GENBIO 2 - MOD 6

Autotrophic nutrition

is observed when an organism is able to synthesize organic materials from inorganic raw

materials

autotrophs

Organisms that exhibit this ability are known as

Chemosynthesis

- is the process of synthesizing organic compounds from carbon dioxide and water using energy

supplied by chemical processes involving oxidation of inorganic substances such as hydrogen sulfide, ammonia

and iron

Chemoautotrophs

are organisms that can undero chemosysthesis

Photosynthesis

is the synthesis of organic compounds (sugar) from carbon dioxide and water using light as

source of energy

Photoautotrophs

are organisms that can undergo photosynthesis

Heterotrophic Nutrition

is observed when organisms obtain organic materials from various sources because they cannot synthesize them. These organisms are known as heterotrophs.

Saprophytic/ Saprotrophic nutrition

is the process of obtaining nutritional requirements from dead and

decaying organic matter

saprophytes/saprotrophs/ saprobionts

Organisms that exhibit this are known as

Parasitic nutrition

is living on another organism called host and obtaining food from them

parasites

. Parasites are harmful to the hosts to the extent of death

of the hos

Endoparasites

live inside the host. Examples are: tapeworms, Ascaris, potato fungus

Exoparasites

- live on the surface of the host. Examples are: ticks, lice, flea, aphids

Obligate parasites

- are unable to survive and reproduce in the absence of a hos

Facultative parasites-

can live independently in the absence of a host but can become parasitic if

opportunity arises. An example is the bootlace fungus (Armillaria mellea) that lives saprotrophically on rotting tree stump

Holozoic nutrition

is the ingestion and digestion of food in the alimentary canal before absorption to

the cells through the blood transportsystem

Herbivores

- eat plants. Examples are: goats, cows and rabbits.

b. Carnivores

- eat animals. Examples are: tigers, lions, and snakes.,

Omnivores

-eat both plants and animals. Example: humans

Detritivores-

feed on detritus (particulate organic materials from dead organisms). Examples are:

earthworms and woodlice.

Insectivorous plants

- trap insects and digest them. Examples are: pitcher plant (Nepenthes),and Venus fly trap (Dionaea muscipula)

Microphagous feeder

-take in very small particles. Examples are: Amoeba and

Paramecium, Daphnia and gastropods

Liquid feeders-

take in liquid food or food with very soft tissues. Examples are: aphids, bees, flies,

mosquitoes

Macrophagous feeder

- take in relatively large particles. Examples are: fish, birds, reptiles and mammals.

Ingestion

taking in of food.

Digestion

-breaking down of food

Mechanical digestion

occurs when food is cut, crushed, chewed and ground to fine pieces through

physical means such as using the teeth and the churning of the stomach

Chemical digestion

occurs when food is broken down into smaller molecules that can be

absorbed by the cells

Carbohydrases

break down carbohydrates into monosaccharides.

Lipases

break down lipids into fatty acids and glycerol.

Proteases act

on proteins and break them into amino acids.

Absorption

s the process by which digested simple molecules from food are transported from the GI tract to the blood and finally distributed to the different cells in the body

Assimilation

- is the process of combining the simple products of digestion or nutrients to make

complex compounds.

Egestion-

is the removal of undigested food (left after completion of absorption). When undigested food

passes through the colon, much water is reabsorbed and the undigested food becomes compact