CHAPTER 11
LIFE PROCESSES IN PLANTS
EXERCISE
Q. 1. Darken the circle of correct answer:
(i) Which part of the plant takes in carbon dioxide from the air for photosynthesis?
(a) Root hair
(b) Leaf veins
(c) Stomata
(d) Sepals
Ans. (c)
(ii) The green colour of leaves of plants is due to
(a) Chlorophyll
(b) Xylem
(c) Phloem
(d) Stomata
Ans. (a)
(iii) How many guard cells are present around the stoma?
(a) 4
(b) 3
(c) 2
(d) 5
Ans. (c)
(iv) Raw materials used by plants during photosynthesis include-
(a) Nitrogen and oxygen
(b) Carbon dioxide and water
(c) Oxygen, hydrogen and carbon dioxide
(d) Water and minerals
Ans. (b)
Q. 2. Fill up the blanks
(a) Plants use energy from the ____ to make ____.
Ans. sun, food
(b) During photosynthesis, plants take in ____ and release _____.
Ans. carbon dioxide, oxygen
Q. 3. State whether the following statements are true or false?
(a) The product of photosynthesis is not a protein.
Ans. True
(b) A plant having red leaves cannot perform photosynthesis.
Ans. False
Q. 4.
Two statements are given below; one is Assertion and other is Reason.
Assertion: The green pigment present in the leaves of plant is called chlorophyll.
Reason: This green pigment is responsible for the green colour of most of the plants.
Choose the appropriate answer from the following options:
(a) Both Assertion and Reason are true and Reason is the correct explanation of A.
(b) Both Assertion and Reason are true but Reason is not the correct explanation of A.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.
Ans. (a)
Q. 5. Match the followings:
Column-I
(i) Chlorophyll
(ii) Stomata
(iii) Photosynthesis
(iv) Transport of water
Column-II
(a) xylem
(b) leaf
(c) guard cell
(d) starch
Ans. (i) – (b), (ii) – (c), (iii) – (d), (iv) – (a)
Q. 6. Answer the following questions briefly.
(a) Name the sugar produced during photosynthesis.
Ans. Glucose.
(b) What is the function of phloem in plants?
Ans. Transportation of food prepared in leaves to all parts of the plant body.
(c) What is the role of stomata in the leaf for production of food?
Ans. The plants obtain carbon dioxide required for production of food from the atmosphere through the stomata.
(d) How would you test the presence of starch in leaves?
Ans. To test the presence of starch in leaves, first a fresh green leaf is boiled in water for a few minutes. Then the leaf is taken out and placed in a test tube containing alcohol. The test tube is kept in hot water so that the alcohol boils. This removes the green colour (chlorophyll) from the leaf and makes it colourless.
After that, the leaf is washed with water and placed on a dish or petriplate. A few drops of iodine solution are then added to the leaf. If the leaf turns blue-black in colour, it shows the presence of starch in the leaf.
(e) Write an experiment to show that oxygen is released during photosynthesis.
Ans. To show that oxygen is released during photosynthesis, some fresh branches of an underwater plant like Hydrilla are taken in a beaker filled with water. A little soda water is added to provide carbon dioxide. The plant is then covered with a glass funnel, and a water-filled test tube is inverted over the stem of the funnel. The cut ends of the plant remain inside the funnel facing upward.
The whole setup is kept in sunlight for a few hours. After some time, bubbles of gas are seen coming out from the cut ends of the plant and collecting in the test tube by pushing the water downward. When a burning matchstick is brought near the collected gas, it burns brightly. This proves that the gas collected is oxygen. Therefore, oxygen is released during photosynthesis.
Q. 7.
Imagine a situation where all the plants, and tiny green organisms that perform photosynthesis suddenly disappeared from the Earth. What impact would it have on the air we breathe and the living organisms on the Earth?
Ans. Since the process of photosynthesis returns oxygen to the atmosphere, in absence of organisms that perform photosynthesis, the air we breathe would lack oxygen. In such situation, the living organisms on the Earth will not be able to survive as they will not be able to carry out respiration without oxygen.
Q. 8.
Which side of the leaf contain more stomata?
Ans. B
Q. 9.
Look at the following pictures carefully. In Fig. 11.15 (a) the life process of a potato plant is shown and in Fig 11.15 (b) an experiment conducted on a slice of potato is shown.
Answer the following questions:
(i) What does this colour change tell us about the substance stored in the potato?
Ans. The substance stored in the potato is starch.
