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The transport of dissolved substances into cells.


The breakdown of absorbed substances.


The breakdown of food molecules with a release of energy.


The removal of soluble waste materials.


The removal of nonsoluble waste materials.


The release of biosynthesized substances.


Maintaining the status quo.


Producing more cells.


The study of cells.

Cell Wall

A rigid structure on the outside of certain cells, usually plant bacteria cells.

Middle Lamella

The thin film between the cell walls of adjacent plant cells.

Plasma Membrane

The semipermeable membrane between the cell contents and either the cell wall or the cells surroundings.


A jellylike fluid inside the cell in which the organelles are suspended.


Substances in which at least one atom has an imbalance of protons and electrons.

Cytoplasmic Streaming

The motion of cytoplasm in a cell that results in a coordinated movement of the cell's contents.


The organelles in which nutrients are converted to energy.


The organelles in animal cells responsible for hydroysis reactions that break down proteins, polysaccharides, disaccharides, and some lipids.


Non-membrane-bounded organelles responsible for protein synthesis.

Endoplasmic Reticulum

An organelle of an extensive network of folded membranes that performs several tasks within a cell.

Rough ER

ER that is dotted with ribosomes.

Smooth ER

ER that has no ribosomes.


Organelles that store starches or oil.


Organelles that contain pigments used in photosynthesis.

Central Vacuole

A large vacuole that rests at the center of most plant cells and is filled with a solution that contains a high concentration of solutes.

Waste Vacuoles

Vacuoles that contain the waste products of digestion.


The process by which a cell engulfs foreign substances or other cells.

Phagocytic Vacuole

A vacuole that holds the matter which a cell engulfs.

Pinocytic Vesicle

Vesicle formed at the plasma membrane to allow the absorption of large molecules.

Secretion Vesicle

Vesicle that holds secretion products so that they can be transported to the plasma membrane and released.

Golgi Bodies

The organelles where proteins and lipids are stored and then modified to suit the needs of the cell.


Spiral strands of protein molucules that form a tubelike structure.

Nuclear Membrane

A high-porous membrane that separates the nucleus from the cytoplasm.


Clusters of DNA, RNA and proteins in the nucleus of a cell.


A network of fibers that hold the cell together, helps the cell to keep its shape, and aids in movement.


Fine, thredlike proteins found in the cell's cytoskeleton.

Intermediate Filaments

Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments.


A lipid in which one of the fatty acid molecules has been replaced by a molecule that contains a phosphate group.

Passive Transport

Movement of molecules through the plasma membrane according to the dictates of smosis or diffusion.

Active Transport

Movement of molecules through the plasma membrane (typically opposite the dictates of osmosis or diffusion) aided by a process that requires energy.

Isotonic Solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution.

Hypertonic Solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution.


Collapse of a walled cell's cytoplasm due to a lack of water.


The rupuring of a cell due to excess internal pressure.

Hypotonic Solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution.

Activation Energy

Energy necessary to get a chemical reation going.

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