Lesson Notes By Weeks and Term v4 - SHS 3
BIOLOGY AND ENTREPRENEURSHIP
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
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: 9
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
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
Welcome, future scientists and entrepreneurs! Today, we are exploring a very exciting and practical area of biology where science meets business and solves real-world problems. We often think of biology as the study of plants and animals, but its principles can be used to clean our environment, get valuable resources from the earth, and even create new sources of energy. In Ghana, where we face challenges with water pollution from activities like 'galamsey', and have a strong agricultural sector, understanding these applications can open doors to new careers and solutions for our communities.
This lesson focuses on three main applications where biology is used to solve industrial and environmental problems. The common thread is the use of living organisms, especially microorganisms, to carry out specific chemical processes. A. Application 1: Biological Treatment of Water
Water is essential for life, but human activities often pollute our rivers and water bodies like the Densu, Pra, and Ankobra. Biological water treatment uses living organisms to break down and remove pollutants.
Key Concept: Bioremediation Bioremediation is the use of microorganisms (like bacteria, fungi, or algae) to break down pollutants and clean up contaminated environments. In water treatment, we create conditions that encourage these helpful microbes to "eat" the waste.
The Process: Activated Sludge System This is a common method used in large-scale wastewater treatment plants. Imagine the process at the Tema or Accra treatment plants. Step 1: Primary Treatment (Physical) Wastewater first enters a chamber where large objects like plastics, rags, and stones are screened out. It then flows into a large tank called a sedimentation tank. Here, the water sits for a while, allowing heavy solid particles (sludge) to settle at the bottom and lighter materials like oil and grease to float to the top. These are physically removed. Step 2: Secondary Treatment (Biological) - The Key Stage The water from the primary stage, which still contains dissolved organic waste (like human waste, food scraps), is moved to an aeration tank. This tank is filled with a mixture of bacteria, protozoa, and other microbes, called activated sludge. Air is bubbled vigorously through the tank (aeration). This provides the oxygen that the aerobic bacteria need to thrive and respire. The Biological Action: These aerobic bacteria use the dissolved organic waste as their food source. They break down complex, harmful organic compounds into simpler, harmless substances like carbon dioxide, water, and more bacterial cells. *Example:* A bacterium like *Pseudomonas* can break down complex organic molecules found in sewage. After several hours, the water and the microbe-rich sludge move to a final settling tank (clarifier). The microbial clumps (flocs) settle at the bottom. A portion of this settled sludge (the "activated" part, rich in healthy bacteria) is recycled back to the aeration tank to treat new incoming wastewater. The rest is removed for disposal or further treatment. Step 3: Tertiary Treatment (Chemical/Physical) The clear water from the top of the final settling tank is now largely clean but may still contain disease-causing organisms. It is disinfected, usually with chlorine, to kill any remaining pathogens before being safely discharged into a river or the sea.