1. What is holozoic nutrition
holo means-whole
zoikos means-of animals
2. • is a method of nutrition.
• involves the ingestion of liquid or solid organic
material.
• digestion, absorption and assimilation of it.
• to utilize it.
3. • This method suggests phagocytosis where the
cell membrane completely surrounds a food
particle.
• This type of nutrition occurs mainly in single
celled organisms such as Amoeba.
4. 5 steps of holozoic nutrition.
• 1. (ingestion):Here, the food is first taken into the body
through an opening called a mouth (ingestion).
• 2. (digestion): then it is converted into a simple and
soluble form by various enzymes (digestion);
• 3. (absorption )simplified products thus formed are
then absorbed (absorption);
• 4. Assimilation); the conversion of nutrient into the
fluid or solid substance of the body (Assimilation);
• 5. (egestion): and finally the undigested part of food is
removed from the body (egestion).
5. Amoeba proteus
• It has intracellular mode of digestion.
• Intra means inside the cell.
• It feeds on many tiny (small) organisms .
• These organisms live in fresh water and
shallow lakes.
• It also feeds on particulate organic matter.
6. Ingestion
• Food may be ingested at any point on its
surface.
• When it comes in contact with food it puts out
pseudopodia ( podia means feet) around it.
7.
8. • These pseudopodia fuse together around food
particle forming a food
vacuole
9. food vacuole
• This food vacuole undergoes many changes as
digestion proceeds.
• First it grows smaller
• The larger
• Again smaller.
10. Role of Lysosomes
• Lysosomes contain hydrolytic enzymes ,fuse
with food vacuole and enzymes are secreted
in food vacuole.
11. First phase of digestion
• It includes killing and softening of
food in acidic medium(pH 5.6).
• Later it becomes alkaline pH 7.3
during which digestion is completed.
12. Absorption through fine canals
• When digestion is complete in food
vacuole ,membrane makes
numerous small canals.
13. • The products of digestion are passed
into the canals and into surrounding
cytoplasm.
• Later it is used by amoeba for various
metabolic reactions.
14. Egestion
• Un digested material leaves amoeba
through a process called egestion in
to water around amoeba.
• It takes place at any point on its
surface.
