1. Give one word for the following :
1) An anaerobic organism .
Ans: Yeast .
2) The breakdown of food in the cell with the release of energy .
Ans: Cellular respiration .
3) The product of pastial breakdown of glucose.
Ans: Lactic acid .
4) The number of times a person breathes in a minute .
Ans: Breathing rate .
2. State whether true or false. If false correct the sentence :
1) Plants takes in carbon dioxide during respiration.
2) Increased physical activity enhances the rate of breathing.
3) Frogs can breathe through their lungs alone.
4) Breakdown of food does not occur in the absence of oxygen in the cells.
Answers :
1) False . Plants take in oxygen during respiration.
2) True .
3) False . Frogs can also breathe through their skin.
4) False . Breakdown of food also occurs in the absence of oxygen and it is called anaerobic respiration.
3. Answer the following questions :
1) Why are yeast used to make wine and beer.
Ans: Yeast respire anaerobically and during this process yield alcohol. Therefore yeast are used to make wine and beer.
2) Give two points of differences between respiration and photosynthesis in plants.
Ans :
| Respiration in plants | Photosynthesis in plants |
| i) Plants inhale oxygen and exhale carbon dioxide. | i) Plant inhale carbon dioxide and exhale oxygen |
| ii) End product are CO2 and water . | ii) End products are oxygen and carbohydrates. |
1) Our nostrils has hair. What is the use of having hair in our nasal cavity?
Ans: The hair in our nasal cavity trap the dirt laden particles and present it from entering our respiratory system .
2) Farmers loosen the soil before sowing seeds. Give reason.
Ans: Farmers loosen the soil to help the roots of the growing plant to respire through the air present in the spaces between soil particle.
4. Give the name of respiratory organs in the following animals:
1. Fish
2. Earthworm
3. Human beings
Ans:
1. a) Fish – Gill
2. b) Earthworm – Skin
3. c) Human beings – Lungs .
5. The process of fermentation is based on which principle?
Ans: The process of fermentation is based on anaerobic respiration.