AP BIOLOGY

Detailed explanation-1: -There is a form of passive transport called facilitated diffusion. It occurs when molecules such as glucose or amino acids move from high concentration to low concentration facilitated by carrier proteins or pores in the membrane.

Detailed explanation-2: -There are two main modes of transport of molecules across any biological membrane. These are passive and active transport. 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: -Diffusion is a type of passive transport, where molecules move from high concentration to low concentration. This means that the concentration of oxygen in the air must be higher than it is in the blood. The concentration of carbon dioxide is also different between the alveolar air and the blood of the capillary.

Detailed explanation-4: -In passive transport, substances simply move from an area of higher concentration to an area of lower concentration, which does not require the input of energy. Concentration gradient, size of the particles that are diffusing, and temperature of the system affect the rate of diffusion.

Detailed explanation-5: -Passive transport does not require the cell to expend any energy and involves a substance diffusing down its concentration gradient across a membrane.