Biology Chapter 3B - 2 Cellular transport

Explain the difference between simple diffusion and passive mediated transport?

In diffusion the molecules are moving from greater concentration to lesser concentration with the concentration gradient. Passive mediated transport is the movement of molecule with the concentraion gradient but a membrane transport protein helps the molecule cross by either a protein channel or a carrier protein.

passive mediated transport

the movement of molecules across cellular membranes without the expenditure of cellular energy but with the help of a membrane transport protein.

exocytosis

the process by which the cell releases the contents of vacuoles and vessicles outside the cell. The vacuole or vessicle fuses with the plasma membrane and releases its contents. Secretion is an example

phagocytosis

the process of a cell engulfing a substance and bringing it within the cell through a phagocytic vacuole. cellular eating

pinocytosis

the process of a cell taking in fluid by forming vesicles - cellular drinking

protein channel

tiny pores in the membrane that allow only certain substances through.

List and explain the difference between the two types of membrane transport proteins?

Carrier protein - binds to the molecules with a receptor site and then carries the molecule through the membrane. Protein channel - forms tiny pores or holes in the membrane through which specific substances pass. They can open and shut to allow only specific molecules through

Explain the similarities and differences between passive mediated transport and active transport?

Differences - In passive mediated transport no energy is used by the cell and the molecules are moving with the concentration gradient. In active transport energy is required and the molecules are moving against the concentration gradient. Similarities - They both uses a helper protein to move the molecule. They both use a carrier protein that binds to the molecule and changes shape to move the molecule across the membrane.

Explain the process of endocytosis

Endocytosis is the process a cell uses to transport substances in bulk across the membrane. The plasma membrane folds inward until it completely surrounds the substance. Once the substance is completely surrounded, the membrane is pinched off into the inside of the cell. Phagocytosis and Pinocytosis are the two types of endocytosis.

carrier protein

a protein embedded in the cellular membrane that functions to transport specific molecules across the cellular membrane. The carrier protein binds with the molecule and changes shape to cross the membrane and then returns to its normal shape once the molecule is within the cell.

membrane transport protein

embedded proteins in the cellular membrane that help molecules cross the plasma membrane

endocytosis

is the process a cell uses to transport substances in bulk across the membrane using phagocytosis or pinocytosis.

passive transport

the movement of molecules across cellular membranes without the expenditure of cellular energy