Transport
Aperçu
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.
Objectifs
- 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
Note de cours
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Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Transport. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.
Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.
- 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
Disponible sur l'application Green Bridge
Téléchargez l'application Green Bridge CBT sur votre téléphone ou votre ordinateur pour accéder aux notes de cours complètes, aux questions pratiques, et plus encore.
Disponible sur l'application Green Bridge
Téléchargez l'application Green Bridge CBT sur votre téléphone ou votre ordinateur pour accéder aux notes de cours complètes, aux questions pratiques, et plus encore.
Livres recommandés
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