Cell Membrane - Structure and Function - UNSOLVED PRACTICE SET
Chapter: The Fundamental Unit of Life | Topic: Cell Membrane Structure and Function
CELL MEMBRANE - STRUCTURE AND FUNCTION - UNSOLVED PRACTICE SET
Topic: Cell Membrane Structure and Function
Multiple Choice Questions
Q1. The fluid mosaic model of the cell membrane was proposed by:
- Robert Hooke
- Singer and Nicolson
- Schleiden and Schwann
- Rudolf Virchow
Q2. The main components of the cell membrane are:
- Proteins and nucleic acids
- Phospholipids and proteins
- Carbohydrates and lipids
- Nucleic acids and carbohydrates
Q3. The hydrophilic heads of phospholipids in the cell membrane face:
- Towards each other
- Outwards towards the aqueous environment
- Away from water
- Towards the cytoplasm only
Q4. Which property of the cell membrane allows it to fuse with other membranes and change shape?
- Rigidity
- Fluidity
- Permeability
- Selectivity
Q5. The cell membrane is described as "selectively permeable" because it:
- Allows all substances to pass through freely
- Blocks all substances from entering
- Allows only certain substances to pass through
- Allows only water to pass through
Short Answer Questions
Q6. Describe the structure of a phospholipid molecule and explain how arrange themselves to form the cell membrane.
Q7. What is the fluid mosaic model? Why is the cell membrane described as "fluid" and "mosaic"?
Q8. Differentiate between integral proteins and peripheral proteins of the cell membrane.
Q9. Explain the role of cholesterol in maintaining the fluidity of the cell membrane in animal cells.
Long Answer Questions
Q10. Draw a well-labelled diagram showing the fluid mosaic model of the cell membrane. Label the following: phospholipid bilayer, integral proteins, peripheral proteins, cholesterol, and glycoproteins.
Q11. Explain the various functions performed by the cell membrane. How does the structure of the membrane support these functions?
APPLICATION / ANALYSIS
Q12. A biology teacher demonstrates an experiment using an artificial lipid bilayer (liposome) and a real cell membrane:
(a) Water passes easily through both membranes, but glucose passes slowly through the real cell membrane and not at all through the artificial bilayer. Explain this observation.
(b) If the temperature is increased from 20°C to 40°C, the rate of diffusion across the cell membrane increases. Explain why, with reference to membrane fluidity.
(c) Some drugs are designed to target specific cells (like cancer cells) by recognizing surface markers. What membrane components are these drugs likely recognizing?
Q13. In winter, some plants produce more unsaturated fatty acids in their cell membranes, while in summer, they produce more saturated fatty acids.
(a) Explain how this helps the plant maintain membrane fluidity in different temperatures.
(b) If a plant could not make this adjustment, what would happen to its cell membranes in extreme cold? Explain.