achene
A one-seeded dry indehiscent fruit that is held freely within the pericarp.
adenosine triphosphate (ATP)
A nucleotide found in the mitochondria of a cell and the principle source of energy for cellular reactions.
adventitious
Growing from an unusual place, as in plant roots that grow from stems or leaves.
angiosperm
A flowering plant that has seeds enclosed in fruit.
anther
The part of the stamen of a flower that produces pollen.
autotroph
An organism that uses the process of photosynthesis to make its own food.
berry
A fruit with fleshy walls (pericarps), without a stone, and often with a number of seeds, such as grapes or oranges.
capsule
A dry dehiscent fruit that splits open to release seeds and comes from flowers that had many pistils.
caryopsis
A dry indehiscent fruit in which seeds are firmly attached to the fruit wall.
cell
The basic unit of a plant that contains many different organelles (structures) that drive plant processes.
cellulose
Polysaccharide material that makes cell walls.
chlorophyll
A green pigment located in the chloroplasts of plant cells that is a receptor of light energy in the red and blue wavelengths.
chloroplast
A plastid that contains chlorophyll and is the site where photosynthesis occurs.
chromoplast
A pigmented plastid that contains carotenoids. The chromoplasts are often responsible for the saturated yellow, orange, and red colors found in flowers, aging leaves, fruit, and some roots such as carrots.
collenchyma
Plant tissue that has thickened cell walls made of cellulose and that provides support and minimizes breakage.
cortex
Plant tissue of the outer layers of plant stems and roots.
cytoplasm
Part of a cell that surrounds the organelles and nucleus and contains amino acids, sugars, enzymes, and waste products (on their way to disposal).
cytoskeleton
Protein filaments and motor proteins in the cell, composed of three major structural fibers: microtubules, microfilaments (also called actin filaments), and intermediate filaments.
dehiscent
A type of fruit that will split open at maturity and freely release seeds for dispersal.
deoxyribonucleic acid (DNA)
A substance in cells that contains a plant’s genetic material and provides genetic information to ribonucleic acid (RNA).
drupe
A fruit with a fleshy, soft mesocarp and a seed enclosed by a hard, stony endocarp.
endoplasmic reticulum (ER)
A complex, folded membrane system that provides a channel for transporting proteins and lipids in the cell.
epidermis
Cells that cover the outside areas of a plant and protect the plant from environmental stresses, minimize water loss, and provide a site for gas exchange.
filament
A thin stalk in the stamen of a flower that supports the anther.
follicle
A dry dehiscent fruit that splits along the length of the fruit releasing seeds for dispersal.
Golgi bodies
Cell organelles that control the flow of molecules in the cell, modifying some before packaging them into vesicles for transport to other parts of the cell or for excretion outside the cell.
guard cell
Specialized epidermal plant cells around pores that open to allow for gas exchange and control water loss.
gymnosperm
A nonflowering plant with seeds that develop without an ovary.
hetrotroph
An organism that uses external sources of food or energy.
indehiscent
A type of fruit that keeps the seeds within the fruit walls after leaving the parent plant.
inflorescence
Clusters of single flowers gathered on a stem.
internodes
The spaces between nodes.
leaf mesophyll
Plant tissue that makes up the internal layers of leaves.
legume
A dry, dehiscent pod that opens along two seams at maturity.
leucoplast
A colorless plastid that performs functions such as synthesizing starch and forming oils and proteins.
lysosome
Digestive system in the cell, uses enzymes to break down large molecules like proteins, polysaccharides, lipids, and nucleic acids.
meristematic
Least differentiated cells that are responsible for cell formation and growth.
mitochondria
The parts of a cell that drive the process of respiration and energy transfer.
nodes
The places on a plant stem where leaves develop.
nucleolus
A part of the cell nucleus that is responsible for the formation of ribosomes.
nucleus
A large organelle found in a plant cell that contains the plant’s genetic material. Two primary functions of the nucleus are to control cellular activities by determining when and which proteins are produced and to store the cell’s genetic information and pass this information on through cellular division. The nucleus contains deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
nut
A dry, indehiscent fruit that has a hardened pericarp with a loose seed inside.
oil bodies
Lipid droplets, spherical in nature, that are found throughout cells in the plant and are most concentrated in fruits and seeds.
parenchyma
Plant tissue that is made up of the vascular tissue of the cortex (outer layers), pith (inner layers) of stems and roots, and leaf mesophyll (internal layers of leaves).
periderm
The outside cell layer in woody plants that provides protection and prevents water loss.
petal
A modified leaf that surrounds the female and male reproductive parts of a flower.
phloem
A modified leaf that surrounds the female and male reproductive parts of a flower.
pistil
The female organs of a flower that include the stigma, style, and ovary.
pith
The inner layer of plant tissue of stems and roots.
plasma membrane
Permeable layer inside the cell wall that controls what substances enter or leave the cell.
plastid
An organelle that contains food or pigment.
pome
A fruit with a tough endocarp that encloses the seeds.
ribonucleic acid (RNA)
A substance that manufactures proteins based on the genetic information provided by DNA and plays a significant role in gene expression.
ribosome
Consists of ribosomal RNA (rRNA) and protein and is actively involved in the synthesis of proteins.
samara
A dry indehiscent fruit in which part of the fruit wall is extended to form a wing.
schizocarp
A dry indehiscent fruit that splits at maturity into two or more seeded parts. It is found in the carrot family.
sclerenchyma
Plant cells that have thick, lignified walls that provide physical strength and support to stems, especially in woody plants.
sepal
A modified leaf that surrounds and protects a flower bud.
silique
A dry dehiscent fruit with a seedpod that splits along two sides while the seed inside remains attached to part of the fruit structure.
stamen
The male portion of the flower that contains the anther and the filament.
stomata
Pores in epidermal plant cells that open to allow for gas exchange and control water loss.
Stroma
The aqueous space outside the stacks of thylakoids.
thylakoid
A disc-shaped sac surrounded by membranes on which the light reactions of photosynthesis take place.
tonoplast
A permeable membrane that surrounds the vacuole and regulates the entrance and exit of cell sap, waste products, pigments, and other liquids.
turgor
The pressure within a plant cell that helps provide rigidity and support to plant structures.
vacuole
A large cavity found within plant cells that stores cell sap, waste products, pigments, or other liquids.
xylem
Plant tissue that conducts water and nutrients from the roots throughout the plant and can provide structural support to the plant.