Biology: Chapter 7

Lysosome

A vesicle found in all animals cells and rarely in plant cells that contains digestive enzymes for breakdown of excess or worn out cellular substances.

Cell

Basic unit of structure and organization of all living organisms.

Dynamic equilibrium

Condition of continuous, random movement of particles but no overall change in concentration of materials.

Osmosis

Diffusion of water across a selectively permeable membrane.

Exocytosis

Energy-requiring process by which a cell expels wastes and secretes substances at the plasma membrane.

Endocytosis

Energy-requiring process by which large substances from the outside environment can enter a cell.

Active transport

Energy-requiring process by which substances move across the plasma membrane against a concentration gradient.

Golgi apparatus

Flattened stack of tubular membranes that modifies, sorts, and packages proteins into vesicles and transports them to other organelles or out of the cell.

Plasma membrane

Flexible, selectively permeable boundary that helps control what enters and leaves the cell.

Ribosome

Found in all cells, simple organelle that is the site of protein synthesis and helps to manufacture them.

Plasma Membrane

Found in all cells, the flexible boundary that controls the movement of substances into and out of the cell.

Endoplasmic reticulum

Highly folded membrane system in eukaryotic cells that is the site for ribosome attachment.

Cell wall

In plants, the rigid barrier that surrounds the outside of the plasma membrane, is made of cellulose, and provides support and protection to the cell.

Flagellum

Long, tail-like projection with a whiplike motion that helps a cell move through a watery environment.

Mitochondrion

Membrane-bound organelle that converts fuel into energy available to the rest of the cell.

Prokaryotic cell

Microscopic, unicellular organism without a nucleus or other membrane-bound organelles.

Centriole

Organelle that plays a role in cell division and is made of microtubules.

Facilitated diffusion

Passive transport of ions and small molecules across the plasma membrane by transport proteins.

Phospholipid bilayer

Plasma membrane layers composed of phospholipid molecules arranged with polar heads facing the outside and nonpolar tails facing the inside.

Cilia

Projections from cell surface that aid in locomotion and feeding; also used to sweep substances along surfaces and is found in some animal cells, protist cells, and prokaryotes.

Flagella

Projections that aid in locomotion and feeding found in some animal cells, prokaryotes, and some plant cells.

Selective permeability

Property of the plasma membrane that allows it to control movement of substances into or out of the cell.

Transport protein

Protein that moves substances or wastes through the plasma membrane.

Cytoplasm

Semifluid material inside the cell's plasma membrane.

Cilium

Short, hairlike projection that functions in cell movement.

Hypotonic solution

Solution that has a lower concentration of solute; more water outside of the cell than inside the cell, decreased.

Organelle

Specialized internal cell structure that carries out specific cell functions such as protein synthesis and energy transformation.

Cell theory

States that (1) organisms are made of one or more cells; (2) cells are the basic unit of life; and (3) all cells come only from other cells, passing copies of their genetic material on to their daughter cells.

Cytoskeleton

Supporting network of protein fibers that provide a framework for the cell within the cytoplasm. That is found in all eukaryotic cells.

Nucleus

The membrane-bound organelle known as the control center of the cell that contains coded directions for the production of protein and cell division and is found in all eukaryotic cells. (DNA)

Facilitated Diffusion

The movement of materials across the plasma membrane using proteins.

Diffusion

The movement of particles from an area of high concentration to an area of lower concentration.

Nucleolus

The site of ribosome production within the nucleus of eukaryotic cells.

Vacuole

A membrane bound vesicle for the temporary storage of materials such as foods, enzymes, and wastes. Found in all plant cells (1 large) and a few in rare animal cells.

Mitchocondrion

A membrane-bound organelle found in all eukaryotic cells that makes energy available to the rest of the cell.

Chloroplast

A double-membrane organelle found within thylakoids containing chlorophyll; where photosynthesis takes place. (capturing light energy and converts it to chemical energy through photosynthesis).

Fluid mosaic model

A plasma membrane with components constantly in motion, sliding past one another within the lipid bilayer.

Hypertonic solution

A solution having a higher concentration of solute than inside a cell, which shrinks or shrivels when water leaves the cell by osmosis, increased.

Isotonic solution

A solution with the same concentration of water and solutes as inside a cell, resulting in the cell retaining its normal shape because there is no net movement of water.

Golgi Apparatus

A flattened stack of tubular membranes found in all eukaryotic cells that modifies proteins and packages them for distribution outside the cell.

Endoplasmic Reticulum

A highly folded membrane that is found in all eukaryotic cells that is the site of protein synthesis.

Eukaryotic cell

Unicellular organism with membrane-bound nucleus and organelles; generally larger and more complex than a prokaryotic cell.