Compare the ribosomes of prokaryotic and eukaryotic cells.
Mention the important functions of plasma membrane.
What are tight junctions?
Tight junctions are specialized intercellular connection sites where the membranes of two adjacent cells are fused together to form a barrier that prevents the leakage of fluids and solutes between cells.
Explain the different types of membrane transport mechanism in cells, highlighting their significance.
Membrane transport is essential for maintaining cellular homeostasis. The primary mechanisms include:
Significance: These mechanisms ensure the cell receives nutrients, removes waste, and maintains electrochemical gradients necessary for nerve impulses and muscle contraction.
Describe the composition of plasma membrane. Add a note on structure and function of desmosomes.
The plasma membrane follows the Fluid Mosaic Model:
Desmosomes: These are "spot-weld" junctions that mechanically attach cells to each other, providing structural integrity to tissues like skin and heart muscle.
Differentiate between RER and SER.
| Rough Endoplasmic Reticulum (RER) | Smooth Endoplasmic Reticulum (SER) |
|---|---|
| Studded with ribosomes. | Lacks ribosomes. |
| Primarily involved in protein synthesis. | Involved in lipid synthesis and detoxification. |
Describe the structure of mitochondria with suitable diagram. Add a note on its functions.
Structure: Double-membrane organelle. The outer membrane is smooth, while the inner membrane is folded into cristae. The interior space is the matrix containing mitochondrial DNA and ribosomes.
Functions: Known as the "powerhouse of the cell," it is the site of cellular respiration and ATP production. It also plays a role in calcium storage and apoptosis.
Describe the structure and function of peroxisomes. Add a note on function of lysosomes.
Peroxisomes: Small, membrane-bound organelles containing oxidative enzymes like catalase. They break down long-chain fatty acids and detoxify harmful substances (like hydrogen peroxide) into water and oxygen.
Lysosomes: These are the "suicidal bags" of the cell, containing hydrolytic enzymes used for intracellular digestion, recycling of old organelles (autophagy), and breaking down foreign substances.
What do you mean by cell cycle?
The cell cycle is the series of events that take place in a cell leading to its division and duplication of its DNA to produce two daughter cells.
Describe the structure of microtubules with diagram. Add a note on functions of microtubules.
Structure: Hollow tubes about 25nm in diameter, made of alpha and beta-tubulin dimers arranged into 13 protofilaments.
Functions:
Describe various components of blood and explain their functions.
Describe the ultrastructure of skeletal muscle with suitable diagram. Add a note on function of skeletal muscle.
Structure: Composed of long, cylindrical, multinucleated fibers with visible striations. Striations are caused by the arrangement of actin (thin) and myosin (thick) filaments into sarcomeres.
Function: Facilitates voluntary movements, maintains posture, and generates body heat through contraction.