Cell Structure, Organelles, Functions and Plant-Animal Cell Differences for SS 1

Class: SS 1
Term: Second Term
Week: 1
Age: 15 years
Duration: 60 minutes
Subject: Biology
Curriculum Theme: Organization of Life and Biochemical
Focal competence: Using a microscope in observing and drawing biological Specimens
Key competencies/values: Critical Thinking; Communication; Collaboration; ICT and Digital Competencies; Digital Competencies
Skills:

• Demonstrating osmosis and diffusion in plant and animal cells
• Drawing cell structure

Previous Lesson: Trophic Levels
Topic: Cell Structure And Functions
Subject Matter: Meaning of cell, Cell Structure, Functions of Cell Organelles, Differences between Plant and Animal Cells

Specific Objectives

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

Cognitive Domain

• define cell;
• identify parts of the cell under the microscope;
• describe the structure of parts of the cell using appropriate biological terms;
• match each organelle with its specific function in the cell;
• explain the functions of cell organelles.

Affective Domain

• appreciate the complexity and organisation of living cells;
• show interest in exploring further details of cell biology.

Psychomotor Domain

• draw plant and animal cells accurately;
• handle a microscope to observe cell specimens (if available).

Social Domain

• collaborate effectively in group discussions about cell structures and functions.

Reference Materials

The following resources were used in planning this lesson:

• 2025 New Revised Senior Secondary Education Curriculum (SSEC)
• Relevant State Unified Scheme of Work
• Modern Biology for Senior Secondary Schools
• The HeadTeacher Scheme of work For The New Revised Senior Secondary Education Curriculum (SSEC)

Instructional Materials

The teacher will teach this lesson with the aid of:

• Microscope
• Short animations/videos of organelles performing functions
• Diagrams/charts/pictures of both plant and animal cells
• Onion bulbs
• Spatula
• Slides and cover slips
• Droppers
• Stains (e.g., iodine solution)

Rationale for the Lesson

Understanding cell structure and function is foundational to all biological studies, as the cell is the basic unit of life. This lesson helps students grasp how living organisms are organised at the microscopic level and how different parts of a cell work together to sustain life. It provides essential knowledge for comprehending more complex biological processes and concepts in subsequent topics.

Prerequisite/Previous Knowledge

Students should have a basic understanding of living and non-living things and the general characteristics of life from their Junior Secondary Biology classes.

Lesson Content/Board Summary

Cell Structure And Functions

Meaning of Cell

The cell is the basic structural, functional, and biological unit of all known organisms. It is the smallest unit of life that can replicate independently and is often called the “building block of life.”

General Cell Structure

All cells, whether plant or animal, share some fundamental components:

1. Cell Membrane (Plasma Membrane): An outer boundary that controls the movement of substances into and out of the cell.
2. Cytoplasm: The jelly-like substance filling the cell, enclosed by the cell membrane. It contains organelles and is the site of many metabolic reactions.
3. Nucleus: The control centre of the cell, containing the genetic material (DNA) and regulating cell activities.

Functions of Cell Organelles

Organelles are specialised structures within a cell that perform specific functions necessary for the cell’s survival.

1. Nucleus:
   1. Controls all cell activities, including growth, metabolism, and reproduction.
   2. Stores the cell’s genetic material (DNA) in the form of chromosomes.
   3. Contains the nucleolus, which is involved in ribosome synthesis.
2. Mitochondria:
   1. Often called the “powerhouse of the cell.”
   2. Site of cellular respiration, where glucose is broken down to release energy (ATP) for the cell’s activities.
3. Endoplasmic Reticulum (ER): A network of membranes involved in the synthesis, modification, and transport of proteins and lipids.
   1. Rough Endoplasmic Reticulum (RER): Has ribosomes attached to its surface; involved in the synthesis and folding of proteins that are destined for secretion or insertion into membranes.
   2. Smooth Endoplasmic Reticulum (SER): Lacks ribosomes; involved in lipid synthesis, detoxification of drugs and poisons, and storage of calcium ions.
4. Ribosomes: Small organelles responsible for protein synthesis (translation of mRNA into protein). They can be free in the cytoplasm or attached to the RER.
5. Golgi Apparatus (Golgi Complex/Body):
   1. Modifies, sorts, and packages proteins and lipids synthesised in the ER.
   2. Involved in the formation of lysosomes and peroxisomes.
   3. Packages materials into vesicles for secretion or transport to other organelles.
6. Lysosomes (mainly in animal cells): Contain digestive enzymes that break down waste materials, cellular debris, and foreign invaders (like bacteria).
7. Vacuoles: Membrane-bound sacs involved in storage and waste removal.
   1. Plant Cells: Typically have one large central vacuole that stores water, nutrients, and waste products, and helps maintain turgor pressure.
   2. Animal Cells: Have several small, temporary vacuoles for various purposes like storage or transport.
8. Chloroplasts (only in plant cells and some protists):
   1. Contain the green pigment chlorophyll.
   2. Site of photosynthesis, where light energy is converted into chemical energy (glucose).
9. Cell Wall (only in plant cells, fungi, and some protists):
   1. A rigid outer layer made primarily of cellulose in plants.
   2. Provides structural support, protection, and prevents excessive water uptake.
10. Cytoplasm: The entire content within the cell membrane, excluding the nucleus. It includes the cytosol (the jelly-like fluid) and the organelles suspended within it. It is the site of many metabolic pathways.
11. Centrioles (mainly in animal cells): Involved in cell division by forming spindle fibres that help separate chromosomes.

Differences Between Plant and Animal Cells

While both plant and animal cells are eukaryotic and share many common organelles, they also have distinct differences that reflect their specialised functions.

