Transport
Overview
A single-celled organism can rely on diffusion alone to move substances in and out, but a human body with trillions of cells cannot. Transport systems solve this problem: the circulatory system carries oxygen, nutrients, hormones, and waste products around the body in blood, while in plants the vascular system moves water, minerals, and sugars through xylem and phloem.
In this lesson you will learn the composition of blood, the structure and function of the heart, how arteries, veins, and capillaries differ, how the immune system defends against pathogens, and how transpiration drives the movement of water through a plant. This is one of the largest topics in the specification and appears across both Paper 1 and Paper 2.
Objectives
- Understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell
- Understand the need for a transport system in multicellular organisms
- Describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant
- Describe the role of xylem in transporting water and mineral ions from the roots to other parts of the plant
- Understand how water is absorbed by root hair cells
- Understand that transpiration is the evaporation of water from the surface of a plant
- Understand how the rate of transpiration is affected by changes in humidity, wind speed, temperature and light intensity
- Investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot
- Describe the composition of the blood: red blood cells, white blood cells, platelets and plasma
- Understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy
- Understand how adaptations of red blood cells make them suitable for the transport of oxygen, including shape, the absence of a nucleus and the presence of haemoglobin
- Understand how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen
- Understand how vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity
- Understand how platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms
- Describe the structure of the heart and how it functions
- Explain how the heart rate changes during exercise and under the influence of adrenaline
- Understand how factors may increase the risk of developing coronary heart disease
- Understand how the structure of arteries, veins and capillaries relate to their function
- Understand the general structure of the circulation system, including the blood vessels to and from the heart and lungs, liver and kidneys
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Transport. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which blood vessel carries oxygenated blood from the lungs to the heart? A) Pulmonary artery B) Aorta C) Vena cava D) Pulmonary vein Answer: D
- What is the function of platelets? A) Carrying oxygen B) Producing antibodies C) Blood clotting at wound sites D) Transporting hormones Answer: C
- Which plant tissue transports dissolved sugars? A) Xylem B) Phloem C) Epidermis D) Palisade mesophyll Answer: B
- Which factor would DECREASE the rate of transpiration? A) Higher temperature B) Higher wind speed C) Higher humidity D) Higher light intensity Answer: C
- Why is the left ventricle wall thicker than the right? A) It receives more blood B) It needs to generate higher pressure for the systemic circulation C) It pumps blood to the lungs D) It contains more valves Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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