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Chapter 6: Nutrition in Plants

Study the first subtopic below. Unlock photosynthesis, leaf structure, light & dark stages, storage organs, macro- and micro-elements and assessment in the app.

Key Terms and Concepts

Nutrition — The process by which living organisms obtain and use food for energy, growth, repair and reproduction.

Autotroph — An organism that makes its own food from simple inorganic substances (e.g. green plants).

Heterotroph — An organism that cannot make its own food and depends on other organisms (e.g. animals, fungi).

Photosynthesis — The process by which green plants make glucose from carbon dioxide and water using light energy absorbed by chlorophyll.

Chlorophyll — The green pigment in chloroplasts that traps light energy.

Stoma (plural: stomata) — A tiny pore in the leaf surface, surrounded by two guard cells, for gas exchange.

Macroelement — An essential element needed in large amounts (N, P, K, Ca, Mg, S).

Microelement (trace element) — An essential element needed in very small amounts (Fe, Mn, Zn, Cu, B, Mo, Cl).

6.1 Concept of Nutrition (Free full subtopic)

All living things need food. Nutrition has two main modes: autotrophic and heterotrophic.

Autotrophic nutrition and its variants

Autotrophs build complex organic food from simple inorganic raw materials. There are two variants:

Photoautotrophs (photosynthesis). Use light energy. Examples: green plants, algae, and some bacteria (cyanobacteria).
Chemoautotrophs (chemosynthesis). Use energy from chemical reactions. Examples: nitrifying bacteria (Nitrosomonas, Nitrobacter) and sulphur bacteria.

Heterotrophic nutrition (for comparison)

Holozoic: eating and digesting solid food (humans, goats).
Parasitic: living on or in a host and harming it (tapeworm, Striga/witchweed, dodder).
Saprophytic: feeding on dead or decaying matter (mushrooms, moulds).

Special case

Insectivorous plants (sundew, Venus flytrap, pitcher plant) photosynthesize but also trap insects to get nitrogen from poor soils.

Quick reminder – photosynthesis equation (you will study this fully next):
Carbon dioxide + Water → Glucose + Oxygen
(in the presence of light and chlorophyll)

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6.2 Photosynthesis – process, equation and products
6.3 Structure of the leaf and adaptations for photosynthesis
6.4 Light and dark stages
6.5 Importance of photosynthesis
6.6 Storage organs (tuber, bulb, corm, rhizome)
6.7–6.9 Essential elements, macroelements and microelements (functions, deficiency, excess)
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More Form One Biology chapters

Chapter 1 Introduction to Biology · Full free
Chapter 2 Scientific Processes
Chapter 3 Cell Structure and Organization
Chapter 4 Introduction to Classification
Chapter 5 Viruses, Bacteria and Protoctists
Chapter 6 Nutrition in Plants · You are here (preview)