(ii) This stored substance is not produced in the potato itself. Where does this substance in potatoes come from?
Ans. This substance in potatoes comes from the leaves.
(iii) In which part of the plant food is synthesised? Name the process of synthesis of food in the plant.
Ans. Food is synthesised in the leaves of the plant. The name of the process of synthesis of food in the plant is photosynthesis.
(iv) Describe the journey of the food from the place of its synthesise to the place where it is stored (potato). Name the structure that carries this food.
Ans. The food prepared in the leaves is transported to the potato through a set of thin tube-like structure. These structures are called phloem.
Q. 10.
Ritu set up an experiment with sprouted chickpea seeds in an air-tight closed glass jar (Fig. 11.16). After a few days, she noticed that the limewater turned milky.
Answer the questions:
(i) What idea might she be investigating through this experiment?
Ans. Through the experiment the idea she might be investigating is that plants release carbon dioxide during respiration.
(ii) What does this change in limewater show?
Ans. This change in limewater shows that carbon dioxide is produced inside the jar.
(iii) Which life process carried out by the germinating chickpeas is responsible for this change?
Ans. The life process carried out by the germinating chickpeas, responsible for this change is respiration.
(iv) If Ritu had used dry seeds instead of sprouted ones, would the result be the same? Give reason to your answer?
Ans. If Ritu had used dry seeds instead of sprouted seeds, the result would have been different. This is because dry seeds respire very slowly and produce only a very small amount of carbon dioxide. Therefore, the lime water would not turn milky easily.
(v) During the experiment, if the limewater did not turn milky even after a few days, list two possible errors in the setup.
Ans. Two possible mistakes in the setup may be—
(a) The glass jar was not properly air-tight, so the carbon dioxide produced escaped outside.
(b) There was not enough oxygen inside the jar for proper respiration to occur.
(vi) How does this experiment help us understand the role of respiration in plant growth?
Ans. This experiment helps us understand that during respiration, plants break down glucose in the presence of oxygen and release carbon dioxide, water and energy. The energy produced is used for important activities like cell division, absorption of nutrients, repair of tissues and making new substances. These processes help in the growth of plants.
OLD Question Answer
Electric effects and their action
1) Draw the symbols of the following components of an electric circuit with your thumbs. Connectors switch from closed position, bulbs, cells, switches to off position and batteries
Answer: FOR STUDENTS
2) 14.21 To see the picture, read the letter and draw the picture.
3) See figure 14.22, the four cells are now fitted with eight holes. Arrange the four cell battery and draw a line to show how it should be connected.
4) As shown in figure 14.23, the bulb is not lit. Do you know why? The required annual occurrence of light bulbs.
5) Name any two functions of electric current.
Answer:- 1) Magnetic action.
6) When current flows through the coil, the magnetic field near the coil is deflected in a north-south direction. explain
Answer:-
7) Refer to figure 14.24 What is the deflection of the magnetic field in the pole of the plate?
8) Fill in the blanks:
a) The long line of cell symbols indicates the ________ region of the cell.
b) Additive of two or more cells is called ________.
c) When current is passed through the coil heater, it is ________.
d) The protection system based on the action of electric current or heat generation is called ________.
9) If the following statements are wrong, correct them and if they are correct, recognize them correctly:
A) It is a battery of two cells and the negative end of the cell should be connected to the negative end of the second cell. (true\false)
Answer: False.
b) If the current flowing through the fuse is too high, the fuse will blow. (true\false)
Answer: Pure.
c) Iron pieces are not attracted to electromagnets. (true\false)
Answer: False.
d) An electric clock has only so many electromagnets. (false\correct)
Answer: Pure.
10) Do you think it would be effective to use electromagnets to separate the garbage piles of plastic? explain
Answer: – Don’t forget the ladder. Because electromagnets attract magnetic materials. Plastic magnets are not magnetic materials and do not attract electromagnets.
11) This electrician has done repair work on your house. They are looking for fuses and slabs. Do you agree? Explain the reason for your reaction.
Answer: Do not agree with the ladder. Because the fuse is made of special metal and if it is electrically operated, it will heat up and burn.
12) 14.4 Using this cell line chain, this needle and this bulb, Jubedai spelled it out. The bulb lit up in spite of the light behind him. Jubedak helps to determine the possibility of forgetting words.
13) Refer to Figure 14.25
a) Which bulb is lit in the off position?
Ans: In the off position no bulb is lit.
b) If the switch is turned on, will the bulbs A, B and C light up?
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