Extra Questions for Chapter 9 Life Processes in Animals Class 7 Science Curiosity
Class 9 Life Processes in Animals Extra Questions
Very Short Answer Questions
Question 1. What is rumen?
Answer
Rumen is a large, sac-like structure found in ruminants, such as cattle and deer.
Question 2. What are ruminant animals?
Answer
The grazing animals like cows, buffaloes and deer are known as ruminants.
Question 3. Where are faeces formed in the human body?
Answer
Faeces are formed in the human body in large intestine.
Question 4. Where food is absorbed in our body?
Answer
Absorption of food takes place in small intestine.
Question 5. What are the structures found in the cytoplasm of an amoeba?
Answer
The cytoplasm of an amoeba contains structures such as the nucleus, food vacuoles, and contractile vacuoles.
Question 6. Where faeces are stored?
Answer
Faeces are stored in rectum.
Question 7. Name the end products of carbohydrates.
Answer
Simple sugars such as glucose.
Question 8. What is the process of taking in food called?
Answer
Ingestion is the process of taking in food.
Question 9. How do birds digest food without teeth?
Answer
Birds use a gizzard, a special stomach chamber, to grind food. They swallow small stones (grit) that help the gizzard crush food, breaking it down for digestion.
Question 10. What is the flap-like valve that prevents food from entering the windpipe called?
Answer
The epiglottis is a flap-like valve located at the base of the tongue.
Question 11. What is the process of bringing back partially digested food to the mouth for additional chewing in ruminants called?
Answer
Rumination is the process in which ruminants, such as cows and deer, bring back partially digested food to their mouths for further chewing.
Question 12. How is food pushed down from mouth to stomach?
Answer
Food is pushed down by the movement of the wall of the food pipe.
Question 13. What is the role of bile in digestion?
Answer
Bile helps digest fats by breaking them into tiny droplets, increasing their surface area for digestion.
Question 14. What is the process of utilizing absorbed food for various activities called?
Answer
The process of using absorbed food for various activities is known as assimilation.
Question 15. What does animal nutrition include?
Answer
Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body.
Question 16. What is the undigested waste material called that enters the large intestine?
Answer
The undigested waste material that enters the large intestine is called faeces.
Question 17. Which organ produces bile juice?
Answer
The liver is a vital organ responsible for producing bile juice, which is essential for digesting fats.
Question 18. What is the complex carbohydrate found in the diet of herbivorous animals?
Answer
Cellulose is the complex carbohydrate found in the diet of herbivorous animals.
Question 19. What are the finger-like projections on the inner walls of the small intestine called?
Answer
Villi are the tiny, finger-like projections found on the inner walls of the small intestine.
Question 20. What is the locomotor organ of amoeba?
Answer
Pseudopodia are the locomotor organs of amoeba. Amoeba uses it to move and capture food.
Question 21. What is digestion?
Answer
Digestion is the process of breaking down complex components of food, such as carbohydrates, into simpler substances. These simpler substances are then absorbed and assimilated by the body.
Question 22. Define egestion.
Answer
The process of removal of faecal matter from the body through the anus is called egestion.
Question 23. Name the part of the digestive canal involved in chewing food.
Answer
Mouth or Buccal cavity
Question 24. What does saliva do to food in our mouth?
Answer
The saliva breaks down the starch into sugars.
Question 25. Name different modes of feeding in animals?
Answer
Scraping, chewing, brewing, capturing and swallowing, sucking etc. are the different mode of feeding in animals.
Short Answer Questions
Question 1. What kills bacteria that enter along with the juices to act?
Answer
The acid kills many bacteria that enter along with the juices to act. This process helps to maintain a safe environment for digestion and prevents the growth of harmful bacteria.
Question 2. What are the main steps involved in the process of respiration in animals?
Answer
The main steps of respiration in animals include inhalation, where oxygen is taken into the body; gas exchange in the lungs or tissues, where oxygen is exchanged for carbon dioxide; and exhalation, where carbon dioxide is expelled from the body. This process is crucial for supplying oxygen to cells and removing waste gases.
Question 3. What are villi, and why are they important in the small intestine?
Answer
Villi are tiny finger-like projections on the inner lining of the small intestine. They increase the surface area to absorb nutrients into the blood, helping the body use food for energy and growth.
