This chapter explores the fundamental unit of life, the cell, its structure, functions, and significance in living organisms.
THE FUNDAMENTAL UNIT OF LIFE – Formula & Equation Sheet
Essential formulas and equations from Science, tailored for Class 9 in Science.
This one-pager compiles key formulas and equations from the THE FUNDAMENTAL UNIT OF LIFE chapter of Science. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
Osmosis: Water movement = towards higher solute concentration
In osmosis, water moves across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration, essential for cell turgidity.
Diffusion: Substance movement = high concentration to low
Diffusion refers to the process where particles move from an area of higher concentration to an area of lower concentration until equilibrium is reached, crucial for gas and nutrient exchange in cells.
Cell Theory: All living things are made up of cells
The cell theory states that all living organisms consist of one or more cells and that the cell is the basic unit of life, pivotal for understanding biological organisms.
Mitosis: Mother cell → 2 identical daughter cells
Mitosis is the process of cell division where one mother cell divides to form two identical daughter cells, essential for growth and repair in multicellular organisms.
Meiosis: Mother cell → 4 genetically diverse gametes
Meiosis is a specialized type of cell division that results in four gametes, each with half the number of chromosomes of the original cell, crucial for sexual reproduction.
Plasmolysis: Cell shrinks in hypertonic solution
Plasmolysis occurs when plant cells lose water in a hypertonic environment, causing the cell membrane to pull away from the cell wall, demonstrating osmosis.
Endocytosis: Cellular ingestion of materials
Endocytosis is the process by which cells engulf external material through their membrane, forming vesicles, essential for nutrient uptake.
ATP = ADP + P + Energy
ATP (Adenosine Triphosphate) is converted to ADP (Adenosine Diphosphate) and inorganic phosphate, releasing energy, crucial for cellular activities.
Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
This equation depicts photosynthesis, where carbon dioxide and water, in the presence of light, produce glucose and oxygen, vital for plant nutrition.
Cell Membrane Function: Selectively permeable barrier
The cell membrane regulates entry and exit, allowing specific molecules to pass while preventing others, key for maintaining homeostasis.
Equations
Nucleus: Structure = Nuclear envelope + Nucleoplasm + Chromatin
The nucleus consists of a double membrane (nuclear envelope), nucleoplasm, and chromatin, which houses genetic material and controls cellular activities.
Endoplasmic Reticulum (ER): RER + SER
The endoplasmic reticulum is divided into rough ER (with ribosomes for protein synthesis) and smooth ER (for lipid synthesis and detoxification), essential for intracellular transport.
Golgi Apparatus: Cisternae = Modification + Packaging
The Golgi apparatus is a stack of membranes (cisternae) responsible for modifying, sorting, and packaging proteins and lipids for secretion or delivery within the cell.
Lysosome: Digestive enzymes used for:
Lysosomes contain digestive enzymes for breaking down waste materials and cellular debris, referred to as the cell's 'suicide bags'.
Mitochondria: Glucose + O₂ → CO₂ + H₂O + ATP
In cellular respiration, glucose and oxygen are converted into carbon dioxide, water, and ATP, highlighting the energy transformation in cells.
Plastids: Chloroplasts = Photosynthesis
Chloroplasts are plastids containing chlorophyll for photosynthesis, converting light energy into chemical energy in the form of glucose.
Vacuoles: Storage = Nutrients + Waste
Vacuoles are storage organelles for nutrients, waste products, and other substances, facilitating balance in cellular environment.
Ribosomes: Protein Synthesis = mRNA + tRNA
Ribosomes facilitate protein synthesis by decoding messenger RNA (mRNA) and binding transfer RNA (tRNA) to form chains of amino acids.
Chromosomes during Mitosis: 2n = Diploid
During mitosis, chromosomes are duplicated, forming sister chromatids which segregate into daughter cells maintaining diploid number.
Chromosomes during Meiosis: n = Haploid
Meiosis results in gametes with half the chromosome number (haploid), preparing for sexual reproduction.
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