Life Processes Class 10
1. What Are Life Processes
Maintenance tasks carried out by all living
organisms
Happen continuously, even during sleep
Require constant molecular movement
Viruses show no molecular movement
outside host — debated if truly alive
Four Life Processes
Nutrition — obtaining food and energy
Respiration — releasing energy from food
Transportation — moving food, oxygen, and
waste
Excretion — removing metabolic waste
2. Nutrition
Process of obtaining energy and raw
materials for growth and repair
Two types: Autotrophic and Heterotrophic
Autotrophic Nutrition
Organisms make their own food
Use CO₂ + water + sunlight
Examples: green plants, some bacteria
Store energy as starch (plants) or glycogen
(animals)
Heterotrophic Nutrition
Organisms cannot make their own food
Consume food made by other organisms
Break down food using enzymes
Examples: animals, fungi
Depend directly or indirectly on autotrophs
Types of Heterotrophs
Saprophytes — break food outside body,
then absorb (fungi, yeast, bread mould)
Parasites — get nutrition from living host
without killing it (cuscuta, leeches,
tapeworms, ticks)
Holozoic — ingest whole food and digest
inside (amoeba, humans)
3. Photosynthesis
Green plants convert CO₂ and water into
glucose using sunlight and chlorophyll
Unused glucose stored as starch
Equation: 6CO₂ + 12H₂O + sunlight →
C₆H₁₂O₆ + 6O₂ + 6H₂O
Three Steps
Step 1 — Absorption of light by chlorophyll
in chloroplasts
Step 2 — Conversion of light energy to
chemical energy + splitting of water into H
and O
Step 3 — Reduction of CO₂ to
carbohydrates using hydrogen and
chemical energy
Stomata
Tiny pores on leaf surface
CO₂ enters and O₂ exits through stomata
Each stoma surrounded by a pair of guard
cells
Guard cells swell → pore opens
Guard cells shrink → pore closes
Stomata close when photosynthesis is not
needed to prevent water loss
Raw Materials for Plants
Carbon dioxide — from air via stomata
Water — from soil via roots and xylem
Sunlight — energy source
Minerals — nitrogen, phosphorus, iron,
magnesium from soil
Nitrogen — needed for protein synthesis;
absorbed as nitrates/nitrites
4. Heterotrophic Nutrition in
Amoeba
Unicellular organism
Feeds using pseudopodia — temporary
finger-like extensions
Pseudopodia wrap around food → form
food vacuole
Enzymes inside vacuole digest food into
simpler molecules
Digested food diffuses into cytoplasm
Undigested material expelled out
Paramoecium
Also unicellular but fixed shape
Food moved to a specific spot using cilia
(hair-like structures)
5. Nutrition in Human Beings
Digestive system = alimentary canal
(mouth to anus)
Organs and Their Functions
Mouth — salivary amylase breaks starch
into sugar; teeth crush food; tongue mixes
Oesophagus — peristalsis moves food
downward; no digestion
Stomach — HCl creates acidic medium;
pepsin digests proteins; mucus protects
wall
Liver — produces bile juice; makes food
alkaline; emulsifies fats
Pancreas — produces trypsin (digests
proteins) and lipase (digests fats)
Small intestine — completes digestion; villi
absorb nutrients into blood
Large intestine — water reabsorbed into
blood
Rectum and Anus — undigested waste
expelled as faeces
End Products of Digestion
Proteins → Amino acids
Carbohydrates → Glucose
Fats → Fatty acids + Glycerol
Villi
Finger-like projections lining small
intestine
Increase surface area for absorption
Richly supplied with blood vessels
Carry absorbed nutrients to all body cells
Herbivores vs Carnivores
Herbivores have longer small intestine —
cellulose is hard to digest
Carnivores have shorter small intestine —
protein is easier to digest
6. Respiration
Breaking down glucose to release energy
inside cells
Energy stored as ATP (Adenosine
Triphosphate) — energy currency of cell
Glycolysis
First step of all respiration
Occurs in cytoplasm
Glucose → Pyruvate
Releases 2 ATP
Does not need oxygen
Aerobic Respiration
Occurs in mitochondria
Needs oxygen
Pyruvate → CO₂ + H₂O + large energy (36–38
ATP)
Used by most animals and plants
Anaerobic Respiration
Occurs in cytoplasm
No oxygen needed
Releases only 2 ATP
In Yeast
Pyruvate → Ethanol + CO₂ + 2 ATP
Used in bread, wine, beer making
In Muscles (during intense exercise)
Pyruvate → Lactic acid + 2 ATP
Lactic acid buildup causes muscle cramps
Aerobic vs Anaerobic Comparison
Aerobic — O₂ needed, mitochondria, 36–38
ATP, CO₂ + H₂O
Anaerobic — no O₂, cytoplasm, 2 ATP,
ethanol or lactic acid
7. Breathing in Human Beings
Air path: Nostrils → Nasal passage → Trachea
→ Bronchi → Bronchioles → Alveoli
Trachea
Supported by cartilage rings to keep it
open
Connects throat to bronchi
Lungs
Two lungs in chest cavity
Each lung contains millions of alveoli
Alveoli
Tiny balloon-like sacs at end of bronchioles
