Transport in Cells

  • Transport in cells refers to the movement of materials into, out of, and within cells. This includes the movement of water, ions, and other substances like glucose and amino acids.
  • Transport can be either passive (not requiring energy) or active (requiring energy).


  • Diffusion is a passive form of transport, moving substances from a region of high concentration to an area of low concentration until a balance is achieved, also known as equilibrium.
  • The rate of diffusion depends on temperature, concentration gradient, and the surface area to volume ratio of the diffusing substance.


  • Osmosis is a specific kind of diffusion and involves the movement of water molecules.
  • In osmosis, water moves from an area of high water potential (or low solute concentration) to an area of low water potential (or high solute concentration).
  • The rate of osmosis is affected by the concentration gradient, temperature and surface area to volume ratio.

Active Transport

  • Active transport is the transfer of ions or molecules across a cell membrane from an area of lower concentration to an area of higher concentration.
  • It requires energy in the form of ATP because it is moving substances against the concentration gradient.
  • Active transport enables cells to absorb ions from very dilute solutions, an essential mechanism in plants for obtaining nutrients from the soil.

Transport in the Human Body

  • The human body uses a circulatory system for transportation of substances.
  • Blood transports nutrients, oxygen, carbon dioxide, hormones, and heat around the body.
  • The heart pumps the blood, and the blood vessels (arteries, veins, and capillaries) serve as the transport routes.
  • Arteries carry blood away from the heart, veins bring blood back to the heart, and capillaries connect arteries and veins.

Transport in Plants

  • In plants, the xylem and phloem play crucial roles in transport.
  • Xylem moves water and dissolved minerals from the roots to other parts of the plant.
  • Phloem transports sugars, amino acids, and other organic products from leaves (where photosynthesis takes place) to other parts of the plant.

Hope this helps you in revising the topic of “Transport” for your Structure and Functions in Living Organisms module!