The direction of water movement into or out of a cell can have dire consequences on the
survival of a cell.
By knowing the concentrations of solute and solvent on the inside and outside of a cell,
we can predict the direction of osmosis and
There are hundreds of examples of these special proteins which are very specific (like
enzymes) and change shape in order to allow the passage of certain substances into or out
of the cell.
Although facilitated diffusion is *fast and *spec
Note that we are describing the solute concentration outside the cell relative to the solute
concentration inside the cell.
Solute and solvent concentrations can be expressed as percentages of the entire solution.
When added together,
Plant cells wouldn't generally burst thanks to their protective cell walls. In fact, most
cells in large organisms are not in contact with fresh water on a regular basis - rather, they
tend to be bathed in blood or other *isotonic fluids which
We will consider each major structures of eukaryotic plant and animal cells (some of
which are found in prokaryotic cells) one by one.
Because these structures act like specialized organs, they are called *organelles, literally
Lysosomes are the clean up crew, they take care of junk removal!
Lysosomes are small organelles (membrane-bound sacs) filled with enzymes. They are
found in the cytoplasm of all animal cells, but are rare in plant cells. (plant cells store
the membrane of the vacuole surrounding the material fuses with the cell membrane ,
forcing the contents out of the cell.
Ex) contractile vacuoles in unicellular freshwater protists help rid them of excess water
The cell theory states:
Eukaryotic cells are generally *larger and *more complex than prokaryotic cells.
Eukaryotes display great variety. Some, like the protists, live solitary lives as *unicellular
organisms. Others form large multicellular organisms (ex. Plan
Most of the time, it is spread throughout the nucleus in the form of chromatin (a complex
of dna bound to proteins), but when a cell divides this condenses into chromosomes
which can be seen under a microscope.
The nucleus usually contains one o
The exact way in which large molecules or even clumps of material move across the cell
membrae depends on the size and shape of the material being moved into or out of the
Due to the large changes made to the cell membrane, this is al