Question 4. What is mechanical digestion, and where does it happen in humans?
Answer
Mechanical digestion is breaking food into smaller pieces by chewing. It happens in the mouth, where teeth crush and chew food to make it easier to swallow and digest.
Question 5. What happens to the food in stomach of the digestive tract?
Answer
The inner lining of the stomach secretes mucus, hydrochloric acid, and digestive juices. The mucus protects the lining of the stomach. The hydrochloric acid kills many bacteria that enter with food and creates an acidic environment in the stomach. Additionally, the digestive juices break down proteins into simpler substances.
Question 6. How does peristalsis help move food through the digestive system? Give an example from the human body.
Answer
Peristalsis is the wave-like muscle contractions that push food through the digestive system. The walls of the food pipe (oesophagus) and other parts of the alimentary canal contract and relax to move food forward. For example, when you swallow chewed food, peristalsis in the oesophagus gently pushes it down to the stomach, even if you’re lying down, so food doesn’t get stuck.
Question 7. Glucose is considered as the source of instant energy, why?
Answer
Glucose is the simplest form of carbohydrate and can be easily broken down to provide energy. This property makes glucose a source of instant energy for the body. Furthermore, glucose mixes directly into the bloodstream, ensuring it is readily available for immediate use by our cells.
Question 8. What is the role of bile in the small intestine, and why is it important for digestion?
Answer
Bile, produced by the liver, is a mildly basic liquid that flows into the small intestine. It neutralizes the acid from the stomach, making the food less acidic, and breaks fats into tiny droplets, which makes them easier to digest. This is important because it helps the small intestine’s digestive juices break down fats completely, so nutrients can be absorbed into the blood for energy and growth.
Question 9. How does the large intestine work, and why are fibre rich foods important for it?
Answer
The large intestine absorbs water and some salts from undigested food, turning it into a semi-solid stool that’s stored in the rectum until it’s expelled through the anus (egestion). Fibre rich foods, like fruits, vegetables, and whole grains, add bulk to the stool, making it easier to pass and keeping the large intestine healthy. For example, eating apples helps prevent hard stools and digestive problems.
Question 10. Name the main organs of digestive system.
Answer
The main organs of digestive system are liver, Gall bladder Stomach, Pancreas, Small intestine, Large intestine, Rectum, Anus. The digestive tract and the associated glands together constitute the digestive system.
Question 11. Explain the role of the liver and pancreas in digestion.
Answer
The liver produces bile juice, which is stored in the gall bladder and released into the duodenum. Bile helps digest fats by breaking them into tiny droplets. The pancreas secretes pancreatic juice containing enzymes that digest carbohydrates, proteins, and fats into simpler forms.
Question 12. What is the function of the large intestine in digestion?
Answer
The large intestine absorbs water and salts from undigested food material. It helps in concentrating the waste material, forming faeces. Faeces are temporarily stored in the rectum and eliminated through the anus in a process called egestion.
Question 13. Explain tooth decay?
Answer
Our mouth contains some useful bacteria, but if we do not clean our teeth and mouth after eating, harmful bacteria can also begin to thrive. These harmful bacteria break down the sugars from leftover food and release acids. Over time, these acids gradually damage the teeth and lead to tooth decay.
Question 14. Describe the process of digestion in the human stomach.
Answer
In the human stomach, food is digested with the help of gastric juice secreted by gastric glands. The stomach is a muscular organ that churns and mixes the food with gastric juice, which contains hydrochloric acid and digestive enzymes. This process breaks down food into simpler forms for absorption.
Question 15. How are absorbed nutrients utilized in the body?
Answer
Absorbed nutrients such as glucose, amino acids, fatty acids, and glycerol are utilized in the body through a process called assimilation. These nutrients are used for various activities, including providing energy for metabolic processes, growth, maintenance, and repair of cells and tissues.
Question 16. Why can't humans digest cellulose, even though it is present in their diet?
Answer
Humans lack the necessary enzymes and symbiotic bacteria to digest cellulose. Grass-eating animals like cows have specialized stomachs with symbiotic bacteria that can break down cellulose, but humans do not possess these adaptations.
Question 17. Explain how amoeba obtains and digests its food.
