Question

during exocytosis, what happens to the vesicle within the cell?
a. it fuses with the cell membrane and releases its contents outside the cell.
b. it breaks down into smaller molecules.
c. it is engulfed by the cell membrane.
d. it stores waste products within the cell.

which of the following best describes simple diffusion?
a. the movement of molecules against their concentration gradient using energy
b. the movement of water molecules through a semi-permeable membrane
c. the engulfing of large particles by the cell membrane
d. the movement of small molecules from high to low concentration through the phospholipid bilayer

Explanation:

• For the first question (exocytosis):
• Exocytosis is a process where vesicles within the cell move to the cell membrane.
• The vesicle fuses with the cell membrane and releases its contents outside the cell.
• Option b (breaking down into smaller molecules) is not the process of exocytosis.
• Option c (engulfed by the cell membrane) is more related to endocytosis (the opposite process of exocytosis).
• Option d (storing waste) is not the function of exocytosis; exocytosis is about secretion.
• For the second question (simple diffusion):
• Option a (movement against concentration gradient using energy) is active transport.
• Option b (movement of water molecules through a semi - permeable membrane) is osmosis.
• Option c (engulfing large particles) is endocytosis.
• Simple diffusion is the movement of small, non - polar molecules (like oxygen, carbon dioxide) from an area of high concentration to an area of low concentration through the phospholipid bilayer.

Answer:

• First question: a. It fuses with the cell membrane and releases its contents outside the cell.
• Second question: d. The movement of small molecules from high to low concentration through the phospholipid bilayer.