Diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans for several reasons:


In multicellular organisms, cells are often located far away from the external environment where oxygen is available. Diffusion is an effective method for transporting substances only over short distances. As the size of an organism increases, the distance between its cells and the external environment also increases, making DiffusionDiffusion is the movement of particles from an area where they are more concentrated to an area where they are less concentrated. This process, which happens randomly, is driven by differences in concentration, energy, or chemical potential. alone too slow to transport oxygen to all cells efficiently.

Volume-to-Surface Area Ratio

Multicellular organisms have a larger volume-to-surface area ratio. While the volume of the organism increases with size, the surface area does not increase at the same rate. This means there is less surface area available for diffusion relative to the volume that requires oxygen.

Energy Requirements

Larger organisms, like humans, have higher metabolic rates and thus higher oxygen and nutrient requirements. Diffusion is a passive process and is not efficient enough to transport the large amounts of oxygen needed quickly across the body.

Complex Body Structures

Multicellular organisms have complex body structures with specialized cells and tissues. These specialized structures, such as muscles and organs, require a direct and continuous supply of oxygen which cannot be met by simple diffusion.

Controlled Distribution

Organisms like humans need a regulated supply of oxygen to different parts of the body based on varying demands (e.g., more oxygen to muscles during exercise). Diffusion cannot selectively increase or decrease the supply to specific areas as needed.

Due to these limitations, multicellular organisms have evolved specialized respiratory and circulatory systems to efficiently transport oxygen and other essential nutrients throughout the body. In humans, this is achieved through the coordinated function of the respiratory system (lungs) and the circulatory system (heart and blood vessels).

Diffusion: An Overview from Tiwari Academy
Diffusion is a fundamental process involving the net movement of atoms, ions, molecules, or energy from an area of higher concentration to an area of lower concentration. It is driven by a gradient in Gibbs free energy or chemical potential and can occur in various contexts, including physics, chemistry, biology, and even in fields like sociology and finance. The concept is rooted in the idea that a substance or collection will spread out from a point of higher concentration.

A key aspect of diffusion is its dependence on the random walk of particles, leading to mixing or mass transport without the need for directed bulk motion. This contrasts with advection, where there is bulk flow due to a pressure gradient. Diffusion can be described by Fick’s laws if it follows normal (or Fickian) patterns; otherwise, it’s termed anomalous (or non-Fickian) diffusion.

Diffusion is not just limited to the movement of particles; it also includes the spread of ideas, data, and even price values in various fields. The process is essential in many natural phenomena and technological applications, from the diffusion of oxygen into blood in human lungs to the spread of innovations in a population.

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List of Questions of Class 10 Science Chapter 5

Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
What criteria do we use to decide whether something is alive?
What are outside raw materials used for by an organism?
What processes would you consider essential for maintaining life?
What are the differences between autotrophic nutrition and heterotrophic nutrition?
Where do plants get each of the raw materials required for photosynthesis?
What is the role of the acid in our stomach?
What is the function of digestive enzymes?
How is the small intestine designed to absorb digested food?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
How is oxygen and carbon dioxide transported in human beings?
How are the lungs designed in human beings to maximise the area for exchange of gases?
What are the components of the transport system in human beings?
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
What are the components of the transport system in highly organised plants?
How are water and minerals transported in plants?
How is food transported in plants?
Describe the structure and functioning of nephrons.
What are the methods used by plants to get rid of excretory products?
How is the amount of urine produced regulated?
How are fats digested in our bodies? Where does this process take place?
What is the role of saliva in the digestion of food?
What are the necessary conditions for autotrophic nutrition and what are its byproducts?
What are the differences between aerobic and anaerobic respiration?
How are the alveoli designed to maximise the exchange of gases?
What would be the consequences of a deficiency of haemoglobin in our bodies?
Describe double circulation of blood in human beings. Why is it necessary?
What are the differences between the transport of materials in xylem and phloem?
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Last Edited: November 16, 2023