Transport
Overview
A single-celled organism can swap gases with its surroundings directly through its membrane, but a human body has trillions of cells, many of them buried deep inside. Without a transport system to carry oxygen, nutrients, and waste, those inner cells would die within minutes.
In this lesson you will explore the composition of blood and the roles of its components, the structure and function of the heart and blood vessels, and how the double circulatory system keeps the body supplied. These are some of the most heavily examined topics on Paper 1.
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 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
- Describe the structure of the heart and how it functions
- Understand how the structure of arteries, veins and capillaries relates to their function
- Understand the general structure of the circulation system, including the blood vessels to and from the heart and the lungs
Mind map
This topic is mapped out so you can see how the ideas connect.
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Flashcards
Quick recall practice on the facts this topic is tested on.
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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 component of blood transports oxygen? A) Plasma B) White blood cells C) Red blood cells D) Platelets Answer: C
- The pulmonary artery carries: A) Oxygenated blood to the lungs B) Deoxygenated blood to the lungs C) Oxygenated blood to the body D) Deoxygenated blood to the body Answer: B
- Which blood vessel has valves to prevent backflow? A) Artery B) Capillary C) Vein D) Aorta Answer: C
- Why do multicellular organisms need a transport system? A) Their cells are too large for diffusion B) Their SA:V ratio is too small for diffusion alone C) They do not have cell membranes D) They cannot respire without one Answer: B
- Antibodies are produced by: A) Red blood cells B) Platelets C) Phagocytes D) Lymphocytes Answer: D
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Practice Mock Questions
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