Class 7 Science Nutrition in Animals Notes and Questions Answers
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Class 7 Science Chapter – Nutrition in Animals Notes and Questions Answers

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Description: Complete Class 7 Science Nutrition in Animals chapter with easy notes, NCERT-based questions and answers, MCQs, and exam preparation guide.

📖 Nutrition in Animals – Easy Notes

Introduction: All living organisms require food to get energy for various life activities. Nutrition is the process by which organisms obtain food and utilize it for growth, repair, and energy. In animals, the mode of nutrition is heterotrophic because they depend on plants or other animals for food.

Class 7 Science Chapter 2 Nutrition in Animals Notes and Questions Answers | NCERT Solutions with MCQ
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1. Need for Nutrition

  • Food provides energy to perform activities.
  • It helps in the growth and repair of the body.
  • Food protects from diseases by building immunity.

2. Different Modes of Nutrition in Animals

  • Herbivores: Animals that eat only plants (e.g., cow, goat).
  • Carnivores: Animals that eat other animals (e.g., lion, tiger).
  • Omnivores: Animals that eat both plants and animals (e.g., human, dog).

3. Human Digestive System

The human digestive system consists of an alimentary canal and digestive glands.

  • Mouth: Food is chewed with the help of teeth and mixed with saliva.
  • Oesophagus: Tube carrying food to the stomach.
  • Stomach: Secretes gastric juice (containing HCl, pepsin, mucus) to digest proteins.
  • Small Intestine: Main site of digestion and absorption. Receives bile juice from liver and pancreatic juice from pancreas.
  • Large Intestine: Absorbs water and forms feces.
  • Anus: Waste is expelled from the body.

4. Role of Digestive Juices

  • Saliva: Breaks down starch into sugar.
  • Gastric Juice: Breaks down proteins into simpler substances.
  • Bile Juice: Breaks down fats into small droplets for easy digestion.
  • Pancreatic Juice: Contains enzymes for digestion of carbohydrates, proteins, and fats.

5. Digestion in Other Animals

  • Ruminants (e.g., Cow): Have a large sac-like structure called rumen. Food is partially digested and then brought back to the mouth for chewing (rumination or cud chewing).
  • Amoeba: Single-celled organism that engulfs food using pseudopodia and digests it inside food vacuoles.

6. Key Points to Remember

  • Nutrition provides energy, growth, and repair.
  • Human digestion involves mechanical and chemical processes.
  • Small intestine is the main site of absorption.
  • Animals show different digestive systems based on their food habits.

❓ Questions and Answers on Nutrition in Animals

MCQs (Choose the correct option)

  1. Which part of the digestive system absorbs water?
    a) Stomach
    b) Small intestine
    c) Large intestine
    d) Oesophagus
    Answer: c) Large intestine
  2. Which enzyme in saliva helps in digestion of starch?
    a) Pepsin
    b) Amylase
    c) Lipase
    d) Trypsin
    Answer: b) Amylase
  3. Bile juice is produced by:
    a) Stomach
    b) Pancreas
    c) Liver
    d) Gall bladder
    Answer: c) Liver
  4. In ruminants, cud is stored in:
    a) Large intestine
    b) Rumen
    c) Small intestine
    d) Mouth
    Answer: b) Rumen
  5. Digestion in amoeba occurs in:
    a) Nucleus
    b) Food vacuole
    c) Cytoplasm
    d) Mitochondria
    Answer: b) Food vacuole
  6. Main site of absorption of nutrients is:
    a) Stomach
    b) Small intestine
    c) Liver
    d) Large intestine
    Answer: b) Small intestine
  7. Which organ secretes insulin along with digestive juice?
    a) Liver
    b) Stomach
    c) Pancreas
    d) Gall bladder
    Answer: c) Pancreas

Very Short Answer Questions

  1. What is nutrition?
    Answer: The process of obtaining and utilizing food for growth, repair, and energy.
  2. Name the organ where protein digestion begins.
    Answer: Stomach.
  3. Which part of the digestive system produces bile juice?
    Answer: Liver.
  4. What are herbivores?
    Answer: Animals that eat only plants.
  5. Name the enzyme present in saliva.
    Answer: Amylase.
  6. What is the main function of large intestine?
    Answer: Absorption of water and formation of feces.
  7. What is rumination?
    Answer: The process in ruminants of bringing back partially digested food to the mouth for chewing again.

Short Answer Questions

  1. Why is digestion necessary?
    Answer: Food contains complex substances which cannot be directly absorbed. Digestion breaks them into simple, soluble forms that can be absorbed by the body.
  2. Differentiate between herbivores and carnivores.
    Answer: Herbivores eat plants (cow, goat) while carnivores eat other animals (lion, tiger).
  3. What is the role of bile juice?
    Answer: Bile breaks down fats into smaller droplets, making them easier to digest.
  4. What are omnivores? Give examples.
    Answer: Animals that eat both plants and animals, e.g., humans and dogs.
  5. Explain digestion in amoeba.
    Answer: Amoeba engulfs food with pseudopodia, forms food vacuoles, and digests food with enzymes inside them.
  6. Why is small intestine considered the most important part of digestion?
    Answer: It is the site where digestion is completed and nutrients are absorbed.
  7. What is the function of pancreas?
    Answer: Pancreas secretes pancreatic juice containing enzymes for digestion of carbohydrates, proteins, and fats.

Long Answer Questions

  1. Describe the process of digestion in human beings step by step.
    Answer: Digestion in humans begins in the mouth, where teeth chew food and saliva digests starch. Food moves down the oesophagus into the stomach, where gastric juice digests proteins. From there, it enters the small intestine, where bile breaks fats and pancreatic juice digests all nutrients. Finally, absorption of digested food occurs in the small intestine, while water absorption and waste removal happen in the large intestine.
  2. Explain the structure and function of the human stomach.
    Answer: The stomach is a J-shaped organ. It secretes gastric juice containing hydrochloric acid, mucus, and pepsin. It churns food, kills germs with acid, and digests proteins partially.
  3. How does rumination help ruminants like cow and buffalo?
    Answer: Ruminants swallow grass quickly into rumen, where microbes partially digest cellulose. Later, food is regurgitated and chewed again for better digestion. This process is called rumination.
  4. Discuss the role of liver and pancreas in digestion.
    Answer: The liver produces bile that helps digest fats, while pancreas secretes pancreatic juice containing enzymes that digest proteins, fats, and carbohydrates.
  5. Explain the process of absorption and assimilation.
    Answer: Absorption is the process of digested food passing into the blood from small intestine. Assimilation is the utilization of absorbed food for energy, growth, and repair.
  6. What are the main differences between digestion in humans and amoeba?
    Answer: Amoeba digests food in food vacuoles with enzymes, whereas humans have a complex digestive system involving specialized organs and glands.
  7. Write a note on the importance of a balanced diet in relation to digestion.
    Answer: A balanced diet ensures all nutrients are available for digestion and absorption. It helps the body to remain healthy, active, and disease-free. Without proper nutrition, the digestive system cannot supply adequate energy and materials for growth and repair.