Question

Describe the cellular transport methods that the cell membrane uses to move material

in and out of the cell. (Use the following terms: active transport, passive transport,
osmosis, diffusion, endocytosis, exocytosis, ion pumps plasma membrare.

Answer 1

Step-by-step explanation:

Diffusion

• Molecules move in a random, continual motion and in any direction in a given space. As a result, molecules will move from an area of high concentration to an area of low concentration.
• The concentration gradient is eliminated as diffusion continues (net diffusion).
• As the molecules move in a particular space, they become evenly distributed and reach equilibrium.

Osmosis

• Osmosis occurs across a selectively permeable membrane (like the cell membrane).
• Water moves through the membrane but not solutes (e.g., sodium).
• Water flows across the membrane to the solution that has more solutes.
• Water flows across a membrane because that is where the concentration of water is the lowest.
• The higher the osmolarity of a solution (the more molecules contained in the solution), the lower the water concentration.

Active Transport

• Ion pumps are active transporters.
• Ion pumps move different ions across the cell membrane.
• Ion pumps may move one kind of ion or the pumps may move more than one kind of ion.
• Ions are moved against the concentration gradient. Example: The sodium-potassium exchange pump is a primary active transporter, where three sodium ions are moved out of the cell for every two potassium ions that are moved inside the cell.
• ATP is required.

Passive Transport

• Ions and molecules move from an area of higher concentration to an area of lower concentration.
• ATP is not required for this transport.
• Examples of passive transport include osmosis and simple and facilitated diffusion.

Endocytosis

• Moving materials outside of the cell to the inside of the cell.
• Fluid cytosis (or pinocytosis) is the formation of small vesicles that are filled with fluid that may contain lipids, sugars, or amino acids. The vesicles pinch off from the cell membrane, fuse with a lysosome, and the contents enter the cytoplasm.
• The contents are released into the cytoplasm.

Exocytosis

• This process if the reverse of endocytosis.
• A vesicle is created in the cell. The vesicle fuses with the cell membrane and discharges the contents to the outside of the cell.