Answer
Amoeba engulfs its prey along with a droplet of water using pseudopodia, forming a food vacuole inside the cytoplasm. Digestive enzymes secreted by the food vacuole break down the prey. Undigested food is expelled by changing the shape of the amoeba.
Question 18. How does an amoeba respire and excrete waste products?
Answer
An amoeba takes in dissolved oxygen through the cell membrane by diffusion and releases carbon dioxide into the surrounding water. Waste products are eliminated by expelling undigested food and forming a protective cyst in unfavourable conditions.
Question 19. What is the significance of villi in the small intestine?
Answer
Villi are small finger-like projections on the inner walls of the small intestine that increase the surface area for absorption of digested food. This allows for efficient absorption of nutrients into the bloodstream.
Question 20. What is the site of production of bile? Which component of the food does it digest?
Answer
Bile is produced in the liver and is stored in a sac-like structure called the gallbladder. It plays an important role in the digestion of fats, acting on them to convert them into a simpler form.
Question 21. Name and explain the type of carbohydrates that can be digested by ruminants but not by humans.
Answer
Cellulose is the type of carbohydrate that can be digested by ruminants but not by humans. Ruminants possess a large, sac-like structure located between the small intestine and large intestine, which is essential for the digestion of cellulose. The cellulose in their food is broken down by the action of specific bacteria that are absent in humans.
Question 22. What are secreted inside the stomach?
Answer
Gastric juice is secreted by the walls of the stomach and contains hydrochloric acid (HCl) and pepsin. HCl plays a crucial role in killing germs present in food. After mixing with food, it provides an acidic medium that is essential for activating the pepsin enzyme. Pepsin is responsible for digesting proteins into peptides.
Question 23. Explain digestive enzymes?
Answer
There are different types of enzymes which are used for the digestion of different food materials like carbohydrates, fats, protein etc. The process of digestion involves the association of several catalytic organic compounds such as amylase, pepsin, lipase, trypsin etc. These organic compounds are known as digestive enzymes.
Question 24. What role does villi performs in the small intestine?
Answer
The villi increase the surface area for the absorption of digested food. Their surface is designed to effectively absorb the digested materials and transfer them into the blood. Once absorbed, these substances are transported via blood vessels to various organs of the body.
 |
| Villi present in Small Intestine |
Question 25. How does digestion occur in ruminants grass-eating animals?
Answer
Ruminants quickly swallow grass and store it in a separate part of the stomach called the rumen. Here, the food undergoes partial digestion and is referred to as cud. Later, the cud returns to the mouth in small lumps, and the animal chews it. This process is known as rumination. The cellulose present in grass is digested in the rumen by the action of specific bacteria, which are not found in humans.
Question 26. What happens to the food in large intestine of the digestive tract?
Answer
The food that remains undigested and unabsorbed enters the large intestine from the small intestine. The large intestine is approximately 1.5 metres in length. Its primary function is to absorb water and some salts from the undigested food material.
Long Answer Question
Question 1. What are the different modes of feeding in animals?
Answer
Different modes of feeding in animals include:
- Scraping - removing food from surfaces.
- Chewing - breaking down food into smaller pieces.
- Sucking - drawing in liquids, like nectar.
- Capturing and swallowing - catching prey whole.
- Filtering - sifting tiny food particles from water.
Question 2. What do pancreatic juices digest?
Answer
The pancreatic juice plays a crucial role in digestion by acting on:
- Carbohydrates - breaking them down into simpler sugars.
- Fats - converting them into fatty acids and glycerol.
- Proteins - transforming them into amino acids.
Overall, pancreatic juice helps in simplifying these food components for better absorption in the body.
Question 3. What are the functions of the tongue in human body?
Answer
The functions of the tongue are as follows:
- Speech: It is essential for talking; it is not possible to articulate words without it.
- Mixing: The tongue mixes saliva with food during chewing, aiding in the swallowing process.
- Taste: The presence of taste buds identifies various flavours such as sweet and salty.
 |
| Taste Buds present in Toungue |
Question 4. Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer
Animals, including most bacteria and non-green plants, as well as humans, do not have the ability to synthesize their own food. Therefore, they rely on autotrophs for their food supply, either directly or indirectly. Green plants, such as leafy vegetables and grass, trap solar energy and manufacture their food in the form of glucose. While leafy vegetables and grass are nutritious, they may not provide sufficient energy for human survival alone. Humans require a varied diet that includes proteins and other nutrients that are not typically found in high quantities in raw, leafy vegetables or grass. In conclusion, although leafy vegetables and grass play a vital role in a healthy diet, relying solely on them may not meet all the nutritional needs of humans.
