Question

question 18 (1 point)
which mechanism requires energy?
o a facilitated diffusion
b osmosis
o c diffusion
d active transport

question 19 (1 point)
if someone spills perfume in the room, people all over the room will soon be able to smell it. this is an example of:
o a diffusion
o b active transport
o c osmosis
d facilitated diffusion

Explanation:

• Question 18:
• Facilitated diffusion is a type of passive transport where molecules move across the cell membrane via special transport proteins. It does not require energy as it moves along the concentration gradient.
• Osmosis is the movement of water molecules from an area of higher water concentration to an area of lower water concentration across a semi - permeable membrane. It is a passive process and does not need energy.
• Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. It is a passive process and does not require energy.
• Active transport is the movement of molecules against the concentration gradient (from low to high concentration). This process requires energy (usually in the form of ATP) to move the molecules.
• Question 19:
• Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. When perfume is spilled, the perfume molecules (which are in higher concentration near the spill) move to areas of lower concentration (all over the room) so that people can smell it.
• Active transport requires energy and is against the concentration gradient, which is not the case here as the perfume is spreading out (down the concentration gradient).
• Osmosis is specifically about water movement, and this is about perfume (a solute in a gas, air).
• Facilitated diffusion requires transport proteins and is for specific molecules (usually in a cell - membrane context), which is not relevant for perfume spreading in a room.

Answer:

• Question 18: d. active transport
• Question 19: a. diffusion