BIO101 ‒ Topic 18: Transport in Plants and Animals
Course Code: BIO 101 ¦ Course Name: General Biology
© Lesuyai Organic Guides 2025 (Original ¦ Educational ¦ Professional ¦ Plagiarism-Free ¦ A4 Format)
18.1 Introduction to Transport in Living Organisms
All living organisms need to transport materials within their bodies to sustain life. Transport systems move
water, nutrients, gases, and waste products to and from cells. In unicellular organisms, materials move by
diffusion and osmosis, but in multicellular organisms, specialized transport systems are required because
diffusion alone is too slow for large bodies.
18.2 Importance of Transport Systems
• Supply of oxygen and nutrients to all cells.
• Removal of carbon dioxide and metabolic wastes.
• Distribution of hormones and regulatory substances.
• Maintenance of water balance and homeostasis.
• Support of growth and development.
18.3 Transport in Plants
Plants use two main vascular tissues for transport: xylem and phloem.
18.4 Mechanisms of Transport in Plants
1. Diffusion ‒ Movement of molecules from higher to lower concentration.
2. Osmosis ‒ Diffusion of water through a selectively permeable membrane.
3. Active Transport ‒ Movement of ions against the gradient using energy (ATP).
18.5 Water Transport in Plants
1. Absorption by root hairs through osmosis.
2. Ascent of Sap by cohesion and adhesion forces.
3. Transpiration Pull due to evaporation from leaves.
18.6 Transpiration
Loss of water vapor from plant leaves through stomata.
Importance: cooling, transport, maintaining turgor.
Factors: temperature, humidity, wind, light intensity.
18.7 Translocation (Transport of Food)
Phloem transports food from leaves to other parts; process is bidirectional and requires energy.
18.8 Transport in Animals
Animals require efficient transport of substances between organs via the circulatory system.
18.9 Components of the Circulatory System
Course Code: BIO 101 ¦ Course Name: General Biology
© Lesuyai Organic Guides 2025 (Original ¦ Educational ¦ Professional ¦ Plagiarism-Free ¦ A4 Format)
18.1 Introduction to Transport in Living Organisms
All living organisms need to transport materials within their bodies to sustain life. Transport systems move
water, nutrients, gases, and waste products to and from cells. In unicellular organisms, materials move by
diffusion and osmosis, but in multicellular organisms, specialized transport systems are required because
diffusion alone is too slow for large bodies.
18.2 Importance of Transport Systems
• Supply of oxygen and nutrients to all cells.
• Removal of carbon dioxide and metabolic wastes.
• Distribution of hormones and regulatory substances.
• Maintenance of water balance and homeostasis.
• Support of growth and development.
18.3 Transport in Plants
Plants use two main vascular tissues for transport: xylem and phloem.
18.4 Mechanisms of Transport in Plants
1. Diffusion ‒ Movement of molecules from higher to lower concentration.
2. Osmosis ‒ Diffusion of water through a selectively permeable membrane.
3. Active Transport ‒ Movement of ions against the gradient using energy (ATP).
18.5 Water Transport in Plants
1. Absorption by root hairs through osmosis.
2. Ascent of Sap by cohesion and adhesion forces.
3. Transpiration Pull due to evaporation from leaves.
18.6 Transpiration
Loss of water vapor from plant leaves through stomata.
Importance: cooling, transport, maintaining turgor.
Factors: temperature, humidity, wind, light intensity.
18.7 Translocation (Transport of Food)
Phloem transports food from leaves to other parts; process is bidirectional and requires energy.
18.8 Transport in Animals
Animals require efficient transport of substances between organs via the circulatory system.
18.9 Components of the Circulatory System
