Worksheet: Chapter 2 - Cell: The Building Block of Life

Section 1: The Basics and History

1. Who was the first person to observe a cell in 1665 using a self-designed microscope?
   ________________________________________________________________________________
2. State the three main points of the Cell Theory:
   • 1. ________________________________________________________________________
   • 2. ________________________________________________________________________
   • 3. ________________________________________________________________________
3. What is the limit of resolution of the human eye (when viewed from 25 cm)?
   ________________________________________________________________________________

Section 2: Tools and Measurement

1. Fill in the blank: A 1 millimetre (mm) is equal to ____________ micrometres (µm).
2. Match the microscope feature to its description:
   • Resolution: ________________________________________________
   • Contrast: _________________________________________________
   • Magnification: _____________________________________________
3. Which type of microscope allows scientists to see cell structures at the nanometre scale?
   ________________________________________________________________________________

Section 3: Cell Boundaries and Transport

1. Why is the cell membrane described as "selectively permeable"?
   ________________________________________________________________________________
2. According to the fluid-mosaic model, why is the membrane considered "fluid"?
   ________________________________________________________________________________
3. Define Osmosis:
   ________________________________________________________________________________
4. In an experiment, if a potato piece is placed in a 20% salt solution, will it swell or shrink? Why?
   ________________________________________________________________________________
5. Identify the carbohydrate that primarily makes up the plant cell wall:
   ________________________________________________________________________________

Section 4: The Cell Factory (Organelles)

1. Which organelle is known as the "House of coded instructions" because it contains DNA?
   ________________________________________________________________________________
2. Complete the following organelle functions:
   • Mitochondria: Powerhouse of the cell; produces ________.
   • Ribosomes: Site of ______________ synthesis.
   • Golgi Apparatus: Acts as the cell’s ______________; modifies and packages materials.
   • Lysosomes: Known as "suicide bags" or the ______________ system.
3. Distinguish between the three types of Plastids:
   • Chloroplasts: ________________________________________________
   • Chromoplasts: ________________________________________________
   • Leucoplasts: _________________________________________________

Section 5: Types of Cells and Division

1. What is the main difference between a Prokaryotic cell and a Eukaryotic cell regarding the nucleus?
   ________________________________________________________________________________
2. Why do mature human Red Blood Cells (RBCs) lack a nucleus?
   ________________________________________________________________________________
3. Compare the two types of cell division:

   Feature	Mitosis	Meiosis
   Purpose	Growth and Repair	________________
   Daughter Cells	Two (Identical)	________________
   Chromosome Number	Same as parent	________________

Section 6: Critical Thinking

1. What is contact inhibition, and what happens when animal cells lose this property?
   ________________________________________________________________________________
2. Why do plants look wilted when they do not get enough water? (Hint: Mention the role of the vacuole).
   ________________________________________________________________________________

"The cell represents the basic level at which life exists."