Class 5 Life process

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Life Processes – Complete 5-Page Study Notes
Ch-5: Life Processes (जैव प्रक्रम) 🍎
1. Introduction (प्रस्तावना)
  • The basic functions performed by living organisms to maintain life on earth are called Life Processes.
  • वे सभी प्रक्रम जो सम्मिलित रूप से अनुरक्षण (Maintenance) का कार्य करते हैं, जैव प्रक्रम कहलाते हैं।
  • Key processes: Nutrition, Respiration, Transportation & Excretion.
2. Nutrition (पोषण)
  • Energy is needed even when we are resting to maintain our body.
  • Autotrophic Nutrition: Organisms use simple inorganic materials ($CO_2$, $H_2O$) + Sunlight.
  • उदाहरण: हरे पौधे और कुछ बैक्टीरिया।

Process of Photosynthesis (प्रकाश संश्लेषण)

$6CO_2 + 12H_2O \xrightarrow[\text{Sunlight}]{\text{Chlorophyll}} C_6H_{12}O_6 + 6O_2 + 6H_2O$
  • (i) Absorption of light energy by chlorophyll.
  • (ii) Conversion of light to chemical energy & splitting of $H_2O$.
  • (iii) Reduction of $CO_2$ to Carbohydrates (Glucose).
3. Stomata (रंध्र)
  • Tiny pores on leaf surface for gaseous exchange ($O_2$ & $CO_2$).
  • Opening & Closing is controlled by Guard Cells.
  • Guard cells swell (open) when water flows in, shrink (close) when water flows out.
Stomata
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4. Heterotrophic Nutrition (विषमपोषी पोषण)
  • Organisms depend on others for food.
  • Holozoic: Take in solid food (Humans, Amoeba).
  • Saprophytic: Feed on dead/decaying matter (Fungi).
  • Parasitic: Derive nutrition without killing (Cuscuta, Ticks).
5. Nutrition in Amoeba
Food $\to$ Pseudopodia
(Finger-like)
→
Food Vacuole
(Digestion)
→
Diffusion to
Cytoplasm
6. Human Digestive System (पाचन तंत्र)
  • Mouth: Salivary Amylase breaks starch $\to$ sugar.
  • Stomach: Gastric glands release HCl (acidic medium), Pepsin (digests proteins), & Mucus.
  • Small Intestine: Longest part! Site of complete digestion.
    • Bile (Liver): Makes medium alkaline & emulsifies fats.
    • Pancreatic Juice: Trypsin (Proteins), Lipase (Fats).
    • Villi: Finger-like projections for max absorption.
  • Large Intestine: Absorbs water. Waste is exit via Anus.
Bio-Catalysts: Enzymes are biological catalysts that break complex food into simple ones.
Ex: Pepsin works only in acidic medium (thanks to HCl).
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7. Respiration (श्वसन)

Breakdown of food (Glucose) to release energy.

Breakdown of Glucose Pathways

Glucose (6-C) $\xrightarrow{\text{Cytoplasm}}$ Pyruvate (3-C) + Energy
Absence of $O_2$ (Yeast)
$\to$ Ethanol + $CO_2$
Lack of $O_2$ (Muscles)
$\to$ Lactic Acid (Cramps!)
Presence of $O_2$ (Mitochondria)
$\to$ $CO_2 + H_2O + ATP$
  • ATP: Energy currency of the cell ($30.5$ kJ/mol).
8. Human Respiratory System
  • Nostrils: Hairs & mucus filter dust.
  • Trachea: Supported by Rings of Cartilage (prevents collapse).
  • Alveoli: Balloon-like structures. Max Surface Area! (~80 $m^2$) for gas exchange.
  • Mechanism: We lift ribs & flatten Diaphragm $\to$ Chest cavity expands $\to$ Air sucked in.
9. Transportation of Gases
  • Oxygen is carried by Haemoglobin (Respiratory Pigment) in RBCs.
  • $CO_2$ is more soluble in water, so transported in dissolved form in plasma.
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10. Human Heart (हृदय)
  • Muscular organ, size of a fist. 4 chambers to prevent mixing of $O_2$ and $CO_2$ blood.
  • Double Circulation: Blood goes through heart Twice in one cycle.
    (मनुष्य में दोहरा परिसंचरण होता है।)
RALA RVLV Ventricles have thicker walls!
11. Blood Vessels & Lymph
  • Arteries: Carry blood Away from heart. Thick elastic walls (High pressure).
  • Veins: Bring blood To heart. Thin walls, have Valves to prevent backflow.
  • Platelets: Help in blood clotting at injury sites.
  • Lymph: Colourless fluid, carries digested fats & drains excess fluid.
12. Transport in Plants
  • Xylem: Transports Water & Minerals (Upwards). Uses Transpiration Pull.
  • Phloem: Transports Food (Photosynthates). Uses Energy (ATP). Translocation!
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13. Human Excretory System (उत्सर्जन तंत्र)
  • Main organs: Pair of Kidneys, Ureters, Urinary Bladder, & Urethra.
  • Nitrogenous wastes (Urea/Uric acid) are filtered from blood in kidneys.

Structure of a Nephron (वृक्काणु)

“Functional unit of Kidney”

Bowman’s Capsule Tubular Part
14. Mechanism of Urine Formation
  • (i) Filtration: High pressure in Glomerulus.
  • (ii) Selective Reabsorption: Glucose, Amino acids, Salts & Water are reabsorbed.
  • (iii) Urine: Collected in duct $\to$ Ureter $\to$ Bladder.
15. Excretion in Plants
  • $O_2$ is a waste of Photosynthesis!
  • Excess water removed via Transpiration.
  • Wastes stored in Cellular Vacuoles or as Resins & Gums.
  • Lost through falling leaves or excreted into soil.
Dialysis: Artificial kidney used during kidney failure to filter waste from blood via diffusion.
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Be Alive!
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