Respiration in Plants

Both A and R are False.

Reason — Plants respire continuously, both day and night, to produce energy. All parts of a plant (leaves, stems, roots) respire, not just leaves. Stems respire via lenticels while roots respire via root hairs.

Both A and R are False.

Reason — Respiration is a catabolic process, not anabolic. It breaks down glucose to release energy in form of ATP. It is not a single-step process, it occurs in multiple steps to finally produce ATP.

A is True and R is False.

Reason — In anaerobic respiration in plants (e.g., yeast), the end products are ethyl alcohol and carbon dioxide. In anaerobic respiration incomplete breakdown of glucose takes place, not of cellulose.

A is True and R is False.

Reason — Photosynthesis and respiration are opposite processes.
In photosynthesis glucose is manufactured from carbon dioxide and water and energy, while in respiration glucose is broken down (oxidised) to obtain carbon dioxide water and energy.

Both A and R are False.

Reason — The Krebs cycle occurs in the mitochondria, not in the cytoplasm. While glycolysis and the Krebs cycle are both part of aerobic respiration, but glycolysis occurs in the cytoplasm.

A is False and R is True.

Reason — Lenticels are the openings found on the surface of stem. They help in gaseous exchange through diffusion.

(a) Difference between Aerobic and anaerobic respiration:

(b) Difference between Respiration and combustion:

(c) Difference between Stomata and lenticels:

(d) Difference between Photosynthesis and respiration:

(e) Difference between Anaerobic respiration in plants and animals:

Given below are the ways in which the following structures help in plant respiration:

(a) Lenticel — These help the stem to participate in respiration.

(b) Stomata — These help the leaves to participate in respiration.

(c) Root hairs — These help the roots to participate in respiration.

The differences between aerobic and anaerobic respiration in plants are as follows:

Respiration is said to be the reverse of photosynthesis due to the following reasons :

1. In respiration, the organic food is disintegrated into its inorganic compounds, namely –
   Carbon dioxide and Water. In photosynthesis, the organic food is manufactured from its inorganic components, namely - Carbon dioxide and Water.
2. In respiration, Carbon dioxide is released whereas in Photosynthesis Carbon dioxide is consumed.
3. Oxygen is consumed during respiration while Oxygen is evolved in photosynthesis
4. Energy is liberated in Respiration while in Photosynthesis, energy is absorbed.

Oxidation of organic food particularly carbohydrates in living cells to release energy is called respiration.

Similarities between burning and respiration are —

1. Oxygen is required by both.
2. Energy is released by both.
3. The outcome of both is water and carbon dioxide.

Differences between burning and respiration:

1. Aim — Experiment demonstrating the fact that germinating seeds produce heat.

Procedure —

1. Name two thermo flasks as 'A' and 'B', keep them aside
2. Approximately 200 pea seeds or beans would be used in the experiment. Soak them in water for more than 24 hours.
3. Split the seeds into two equal groups approximately
4. One group of seeds are killed by boiling them and washing them with dilute formaline in order to restrict bacterial decay
5. The live germinating seeds need to be placed in flask A and the boiled/killed seeds in flask B.
6. Introduce a thermometer into each of the flasks and seal their mouths with cotton wool.
7. Take note of the initial reading observed in the thermometer.

Inference —

1. A few hours later, thermometer in the flask A shows a higher reading depicting that the seeds that germinate generate heat.

2. Flask B shows no rise in the temperature.

3. Aim — Experiment demonstrating the fact that germinating seeds produce Carbon dioxide.

Procedure —

1. Name two thermo flasks as ‘A’ and ‘B’, keep them aside.
2. At the base of both the flasks, place wet cotton wool.
3. In flask A, take a few soaked seeds of pea, simultaneously take equal quantity of boiled seeds in flask B.
4. To flask B, add some carbolic acid so as to inhibit bacterial growth on the dead seeds.
5. Seal the flasks with a cork, leave them undisturbed for a couple of days.
6. Observe the changes.

Inference —

1. Post few days, germination of seeds in flask A is observed.

2. Flask B shows no signs of seed germination.

3. Cork is removed to test the gases in each of the flasks. The flask is toppled over a test tube which carries limewater. The test tube is then shaken up.

4. Indication of carbon dioxide as expected in flask A is observed when lime water turns milky, thereby depicting that germinating seeds produce carbon dioxide.

