Question

1. how is facilitated diffusion different from regular diffusion?
2. what type of proteins assist with moving water through the cell membrane during osmosis?
3. what does active transport require?
4. what do pumps force molecules to do?
5. what is bulk transport used for?
6. summarize the following processes of endocytosis.

a. phagocytosis:
b. pinocytosis:
c. receptor - mediated endocytosis:

1. what is one similarity and one difference between endocytosis and exocytosis?

Explanation:

1. Facilitated diffusion uses transport proteins (channels or carriers) to move substances across the membrane, while regular diffusion is the passive movement of substances directly through the lipid - bilayer down their concentration gradient without the help of proteins.
2. Aquaporins are the type of proteins that assist with moving water through the cell membrane during osmosis.
3. Active transport requires energy, usually in the form of ATP, to move substances against their concentration gradient.
4. Pumps force molecules to move against their concentration gradient, from an area of lower concentration to an area of higher concentration.
5. Bulk transport is used for the movement of large amounts of substances (such as macromolecules and particles) in or out of the cell.

19a. Phagocytosis is the process by which a cell engulfs large particles or whole cells, like bacteria or dead cells, by extending pseudopods around the particle and enclosing it in a phagosome.
19b. Pinocytosis is the non - specific uptake of extracellular fluid and dissolved solutes by the cell, forming small vesicles.
19c. Receptor - mediated endocytosis is a specific type of endocytosis where molecules (ligands) bind to specific receptors on the cell surface, leading to the formation of coated vesicles that internalize the ligand - receptor complexes.

1. Similarity: Both endocytosis and exocytosis are forms of bulk transport and involve the formation of vesicles. Difference: Endocytosis brings substances into the cell, while exocytosis releases substances out of the cell.

Answer:

1. Facilitated diffusion uses transport proteins; regular diffusion doesn't.
2. Aquaporins.
3. Energy (usually ATP).
4. Move against their concentration gradient.
5. Movement of large amounts of substances.

19a. Engulfment of large particles/whole cells.
19b. Non - specific uptake of extracellular fluid.
19c. Internalization of ligand - receptor complexes.

1. Similarity: Both are bulk transport, involve vesicles. Difference: Endocytosis brings in; exocytosis releases out.