# method of nutrition
Nutrition in living beings is mainly done by the methods
(i) Autotrophic nutrition
(ii) Heterotrophic nutrition
(i) Autotrophic nutrition: - The process of nutrition by which living beings make their own food without depending on others, it is called Autotrophic nutrition .
Example: trees and plants
Note:- The organisms in which Autotrophic nutrition is found are called autotrophs.
(ii) Heterotrophic nutrition:- The process of nutrition by which organisms depend on others for their food is called Heterotrophic nutrition .
Example:- human, animal
Note:- The organisms in which heterotrophs are found are called heterotrophs.
# types of Autotrophic nutrition
There are mainly three types of Autotrophic nutrition .
(i) Saprophytic nutrition
(ii) Parasitic nutrition
(iii) Holozoic nutrition
(i) Saprophytic nutrition: - The process of nutrition by which organisms absorb their food in the form of dissolved carbonic substances from the bodies of dead organisms and plants is called saprophytic nutrition.
Example:- Fungi, Bacteria, Protozoa
The organisms which obtain food by Saprophytic nutrition are called saprophytes.
(ii) Parasitic nutrition: - The process of nutrition by which organisms obtain their food by living in contact with other living beings permanently or temporarily is called parasitic nutrition.
For example: - Fungi, bacteria, some plants like immortelle, some animals like roundworm, hookworm, tapeworm, entamoeba, histolytic, malaria
Organisms which obtain food through parasitic nutrition are called parasites.
The organism from whose body the parasite gets its food is called host.
(iii) Holozoic nutrition:- The process of nutrition by which organisms do their food in the form of solid or liquid by the way of taking food of animals, it is called Holozoic nutrition .
For example: - amoeba, frog, human
The living beings who get food through Holozoic nutrition are called Holozoics .
• What is photosynthesis?
Answer :- The process by which plants prepare their food is called photosynthesis.
chemical equation for the overall process of photosynthesis
6CO2 + 12H2O ⟶ C6H12O6 + 6O2 + 6H2O
• Which raw materials are needed for photosynthesis?
Answer: Four substances are required for photosynthesis
chlorophyll, carbon dioxide, water, and sunlight
Note :-
1. The process of photosynthesis takes place in the chloroplast.
2. The palisade and spongy parenchyma of leaves are filled with many chloroplasts.
3. Chlorophyll pigments are found in chloroplast.
4. Leaves are called photosynthetic organs.
5. Chloroplasts are called photosynthetic organs.
* * • Amoeba :- Amoeba is a simple protozoan organism. It is a soft water, unicellular and indefinite shaped animal. Its shape is a changing relief due to the formation and deterioration of pseudopods. There is no special composition for nutrition in its body. It takes food with the help of its cotyledons.
The food of amoeba is small pieces of algae, bacteria, diatoms, other small unicellular organisms and small pieces of dead carbonic matter.
# Explain the process of nutrition in Amoeba.
Ans:-
Amoeba shows holozoic nutrition which is comprised of the following steps:
Ingestion, Digestion, Absorption, Assimilation and Egestion.
Ingestion:-Amoeba makes finger like projections called pseudopodia . Amoeba trap food particles with the help of pseudopodia. After that Amoeba takes in the food particle along with water .
Digestion:- Amoeba makes food vacuole after ingestion the food particle. Enzymes are released in the food vacuole for Digestion.
Absorption:-After digestion, nutrients enter the cytoplasm through Osmosis.
Assimilation:-Nutrients are utilized by the cell for various purposes.
Egestion:-Food vacuole goes near the cell membrane to empty its contents outside the cell. This result in the expulsion of waste material from the cell.
• What is alimentary canal?
Answer :- Human beings and all higher class animals have special organs for digestion of food which are called alimentary canal.
** *
# Human alimentary canal
The human alimentary canal is a coiled structure whose length is about 8 to 10 meters. It starts from the mouth and extends till the anus.
# Salivary glands of human oral cavity -
Three pairs of salivary glands are found in the human oral cavity.
1. Parotid gland
2. Submandibular gland
3. Sublingual salivary gland
• What is pharynx?
Answer :- The back part of the oral cavity is called pharynx.
There are two holes in the pharynx.
1. gullet 2. glottis
1. Gullet: - It opens in the front part of the alimentary canal.
2. Glottis: - It opens in the respiratory tract. Next to this there is a strip like structure, which is called epiglottis. When a man eats, this strip covers the larynx, so that the food does not go into the windpipe.
• What is the oesophagus?
Answer :- The food stained with saliva from the oral cavity reaches the oesophagus through the gullet. There is no digestion process in it.
Through this the food reaches the stomach.
• What is peristalsis?
Answer :- Wave-like contraction or contraction and relaxation or expansion starts in the wall of the oesophagus which is called peristalsis.
• What is stomach?
Answer :- It is a wide sac-like structure which starts from the left side of the abdominal cavity and extends in the transverse direction.
The front part of the stomach is called cardiac and the back part is called pyloric.
** **
• What is the small intestine?
Answer :- The small intestine is the longest part of the alimentary canal. Its shape is cylindrical. Digestion is completed in this part of the alimentary canal. In humans, its length is 6 meters and width is 2.5 centimeters.
# There are three parts of the small intestine.
1. duodenum
2. Jejunum
3. Ilium
Note :-
* Duodenum is the first part of the small intestine which starts just after the pyloric part of the stomach. It is C shaped.
* The jejunum is the middle part of the small intestine. Most of the small intestine is the ileum. Final digestion of food takes place in this part. Absorption of digested food also takes place in the ileum.
• What is liver?
Answer :- It is the largest gland of the body. Whose weight is about 1.5 kg.
Bile is secreted from the liver cells. Secreted bile is stored in a small sac-like structure called the gall bladder.
• Write the functions of bile.
Answer :- Bile has the following two functions.
1. By destroying the acidity of the acidic chyme coming from the stomach to the duodenum, it makes it alkaline so that the enzymes of the pancreatic juice can act on it.
2. Breaks down the fats of food with the help of bile salts.
• What is the pancreas?
Answer :- Just below the stomach there is a yellow colored gland which is called pancreas. Enzymes called trypsin, amylase, lipase, nuclease are found in pancreatic juice.
• What is chyle?
Answer :- Complex, insoluble molecules of food are converted into simple soluble molecules. In this condition the chyme becomes even more liquid, this is called chyle.
Absorption of digested food in chyle takes place by the villi of the ileum.
• Large intestine: - The next part of the small intestine opens into the large intestine.
There are two parts of the large intestine.
1. Colon
2. rectum
1. Colon: - The colon is divided into three parts.
(A) Upper colon
(B) Transverse colon
(C) descending colon
The descending colon opens into the rectum, which finally exits the body through the anus.
• What is called cecum?
There is a small tube at the junction of small intestine and large intestine, which is called cecum.
• What is appendix?
There is a finger-like structure at the top of the cecum, whose head is closed. This structure is called appendix .
There is no function of appendix in human alimentary canal.
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