5. The gas in the flask B shows no effect upon coming in contact with limewater, indicating absence of carbon dioxide.

6. Aim — Experiment demonstrating the fact that seed germination undergoes respiration even in complete absence of air

Procedure and Inference —

1. Fill a test tube with mercury that is inverted into a beaker of mercury.
2. Into this tube, push some soaked and peeled off pea seeds before inverting into the mercury beaker.
3. You will observe that seeds will float up and are entirely girdled by mercury.
4. A few days later, few changes are observed. Mercury level drops, presence of some gases are detected in the tube.
5. Pour in some KOH into the tube.
6. Gas in the tube is absorbed, mercury level rises again, depicting that the gas was carbon dioxide
7. Consequently it is proved that the germinating seeds undergo respiration even in the total absence of air.

Below diagram shows the experimental set up (initial and final stages) to demonstrate anaerobic respiration in germinating seeds:

in which glucose is broken down into pyruvate

Reason — Glycolysis is the first phase of respiration in which glucose is broken down into pyruvate.

Stomata and lenticels

Reason — Stomata are tiny pores present on surface of leaves and lenticels are present on stems. Both are responsible for gaseous exchange.

Baker’s yeast

Reason — Anaerobic respiration normally occurs in fungi.

38

Reason — Oxidation of 1 molecule of glucose gives 38 ATP.

In all the parts

Reason — Leaves respire through stomata, stems respire through lenticel and roots respire through their general surface.

Ethyl alcohol

Reason — Anaerobic respiration in plants leads to the formation of Ethyl alcohol.

Cytoplasm

Reason — Glycolysis takes place in cytoplasm whereas Krebs cycle takes place in mitochondria.

Calcium carbonate

Reason — Calcium carbonate is formed when carbon dioxide reacts with lime water.

Glucose

Reason — Glucose is the simplest sugar. Any sugar first breaks to form glucose, which further breaks down to release energy.

Respiration

Reason — Photosynthesis (anabolic process) leads to formation of glucose while respiration(catabolic process) leads to break down of the glucose molecules.

P — Glycolysis, Q — Kreb's cycle

Reason — In glycolysis glucose is broken down to form pyruvate and in Kreb's cycle it is completely oxidised to form CO₂, ATP, and NADH.

Sukhvinder and Aayush

Reason — Anaerobic respiration is the breakdown of glucose in the absence of oxygen. The end products vary depending on the organism:

• In plants and yeast:
  Glucose → Ethanol + Carbon dioxide + Energy
• In animals (like humans during vigorous exercise):
  Glucose → Lactic acid + Energy

As Aayush said Lactic acid so his answer is correct. Sukhvinder said Carbolic acid and lactic acid. Carbolic acid is wrong, but lactic acid is correct for animals. So, Sukhvinder's answer is partially correct.

1. The breakdown of glucose to carbon dioxide and water does not occur in a single step, but in a series of chemical steps. These steps occur in two major phases — (i) glycolysis (glucose → pyruvate) occurring in cytoplasm and (ii) Krebs cycle (pyruvate → CO₂ + 6H₂O + ATP) occurring in mitochondria.
2. Each breakdown step occurs due to a particular enzyme.
3. The energy liberated in the breakdown of glucose molecule is not all in the form of heat, but a large part of it is converted into chemical energy in the form of ATP.

The three inlets of oxygen for respiration in plants are:

1. Stomata in leaves.
2. Lenticels in stem.
3. General surface of the roots.

1. Aerobic respiration
   C₆H₁₂O₆ + 6O₂ $\xrightarrow{\text{enzyme}}$ 6CO₂ + 6H₂O + 38ATP

2. Anaerobic respiration
   C₆H₁₂O₆ ⟶ 2C₂H₅OH + 2CO₂ + 2ATP

Aerobic respiration is the primary and the most efficient way for plants to generate energy. On the other hand, Anaerobic respiration is a backup mechanism for plants when oxygen is limited and occurs temporarily for short periods.

Bacteria and fungi.

In experiments on respiration, the seeds taken as control are boiled to kill them. It is done in order to compare the live seeds that can respire to dead seeds that cannot respire.

1. Soda lime is used to absorb any carbon dioxide released by the seeds.
2. Limewater is used to test for the presence of carbon dioxide as carbon dioxide turns limewater milky.

It is necessary that this experiment is carried out in dark in order to stop the process of photosynthesis so that the carbon dioxide liberated in respiration is not used up for photosynthesis.

We can't use water because it has some dissolved gases like oxygen and carbon dioxide.

In anaerobic respiration in plants, the end product is ethanol and carbon dioxide instead of lactic acid in animals.

(a) Respiration — Respiration is a catabolic process of releasing energy from glucose for carrying out life processes.

(b) Combustion — Combustion or burning is defined as a physio-chemical process in which energy is liberated in the form of heat and light.

(c) ATP — ATP is defined as energy currency of the cell as it acts as the immediate source of energy for different life processes.

