Question

active transport

1. does active transport move molecules down the concentration gradient or against the concentration gradient?
2. does active transport require energy?

3.
what process is shown in figure a?
what process is shown in figure b?

1. what is the difference between endocytosis and exocytosis?

Explanation:

1. Active transport moves molecules against the concentration gradient. This is because it goes from an area of lower concentration to an area of higher concentration.
2. Active transport requires energy. It uses ATP to move substances across the cell - membrane against the concentration gradient.
3. Figure A shows facilitated diffusion. It involves the movement of molecules through transport proteins in the cell - membrane down the concentration gradient. Figure B shows exocytosis. It is the process by which a cell releases substances out of the cell by fusing a vesicle with the cell - membrane.
4. Endocytosis is the process of taking substances into the cell by forming a vesicle from the cell - membrane. Exocytosis is the opposite, where substances are released from the cell by a vesicle fusing with the cell - membrane.

Answer:

1. Against the concentration gradient
2. Yes
3. Facilitated diffusion; Exocytosis
4. Endocytosis takes substances into the cell, exocytosis releases substances out of the cell.