BIOLOGY LESSON NOTE ON THE CELL

Topic: The Cell

Class: SS1

Sex: Mixed

Instructional Materials.  specimen, pictures, 

Aim of the Lesson: To help the learner understand the cell concept

Anticipated Problems: Because of advancement in class, most themes might be new to the learners and might result to difficulty in understanding.

Possible Solution: The teacher explains the concept in details using illustrations and real objects.

Content Objectives: By the end of the lesson, learners should be able to;

1. Define cell
2. State the Cell theory
3. State the form Forms in which cells exist
4. Explain the Cell structure
5. State the Functions of cell components
6. State the Similarities between plant and animal cell
7. State Differences between plant and animal cell

Time Table fit/ previous knowledge: The learners learnt classifications of living things in their previous class

Set Induction: The teacher asks the student to observe the object on the table.

Differentiation Method/Multiple Intelligence: The teacher uses different teaching technique such as discussion, role playing, questioning and use of picture to ensure all the learner benefit from the lesson.

CELL The term cell can be defined biologically as the small units of living matter. Cell dated back to the publication of an English scientist called Robert Hook in 1665. THE CELL DISCOVERY   The cell theory comes from scientific work of two German Biologists, Matthias Schleiden and Theodore Schwan n in 1838. They put their discoveries together to formulate the theory. The cell theory states that “all plants and animals are composed of structural and functional unit s called cells” FORMS IN WHICH CELLS EXIST All living cells both in plants and animals exist in 4 different forms 1. Independent, single or free-living organism. This is found in organisms such as (a) Amoeba (b) Paramecium (c) Euglena (d) Chlamydomonas etc It carries out all activities of living organism 2. Cell as a colony: The organism is made up of many similar cells that are held together by mucilage. They are loosely held together and may be specialized in their individual functions e.g sponges 3. Cell as a filament: Organisms in this category is made up of similar or identical cells that joined end to end to form an unbranched filament e.g Spirogyra 4. Cell as part of living organism: Here all life activities depend on the activities of the cells in the body. The cells specialized for different functions but work together to perform life processes CELL THEORY  The cell theory states that: 1. The cell is the building and working unit in all living organisms 2. All cell come from pre -existing cells 3. Cells contain information and instructions needed for their development and workings in the hereditary materials from the parent to the off-springs. THE CELL STRUCTURE   The structure of the cell as seen under light or electron microscope is shown below Structure of  plant and animal cell FUNCTIONS OF CELL COMPONENTS 1.Cell membrane: Thin and permeable to water, nutrients, waste products and dissolve substances 2. Cell wall: Provide support and shape to the cell 3. Cytoplasm: Medium for all cellular reactions  3. Plastids: (a) Leucoplast – stores starch or oil (b)Chromoplast – gives color to the plants (c) Chloroplast – gives green color and site of photosynthesis 4. Nucleus: It carries hereditary materials and it is the site for all cellular activities 6. Vacuole: It provides supports for the plants and also the site for unused chemical products. Also, it regulates body water content. 7. Protoplasm: All contents of the cell membrane i.e cytoplasm and nucleus 8. Endoplasmic reticulum: Transportation of materials within cytoplasm and across the cell to the nuclear membrane 9. Ribosome: Synthesis of protein 10. Mitochondria: Provides energy needed to form Adenosine triphosphate (ATP) 11. Lysosome: It prevents the cell from digesting itself, it helps to digest and destroy foreign bodies. It secrets digestive enzymes. 12. Golgi complex: Also called Golgi apparatus. It secretes important substances in the body and also transports them within the cell.  SIMILARITIES BETWEEN PLANT AND ANIMAL CELL 1.       They both possess the following structures chromosome, cytoplasm, endoplasmic reticulum, Golgi apparatus, Lysosomes, Mitochondria, Nucleus, Ribosome 2.       They are both unit of functionalities 3.       They both possess hereditary materials DIFFERENCES BETWEEN PLANT AND ANIMAL CELLS s/n PLANT CELL ANIMAL CELL 1 Definite shape No definite shape 2 Cellulose cell wall permanent Cellulose cell wall absent 3 No flexible membrane Flexible membrane present 4 Chloroplast present Chloroplast absent 5 Stores lipid as oil Stores lipid as fat 6 Large central vacuole Vacuole, if present is small 7 Nucleus at the edge of the cell Nucleus at the center of the cell 8 Centriole absent Centriole present 9 Less dense cytoplasm Dense and granular cytoplasm 10 Starch granules present Glycogen granule present

Assessment plan. The teacher uses the following to assess the learners

Class work What is a cell Differentiate between plant and animal cell Home work Draw the structure of plant and animal cell Multiple choice questions. 1. Transportation of materials within cytoplasm and across the cell to the nuclear membrane takes place at Endoplasmic reticulum Ribosome Mitochondria Cytoplasm  2. Synthesis of protein takes place at Endoplasmic reticulum Ribosome Mitochondria Cytoplasm  3. Energy needed to form Adenosine triphosphate (ATP) is provided by Endoplasmic reticulum Ribosome Mitochondria Cytoplasm  Evaluation Define cell State the Cell theory State the form Forms in which cells exist Explain the Cell structure State the Functions of cell components State the Similarities between plant and animal cell State Differences between plant and animal cell Glossary Filament: a slender threadlike object or fiber. Colony: Composed of many physically connected interdependent individuals Conclusion: The cell is a small unit of living matter.