AP BIOLOGY

Detailed explanation-1: -Passive transport does not require the cell to expend any energy and involves a substance diffusing down its concentration gradient across a membrane.

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: -1 Lipid diffusion (simple diffusion) 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-4: -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.