Important questions based on NCERT syllabus for Chapter 6 - Life Processes:
Question-1: What is the function of the guard cell?
Solution: Stomata are tiny pores present on the surface of the leaves. Massive amount of gaseous exchange takes place in the leaves through these pores for the purpose of photosynthesis. The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Similarly, the pore closes when the guard shell shrinks.
Question-2: 'Respiration is a vital function of the body'. Justify.
Solution: 1. The oxygen taken in during respiration is used by the cells to release energy from food. This energy is used by the body to carry out all the life processes, body building, repair and growth.
2. Also the carbon dioxide released during cellular respiration is removed from the body during respiration. If carbon dioxide levels increase in body and is not removed, it will prove to be fatal to the individual.
3. Since respiration is essential to obtain energy for bodily functions and remove carbon dioxide, it is said to be a vital function of the body. Without respiration, the person will die in a few minutes.
Question-3: Explain causes and effects of high blood pressure.
Solution: 1. High blood pressure is also called hypertension and is caused by the constriction of arterioles which results in increased resistance to blood flow. Hypertension is a serious condition which has become a growing problem worldwide. Blood pressure above 140 systole and 100 diastole is called hypertension.
2. Causes: The causes of hypertension can be attributed to lifestyle practices such as physical inactivity, a salt-rich diet through processed and fatty foods, alcohol and tobacco use, etc. Stress is also a major cause of hypertension.
3. Effects: The effects of hypertension can be an enlarged or weakened heart, to a point where it may fail to pump enough blood (heart failure),blood vessel narrowing - in the kidneys, leading to possible kidney failure; also in the heart, brain and legs, leading to potential heart attack, stroke or amputation, respectively, blood vessels in the eyes may rupture or bleed, leading to vision problems or blindness, etc.