Chapter 7 Section 3 Cell Boundaries Biology pgs. 182-189

Objectives Identify Describe Explain _____________________the main functions of the cell membrane and the cell wall ________________ what happens during diffusion _____________________ the processes of osmosis, facilitated diffusion, and active transport. Describe Explain

Membranes Cell membrane Cell wall All cells are surrounded by a _____________________. Many cells also produce a strong supporting layer around the membrane known as a __________________ Cell walls are found in plants, algae, fungi, and many prokaryotes. Cell membrane Cell wall

Cell Membrane Outside of cell Carbohydrate chains Proteins The cell membrane regulates what enters and leaves the cell. Inside of cell (cytoplasm) Protein channel Lipid bilayer Copyright Pearson Prentice Hall

Cell Membrane Lipid bilayer The composition of nearly all cell membranes is a double-layered sheet called a _________________. Lipid bilayer The cell membrane regulates what enters and leaves the cell. Lipid bilayer Copyright Pearson Prentice Hall

Diffusion Through Cell Boundaries Particles in a solution tend to move from an area where they are more concentrated to an area where they are less concentrated. This process is called _________________. diffusion

Osmosis is the diffusion of water. When concentrations of solutions are the same on both sides it is _______________. Isotonic

hypertonic A _________________ environment means a higher concentration of solutes outside the cell. Water will move out of the cell. A ___________________ environment has a lower concentration of solutes. Water will move into the cell. hypotonic

Facilitated diffusion The movement of specific molecules across cell membranes through protein channels is known as _________________________. Facilitated diffusion

Active transport energy Active Transport Sometimes cells move materials in the opposite direction. This process is known as _______________________. Active transport requires _____________or ATP. Active transport energy

endocytosis exocystosis _________________________ is the process of taking material into the cell by means of infoldings, or pockets, of the cell membrane. During _______________________, the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell. exocystosis