ICSE Class 9 Biology Solutions Chapter 7 Respiration in Plants

Class 9th ICSE Biology Solutions Chapter 7 Respiration in Plants

Progress Check

Question 1.
What are the three important aspects about the overall chemical equation of respiration, pertaining to the following ?
(i) Single or several steps
(ii) Direct or enzyme-catalysed
(iii) Forms of energy liberated
Answer:
The overall reaction of respiration is
C₆H₁₂O₆ → C₂ H₅OH + 2CO₂+ 2ATP
(i) It occurs in several steps.
(ii) It is an enzyme catalysed process.
(iii) The energy is liberated in the form of ATP and heat.

Question 2.
List three ways in which respiration is different from
burning :
(i) ……………………
(ii) …………………..
(iii) …………………….
Answer:

Respiration	Burning
1. It occurs in living organisms	1. It occurs in non-living bodies.
2. It occurs in various steps.	2. It occurs in a single step.
3. It is carried out by enzymes	3. It is carried out by heat
4. It is a cellular process	4. It is a non-cellular process

Question 3.
Name the three inlets of oxygen for respiration in the plants.
(i) …………………..
(ii) ……………………
(iii) ……………………
Answer:
The three inlets of oxygen for respiration in plants are:
1. Stomata in leaves.
2. Lenticels in stem.
3. General surface of the roots.

Progress Check

Question 1.
Give the overall chemical equations of the two kinds of respiration in plants :
(i) Aerobic
(ii) Anaerobic.
Answer:
(i) Aerobic respiration :
When the respiration takes place in the presence of oxygen and there is complete oxidation of glucose with the formation of CO₂ and H₂O. This is called aerobic respiration
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 38ATP

(ii) Anaerobic respiration :
Sometimes the plants may temporarily respire even in the absence of oxygen. This type of respiration is called anaerobic respiration.
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + 2ATP.

Question 2.
Mention any one difference other than those reflected In the two chemical equations given above.
Answer:
The aerobic respiration normally occurs throughout life while anaerobic respiration occurs for short periods.

Question 3.
Certain organisms respire only anaerobically throughout their lives. Name any two such organisms.
(i) …………………..
(ii) ………………
Answer:
(i) Mangroves plants
(ii) Forsk (avicenna marina)
(ii) Certain Bacteria and fungi are the organisms which respire anaerobically throughout life.

Progress Check

Question 1.
In experiments on respiration, the seeds taken as control are boiled. Why?
Answer:
The boiled seeds are taken as control reaction because they cannot respire. Therefore, no absorption of 02 hence, no respiration takes place.

Question 2.
What is the use of the following in experiments on respiration?
(i) Soda lime …………………….
………………………………………..
(ii) Limewater ……………………
…………………………………………
Answer:
(i)Soda lime :
It absorbs the CO₂produced during respiration or removes CO₂, from air passes through it.

(ii) Lime water :
When CO₂ passes through it, it turn milky showing the presence of CO₂.

Question 3.
Suppose we conduct an experiment to demonstrate respiration in a green plant. What special precaution is required to be taken in it?
Answer:
The special precaution required to be taken is that the experiment should be carried out in dark or in the bell jar in which the plant is kept should be covered by a black, cloth to prevent photosynthesis.

Question 4.
In the experiment No. 5 we are using mercury in the test-tube and beaker. Why can’t we use water instead?
Answer:
In the experiment we can’t use water instead of mercury because CO₂ produced during experiment will be dissolved in water and it will influence the result of the experiment.

Progress Check

Question 1.
Fill in the blanks :
In anaerobic respiration in plants, the end product is …………………. and ……………… instead of lactic ……………. in animals.
Answer:
In anaerobic respiration in plants, the end product is ethyl alcohol and carbon dioxide instead of lactic acid in animals.

