Lesson Notes By Weeks and Term v4 - SHS 1
ESSENTIALS FOR SURVIVAL
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ESSENTIALS FOR SURVIVAL
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Subject: General Science
Class: SHS 1
Term: 1st Term
Week: 12
Grade code: 2.2.1.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 2.2.1.CS.1
Indicator code: 2.2.1.LI.2
Theme: PROCESSES FOR LIVING
Subtheme: ESSENTIALS FOR SURVIVAL
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Just as we keep our homes and communities in Ghana clean by disposing of rubbish, our bodies must also have a way to get rid of waste. Every second, our body cells are working—breaking down food for energy, building new tissues, and fighting off diseases. These activities, called metabolic processes, produce waste products that can be harmful if they build up. This lesson will explore the fascinating and vital processes our bodies use to remove these wastes, a process known as excretion. Understanding this is crucial for appreciating how to maintain good health, especially considering common health challenges in Ghana like kidney problems, which can arise from issues with waste removal.
A. What is Excretion?
Definition: Excretion is the process by which metabolic waste products and other toxic substances are removed from the body of an organism. Metabolic waste refers to the by-products of chemical reactions that occur inside our body cells (metabolism). Key examples include: Urea: A nitrogen-containing waste product formed in the liver from the breakdown of excess amino acids. Carbon Dioxide (CO₂): A waste product of cellular respiration. Excess Water and Mineral Salts: These are not toxic in small amounts, but their levels must be carefully controlled.
Important Distinction: Excretion vs. Egestion
This is a common point of confusion. It is essential to know the difference.