CBSE Class 7 Science Important Questions Chapter 2 - Nutrition in Animals

Very Short Answer Questions  (1 Mark)

1. Match the Following:-

Ans: The following is the matched table:

2. Fill in the blanks:

a) _______________ is the elimination of unused parts of the food.

Ans: Egestion is the elimination of unused parts of the food.

b) The digestive system in humans consists of ___________________ and_______________.

Ans: The digestive system in humans consists of alimentary canal and digestive glands.

c) The first set of teeth that grow during infancy and fall off between 6-8 years of age is____________.

Ans: The first set of teeth that grow during infancy and fall off between 6-8 years of age is milk teeth.

d) The working of the stomach was discovered by _____________.

Ans: The working of the stomach was discovered by William Beaumont.

Short Answer Questions (2 Mark)

1. Define Nutrition in animals.

Ans: Nutrition in animals is very important. Some of them are plant-eating while others are carnivores. It includes the process of food ingestion, digestion, absorption and assimilation by the cells of their body. It also includes the removal of unused portions of food.

2. Differentiate between absorption and assimilation.

Ans: The difference between absorption and assimilation is as follows:

3. What is the function of the large intestine in digestion?

Ans: The large intestine reabsorbs all the excess water from unabsorbed and undigested food. Thus, it helps in making the unabsorbed portion of the food as faeces and its elimination by excretion. Thus, returning most of the water to the blood can prevent excess water loss as well as eliminate unabsorbed food from the body.

4. List the different types of teeth present in humans and their functions.

Ans: The different types of teeth present in humans and their functions are:

• Incisors: Incisors or the front teeth are the eight visible teeth that are used to bite the food.

• Canines: Next to incisors are the canines that are used to tear flesh or other food items. These are very sharp and come in around nine to twelve years of age.

• Premolars: Next to canines are the premolars which are typically used for grinding and chewing food.

• Molars: Molars are replaced by the eight premolars. They serve the primary function of chewing and grinding food into small particles.

5. What is diarrhoea?

Ans: When excess water from digested food is not reabsorbed, it is passed out through the stool which is loose and watery. Passage of this watery stool frequently is called diarrhoea which is caused by a microbial infection of the alimentary canal. This can lead to severe dehydration that can be controlled by using Oral Rehydration Solutions (ORS).

Long Answer Questions (5 Marks)

1. Explain nutrition in starfish.

Ans: Starfish is an aquatic invertebrate. It has a unique way of obtaining nutrition from other animals.

• Ingestion: The mouth of the starfish is on the underside of their body.They wrap themselves around the prey and open the shell of the prey. Then through their mouth they push their stomach out and ingest the soft animal.

• Digestion: They digest the animal in the stomach and draw its stomach back into its body.

• Absorption and assimilation: This allows them to feed on organisms larger than the ones which can fit into their small mouth.

2. Explain the process of nutrition in amoeba.

Ans: The process of nutrition in amoeba is done through holozoic nutrition and the process is called phagocytosis.

• Ingestion: Amoeba moves closer to its food with the help of pseudopodia and encircles it forming a food vacuole to engulf the food.

• Digestion: The food is then digested using digestive enzymes present in the lysosomes.

• Absorption and assimilation: The digested food is absorbed by the cytoplasm and the energy thus produced from the food is used to perform different life processes. 

• Egestion: To excrete the undigested food, an amoeba ruptures its cell wall and releases it out of the cell.

3. Explain the process of digestion and absorption in the small intestine.

Ans: The process of digestion as well as absorption in small intestine is as follows:

• Digestion: Digestion in the small intestine is accomplished by the action 

of digestive juices from the liver, pancreas and small intestine. The bile juice secreted by the liver helps in the digestion of fats, breaking down the big fat droplets into smaller droplets. It does not contain any enzymes. Pancreatic juice secreted by the pancreas contains enzymes for the digestion of carbohydrates, proteins and lipids. Pancreatic amylase helps in the digestion of carbohydrates while trypsin helps in the digestion of proteins. The enzymes of the intestinal juice eventually break down carbohydrates, proteins and lipids into their simplest components such as glucose, amino acids, fatty acids and glycerol etc.

• Absorption: Absorption takes place through the walls of the intestine 

that are lined with finger-like projections known as villi. These villi improve the surface area available for nutritional absorption. The villi contain blood vessels and hence the digested food is absorbed directly into the bloodstream.

4. Explain the importance of rumen in ruminants.

Ans: Rumen is a part of the stomach in grass-eating animals. It stores the food that the ruminant reproduces, chews again and swallows a second time. Specific bacteria found in the rumen aid in the digestion of cellulose. Ruminants can chew their ruminants for hours every day. The rumen contains many small organisms that aid in the digestion of food such as grass whose cell walls cannot be easily digested by other animals. Cud, or partially digested food, is then reintroduced into the mouth for easier chewing. This process of cud-chewing even when the animal is not eating is called rumination. The rumen ferments this food through the formation of gas, which must be expelled by belching to prevent bloating.

Important Points to Remember

Nutrition in Animals

• Nutrient requirement, mode of intake food and its utilisation by the body is the process of animal nutrition.

• Ingestion, digestion, absorption, assimilation and egestion are the stages of nutrition in animals.

• Ingestion is taking in food. Various animals use different organs for ingestion.

• The breakdown of complex components of food into simpler substances is called digestion.

