Osmosis and Diffusion Terms to Know
Test is tomorrow 11/11
 Prokaryotic cells- also known as prokaryote, a single celled an organism
that does not protect the DNA inside a nucleus. Example: Bacteria
 Eukaryotic Cells- cell containing a nucleus and other membrane bound
organelles. Found in multicellular organisms such as plants and animals
 Passive transport- the movement of substances across the cell membrane
WITHOUT the use of energy.
 Protein channels- Channels located within the cell membrane that help
move substances from one side of the membrane to the other
 Facilitated diffusion- the movement of substances across the cell
membrane with the help of protein channels
 Aquaporin- protein channel that allows water to travel from one side of the
membrane to the other.
 Osmosis- the movement of water across the cell membrane from an area of
high water concentration to an area of low water concentration
 Diffusion- the movement of substances such as gases, nutrients and ions
across the cell membrane from areas of high solute concentration to an
area of low solute concentration
 Concentration gradient- the gradual difference in concentration of a
dissolved substance between regions of high density to one of lower
density.
 Solute- The substance placed into a solvent. Such as salt, sugar, protein.
 Solvent- The fluid that the solute is placed or dissolved in. Such as water
 Solution- a mixture of two or more substances, or a mixture of a solute and
solvent. Such as salt water, sugar water, protein water
 Hypertonic solution- is a solution that has a higher concentration of solute
than the cell
 Hypotonic solution- is a solution with a lower concentration of solute than
the cell
 Isotonic solution- a solution that has an equal concentration of solute as
the cell
 Flaccid- drooping or inelastic through lack of water
 Plasmolysis- is the process where cells lose water in a hypertonic solution.
In plants this causes the cell membrane to pull away from the cell wall.
 Turgid-swollen or distended. The celery was extra crisp when the cell was
placed in pure water.
 Cell membrane- a selectively permeable membrane that surrounds the cell,
protects the cell by controlling what can go into or out of the cell
 Cell wall- a tough membrane surrounding plants and some bacteria. In
plants it is made of cellulose. The cell membrane lies just underneath the
cell wall in plants
 Plamodesmata- channels located in the cell wall that allow substance to
pass through the cell wall
 Active transport- movement of substances across a cell membrane using
energy. Usually active transport moves material from areas of low
concentration to areas of high concentration
 Exocytosis- is a process in which an intracellular vesicle (membrane
bounded sphere) moves to the plasma membrane and subsequent fusion
of the vesicular membrane and plasma membrane ensues.
 Endocytosis- is a form of active transport in which a cell transports
molecules (such as proteins) into the cell (endo- + cytosis) by engulfing
them in an energy-using process.
o Pinocytosis- cellular drinking
o Phagocytosis- cellular eating