Walls are one-cell thick
Surrounded by dense blood capillaries
Surface area approximately 80 m²
O₂ from air → crosses wall → into blood
CO₂ from blood → crosses into alveoli →
breathed out
Breathing Mechanism
Inhalation — diaphragm flattens + ribs lift →
chest expands → air rushes in
Exhalation — diaphragm rises + ribs fall →
chest contracts → air pushed out
Haemoglobin
Red pigment in RBCs
Carries oxygen from lungs to body cells
CO₂ more soluble in water → transported
dissolved in blood plasma
Aquatic Organisms
Breathe faster than land animals
Dissolved O₂ in water is much less than in
air
8. Transportation in Human
Beings
Circulatory system has three parts
Heart — pump
Blood — fluid
Blood vessels — tubes (arteries, veins,
capillaries)
Blood Components
Plasma — yellowish liquid; carries food,
CO₂, hormones, nitrogenous waste
Red Blood Cells (RBCs) — carry O₂ using
haemoglobin
White Blood Cells (WBCs) — fight infection;
immune system
Platelets — clot blood at injury points
Blood Vessels
Artery — heart to body; thick elastic walls;
high pressure; no valves; oxygenated blood
Vein — body to heart; thin walls; low
pressure; has valves; deoxygenated blood
Capillary — connects artery to vein; one-cell
thick wall; exchange with body cells
The Heart
Four chambers: Right Atrium, Right
Ventricle, Left Atrium, Left Ventricle
Valves prevent backflow of blood
Left ventricle wall is thicker — pumps
blood to whole body under high pressure
Double Circulation
Blood passes through heart twice in one
cycle
Pulmonary circulation — heart to lungs
and back (deoxygenated → oxygenated)
Systemic circulation — heart to body and
back (oxygenated → deoxygenated)
Oxygenated and deoxygenated blood
never mix in humans
Heart Chambers in Different Animals
Fish — 2 chambers (single circulation)
Amphibians and reptiles — 3 chambers
(some mixing)
Birds and mammals — 4 chambers (double
circulation, no mixing)
Lymph
Fluid that leaks out of capillaries into
tissues
Carries digested fats and some proteins
Returns to blood via lymphatic vessels
Colourless, fewer proteins than blood
9. Transportation in Plants
Two types of transport tissue: Xylem and
Phloem
Xylem
Transports water and minerals
Movement: upward only (roots to leaves)
Made of dead cells
Force: transpiration pull
Phloem
Transports food (glucose/sucrose)
Movement: both upward and downward
Made of living cells
Process called translocation
Transpiration
Loss of water as vapour from leaves
through stomata
Creates suction that pulls water upward
through xylem
Root hair cells absorb water from soil by
osmosis
Water concentration lower inside root than
in soil
Translocation
Food made in leaves moved to all parts of
plant through phloem
ATP energy used to move food into phloem
Water follows by osmosis → pressure builds
→ food pushed to all parts
10. Excretion in Human Beings
Removal of metabolic waste from body
Main waste products: urea, CO₂, excess
water and salts
Excretory Organs
Kidneys — filter blood and produce urine
Lungs — remove CO₂ and water vapour
Skin — removes salts and water through
sweat
Liver — converts ammonia to urea
Kidneys
Two bean-shaped organs in abdomen
Each kidney has about 1 million nephrons
Ureter carries urine from kidney to urinary
bladder
Urine stored in urinary bladder and
expelled through urethra
Nephron
Basic filtering unit of kidney
Glomerulus — ball of capillaries where
blood is filtered
Bowman's capsule — cup around
glomerulus that collects filtrate
Tubule — reabsorbs glucose, useful salts,
and water back into blood
Remaining concentrated liquid = urine
(urea + water + salts)
Nephron Filtration Steps
Step 1 — Blood enters glomerulus under
high pressure
Step 2 — Water, urea, glucose, salts filtered
into Bowman's capsule
Step 3 — Tubule reabsorbs glucose, useful
salts, required water
Step 4 — Concentrated urine passes to
ureter → bladder → expelled
Osmoregulation
Kidneys control water content of body
More water intake → more dilute urine
produced
Dehydration → less, concentrated urine
produced
Dialysis
Used when kidneys fail
Blood filtered externally by dialysis
machine (artificial kidney)
Waste removed; cleaned blood returned to
body
11. Excretion in Plants
Plants produce very little metabolic waste
CO₂ from respiration used in
photosynthesis
O₂ from photosynthesis used in respiration
How Plants Remove Waste
CO₂ and O₂ — exchanged through stomata
(leaves) and lenticels (stems)
Excess water — lost through transpiration
via stomata
Solid waste (resins, gums, tannins) — stored
in old xylem, bark, or cell vacuoles
Waste in leaves — removed when leaves fall
in autumn
Bark — shed periodically carrying stored
waste with it
mindmapstudy.com mindmapstudy.com