Question 2.
The table below is intended to give certain differences between photosynthesis and respiration, but a few points are given wrongly. Strike out the wrong ones and write the correct words instead

PHOTOSYNTHESIS	RESPIRATION
(i) Results in loss in weight	Results in gain in weight
(ii) Sucrose is the product	Sucrose is broken down
(iii) Occurs in green cell only	Occurs in all cells.
(iv) Uses watér and oxygen	Uses glucose and oxygen

Answer:

PHOTOSYNTHESIS	RESPIRATION
(i) Results in gain in weight	Results in loss in weight
(ii) Uses water and carbon dioxide.	Uses glucose and oxygen

Review Questions

A. Multiple Choice Type :

Question 1.
Glycolysis is a process
(a) in which glycogen is broken down into glucose
(b) which occurs in mitochondria
(c) in which glucose is broken down into pyruvate
(d) that occurs next to Krebs cycle.
Answer:
(c) in which glucose is broken down into pyruvate

Question 2.
One same common function is performed by?
(a) Stomata and veins
(b) Stomata and lenticels
(c) Lenticels and sepals
(d) Lenticels and hydathodes
Answer:
(b) Stomata and lenticels

Question 3.
Anaerobic respiration normally occurs in
(a) Grass,
(b) Cactus,
(c) Coconut,
(d) Baker’s yeast
Answer:
(d) Baker’s yeast

B. Very Short Answer Type

Question 1.
Do the plants respire all day and all night or only at night?
Answer:
Respiration is must in living organisms. Therefore, plants respire all day and all night.

Question 2.
Name the following :
(a) Energy currency of cell.
(b) Oxidative breakdown of carbohydrates to release energy.
(c) An organism which respires throughout life anaerobically.
(d) A common phase is both aerobic and anaerobic respiration.
(e) Aerobic respiration requires …………………
(f) A chemical which removes CO₂ from the air.
Answer:
(a) ATP
(b) Respiration
(c) Fungi
(d) Glycolysis
(e) Oxygen
(f) Soda lime.

Question 3.
Mention if the following statements are true or false. If false rewrite them correctly.
(a) Aerobic respiration of one mole of glucose yields 138 ATP.
(b) Anaerobic respiration in plants yields lactic acid.
(c) Carbon dioxide readily dissolves in lime water.
(d) All leaves of a green plant, normally respire anaerobically at night.
Answer:
(a) False- (i) Aerobic respiration of one mole of glucose yields 38 ATP.
(b) False-Anaerobic respiration in plants yields ethanol.
(c) True.
(d) False-All leaves of a green plant, normally respire aerobically during night.

C. Short Answer Type

Question 1.
What happens to the energy liberated in respiration?
Answer:
The energy liberated in respiration is stored in the form of ATP inside the cells. Some part of it is lost as heat.

Question 2.
Why is it usually difficult to demonstrate respiration in green plants?
Answer:
During day time, both photosynthesis and respiration take place in green plants. The CO₂ produced during respiration gets consumed in photosynthesis and thus, there is no evolution of CO₂ Therefore, it is difficult to demonstrate respiration in green plants as there is no evolution of CO₂ during day time.

Question 3.
Explain why respiration is said to be the reverse of photosynthesis?
Answer:
Respiration is said to be the reverse of photosynthesis due to the following reasons :

• In respiration the organic food is broken down into it’s inorganic compounds i.e. CO₂ and H₂O while in photosynthesis the organic food is synthesized from its inorganic components i.e. CO₂ and H₂O.
• In respiration CO₂is given out while in photosynthesis CO₂ is consumed.
• In respiration O₂ is consumed while in photosynthesis O₂ is released or evolved.
• In respiration energy is liberated, while in photosynthesis energy is absorbed.

Question 4.
How is the tilling of the soil useful for the crops growing in it?
Answer:
Tilling makes the soil porous and airy. The underground parts of the plants get sufficient amount of oxygen for respiration. In this way, the tilling helps the plant to grow fast.

Question 5.
Write the full form of ATP and ADP.
Answer:
ATP – Adenosine triphosphate.
ADP – Adenosine diphosphate.

Question 6.
Can cell respiration occur in any organism at a temperature of about 65°C. Give a reason.
Answer:
The cell respiration cannot occur in any organism at a temperature of about 65°C because the enzymes involved in respiration becomes inactivated at high temperature.