Question 5. What do you mean by rumination?
Answer
Rumination is a process that occurs in certain animals, known as ruminants. It involves the following steps:
- Animals quickly swallow their food, which is often grass.
- The food is stored in a part of the stomach called the rumen.
- Later, the partially digested food, known as cud, returns to the mouth.
- The animal then chews the cud thoroughly before swallowing it again.
This process helps in the digestion of tough plant materials, particularly cellulose, which many animals, including humans, cannot digest effectively.
Question 6. What do you mean by animal nutrition?
Answer
Animal nutrition refers to the study of the nutritional needs of animals, which includes:
- The requirement for nutrients essential for growth, maintenance, and reproduction.
- The mode of food intake, which varies among different species.
- The utilisation of food within the body for various physiological processes.
Understanding these aspects is crucial for improving animal health and productivity.
Question 7. What happens to the food in small intestine of the digestive tract?
Answer
The small intestine is highly coiled and is about 7.5 metres long. Liver is the largest gland in the body. It secretes bile juice that is stored in a sac called the gall bladder. It digests fats. The pancreas is cream colour red gland secretes pancreatic juice that acts on carbohydrates and proteins and changes them into simpler forms. The carbohydrates get broken into simple sugars such as glucose, fats into fatty acids and glycerol, and proteins into amino acid, she digested food can now pass into the blood vessels in the wall of the intestine having thousands of finger-like villi. The surface of the villi absorbs the digested food materials. The absorbed substances are transported via the blood vessels to different organs of the body.
Question 8. Explain how amphibians like frogs breathe differently from humans.
Answer
Frog Breathing (Amphibians):
- Frogs are amphibians that live in water and on land, so their breathing changes with their life stages.
- As tadpoles (baby frogs), they live in water and breathe using gills, which take oxygen dissolved in water and release carbon dioxide, like fish.
- As adult frogs, they live on land and use lungs to breathe air, similar to humans.
- Adult frogs also breathe through their moist skin in water or damp places, where oxygen passes into the blood and carbon dioxide comes out.
- Example: A frog near a pond uses both lungs and skin to breathe, helping it survive in wet environments.
Human Breathing:
- Humans breathe only through lungs, using the respiratory system to take in oxygen and remove carbon dioxide.
- Air enters through the nostrils, where nasal passages with hairs and mucus trap dust and dirt for cleaner air.
- Air travels through the windpipe (trachea) to the lungs, which are protected by the rib cage.
- In the lungs, tiny sacs called alveoli allow oxygen to enter the blood and carbon dioxide to be exhaled.
- The diaphragm, a muscle below the lungs, moves down to pull air in (inhalation) and up to push air out (exhalation).
- Example: When you breathe deeply before running, your diaphragm helps your lungs fill with oxygen for energy.
Question 9. Explain the process of digestion in humans, covering the roles of the mouth, stomach, and small intestine. Describe one way to maintain healthy digestion.
Answer
- Mouth: Digestion starts in the mouth, where teeth chew food into smaller pieces (mechanical digestion). Saliva moistens the food and contains juices that break down starch into sugar. For example, chewing rice makes it taste sweet because of saliva.
- Stomach: The chewed food moves to the stomach through the food pipe by peristalsis. The stomach churns food with its walls and releases digestive juice, acid, and mucus. The juice breaks down proteins, the acid helps digestion and kills bacteria, and mucus protects the stomach lining, turning food into a semi-liquid mass.
- Small Intestine: The semi-liquid food enters the small intestine, which is 6 meters long. It receives bile from the liver to break fats into droplets and pancreatic juice to digest carbohydrates, proteins, and fats. Villi in the small intestine absorb nutrients into the blood for energy and growth.
- Maintaining Healthy Digestion: Eat fibre-rich foods like fruits, vegetables, and whole grains, as suggested in the notes. For example, eating bananas helps the large intestine form soft stool, preventing digestive problems and keeping the digestive system healthy.