Exploring Cell Properties and Functions: Feeding, Autotrophy, and Excretion Biology SS 1 First Term Lesson Notes Week 6

Subject: Biology

Class: SS1

Term: First Term

Week: 6

Age (years): 15-16

Topic: Some Properties and Functions of the Cell

Sub-topic: Feeding, Autotrophy, Heterotrophy, Enzymes, and Excretion

Duration: 2 hours

Behavioural Objectives:

By the end of this lesson, students should be able to:

1. Define feeding and describe its types: micronutrients and macronutrients.
2. Explain autotrophy and its processes: photosynthesis and chemosynthesis.
3. Define heterotrophy and differentiate it from autotrophy.
4. Describe the role of enzymes in biological processes.
5. Explain excretion and identify excretory organ cells in living organisms.
6. Discuss the waste products of metabolic activities and how they are excreted.

Keywords:

Feeding, Micronutrients, Macronutrients, Autotrophy, Heterotrophy, Photosynthesis, Chemosynthesis, Enzymes, Excretion, Metabolism

Set Induction:

Begin the lesson by asking students what they think cells need to survive and grow. Discuss the importance of nutrients and how cells obtain them.

Entry Behaviour:

Students should have a basic understanding of cell structure and functions from previous lessons.

Learning Resources and Materials:

• Diagrams illustrating feeding types and metabolic processes
• Videos on photosynthesis and chemosynthesis
• Samples of different nutrient sources (e.g., fruits, vegetables, meats)
• Interactive presentations

Building Background / Connection to Prior Knowledge:

Connect the lesson to previous topics on cellular structure and metabolism, highlighting how cells depend on nutrients for energy and function.

Embedded Core Skills:

• Critical thinking: Analyzing the role of nutrients and enzymes in cellular functions.
• Collaboration: Working in groups to discuss and present findings.
• Research skills: Exploring various sources of nutrients and their impacts on health.

Learning Materials:

• Textbook: “Biology for Senior Secondary Schools”
• Online resources and simulations related to cell metabolism
• Interactive worksheets for nutrient classification

Reference Books:

1. Biology for Senior Secondary Schools by E. B. Olaniyan
2. Comprehensive Biology by J. A. Akintunde

Instructional Materials:

• PowerPoint presentations with graphics
• Models showing the processes of photosynthesis and chemosynthesis
• Handouts summarizing key concepts

Content:

1. Feeding:

• Definition: Feeding refers to the process by which organisms obtain nutrients from their environment to support growth, maintenance, and energy needs.
• Types:
  • Micronutrients: These are nutrients needed in small amounts, such as vitamins and minerals (e.g., Vitamin C, iron). They are crucial for various biochemical functions in cells.
  • Macronutrients: These are nutrients required in larger amounts, including carbohydrates, proteins, and fats. They provide the energy and building blocks necessary for cellular functions.

2. Autotrophy:

• Definition: Autotrophy is the ability of organisms to produce their own food from inorganic substances.
  • Photosynthesis: The process by which green plants, algae, and some bacteria convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen. For example, plants use sunlight to convert CO2 and H2O into C6H12O6 (glucose).
  • Chemosynthesis: A process used by certain bacteria to obtain energy by oxidizing inorganic molecules, often found in extreme environments (e.g., deep-sea hydrothermal vents). An example is the conversion of hydrogen sulfide into organic compounds.

3. Heterotrophy:

• Definition: Heterotrophy refers to organisms that cannot produce their own food and rely on consuming other organisms or organic matter. Examples include animals and fungi.

4. Role of Enzymes:

• Enzymes are biological catalysts that speed up chemical reactions in cells without being consumed. They are specific to substrates and play a crucial role in metabolic processes. For example, amylase breaks down starch into sugars, facilitating digestion.

5. Excretion:

• Definition: Excretion is the process by which living organisms remove waste products generated from metabolic activities.
• Excretory Organ Cells: Cells specialized in excretion include kidney cells in animals, which filter waste from the blood, and contractile vacuoles in some protists, which expel excess water.
• Waste Products: Common waste products include urea (from protein metabolism), carbon dioxide (from cellular respiration), and ammonia (from amino acid breakdown).
• Forms of Excretion:
  • In Animals: Waste is typically excreted as urine or feces.
  • In Plants: Waste products can be excreted through transpiration (water vapor) or stored in leaves that later fall off.