Question 7.
Fill in the blanks :
(a) …………….. are the openings found on older stems.
(b) Glycolysis occurs in the …………….. of the cells.
(c) ……………. is a respiratory substance.
(d) Rate of ………………. is more than the rate of ……………. in the daytime in case of green plants.
(e) …………….. is a chemical which absorbs oxygen of the air.
(f) ……………. is used to create vacuum to show anaerobic respiration.
Answer:
(a) Lenticels
(b) Cytoplasm
(c) Glucose
(d) Photosynthesis, respiration
(e) Chloroform and Acetone
(f) Formaldehyde

D. Long Answer Type

Question 1.
What is respiration? How are respiration and burning similar and how are they different?
Answer:
The oxidation of organic food, particularly, carbohydrates in the living cells to release energy is called respiration.
Similarities between respiration and burning :
(i) Both require oxygen.
(ii) Both produce energy.
(iii) Both results in the formation of CO₂ and water.

Respiration	Burning
1. It occurs in living organisms	1. It occurs in non-living bodies.
2. It occurs in various steps.	2. It occurs in a single step.
3. It is carried out by enzymes	3. It is carried out by heat
4. It is a cellular process	4. It is a non-cellular process

Question 2.
How are aerobic and anaerobic respiration different in plants.
Answer:

Aerobic respiration	Anaerobic respiration
1. It takes place in the presence of oxygen	It takes place in the absence of oxygen.
2. Complete oxidation of food take place.	The oxidation of food is incomplete.
3. It is the most common method of respiration.	It is not a common method of respiration and is seen only in a few organisms.
4. It liberates a large amount of energy.	It liberates very less energy as compared to aerobic respiration.
5. End products are carbon dioxide and water.	End products are ethyl alcohol and carbon dioxide

Question 3.
Describe one experiment each you would perform to demonstrate the following phenomena : The germinating seeds
(a) produce heat,
(b) give out carbon dioxide
(c) can respire even in total absence of air.
Answer:
(a) Experiment demonstrating that the germinating seeds produce heat.
Take two thermos flasks ‘A’ and ‘B’ Take about 200 seeds (bean or pea) and soak them in water for more than 24 hours. Divide the seeds into two equal groups. Kill one group of seeds by boiling them and then wash them with dilute formalin to prevent bacterial decay.

Put the live germinating seeds in flask (A) and the killed one in flask (B). Insert a thermometer in each flask and plug their mouths with cotton wool. Note the initial reading in the thermometer. After a few hours, the thermometer in flask (A) will show a higher reading indicating that germinating seeds produce heat. There will not be any rise in temperature in flask (B).

(b) Experiment showing that germinating seeds give out CO₂.

Take two flasks ‘A’ and ‘B’ Place some wet cotton wool at the bottom of both the flasks. Place some soaked seeds of pea in flask (A) and equal number of boiled or dead seeds are placed in flask (B). Add some carbolic acid to flask (B) to prevent growth of bacteria on dead seeds. Cork the flasks and allow them to remain as it for a few days. After a few days the seeds in flask (A) will be found germinated and the seed in flask (B) will show no signs of germination.

The gases in each flasks are then tested by removing the cork and tilting the flask over a test tube containing lime water and then shaking up the test tube. The expected CO₂ present in flask (A) will turn lime water milky showing that germinating seeds give out CO₂ While the gas in flask (B) will show no effect in lime water.

(c) Experiment showing the germinating seeds can respire in total absence of air.

Take a few seeds soaked and peeled off peas and push them into the mouth of a test tube filled with mercury and inverted in a beaker of mercury as shown in fig. The seeds will float to the top and will be completely surrounded by mercury. After a few days, you will see that the level of the mercury will fall and presence of some gas in the test tube.

Put some KOH in the test tube. You will see that the gas present in the test tube will be absorbed and the level of mercury will again rise showing that the gas was CO₂ Hence, proved that the germinating seeds respire even in the total absence of air.

Question 4.
How do the following structures help in respiration in plants?
(a) Lenticels ………………..
(b) Stomata …………………..
(c) Root hairs ………………….
Answer:
(a) Lenticels help the stem to participate in respiration.
(b) Stomata – Leaves.
(c) Root hairs – Roots.

E. Structured / Application / Ski 11 Type

Question 1.
Given below is a set of six experimental set-up (A-F), kept in this state for the about 24 hours.

(a) In how many flasks, the different plant parts have been kept under observation?
(b) What is the purpose of keeping a test-tube containing lime water in each flask?
(c) In which tube/tubes the limewater will turn milky?
(d) What is the purpose of the set-up F?
(e) What conclusion can you draw from this experiment?
Answer:
(a) Five flasks are having different plant parts.

