CHAPTER 6 : NUTRITION
Type of Nutrition
- Nutrition – process by which organisms obtain energy and nutrients from food, for growth, maintenance and repair of damaged tissues.
- Nutrients – the important substances which are required for nourishment of an organisms.
- Living organisms are divided into two groups (based on the nutritional habits): autotrophs and heterotrophs.
(i) Autotroph
- Autotrophs – organisms that are able to synthesise complex organic compounds from raw, simple inorganic substances (water and air) by using light or chemical energy. These organisms manufacture their own food by photosynthesis or chemosynthesis.
- Photoautotrophs – chlorophyll containing organisms that utilise solar energy for building organic substance.
- Photoautotropic nutrition = holophytic nutrition.
- Chemoautotrophs – organisms synthesise organic substances by utilising chemical energy.
| Autotrophs | Example |
| Photoautotroph | Trees |
| Chemoautotroph | Bacteria |
(ii) Heterotroph
- Heterotrophs – organisms that are not able to synthesise their own nutrients but they obtain the nutrients from other organisms.
- Holozoic nutrition – organisms feed by ingesting solid organic matter that digested and absorbed into the bodies.
- Saprophytism – organisms feed on dead and decaying organic matter.
- Parasitism – organisms obtains nutrients (absorbs readily digested food) by living on / in the body of another living organisms (the host)
thanks to http://doktorkartunis.blogspot.com/2012/05/biology-form-4-notes-nutrition.html. mind maps are taken from this blog.
