Primary Science


Transport in Plants and Humans (Upper Block Science)

Welcome to the exciting world of transport in plants and humans!

From the tiniest cells to the most complex organisms, the ability to move nutrients and water is essential for survival. In this article, we will explore the similarities and differences between how plants and humans transport vital substances throughout their bodies. You will discover the amazing structures and mechanisms that enable plants to absorb water and nutrients from the soil and distribute them to different parts of their bodies. You will also learn how the human circulatory and digestive systems work together to transport oxygen, nutrients, and waste products throughout the body.

So, let’s dive right in and explore the world of transport systems (Upper Block Science)!


An Overview: Transport in Plants and Humans

Plant Transport System


The plant transport system consists of the food-carrying tubes (phloem) and the water-carrying tubes (xylem). You can find these two transport tubes in all parts of the plant. Yes, even the flowers, leaves, roots and stem!

The water-carrying tubes transport water and mineral salts from the roots to the rest of the plant.

The food-carrying tubes transport food (sugar/ glucose) made in the leaves (green parts) of the plant to all parts of the plant.

Image via Teachoo

Anyway, did you know that photosynthesis and respiration are two vital processes that are necessary for the survival of plants? Both rely on the plant transport system to move essential substances to where they are needed.

What is photosynthesis?

As humans, we rely on eating and drinking to obtain the energy and nutrients necessary for survival. However, unlike us, plants, algae, and some bacteria have the remarkable ability to produce their own food using light energy from the sun.

This process, known as photosynthesis, involves the conversion of light energy into chemical energy in the form of organic compounds, such as glucose. Photosynthesis is a vital process for these organisms, as it provides the energy they need to grow, develop, and reproduce, while also releasing oxygen into the environment, which is essential for the survival of many other organisms, including humans.

The formula for photosynthesis is: sunlight + water + carbon dioxide -> glucose + oxygen.

What is respiration?

Respiration is an essential process for the survival of living organisms. By breaking down food (glucose) as an energy source,  it provides the energy needed for all life functions.

This process involves the exchange of gases, specifically the intake of oxygen and the release of carbon dioxide. The plant’s vascular system transports oxygen that enters through tiny openings on the leaves’ surface (stomata).

The formula for respiration is: glucose + oxygen -> carbon dioxide + energy.

Human Transport System


In humans, we have a similar transport system known as the circulatory system.

It consists of the blood vessels, blood, and heart. Like delivery men, our red blood cells play a crucial role in this system. Its role is to transport important substances (including digested food, oxygen and carbon dioxide) throughout the body.

Image via Anonymous

The circulatory system works closely with the respiratory system. Together, these systems ensure that the body’s cells and tissues receive the necessary oxygen and nutrients to carry out their functions, while waste products are efficiently removed from the body.

How does the human circulatory system work?


When we inhale, our lungs will take in oxygen. The blood will pick up the oxygen and transport it via the circulatory system to the heart. The heart then pumps the oxygenated blood (blood rich in oxygen) to all parts of the body. The cells of the body then utilises the oxygen through a process called respiration, releasing carbon dioxide as a waste product.
After the body’s cells have utilized the oxygen, the deoxygenated blood (carbon dioxide-rich blood) returns to the heart. The heart then pumps the deoxygenated blood to the lungs, where carbon dioxide diffuses out of the blood and is exhaled.


Let’s compare: Plant transport system vs Human Circulatory System

Similarities between Transport in Plants and Humans

The plant transport system and the human circulatory system share similarities in their function and structure.

Firstly, both transport systems are responsible for transporting substances (such as water and food) throughout the organism. The plant transport system moves water, minerals, and nutrients from the roots to the leaves and other parts of the plant. Similarly, the human circulatory system transports blood, which carries oxygen, nutrients, and waste products, to all parts of the body.

Secondly, both systems consist of specialized tubes that transport these substances. In plants, the transport system is made up of xylem and phloem, which are specialized tissues that move water and nutrients, respectively. In humans, the circulatory system is made up of blood vessels, including arteries, veins, and capillaries, that transport blood throughout the body.


Differences between Transport in Plants and Humans

While we have explored the similarities between both systems, they have different mechanisms.

The plant transport system moves substances, such as water and nutrients, in a single one-way direction. In contrast, the human circulatory system transports substances, such as oxygen and nutrients, in a cyclical or circular direction via the blood.



The human circulatory system has a closed circulatory system where blood circulates constantly from the heart which pumps through blood vessels and back to the heart.

Whereas in plants, movement of substances is either unidirectional (upwards), or multidirectional (up and down). Roots absorb water and mineral salts, which travel up the xylem. While food/glucose produced by chloroplasts can move up or down and be transported anywhere in the plant.


Extra information:



Plants lose water through transpiration. This happens when they release water vapor through the stomata, small pores on the surface of leaves. The loss of water via transpiration maintains a diffusion gradient across the leaf to the xylem vessels in the leaves. As a result, it helps to pull water up from the roots through the xylem vessels.

The human circulatory system transports oxygen and carbon dioxide, while the plant transport system does not transport oxygen and carbon dioxide.

The heart is an essential component of the human circulatory system, as it pumps blood throughout the body. In contrast, the plant transport system does not need a pump to move substances throughout the plant.

The circulatory system transports substances via blood through blood vessels. Whereas, the plant transport system transports substances through the food-carrying tubes and water-carrying tubes.


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