CBSE – 7th Standard Science

Question Bank – Chapter 10 – Respiration in Organisms




Q1. What is respiration?

Ans. Respiration is biological process. All living organisms need to respire to get the energy from food needed for their survival.


Q2. What is breathing?

Ans. Breathing is a part of the process of respiration during which an organism takes in the oxygen-rich air and gives out air rich in carbon dioxide.


Q3. What is cellular respiration, where it takes place?

Ans. The air is transported to each cell where oxygen in the air helps in the breakdown of food this process in cell releases energy is called cellular respiration. Cellular respiration takes place in the cells of all organisms.


Q4. What do you understand by the term breathing rate?

Ans. The number of times a person breathes in a minute is termed as the breathing rate. During breathing inhalation and exhalation take place alternately


  1. Why does an athlete breathe faster and deeper than usual after finishing the race?

Ans.  An athlete needs extra energy after finishing race breathes faster, as a result more oxygen is supplied to cells it speeds up the breakdown of food and more energy is released, deep breaths helps to inhale more oxygen.


Q5. What is average breathing rate while resting and after running?

Ans. On average, an adult human being at rest breathes in and out 15-18 times in a minute but after heavy exercise, the breathing rate can increase up to 25 times per minute.


Q6. List differences  between aerobic and anaerobic respiration.

Ans.  In the cell, the food is broken down into carbon dioxide and water with the use of oxygen it is called aerobic respiration.  Food can also be broken down, without using oxygen this is called anaerobic respiration alcohol and carbon dioxide are its product.


Q7. What are anaerobes? Are they useful for industries?

Ans. There are some organisms survive in the absence of air they are called anaerobes. Yeasts are single-celled organisms. They respire anaerobically and during this process yield alcohol therefore, used to make wine and beer.


Q8. Name some organs used  in the process of breathing?

Ans. Nostrils, nasal cavity, windpipe and Lungs are the most important organs for breathing.


Q9. How do ribs and Diaphragm help in breathing?

Ans. During inhalation, ribs move up and outwards and diaphragm moves down. This  increases space in chest cavity and air rushes into the lungs and get filled with air,

during exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs .


Q10. Why do we often sneeze when we inhale a lot of dust-laden air?

Ans. The air around us has various types of unwanted particles, such as smoke, dust, pollens, Sneezing expels these foreign particles from the inhaled air and a dustfree, clean air enters our body.


Q11. How do other organisms breath ?

Ans. In animals like cow, buffalo, dog and cat the respiratory organs and the process of breathing are similar to those in humans.


Q12. How do cockroaches, snails, fish, earthworms, ants and mosquitoes breath. Do they also have lungs like those of human beings?

Ans. Insects have a network of air tubes called tracheae for gas exchange, Earthworms breathe with their skins.  Frogs have a pair of lungs and they can also breathe through their skin.


Q13. What helps animals to breathe under water?  

Ans. Gills in fish help them to use oxygen dissolved in water, gills are skin projection full of blood vessels to exchange oxygen underwater.


Q14. Why athlete get muscle cramps after heavy exercise?

Ans. The cramps occur when muscle cells respire anaerobically. The partial breakdown of glucose produces lactic acid. The accumulation of lactic acid causes muscle cramps. We get relief from cramps after a hot water bath or a massage.


Q15. How do plants respire?

Ans. In a plant leaves have tiny pores called stomata through which they exchange gases and the roots take in air present in the soil. The breakdown of glucose in the plant cells is similar to that in other living beings.


Q16. Is anaerobic respiration possible in human ?

Ans. Our muscle cells can also respire anaerobically, but only for a short time, during heavy exercise, the demand for energy is high. But the supply of oxygen to produce the energy is limited. Then anaerobic respiration takes places in the muscle cells to fulfill it.


Q17. Why one should avoid smoking?

Ans. Smoking damages lungs. Smoking is also linked to cancer it must be avoided.