(b) Lime water absorb CO₂ present in the flask. If Co₂ is produced, the lime water turns milky.

(c) All the five flask containing plant parts will show respiration and thus, the tubes containing lime water will turn milky. Whereas, the flask F containing no plant part will remain as such i.e. there will be no change.

(d) Set up F is a control experiment.

(e) It is concluded from this experiment that CO₂ is produced during respiration.

Question 2.
The following two chemical reactions are supposed to indicate a certain process occurring in the green plants under two different conditions :
(a) C₆H₁₂O₆ + 6O₂ → 6CO₂ + ……..+ 38ATP
(b) C₆H₁₂O₆ →…… + 2CO₂ + 2ATP
(i) Fill in the blank in each reaction.
(ii) Name the process represented by the two chemical equations.
(iii) What are the conditions under which the two reactions
(a) and (b) are occurring respectively?
Answer:
(a) (i) H₂0
(ii) C₂H₅OH

(b) (i) Aerobic respiration
(ii) Anaerobic respiration
(iii) The reaction (1) can be completed only in the presence of oxygen while reaction (2) can be completed in the absence of oxygen.

Question 3.
The following diagram refers to an apparatus which is used to demonstrate a physiological process :
(a) What is the purpose of keeping potassium hydroxide solution in test tubes X and Y?
(b) Why has coloured water risen in tubing 1?
(c) What is the purpose of keeping boiled peas soaked in a disinfectant in test tube Y?
(d) Name the biological process which causes the above rise.
(e) Define the biological process shown in the experiment.

Answer:
(a) Potassium hydroxide solution kept in the test tube to check the presence of CO₂ Because KOH can absorb CO₂ if t produced.

(b) When the process of respiration takes place in test tube X, the O₂ present in test tube is consumed. The CO₂ produced due to respiration is absorbed by KOH present in test tube. Hence, a space is developed due to the consumption of oxygen and hence, the water (coloured) rises in the tubing 1.

(c) In test tube Y, the boiled peas soaked in disinfectant are kept, because the boiled seeds are dead, they cannot respire. Therefore, no process of respiration take place in test tube Y.

(d) Respiration is the cause of the above rise.

(e) The catabolic process of releasing energy from simple sugar for carrying out life processes is called respiration.

Question 4.
In order to study and prove a particular physiological process in plants, the following experiment was set up. Study the same and then answer the questions that follow:

(a) Name the physiological process being studied.
(b) What is the function of soda lime in the bottle ‘A’ and why is limewater placed in bottle ‘B’?
(c) What change would you expect to observe in bottle ‘D’?
(d) Represent the physiological process named in (i) above in the form of a chemical equation.
(e) In order to obtain accurate results, the bottle ‘C’ should be covered with a black cloth. Why?
(f) If bottle ‘C’ were fitted with a 3-holed rubber stopper and a thermometer were introduced in such a way that it’s bulb reaches close to the germinating seeds, what would you observe? Why?
Answer:
(a) The experiment was set up to study that CO₂is given off from living plant material respiration.

(b) Soda lime is kept in bottle ‘A’ so as to check the (presence of) passage of CO₂ present in bottle ‘B’. Because the soda lime has a tendency to absorb CO₂ present in air.
The lime water present in the bottle ‘B’ shows that no CO₂ is entering in bottle C with the air passing through bottle ‘C’.

(c) The bottle ‘D’ having lime water will show that CO₂ is produced due to respiration take place in bottle ‘C’ having germinating seeds in it. Due to the CO₂ produced in bottle C the lime water turn milky which it passes through bottle ‘D’.

(d)C₆H₁₂O₆+ 6O₂ → 6CO₂ + 6H₂O + (Energy) 38ATP

(e) The bottle ‘C’, when is covered with black cloth, there will be no scope of photosynthesis. Hence, the process of respiration can only be observed.

(f) By introducing a thermometer in bottle ‘C’, the change in temperature is checked or observed. If respiration take place, there will be rise in temperature and if there is no rise in temperature, no respiration occurs. Therefore, a threeholed rubber stopper and a thermometer were introduced.

ICSE Class 9 Biology Solutions