Class 10 Life Processes Previous Years Questions : Solutions

Life Processes Previous Years Questions : Solutions

1. List the steps of preparation of temporary mount of a leaf peel to observe stomata. [CBSE 2018] [2Marks]
   Sol:
   The following steps of preparation of temporary mount of a leaf peel to observe stomata are :
   (i)Remove a healthy leaf from the plant.
   (ii)Remove a part of peel from the lower surface of the leaf.
   (iii) Place it in glass have water.
   (iv) Put a few drops of safranin stain on it.
   (v) After 2-3 min put the peel on a glass slide.
   (vi) Put a drop of glycerin over peel and place a coverslip over it with the help of needle to avoid air bubbles.
   (vii) Remove excess stain and glycerin with the help of blotting paper.
   (viii) Observe slide under low and high power magnification of a compound microscope.
2. List four precautions in proper sequence which we observe while preparing a temporary mount of leaf peel. [CBSE 2019] [2 Marks]
   Sol:
   Precautions :
   (i) Cut the peel in proper size to avoid its folding.
   (ii) Do not over strain or under strain the peel.
   (iii) Handle peel with with a brush, as it needle can damage it.
   (iv) Keep peel away from drying by using glycerin.
3. List in tabular form two differences between pepsin & trypsin. [CBSE 2019] [2 Marks]
   Sol:
   
4. In the experiment of preparing a temporary mount of a leaf peel to observe stomata we use two liquids other than water. Name these two liquids & state when and why these liquids are used? [CBSE 2019] [2 Marks]
   Sol:
   Two liquids used :
   (i) Safranin
   (ii) Glycerin
   Uses of Liquids :
   (i) Safranin is used to stain the peel.
   (ii) Glycerin is used to moisturise the peel as it peel doesn’t dry out.
5. A student has set up an apparatus to show that “CO₂ is released during respiration”. After about 1 hour he observes no change in the water level in the delivery tube. Write two possible reasons for the failure of the experiment. [CBSE 2019] [2 Marks]
   Sol:
   (i) The setup needs to be sealed with Vaseline to make it airtight so that the evolved CO2​ does not leak out.
   (ii) KOH solution may be missing in the setup or may be old
6. Explain the ways in which glucose is broken down in absence or shortage of oxygen. [CBSE 2019] [3 Marks]
   Sol:
   First, In cytoplasm Glucose is converted into pyruvate and energy. In the absence of oxygen, pyruvate is converted into Ethanol, Carbondioxide and Energy form and In the shortage of oxygen, in our muscle cells pyruvate is converted into Lactic acid and Energy form.
   
7. List four functions of the human heart. Why is double circulation necessary in the human body? [CBSE 2019] [3 Marks]
   Sol:
   The following function of human heart :
   (i) Receives deoxygenated blood from different parts of the body.
   (ii) Sends or pump blood to lungs for oxygenation.
   (iii) Receives oxygenated blood from the lungs.
   (iv) Pumps or transfer oxygenated blood to different parts of the body.
   Double circulations does not allow the mixing of the oxygenated and deoxygenated blood by transporting the blood twice through the heart. This separation ensures highly efficiency supply of oxygen for their energy needs.
8. What is haemoglobin? State the consequences of deficiency of haemoglobin in our bodies. [CBSE 2019] [3 Marks]
9. .
   1. In the process of respiration., state the function of alveoli.
   2. Rate of breathing in aquatic organisms is much faster than in terrestrial organisms. Give reasons.
   3. Complete the following pathway showing the breakdown of glucose: [CBSE 2020] [3 Marks]
      
10. .
    1. Mention any two components of blood.
    2. Trace the movement of oxygenated blood in the body.
    3. write the function of valves present in between atria & ventricles.
    4. Write one structural difference between the composition of artery & veins. [CBSE 2018] [5 Marks]
11. .
    1. Define excretion.
    2. Name the basic filtration unit present in the kidney.
    3. Draw excretory system in human beings & label the following organs of excretory system which perform following functions:
       1. form urine
       2. is a long tube which collects urine from kidney
       3. store urine until it is passed out [CBSE 2018] [5 Marks]
12. Give reasons:
    1. Ventricles have thicker muscular walls than atria.
    2. Transport system in plant is slow.
    3. Circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
    4. During the daytime, water & minerals travel faster through xylem as compared to the night.
    5. Veins have valves whereas arteries do not. [CBSE 2020] [5 Marks]
13. Design an activity to show that chlorophyll is essential for photosynthesis. [CBSE 2020] [5 Marks]
    Sol:

	Pepsin	Trypsin
(i)	Pepsin is an enzyme that acts only in acidic medium.	Trypsins is an enzyme that acts in alkaline medium.
(ii)	Pepsin is secreted by the gastric juice.	Trypsin is secreted by the pancreatic juice.
(iii)	Pepsin is situated in gastric glands.	Trypsin is situated in the pancreas.
(iv)	Pepsin is secreted in the stomach.	Trypsin is secreted in the small intestine.