Q 1 – Where does cellular respiration take place?
Ans. Cellular respiration takes place in the cells of all organisms.
Q 2 – What is aerobic respiration?
Ans. The process of breakdown of glucose with the use of oxygen is called aerobic respiration.
Q 3 – Define inhalation.
Ans. The process of taking in of air rich in oxygen into the body is called inhalation.
Q 4 – Which gas do humans take in while breathing?
Ans. Oxygen
Q 5 – Which gas do humans give out while breathing?
Ans. Carbon dioxide
Q 6 – Define exhalation.
Ans. The process of giving out of air rich in carbon dioxide is called exhalation.
Q 7 – Give one usage of yeast.
Ans. Yeast is used for making alcoholic beverages like beer, wine, etc.
Q 8 – When do our muscle cells respire anaerobically?
Ans. When there is a temporary deficiency of oxygen in the muscle cells; they begin to respire anaerobically.
Q 9 – Give two therapies to release muscle cramps.
Ans.
- Hot water bath
- Gentle massage.
Q 10 – What are the functions of hair and mucus inside the nose?
Ans. Hair and mucus present inside the nose prevent dust, dirt and germs from entering the respiratory system of our body.
Q 11 – Name the breathing organs of fish.
Ans. Gills
Q 13 – Where are the lungs of human beings present?
Ans. Chest cavity
Q 14 – Name one significant process of getting energy.
Ans. Respiration
Q 15 – Define respiration.
Ans. The process in living organisms involving the production of energy, typically with the intake of oxygen and release of carbon dioxide from the oxidation of complex organic substances is termed as respiration.
Q 16 – Define anaerobic respiration.
Ans. The process of breakdown of glucose without the use of oxygen is termed as anaerobic respiration. In this process, glucose is used to get energy and carbon dioxide and alcohol are made as waste products.
Q 17 – What are yeasts?
Ans. Yeasts are single-celled fungi that reproduce asexually by budding. They respire anaerobically and yield alcohol during the process. Hence, they are used in the making of alcoholic drinks, such as wine, beer, etc.
Q 18 – Why does anaerobic respiration take place in our muscles sometimes?
Ans. During heavy physical work like cycling, running, jumping, etc., the demand of energy is high but the supply of oxygen is limited. Hence anaerobic respiration takes place in the muscle cells to fulfil the demand of energy.
Q 19 – What causes muscle cramps?
Ans. Under anaerobic condition the partial breakdown of glucose produces lactic acid in the cells. The ac-cumulation of lactic acid causes muscles cramps.
Q 20 – What is breathing rate?
Ans. The number of times a person breathes per minute is known as the breathing rate. A single breath means one inhalation and one exhalation; both take place alternatively.
Q 21 – Why do we feel hungry after physical activity?
Ans. During physical activity the demand of energy in the body increases. For the fulfilment of this energy requirement, we breathe faster, as a result of which oxygen is supplied to the cells. Hence, the rate of breakdown of food increases and more energy is released. So we feel hungry.
Q 22 – Explain the respiratory system in cockroaches.
Ans. A cockroach has small openings on the sides of its body, called spiracles. It also has a network of air tubes called tracheae for gas exchange. Oxygen rich air rushes through spiracles into the tracheal tubes, diffuses into the body tissue and reaches every cell of the body. Similarly, carbon dioxide from the cells goes into the tracheal tubes and moves out through spiracles.
Q 23 – What are the harmful effects of smoking?
Ans. Smoking damages lungs. Smoking is also linked to cancer.
Q 24 – Describe the process of breathing in human beings.
Ans. When we breathe in, air enters through nasal cavity. The hair and mucus present in the nasal cavity traps dust and other particles present in air. Air from nasal cavity then reaches the pharynx in the neck region and the larynx. Below the larynx is the trachea. The trachea divides into two bronchi, right and left, which leads to the lungs.
In the lungs, each bronchus branches into smaller tubes called bronchioles. At the end of the bronchioles, small rounded structures called air sacs or alveoli are present. Each alveolus is made up of a very thin membrane surrounded by blood vessels. Exchange of gases occur in air sacs through the process of diffusion.
In short passage of air from nose can be depicted as:
Nose ➝ Nasal cavity ➝ Pharynx ➝ Larynx ➝ Trachea ➝ Bronchi ➝ Bronchioles ➝ Alveoli (air sac)
Q 25 – Why do we yawn, especially when we feel drowsy and sleepy?
Ans. When we feel drowsy or sleepy our breathing rate slow down. The lungs do not get enough oxygen from air resulting in yawning. Yawning brings extra oxygen into the lungs.
