Excretion
Overview
Every metabolic reaction in your body produces something useful, but many also generate waste that would become toxic if it were allowed to accumulate. Excretion is the process that removes these metabolic waste products and keeps your internal chemistry within safe limits.
This topic covers how carbon dioxide and oxygen arise as waste products of metabolism in plants and how they leave through stomata, as well as the roles of the lungs, kidneys and skin as excretory organs in humans.
Objectives
- Understand the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf
- Know the excretory products of the lungs, kidneys and skin (organs of excretion)
Mind map
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Flashcards
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Excretion. 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 of the following is an example of excretion? A) Passing faeces B) Exhaling carbon dioxide C) Vomiting food D) Sweating salt from food Answer: B
- Where is urea produced in the body? A) Kidneys B) Lungs C) Liver D) Skin Answer: C
- During the day, the main waste gas released by a plant is: A) Carbon dioxide B) Nitrogen C) Oxygen D) Water vapour Answer: C
- Through which structures do waste gases leave a plant leaf? A) Xylem vessels B) Phloem tubes C) Root hairs D) Stomata Answer: D
- Why is carbon dioxide removal important for the body? A) It makes blood too alkaline B) It dissolves to form acid, lowering blood pH C) It blocks oxygen from entering cells D) It causes dehydration Answer: B
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Practice Mock Questions
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