Teaching Methods/Instructional Techniques

Discussion, Explanation, Demonstration, Question and Answer, Visual Aids, Group Work, Practical Activity

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Questioning/Activating Prior Knowledge

Teacher’s Activity: The teacher greets the students and asks them to recall the basic characteristics of living things. The teacher then asks what they think is the smallest unit that makes up all living things.

Pupils’ Activity: Pupils respond by listing characteristics of living things and attempt to answer the question about the smallest unit.

Learning Point: Basic unit of life

Step 2: Meaning and General Structure of Cell

Time: 10 minutes

Teaching Skill: Explanation/Visualisation

Teacher’s Activity: The teacher defines the cell as the basic unit of life and introduces the concept of cell theory. The teacher then displays diagrams/charts of a generalised cell and points out the main components: cell membrane, cytoplasm, and nucleus.

Pupils’ Activity: Pupils listen attentively, observe the diagrams, and ask questions for clarification.

Learning Point: Cell definition and components

Step 3: Introduction to Cell Organelles

Time: 10 minutes

Teaching Skill: Explanation/Identification

Teacher’s Activity: The teacher introduces the concept of organelles as specialised structures within the cytoplasm. Using the diagrams, the teacher points out various organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, etc., briefly mentioning their presence.

Pupils’ Activity: Pupils identify the organelles on the diagrams and listen to the teacher’s explanation.

Learning Point: Identification of organelles

Step 4: Functions of Cell Organelles

Time: 10 minutes

Teaching Skill: Demonstration/Discussion

Teacher’s Activity: The teacher guides students to watch short animations/videos of organelles performing their functions (e.g., nucleus controlling, mitochondria producing energy, ER transporting). After each video segment, the teacher facilitates a discussion on the specific function of the observed organelle, linking it to the overall cell activity. The teacher focuses on Nucleus, Mitochondria, and Endoplasmic Reticulum as per the content scope, and other key organelles.

Pupils’ Activity: Pupils watch the videos, discuss what they observe, and present their findings on the functions of each organelle.

Learning Point: Organelle functions understood

Step 5: Differences Between Plant and Animal Cells

Time: 10 minutes

Teaching Skill: Comparison/Analysis

Teacher’s Activity: The teacher displays separate diagrams/charts of plant and animal cells. The teacher highlights the unique features of each, such as the cell wall and chloroplasts in plant cells, and their absence in animal cells, as well as differences in vacuole size and centrioles. The teacher then leads a discussion to compare and contrast the two cell types.

Pupils’ Activity: Pupils observe the diagrams, identify the differences, and participate in the comparative discussion.

Learning Point: Plant-animal cell differences

Step 6: Drawing and Labelling Cells

Time: 5 minutes

Teaching Skill: Guided Practice/Drawing

Teacher’s Activity: The teacher guides students to draw and label diagrams of both plant and animal cells. The teacher instructs them to colour-code unique parts (e.g., cell wall green, chloroplasts dark green) to clearly distinguish them.

Pupils’ Activity: Pupils draw and label the plant and animal cells in their notebooks, following the teacher’s guidance and colour-coding instructions.

Learning Point: Cell diagrams drawn

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define a cell.
2. Name three major parts common to all cells.
3. State the function of the nucleus and mitochondria.
4. Mention two key differences between a plant cell and an animal cell.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Cell knowledge assessed

Step 8: Note-Taking

Time: 10 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on the meaning of cell, cell structure, organelle functions, and plant-animal cell differences into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Board notes recorded

Step 9: Conclusion

Time: 5 minutes

Teaching Skill: Consolidation

Teacher’s Activity: The teacher summarises the key points of the lesson, reiterating that the cell is the fundamental unit of life, with specialised organelles performing vital functions, and highlighting the distinct features of plant and animal cells. The teacher encourages students to observe their surroundings and think about how these microscopic units contribute to the macroscopic world.

Pupils’ Activity: Pupils listen and ask any final questions.

Learning Point: Lesson concepts reinforced

Continuous Assessment/Further Study

Type: Homework

Instruction: Answer the following questions in your biology notebook.

1. Draw a well-labelled diagram of an animal cell and a plant cell.
2. Explain the importance of the cell wall in plant cells.
3. Identify two organelles involved in energy production and protein synthesis, stating their specific roles.
4. Research and write a short paragraph on how the discovery of the microscope contributed to our understanding of cells.

Lesson Keywords

• Cell – The basic structural and functional unit of all known living organisms.
• Organelle – A specialised subunit within a cell that has a specific function.
• Nucleus – The control centre of the cell, containing genetic material.
• Mitochondria – The “powerhouse” of the cell, responsible for energy production.
• Endoplasmic Reticulum – A network of membranes involved in protein and lipid synthesis and transport.
• Chloroplast – An organelle in plant cells where photosynthesis occurs.
• Cell Wall – A rigid outer layer in plant cells that provides support and protection.
• Cytoplasm – The jelly-like substance filling a cell, containing organelles.
• Cell Membrane – The outer boundary of the cell that regulates substance movement.

Differentiation

Support: Provide simplified diagrams and pre-labelled charts for students who struggle with drawing and identification. Pair weaker students with stronger ones for the drawing activity and video discussions. Focus on the core definitions and functions of the most common organelles.

Extension: Challenge advanced students to research and present on additional organelles not extensively covered (e.g., peroxisomes, cytoskeleton) or to explain how organelle dysfunction can lead to diseases. Encourage them to observe prepared slides of plant and animal cells under the microscope if available, identifying as many organelles as possible.

Suggested Lesson Videos

For further understanding of cell structure and functions, students can search on YouTube for:

• cell structure and function SS1 biology
• plant vs animal cell differences animation