• Absorption is the process by which food in soluble form passes into the body fluid like blood and is transported to different parts of the body.

• Assimilation involves utilising the absorbed nutrients for energy, growth and development.

• Egestion is the process of removal of undigested waste.

• Modes of feeding differ in different organisms. For example, bees and hummingbirds suck the nectar of plants, infants of mammals feed on mother’s milk, python swallows animals they prey upon, few aquatic animals filter tiny particles floating nearby and feed upon them.

• Amoeba is a microscopic, single-celled organism found in pond water. It constantly changes its shape and position.

• Pseudopodia is a finger-like projection that is pushed out by amoeba.

• Amoeba ingests food with the help of pseudopodia (false feet) and ingests it in the food vacuole.

• Amoeba feeds on bacteria, microscopic algae and small unicellular organisms.

• The food digested by amoeba is used for growth, maintenance and multiplication.

• Amoeba releases unwanted waste through its body surface.

Nutrition in Humans

• The human digestive system is highly complex.

• The human digestive system consists of the buccal cavity, oesophagus, stomach, small intestine, large intestine ending in rectum and anus.

• The human digestive tract is also called an alimentary canal.

• The digestive tract and associated glands like salivary glands, liver and pancreas make up the digestive system.

• Digestion begins in the mouth and continues in the stomach and the small intestine.

• The cavity of the mouth with all its internal parts like cheeks, teeth, tongue and salivary glands is called the buccal cavity.

• The alimentary canal begins from the buccal cavity.

• Salivary glands, liver and pancreas play a very important role in the process.

• Salivary glands present in the human mouth secrete saliva.

• Saliva moistens the food and helps in chewing of food by teeth. It also contains an enzyme which breaks down the starch into sugars.

• The oesophagus is the food pipe through which the swallowed food passes.

• The liver is the largest gland in our body, secretes bile that is stored in the gallbladder.

• The stomach is a thick-walled bag, receives food from oesophagus at one end and opens into the small intestine at the other.

• Bile plays a vital role in the digestion of fats.

• The pancreas is located just below the stomach and secretes pancreatic juice that acts on carbohydrates, fats and proteins and changes them into simpler forms.

• Digested food is absorbed in the small intestine.

• The small intestine is a coiled structure that receives secretions from the liver and the pancreas.

• Villi are thousands of finger-like projections present in the inner walls of the small intestine.

• The digested food materials are absorbed by the surface of the villi.

• Semi-solid waste in the form of faeces is expelled through the anus.

• A fleshy muscular organ inside the human mouth that is attached to the buccal cavity is the tongue.

• The tongue is used for speaking, mixing saliva with food, swallowing the food and detecting different tastes of food with the help of taste buds.

• The teeth help in chewing the food and breakdown the big pieces of food into small pieces.

• All human beings bear two sets of teeth. The first set of teeth called milk teeth appears after the age of six months. Eventually, these milk teeth are replaced by permanent teeth.

• An adult human has 32 permanent teeth - incisors, canines, molars and premolars.

• Tooth decay is the damage of the teeth due to harmful bacteria breaking down the sugars and releasing acids.

• Tooth decay leads to toothache and even loss of teeth.

Nutrition in Ruminating Animals

• Ruminants are grass-eating animals.

• Ruminants digest their food in two steps.

• The rumen is a separate part of the stomach of ruminants where the swallowed food is stored.

• Rumination is a process where the ruminants quickly swallow grass and store it in the rumen. In the rumen, the grass is partially digested and forms a cud. Later, the cud returns back to the mouth in small lumps and the animal chews it.

• Cellulose is the carbohydrate present in grass.

• Ruminants have a large sac-like structure called caecum that is present between the small intestine and the large intestine.

• Certain kinds of bacteria present in caecum help in digestion of the cellulose of the food.

The reference notes relating to Important Questions Of Chapter 2 of Science for Class 7 given above will benefit you in understanding the concepts and basic terms of human and animal digestive systems. The important questions and the reference notes related to the chapter created by Vedantu will give a thorough practice and revision for the exams.

5 Important Topics of Class 7 Science Chapter 2 You Shouldn’t Miss!

Benefits of Class 7 Science Important Questions Chapter 2 Nutrition in Animals

• Simplifies Complex Topics: Important questions break down complicated concepts like animal digestion into easy-to-understand parts.

• Identifies Key Areas: They highlight the most important sections of the chapter, helping you focus on what matters most for exams.

• Enhances Retention: Repeated practice with these questions improves memory and understanding of the digestion process in various animals.

• Time Management: Practising these questions helps you manage your time better during the exam by familiarising you with common question formats.

• Strengthens Basics: These questions reinforce fundamental concepts, ensuring a solid grasp of the material before moving to advanced topics.

• Quick Revision Tool: They serve as a quick revision resource, making it easier to recall essential points before tests or exams.

Conclusion 

Vedantu’s Important Questions for Class 7 Science Chapter 2, Nutrition in Animals, are a great way to deepen your understanding of the chapter. By practising these questions, you'll be able to clarify your concepts on digestion and nutrition in animals, preparing you well for exams. Our expertly designed questions help you focus on important areas, making learning easier and more effective. Download the FREE PDF to access these questions anytime, ensuring you are always ready for revisions. Get the most out of your study sessions and boost your confidence with these well-designed questions.

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