Evaluation:

Fill-in-the-Blank Questions (15 Questions):

1. The nutrients needed in small amounts for cellular function are called _____. a) Macronutrients
   b) Micronutrients
   c) Proteins
   d) Carbohydrates
2. Photosynthesis is the process by which _____. a) Animals produce energy
   b) Plants convert sunlight into chemical energy
   c) Fungi absorb nutrients
   d) Bacteria break down waste
3. The primary waste product of protein metabolism is _____. a) Glucose
   b) Urea
   c) Oxygen
   d) Carbon dioxide
4. Autotrophs produce their own food through _____. a) Ingestion
   b) Photosynthesis
   c) Absorption
   d) Fermentation
5. Heterotrophs must obtain their nutrients from _____. a) Inorganic substances
   b) Other organisms
   c) Light
   d) Water
6. Enzymes are known as biological _____. a) Catalysts
   b) Inhibitors
   c) Substrates
   d) Reactants
7. Chemosynthesis is primarily performed by _____. a) Plants
   b) Animals
   c) Certain bacteria
   d) Fungi
8. The waste products of metabolic activities are typically _____. a) Stored indefinitely
   b) Excreted from the body
   c) Used for energy
   d) Transformed into nutrients
9. The organ responsible for filtering waste from the blood in humans is the _____. a) Liver
   b) Heart
   c) Kidney
   d) Lung
10. Macronutrients include _____. a) Vitamins
    b) Water
    c) Carbohydrates
    d) Minerals
11. Plants excrete waste products mainly through _____. a) Root absorption
    b) Photosynthesis
    c) Transpiration
    d) Respiration
12. The process of breaking down starch into sugars is facilitated by the enzyme _____. a) Lipase
    b) Amylase
    c) Protease
    d) Cellulase
13. An example of a micronutrient is _____. a) Carbohydrates
    b) Iron
    c) Protein
    d) Lipid
14. The main role of enzymes in the body is to _____. a) Slow down reactions
    b) Act as structural components
    c) Speed up chemical reactions
    d) Store energy
15. Waste products can be excreted in the form of _____. a) Water vapor
    b) Gases
    c) Solid waste
    d) All of the above

Class Activity Discussion: FAQs (15 Questions and Answers):

1. Q: What are micronutrients? A: Micronutrients are nutrients needed in small amounts, such as vitamins and minerals, crucial for various bodily functions.
2. Q: How do autotrophs obtain their energy? A: Autotrophs obtain energy by producing their own food through processes like photosynthesis or chemosynthesis.
3. Q: What is the difference between autotrophy and heterotrophy? A: Autotrophs produce their own food, while heterotrophs rely on consuming other organisms or organic matter for nutrients.
4. Q: Why are enzymes important? A: Enzymes are important because they speed up biochemical reactions, allowing essential processes to occur more efficiently.
5. Q: What is excretion? A: Excretion is the removal of waste products generated from metabolic activities in living organisms.
6. Q: What types of waste products do cells excrete? A: Cells excrete waste products such as urea, carbon dioxide, and ammonia.
7. Q: How do plants excrete waste? A: Plants excrete waste through transpiration and by dropping leaves that contain stored waste.
8. Q: What role do the kidneys play in excretion? A: The kidneys filter waste from the blood and produce urine to excrete these wastes.
9. Q: What is the function of enzymes in digestion? A: Enzymes in digestion help break down food into smaller, absorbable molecules.
10. Q: What is photosynthesis? A: Photosynthesis is the process by which plants convert light energy into chemical energy to produce glucose.
11. Q: What is chemosynthesis? A: Chemosynthesis is the process used by certain bacteria to obtain energy from inorganic molecules, typically in extreme environments.
12. Q: What happens to excess nutrients in the body? A: Excess nutrients can be stored or excreted as waste, depending on the nutrient type and body needs.
13. Q: How do enzymes affect metabolic processes? A: Enzymes increase the rate of metabolic processes, ensuring that reactions occur at a speed necessary for life.
14. Q: What is the role of the liver in excretion? A: The liver processes and detoxifies waste products before they are excreted by the kidneys.
15. Q: How do environmental factors affect enzyme activity? A: Environmental factors like temperature and pH can affect enzyme shape and function, impacting their activity.

Presentation:

Step 1: Review the previous lesson on cell structure and functions, focusing on the importance of nutrients and energy.
Step 2: Introduce the new topic by explaining the concepts of feeding, autotrophy, and heterotrophy, using examples and illustrations.
Step 3: Encourage student participation by asking them to provide examples of different feeding types and discussing the role of enzymes in everyday life.

Activities:

Teacher’s Activities:

• Conduct a class discussion to identify various nutrients found in common foods.
• Use visual aids to explain photosynthesis and chemosynthesis processes.
• Facilitate hands-on activities to observe enzyme action in digestion.

Learner’s Activities:

• Participate in group discussions about the importance of nutrients.
• Conduct experiments to observe enzyme activity.
• Complete fill-in-the-blank questions and evaluate their understanding.

Assessment:

Evaluation Questions (10 Questions):

1. Define autotrophy and give an example.
2. What is the primary function of enzymes?
3. How do heterotrophs obtain their nutrients?
4. Explain the difference between micronutrients and macronutrients.
5. Describe the excretion process in humans.
6. What are the waste products produced by cellular respiration?
7. How do autotrophs contribute to the ecosystem?
8. What role does the liver play in metabolism?
9. Provide an example of a chemosynthetic organism.
10. Why is it important for cells to excrete waste?

Conclusion:

The teacher will move around the classroom to mark students’ answers and conduct necessary evaluations. Students will be encouraged to reflect on the significance of understanding cell properties and functions, especially concerning feeding and waste management.