Lesson Notes By Weeks and Term v4 - SHS 3
BIOLOGY AND ENTREPRENEURSHIP
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BIOLOGY AND ENTREPRENEURSHIP
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Biology
Class: SHS 3
Term: 1st Term
Week: 5
Grade code: 3.1.2.LI.4
Strand code: 1
Sub-strand code: 2
Content standard code: 3.1.2.CS.1
Indicator code: 3.1.2.LI.4
Theme: EXPLORING BIOLOGY IN SOCIETY
Subtheme: BIOLOGY AND ENTREPRENEURSHIP
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This lesson moves beyond the traditional view of biology as a subject of diagrams and dissections. We will explore how fundamental biological principles are being used to solve major societal problems and create profitable businesses in Ghana and around the world. We will investigate how living organisms, particularly microorganisms, can be harnessed to purify our polluted water bodies, extract valuable minerals like gold more safely, and create renewable energy sources. This knowledge opens up exciting career and entrepreneurial pathways for students of biology, turning scientific understanding into practical, income-generating solutions for our communities.
This lesson focuses on three key applications of biology in industry and entrepreneurship. A. Application in Water Treatment (Bioremediation)
The Problem: Our water sources in Ghana, such as the River Pra, Densu, and Ankobra, are often polluted by domestic sewage, industrial waste, and activities like illegal mining ('galamsey'). This water is unsafe for drinking and harms aquatic life.
The Biological Solution: Bioremediation Bioremediation is the use of living organisms, mainly microorganisms (bacteria and fungi), to break down and clean up environmental pollutants. In water treatment, we use specific bacteria that "eat" the harmful organic waste, converting it into harmless substances like carbon dioxide, water, and more bacterial cells.
The Process: The Activated Sludge Method This is a common method used in large-scale wastewater treatment plants, like those managed by the Ghana Water Company Ltd. (GWCL). Step 1: Primary Treatment (Physical) Wastewater first enters a chamber where large objects like plastics, rags, and stones are removed by screens. It then flows into a large tank called a settling tank or primary clarifier. Here, heavier solid particles (sludge) sink to the bottom, and lighter materials like oil and grease float to the top and are skimmed off. This is a purely physical process. Step 2: Secondary Treatment (Biological) - The Core Biological Process The liquid portion from the primary treatment is moved to an aeration tank. This tank is filled with a rich culture of aerobic bacteria and other microorganisms (the "activated sludge"). Large pumps bubble air (oxygen) through the water. This is crucial because the "good" bacteria we are using are aerobic – they need oxygen for respiration. As the bacteria respire, they use the dissolved organic pollutants in the water as their food source. They break down complex, harmful organic molecules into simpler, harmless ones (CO₂, H₂O). The bacteria multiply rapidly and clump together to form sticky masses called flocs. These flocs absorb more pollutants from the water, acting like tiny biological sponges. After several hours, the water flows into a secondary settling tank. Here, the heavy flocs (now full of bacteria and waste) sink to the bottom, forming more sludge. A portion of this sludge is recycled back to the aeration tank to maintain a high population of active bacteria. The rest is removed for further treatment or disposal. Step 3: Tertiary Treatment (Chemical/Disinfection) The water, now about 90-95% clean, is treated with chlorine or exposed to UV light to kill any remaining pathogenic bacteria before it is discharged into a river or sent for further purification for drinking.