AP BIOLOGY

Detailed explanation-1: -Passive transport requires no energy input, as compounds are able to move freely across the membrane based only on a favourable concentration gradient (Figure 1.11).

Detailed explanation-2: -Passive transport, most commonly by diffusion, occurs along a concentration gradient from high to low concentration. No energy is necessary for this mode of transport.

Detailed explanation-3: -Passive transport occurs when substances cross the plasma membrane without any input of energy from the cell. No energy is required because the substances are moving from an area where they have a higher concentration to an area where they have a lower concentration.

Detailed explanation-4: -There are two major ways that molecules can be moved across a membrane, and the distinction has to do with whether or not cell energy is used. Passive mechanisms like diffusion use no energy, while active transport requires energy to get done.

Detailed explanation-5: -area with lower concentration. The difference between the concentrations is called the “concentration gradient”. Diffusion goes down the gradient until an equilibrium is reached.