Question

explain: cell transport
complete the chart after completing the scenarios.
comparing types of transport across the plasma membrane
diffusion
osmosis
facilitated diffusion
pumps
endocytosis
exocytosis

Explanation:

• Diffusion: Passive transport (no energy - ATP needed), moves with concentration gradient (from high to low), small non - polar molecules (e.g., oxygen). Molecules spread out due to random motion.
• Osmosis: Passive transport (water movement), with concentration gradient (of water), water (small molecule). Movement of water across a semi - permeable membrane.
• Facilitated Diffusion: Passive transport (uses protein channels/carriers but no ATP), with concentration gradient, can be small polar (e.g., glucose) or ions. Protein - mediated movement down the gradient.
• Pumps (Active Transport): Active transport (requires ATP), against concentration gradient, small molecules (e.g., sodium - potassium pump moves ions). Uses energy to move molecules up the gradient.
• Endocytosis: Active transport (requires energy for membrane invagination), can be with or against (if receptor - mediated) for specific molecules, large molecules/particles. Cell membrane engulfs substances.
• Exocytosis: Active transport (energy for vesicle fusion), can be regulated (e.g., secretion of hormones), large molecules (e.g., proteins). Vesicle fuses with membrane to release contents.

Answer:

Type of Transport	Passive or active transport?	Requires energy (ATP)?	With or against concentration gradient?	Moves small or large molecules?	Description
Osmosis	Passive	No	With (of water)	Small (water)	Movement of water across a semi - permeable membrane
Facilitated Diffusion	Passive	No	With	Small (polar or ions)	Protein - mediated movement down the concentration gradient
Pumps	Active	Yes	Against	Small	Energy - driven movement of molecules up the concentration gradient
Endocytosis	Active	Yes	Varies (if receptor - mediated can be specific)	Large	Cell membrane engulfs substances
Exocytosis	Active	Yes	Varies (regulated secretion)	Large	Vesicle fuses with membrane to release contents