Chapter: 03. The Cell
Section A: Multiple Choice Questions (8 Marks)
Section B: Fill in the Blanks (8 Marks)
Section C: True/False Questions (5 Marks)
Section D: Explanation of Terms (6 Marks)
Cytology: The scientific study of cells, including their structure, function, and life cycle. Selectively Permeable Membrane: A membrane, like the cell membrane, that allows only specific substances to pass through while blocking others, controlling what enters and leaves the cell. Protoplasm: The entire living content of a cell, including the cytoplasm and nucleus, enclosed within the cell membrane. Pseudopodia: Temporary, finger-like extensions of the cytoplasm used by some cells (like Amoeba or white blood cells) for movement and engulfing particles. Turgid: The swollen or stiff condition of a plant cell when its vacuole is full of water, pushing the cell membrane against the cell wall. Staining: The process of using special dyes to color different parts of cells to make them more visible and distinguishable under a microscope. Section E: Short Answer Questions (10 Marks)
The two main points of the Cell Theory are: cells are the basic structural and functional units of all living organisms, and all new cells arise from pre-existing cells. Cells have different shapes because their shape is adapted to perform specific functions efficiently. For example, nerve cells are long and branched to transmit signals over long distances. The cell wall is important for plant cells because it provides rigidity, mechanical support, and a definite shape, helping the plant stand upright and protecting the cell’s internal organelles. The main function of the nucleus in a cell is to control all cell activities and store and transmit hereditary information (DNA) from parents to offspring. New cells are needed in our body for growth, to repair wounded tissues, and to replace old and worn-out cells. Section F: Identifying and/or Differentiate Concepts (6 Marks)
Chloroplasts and Chromoplasts: Chloroplasts are green-colored plastids containing chlorophyll, responsible for photosynthesis (food making). Chromoplasts are non-green colored plastids (red, yellow) that give color to flowers and fruits. Plant cell and Animal cell: Plant cells have a rigid cell wall outside the cell membrane, while animal cells do not. Plant cells contain plastids (like chloroplasts) and usually have one large central vacuole, whereas animal cells lack plastids and either have no vacuoles or a few small, temporary ones. Section G: Diagram-Based Questions (7 Marks)
a)
b) No, a cell wall is not present in this cell. This is an animal cell, and cell walls are a distinguishing feature found only in plant cells, providing them rigidity and protection.
c) F (Mitochondrion) helps in releasing energy for the cell.
d) C (Nucleus) controls all activities of the cell.
Answer key