Q 26 – Why do people often breathe out on the spectacles to clean them?
Ans. The warm and moist exhaled air condenses on the surface of spectacles as water vapour. Thus, making spectacles wet helps, to clean them easily with the help of a cloth.
Q 27 – Why do we feel relieved after a massage of the pain in the leg muscles due to cramps?
Ans. Massage improves the circulation of blood leading to increased supply of oxygen in the muscle cells which helps in complete breakdown of lactic acid into C02 and water. Thus, help in relieving of the pain.
Q 28 – Pick the odd-one-out from each of the groups given below on the basis of respiratory organs. Give reason for your answer.
- cockroach, grasshopper, snail, ant
- lizard, cow, earthworm, snake
- crocodile, whale, dolphin, fish
- snake, tadpole, crow, goat
Ans.
- Snail; as other breathe through tracheae
- Earthworm; as other breathe through lungs
- Fish; as other have lungs for respiration
- Tadpole; as other breathe through lungs
Q 29 – What is difference between pores present in insects and leaves of a plant?
Ans. Pores in insects are known as spiracles whereas pores in the leaves of a plant is known as stomata. The differences between these two pores are:
- Spiracles are present on the sides of insects’ body whereas stomata are present more on the lower surface of leaves and fewer on the upper surface of leaves.
- Spiracles lead to an extensive network of tracheal system which is absent in the leaves.
- Spiracles are fewer in number as compared to stomata.
Q 30 – The cellular respiration process takes place in which cell organelle?
Ans. Cellular respiration takes place in the mitochondria of the cell.
Q 31 – In some animals, exchange of gases takes place through its thin and moist skin. Name one such animal.
Ans. Earthworm is an animal where exchange of gases during breathing or respiration takes place through its thin and moist skin.
Q 32 – Our nostrils has hair and mucous. What is the need to have them in our nasal cavity?
Ans. Our nostrils possess hairs and mucous lining. These help in preventing dirt, dust and germs from entering our respiratory system.
Q 33 – Sometimes we see that farmers loosen the soil. What is the reason behind it?
Ans. The farmers sometimes loosen the soil. This helps the root to respire through the air present in the space between soil particles.
Q 34 – Various organs constitute the respiratory system of human. These organs are located according to their functions. Identify them.
Ans. The various organs in the respiratory system of human are nostrils, nasal passage, nasal cavity, windpipe and lungs.
Q 35 – The vocal ability of humans is the responsibility of an organ commonly known as voice box. What is its scientific name?
Ans. The organ that is responsible for speech is larynx or voice box. It lies between pharynx and trachea.
Q 36 – What changes are observed in diaphragm during inhalation?
Ans. During the process of inhalation diaphragm contracts and moves downwards.
Q 37 – When we exhale or breathe out, percentage of a certain gas is high. Name the gas.
Ans. The gas, carbon dioxide is in higher percentage or amount, when we exhale or breathe out.
Q 38 – Insects have a special organ present to carry out respiration. What is that organ called?
Ans. Insects possess special organ called spiracles for respiration.
Q 39 – Certain small pores are present on the surface of plant through which gaseous exchange occurs. Identify these pores?
Ans. Stomata are the tiny pores that are present on the surface of plant through which gaseous exchange occurs.
Q 40 – Floor of chest cavity refers to which organ of respiration?
Ans. Diaphragm is known as the floor of chest cavity.
Q 41 – Respiration is a continous process. What is the need for it to be continuous rather than being like photosynthesis?
Ans. Process of respiration yields energy which is required to perform a variety of routine activities. Thus, it needs to be a continuous process.
Q 42 – A part from stomata another structure is used by plants to respire. Name that structure.
Ans. Lenticels.
Q 43 – Explain cellular respiration.
Ans. The process of braeakdown of food in the cell with the release of energy is called cellular respiration.
Q 44 – The process of fermentation is based on which principle?
Ans. Anaerobic respiration.
Q 45 – Is the rate of breathing same for all the respiring organism?
Ans. No, different organisms respire at different rate because they all perform different activities at all times.
Q 46 – On a very cold morning, Boojho and Paheli were talking with each other as they walked down to their school. They observed that the air coming out of their mouth looked like smoke. They were asumed and wondered how it happened. Help them to find the answer
Ans. On a cold day, the warm and moist air exhaled by us condenses into moist when it comes in contact with the cold air of the atmosphere, this looks like white smoke.
Q 47 –On a very cold morning Radhika was amused and wondered to see that the air coming out of her mouth looked like smoke. Help her to find the answer.
Ans. On a cold day, when warm and moist air comes in contact with the cold air outside, it condenses into mist. This look like smoke.