THE FUNDAMENTAL UNIT OF LIFE - Quick Look Revision Guide
Your 1-page summary of the most exam-relevant takeaways from Science.
This compact guide covers 20 must-know concepts from THE FUNDAMENTAL UNIT OF LIFE aligned with Class 9 preparation for Science. Ideal for last-minute revision or daily review.
Complete study summary
Essential formulas, key terms, and important concepts for quick reference and revision.
Key Points
The cell is the basic unit of life.
Cells serve as the structural and functional units of all living organisms.
Robert Hooke discovered cells in 1665.
Using a microscope, he observed cork and termed the box-like structures 'cells'.
Cell theory consists of three main propositions.
All living things are made of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.
Plasma membrane is selectively permeable.
It controls the movement of substances in and out of the cell, allowing some to pass while blocking others.
Diffusion is the movement of substances.
It involves the movement of molecules from an area of high concentration to low concentration.
Osmosis is specific to water movement.
It's the net diffusion of water through a selectively permeable membrane towards higher solute concentration.
Plant cells have a cell wall.
The rigid cell wall provides structural support and protection, made primarily of cellulose.
The nucleus controls cell activities.
It houses genetic material (DNA) and directs cellular functions including growth and metabolism.
Cytoplasm contains organelles.
This gel-like substance surrounds organelles and supports their functions within the cell.
Mitochondria are the powerhouses.
They generate ATP, the energy currency of the cell, through aerobic respiration.
Rough ER synthesizes proteins.
Ribosomes attached to rough ER produce proteins for export or membrane incorporation.
Smooth ER synthesizes lipids.
It plays a role in lipid metabolism and detoxifying drugs within the cell.
Golgi apparatus modifies and packages proteins.
It processes and sends proteins and lipids to their destinations inside or outside the cell.
Lysosomes are the cell's 'suicide bags'.
These organelles contain enzymes that digest waste materials and cellular debris.
Vacuoles store substances.
They act as storage for nutrients, waste products, and help maintain turgor pressure in plant cells.
Plastids are found in plant cells.
Types include chloroplasts for photosynthesis and leucoplasts for storage of starch and oils.
Nuclear membrane has pores.
These pores regulate the exchange of materials between the nucleus and the cytoplasm.
Meiosis produces gametes.
A specialized cell division that reduces chromosome numbers for reproduction.
Mitosis facilitates growth and repair.
It results in two identical daughter cells, essential for tissue growth and maintenance.
Prokaryotic cells lack membrane-bound organelles.
This includes an undefined nuclear region called nucleoid, distinguishing them from eukaryotes.
