Definitions [6]
Define the following:
Saprozoic
Saprozoic nutrition refers to nutrition in which animals feed on dead or decaying matter.
Define parasitic nutrition.
Parasitic nutrition is that nutrition in which an organism derives its food from the body of another living organism (called its host) without killing it.
Define saprophytic nutrition.
Saprophytic nutrition is that nutrition in which an organism obtains its food from decaying organic matter of dead plants, dead animals and rotten bread.
Define parasite.
A parasite is an organism (plant or animal) which feeds on another living organism called its host. A parasite receives its food from the host but provides no benefit to the host in return, and it usually harms the host.
Define the following term:
Photolysis of water
Releasing electrons and dividing the water molecule (H2O) into its two components (Hydrogen and Oxygen). Photolysis is the term used to describe this reaction, which is characterised by the fracturing of molecules by light (photo = light, lysis = breaking).
Photosynthesis is the process by which living plant cells, containing chlorophyll, produce food substances (glucose and starch) from carbon dioxide and water by using light energy. Plants release oxygen as a byproduct during photosynthesis.
Key Points
- According to WHO, nutrition means taking in food in relation to the body’s dietary needs.
- It includes five main processes: ingestion, digestion, absorption, assimilation and egestion, which together describe how the body handles food.
- Photosynthesis converts sunlight into chemical energy using CO₂ and water, producing glucose and releasing oxygen as a byproduct.
- Green plants are autotrophs (make their own food); all other organisms are heterotrophs. All life depends on sunlight for energy.
- Three essentials for photosynthesis: chlorophyll, light, and CO₂.
- Experiment 1 - Variegated leaf tested for starch showed that photosynthesis occurs only in green parts in the presence of light.
- Experiment 2 - Leaf part enclosed with KOH-soaked cotton (absorbs CO₂) tested negative for starch → proved CO₂ is necessary for photosynthesis.
