Chapter 2 (Nutrition in Animals) of Class 7 Science NCERT Book (PDF) is available here for download in PDF format. Download now & prepare for CBSE Class 7 Science exam in academic session 2021-22. It is one of the most important chapters of the CBSE Class 7th Science NCERT textbook & many essential questions are framed from this chapter.
Snapshot from Chapter 2 of Class 7 Science NCERT Textbook:
Important topics of this chapter:
Some important topics of this chapter are Amino acid, Absorption, Amoeba, Assimilation, Bile, Buccal cavity, Food vacuole, Canine,
Cellulose, Digestion, Egestion, Fatty acid, Gall bladder, Liver, Glycerol, Incisor, Ingestion, Milk teeth, Molar, Permanent teeth, Oesophagus, Pseudopodia, Pancreas, Premolar, Rumen, Ruminant, Rumination, Salivary glands, Villi, Saliva. Problems from these topics have been frequently asked in various exams conducted by various CBSE Schools.
Important points from the summary of this chapter:
⇒ Animal nutrition involves nutrient requirement, mode of intake of food & its utilisation in the body.
⇒ The human digestive system consists of the alimentary canal &
secretory glands. It consists of the
- buccal cavity,
- small intestine,
- large intestine ending in the rectum
⇒ The main digestive glands which secrete digestive juices
- the salivary glands,
- the liver and
- the pancreas.
⇒ The stomach wall & the wall of the small intestine also secrete digestive juices.
⇒ The modes of feeding vary in different organisms.
⇒ Nutrition is a complex process involving:
⇒ Digestion of carbohydrates, like starch, begins in the buccal cavity. The
digestion of protein starts in the stomach.
⇒ The bile secreted from the liver, the pancreatic juice from the pancreas & the digestive juice from the intestinal wall complete the digestion of all components of food in the small intestine.
⇒ The digested food is absorbed in the blood vessels from the small intestine.
⇒ The absorbed substances are transported to different parts of the body.
⇒ Water & some salts are absorbed from the undigested food in the
⇒ The undigested & unabsorbed residues are expelled out of the body as faeces through the anus.
⇒ The grazing animals like cows, buffaloes & deer are known as ruminants.
⇒ They quickly ingest, swallow their leafy food & store it in the rumen. Later, the food returns to the mouth & the animal chews it peacefully.
⇒ Amoeba ingests its food with the help of its false feet or pseudopodia.
⇒ The food is digested in the food vacuole.