GCSE Biology (AQA)

331 videos | 14 hours

Multicellular Organisms

Please subscribe to watch this video.

This, and all other videos, are included in our premium subscriptions.

Premium accounts get access to all videos.

Cell Biology Transport in Cells

Multicellular Organisms

2:58 Diffusion in Action
Spec 4.1.3.1
Previous Single-Celled Organisms Next Diffusion in the Lungs
  • Multicellular organisms have smaller surface area to volume ratios compared to single-celled organisms.
  • Diagrams illustrate the difference in surface area to volume ratios between single-celled and multicellular organisms.
  • As organisms increase in size, their surface area to volume ratio decreases.
  • A lower surface area to volume ratio results in a reduced rate of diffusion.
  • Multicellular organisms cannot rely solely on diffusion for substance exchange like single-celled organisms.
  • Multicellular organisms require specialized exchange surfaces and transport systems to efficiently manage substance exchange and transport.
  • Examples of specialized exchange surfaces include alveoli in mammal lungs and leaves in plants.
  • Exchange surfaces are areas where substances are exchanged across membranes.
  • Specialized exchange surfaces and transport systems are necessary in both animals and plants due to their surface area to volume ratios and the requirements of diffusion.
  • Mammals have organ systems such as the respiratory, circulatory, and digestive systems to facilitate exchange and transport of substances.
  • In mammals, the respiratory system includes lungs where gas diffusion occurs in the alveoli, and the circulatory system includes the heart and blood vessels.
  • Plants also have specialized systems like the chute system, which includes leaves and stems for gas exchange, and roots for nutrient absorption from the soil.
  • The stem connects the root system to the chute system, facilitating transport throughout the plant.

Please subscribe to access these revision notes.

This, and all other video notes, are included in our premium subscriptions.

Premium accounts get access to all videos and revision notes.