What is Nutrition?What is Nutrition?
The entire process by which organism
obtain energy from food for growth,
maintenance and repair of damaged
tissues
Nutrient – the substances that are
required for the nourishment of an
organism
6.1 Type of Nutrition6.1 Type of Nutrition
Two main types:
1. Autotrophic
2. Heterotrophic
1. Autotrophic 1. Autotrophic
A process in which organisms synthesise
organic substances from inorganic
substances
Autotroph = Auto – self, trophos – feed
(organism which can make their own food)
The source of energy for synthesising food
can be either light energy or chemical
energy.
The synthesis of food using light
energy – photosynthesis (photo –
light)
Photoautotroph – organisms which
produce organic molecules from
carbon dioxide and water using
sunlight as a source of energy
Example: green plants
The synthesis of food using chemical
energy – chemosynthesis (chemo –
chemical)
Chemoautotroph – organisms which
synthesise organic compound by
oxidising inorganic compound
(hydrogen sulphide and ammonia)
Example: certain bacteria
(Nitrosomonas sp. and Nitrobacter sp.)
2. Heterotrophic2. Heterotrophic
A type of nutrition in which organism
obtain energy through the intake and
digestion of organic substances.
Heterotroph =Hetero – other,
trophos – feed (organism that cannot
synthesis their own nutrients but
obtain the nutrients from other
organisms)
They may practice
a) Holozioc nutrition,
b) Saprophytism
c) Parasitism
- holo –like, zoon – animal
- The organism feeds by ingesting
solid organic matter which is
subsequently digested and
absorbed into their bodies
- Examples: humans, herbivores,
carnivores and some carnivorous
pitcher plants and Venus fly-traps
a) Holozoic nutritiona) Holozoic nutrition
- The organism called saprophytes
- Feed on dead and decaying
organic matter
- Digest their food externally
before absorbing the nutrients
into their bodies
- Examples: bacteria, fungi
b) Saprophytismb) Saprophytism
- The organism called parasite
- Obtain nutrient from living on
(ectoparasites) or in (endoparasites)
the body of another living organism
(host)
- They absorbs readily digested food
from its host
- Examples: fleas (ectoparasites), lice,
worms (endoparasites), Rafflesia
plant
c) Parasitismc) Parasitism
Test YourselfTest Yourself
1.Differentiate between autotrophic and
heterotrophic nutrition.
A: Autotrophic nutrition – A process in
which organisms synthesise organic
substances from inorganic substances
Heterotrophic nutrition - A type of
nutrition in which organism obtain
energy through the intake and
digestion of organic substances.
2.Name two types of autotrophic
nutrition.
A: Photosynthesis and chemosynthesis
Test YourselfTest Yourself
3.Name three types of heterotrophic
nutrition.
A: Holozoic nutrition, saprophytism and
parasitism
Test YourselfTest Yourself
4.Name the nutritional habits of the
following organisms;
a) Pitcher plants
A: holozoic nutrition
b) Green algae
A: photosynthesis
d) Tapeworm
A: parasitism
Test YourselfTest Yourself