(a) Glucose and Oxygen

(b) Carbon dioxide and water

(c) Bacteria and Fungi

Full form of ATP — Adenosine triphosphate

Full form of ADP — Adenosine diphosphate

The energy liberated in respiration is stored in the form of ATP inside the cells. Some part of it is lost as heat to the surroundings.

Tilling makes the soil porous and airy. The parts of the plant present below the ground receive adequate oxygen supply to respire. This way tilling facilitates faster crop growth.

During day time, both photosynthesis and respiration takes place in green plants. Evolution of carbon dioxide is an indicator to demonstrate respiration in living organisms. Carbon dioxide produced during respiration in plants gets utilized during photosynthesis and thus, there is no evolution of carbon dioxide. Consequently, it becomes difficult to demonstrate respiration in green plants as there in no evolution of carbon dioxide during day time.

Cell respiration cannot occur in any organism at a temperature of about 65°C because the enzymes involved in respiration become inactivated at high temperatures.

1. (a) 6H₂O
   (b) 2C₂H₅OH
2. (a) The process observed in this chemical reaction here is aerobic respiration
   (b) The process observed in this chemical reaction is anaerobic respiration
3. The reaction occurring in (a) can take place only in the presence of oxygen as it is aerobic respiration. The reaction occurring in (b) can take place even in the absence of oxygen as it is anaerobic respiration.

(a) The different plant parts for observation have been placed in five flasks right from A-E flasks as observed in the diagram.

(b) It is the property of limewater to absorb Carbon dioxide. Hence it is placed in the flask, so as to absorb Carbon dioxide and turn milky in the presence of any Carbon dioxide.

(c) Limewater turns milky in the presence of Carbon dioxide. All five flasks from A to E have plant parts hence respiration takes place in all five parts causing the limewater to turn milky. In flask F, respiration does not take place as there is no plant part, hence no change is observed

(d) In the experiment, the setup F depicts the experiment control, wherein all conditions are maintained in the same way except for the plant part that is absent in flask F.

(e) The experiment clearly shows that Carbon dioxide is produced during the process of respiration.

(a) To check the presence of Carbon dioxide, potassium hydroxide is placed in the test tubes X and Y. Potassium hydroxide has a special property of absorbing Carbon dioxide if produced.

(b) In the test tube X, when the process of respiration takes place, the oxygen is consumed that is present in the test tube. Due to respiration, Carbon dioxide that is produced is absorbed by the KOH in the test tube. Due to consumption of Oxygen, a space is developed causing the colored water to rise in the tubing 1.

(c) It is because the seeds die once they are boiled and hence cannot undergo respiration. This is why respiration does not take place in test tube Y.

(d) The biological process that causes a rise is respiration.

(e) It is respiration. It is a catabolic process wherein energy is liberated from simple sugars to be able to carry out life processes.

(a) The experiment demonstrates that carbon dioxide is produced during the process of respiration in germinating seeds.

(b) Soda lime is placed in bottle ‘A’ as it indicates the passage/presence of Carbon dioxide in bottle A. Another property of soda lime is that is absorbs Carbon dioxide that is present in the air. The clear limewater in bottle B indicates that the air that enters the flask C is free from Carbon dioxide.

(c) The bottle D holding limewater should indicate that carbon dioxide is produced as a result of respiration occurring in bottle ‘C’ possessing the germinating seeds. As carbon dioxide is produced in the bottle C, limewater turns milky that enters the bottle 'D'.

(d) The chemical reaction is as written below:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 38ATP (energy)

(e) The bottle 'C' is covered with a black cloth in order to restrict any chance of photosynthesis so as to make sure the process of respiration only is carried out and observed.

(f) A thermometer is inserted in bottle C to observe the changes in temperature. Respiration causes the temperature to rise, if there is no respiration, the temperature will not rise.

1. Lenticels are the openings found on older stems.

2. Glycolysis occurs in the cytoplasm of the cells.

3. Glucose is a respiratory substance.

4. Rate of Photosynthesis is more than the rate of Respiration in the daytime in the case of green plants.

5. Pyrogallate of potash is a chemical substance which absorbs oxygen of the air.

6. Caustic potash (KOH) is used to create vacuum to show anaerobic respiration.

1. ATP (Adenosine triphosphate)
2. Respiration
3. Fungus
4. Glycolysis
5. Soda lime

Respiration is an essential life process for all living organisms. Therefore, plants also respire all day and all night.

1. False
   Corrected Statement — Aerobic respiration of one mole of glucose yields 38 ATP.

2. False
   Corrected Statement — Anaerobic respiration in plants yields ethanol.

3. True

4. False
   Corrected Statement — All leaves of a green plant normally respire aerobically at night.