?? 1. What is Nutrition?
All living things need food to grow, move, repair themselves, and stay alive. The process by which organisms
obtain and use food is called nutrition. Based on how they get food, organisms
are divided into:
- Autotrophs � make their own food from simple inorganic substances using
sunlight. Example: all green plants, algae
- Heterotrophs � cannot make food; must eat other organisms. Example: all
animals, fungi, most bacteria
?? 2. Photosynthesis � The Plant Food Factory
Green plants make their food through a process called photosynthesis. They use
sunlight energy, CO2 from air, and water from soil to produce glucose and release oxygen.
Flowchart: How Photosynthesis Works
?? Sunlight (Energy)
+
?? CO2 (from air via stomata)
+
?? Water (from soil via roots)
?
Absorbed by Chlorophyll in Chloroplasts of Leaves
? Chemical Reaction Inside Leaf
?
?? Glucose (food/sugar)
+
?? Oxygen (O2) Released
?
Glucose stored as Starch in leaves, seeds, roots, fruits
Word Equation:
Carbon dioxide + Water ? (Sunlight + Chlorophyll) ? Glucose + Oxygen
Chemical Equation: 6CO2 + 6H2O ? C6H12O6 + 6O2
?? AI Image Prompt
A beautifully detailed cross-section of a green leaf showing photosynthesis. The
leaf is cut open to reveal layers inside. Yellow sun rays (labeled "Sunlight") shine from above onto the
leaf surface. Blue upward arrows labeled "CO2 from air" enter through tiny stomata pores on the leaf
underside. A blue root system below absorbs water from soil � water molecules (labeled "H2O") travel
upward through the stem as blue lines. Inside the leaf, bright green chloroplasts are labeled. A glowing
yellow reaction zone in the center produces glucose (honeycomb sugar icons labeled "Glucose") and
releases green oxygen bubbles upward (labeled "O2 released"). The full word equation is written at the
bottom in a neat box. Botanical educational illustration style, vibrant colors, white background,
scientific accuracy.
Fig. 1.1 � Process of photosynthesis in a green leaf
Key Requirements for Photosynthesis:
| What is needed |
Where it comes from |
How it enters the plant |
| Sunlight |
Sun |
Absorbed by chlorophyll in leaves |
| Carbon dioxide (CO2) |
Atmosphere |
Through stomata (tiny pores on leaf surface) |
| Water (H2O) |
Soil |
Absorbed by roots ? travels up via xylem |
| Chlorophyll |
Leaf cells |
Green pigment in chloroplasts |
- Take a leaf kept in sunlight for a few hours
- Boil in water ? boil in alcohol (removes green chlorophyll) ? leaf turns pale white
- Wash with water ? add iodine solution
- Result: leaf turns blue-black ? ? proves starch (food) was made by photosynthesis!
?? 3. Other Modes of Nutrition in Plants
Not all plants rely solely on photosynthesis. Some have evolved special ways to get nutrients:
Flowchart: Classification of Plant Nutrition Modes
?
Autotrophic
Makes own food via
Photosynthesis
E.g. all green plants
Parasitic
Steals food from
host
E.g. Cuscuta (Amarbel)
Insectivorous
Traps insects for
nutrients
E.g. Venus Flytrap, Pitcher Plant
Saprophytic
Feeds on dead matter
E.g.
Mushroom, Fungi
Symbiotic
Mutual benefit with
another organism
E.g. Lichen, Rhizobium-Legume
| Mode |
Description |
Examples |
| Autotrophic |
Makes food via photosynthesis |
Mango, Rose, Wheat, Grass |
| Parasitic |
Attaches to host via haustoria, steals food & water; no chlorophyll |
Cuscuta (Amarbel), Mistletoe |
| Insectivorous |
Traps & digests insects for nitrogen; grows in nitrogen-poor soil |
Venus Flytrap, Pitcher Plant, Sundew |
| Saprophytic |
Secretes enzymes onto dead matter; absorbs digested nutrients |
Mushroom, Bread mould, many bacteria |
| Symbiotic |
Two organisms live together for mutual benefit |
Lichen (fungus + algae), Legume + Rhizobium |
?? AI Image Prompt
A 4-panel educational botanical illustration showing special plant nutrition modes,
each panel labeled in bold: Panel 1 "Cuscuta � Parasite" � a yellow-orange leafless vine twisting
tightly around a green host stem, with small sucker-like projections labeled "Haustoria" going into the
host, stealing nutrients shown as orange arrows. Panel 2 "Pitcher Plant � Insectivore" � a tall
red-green trumpet-shaped pitcher trap with a fly falling into it, sticky liquid inside labeled
"Digestive enzymes". Panel 3 "Venus Flytrap � Insectivore" � the iconic toothed jaw-like leaf snapping
shut around a green fly, with a magnified view of the trigger hairs inside the trap. Panel 4 "Mushroom �
Saprophyte" � a cluster of mushrooms growing on brown decomposing wood/leaves, with tiny enzyme arrows
breaking down the dead material. All panels on a white background with consistent scientific
illustration style, bright colors, and clean labels.
Fig. 1.2 � Special modes of nutrition in plants
?? 4. Nitrogen & Symbiotic Bacteria (Rhizobium)
- Plants need nitrogen to build proteins, but cannot use N2 gas from air directly
- Rhizobium bacteria live in root nodules of legumes
(peas, beans, groundnut)
- Rhizobium fixes atmospheric N2 into nitrates ? plants absorb it through roots
- It is a symbiotic relationship: bacteria get food + shelter; plant gets fixed
nitrogen
- Dead organisms are decomposed by bacteria/fungi ? nitrogen released back into soil
?? 5. Quick Revision
- Autotrophs = make own food (plants). Heterotrophs = eat others
(animals)
- Photosynthesis: CO2 + H2O + Sunlight + Chlorophyll ? Glucose + O2
- CO2 enters via stomata; water via roots ? xylem ? leaves
- Starch test: iodine solution turns blue-black ? starch present
- Cuscuta = parasite; uses haustoria to steal nutrients; has no
chlorophyll
- Pitcher plant, Venus Flytrap = insectivorous (trap insects for nitrogen)
- Fungi (mushroom) = saprophytic (break down dead matter by secreting enzymes)
- Rhizobium in root nodules of legumes = fixes atmospheric nitrogen (symbiotic)
- Lichen = symbiosis between fungus (body/shelter) and algae (food via
photosynthesis)
