organelles within the cell.