TLDR;
This video provides a comprehensive overview of respiration in plants, distinguishing it from photosynthesis and burning. It covers the types of respiration (aerobic and anaerobic), the processes involved, and the various experiments that demonstrate these concepts. The video also explains metabolic activities like anabolism and catabolism and compares respiration in plants versus animals.
- Respiration is the process by which plants release energy from glucose, using oxygen and producing carbon dioxide and water.
- The video details the differences between aerobic and anaerobic respiration, highlighting the importance of oxygen.
- Several experiments are explained to demonstrate the consumption of oxygen and the production of carbon dioxide during respiration.
Introduction [0:00]
The video introduces the chapter on respiration in plants for class nine, explaining that respiration is the process by which energy is released in the body, a process needed by both animals and plants. This energy is essential for various plant activities, including photosynthesis and the transport of water, minerals, and food.
Respiration [0:44]
Plants absorb oxygen to break down glucose, which was formed during photosynthesis. This process releases carbon dioxide and energy. During the day, plants use a small amount of the oxygen released from photosynthesis for their energy needs. At night, when photosynthesis doesn't occur due to the absence of sunlight, plants use more oxygen to break down glucose and release energy, which is stored as ATP (adenosine triphosphate), the energy currency of the cell.
Metabolic Activities [11:24]
Metabolism involves two main activities: anabolism and catabolism. Anabolism is a constructive activity where small components combine to form larger structures, requiring energy. Catabolism, on the other hand, is a destructive activity where complex substances are broken down into simpler ones, releasing energy.
What is Respiration? [14:35]
Respiration is a breakdown process in which living cells oxidize organic substances like glucose to release energy, forming carbon dioxide and water. It is a catabolic process that releases energy from glucose to support life processes. This process occurs within the cell, where glucose is converted into pyruvate in the cytoplasm, and then pyruvate enters the mitochondria to release energy.
Question. [15:59]
Glycolysis is a process where glucose is broken down into pyruvate, occurring in the cytoplasm and not requiring oxygen. This step is common in both aerobic and anaerobic respiration.
Respiration vs Burning [17:17]
Respiration is a cellular process occurring within living cells at body temperature, involving a series of chemical steps facilitated by enzymes. It is a biochemical process where energy is released as ATP and heat, without producing light. Burning, conversely, is a non-cellular process requiring high temperatures, occurring in a single step, and involving a physical and chemical reaction that releases energy as heat and light.
Respiring Plant Parts [21:44]
Respiration in plants occurs through stomata, lenticels on stems, and the general surface of roots. Unlike animals, plants do not have specific respiratory organs; instead, every plant part respires. Gases are transferred through cell-to-cell diffusion due to the low energy requirements of plants. It's important to keep the soil loose around plants to ensure the roots can breathe, preventing the plant from dying due to lack of air.
Respiration during day and Night [24:51]
During the day, plants take in carbon dioxide and release oxygen through photosynthesis. At night, this process reverses, with plants taking in oxygen and releasing carbon dioxide. This is why it's not advisable to sleep under a tree at night, as the plant will be releasing carbon dioxide, which is not a breathing gas for humans.
Two Kinds of Respiration [26:28]
There are two types of respiration: aerobic and anaerobic. Aerobic respiration involves the complete breakdown of glucose in the presence of oxygen, releasing a large amount of energy (around 38 ATP molecules). Anaerobic respiration, on the other hand, involves the incomplete breakdown of glucose in the absence of oxygen, producing ethanol and a small amount of energy.
Aerobic vs.Anaerobic Respiration [29:19]
Aerobic respiration occurs in the presence of oxygen, resulting in the complete breakdown of glucose into carbon dioxide, water, and a large amount of energy (38 ATP molecules). Anaerobic respiration occurs in the absence of oxygen, leading to an incomplete breakdown of glucose into ethyl alcohol, carbon dioxide, and a small amount of energy (2 ATP molecules). Aerobic respiration happens normally throughout a plant's life, while anaerobic respiration occurs temporarily when oxygen is limited.
Experiments. [31:03]
Experiments are designed with an experimental setup and a control setup. The experimental setup maintains normal conditions, while the control setup limits a specific factor, such as oxygen, to observe the difference and prove the experiment's objective.
Experiment 1. [32:28]
This experiment demonstrates that oxygen is used in respiration. Two setups are used: one with germinating seeds and another with dead seeds. Both are sealed with soda lime to absorb carbon dioxide and connected to a water-filled beaker. The water level rises more in the setup with germinating seeds, indicating oxygen consumption.
Experiment 2. [38:34]
This experiment proves that carbon dioxide is produced during respiration in germinating seeds. Germinating seeds and boiled seeds are placed in separate setups. Lime water is introduced to each setup, and the lime water turns milky only in the setup with germinating seeds, confirming carbon dioxide production.
Experiment 3. [40:14]
This experiment further demonstrates that germinating seeds release carbon dioxide. Four conical flasks are connected in a series. Air, free of carbon dioxide, is passed through germinating seeds, and the air that exits is passed through lime water. The lime water turns milky, indicating that the germinating seeds produced carbon dioxide.
Experiment 4. [42:47]
This experiment shows that green plants produce carbon dioxide during respiration. A small potted plant is placed in a sealed bell jar. Air, free of carbon dioxide, is passed into the jar, and the air that exits is passed through lime water. The lime water turns milky, indicating that the green plants produced carbon dioxide. This experiment must be conducted in dark conditions to prevent photosynthesis from using the carbon dioxide.
Experiment 5. [46:36]
This experiment demonstrates that heat is released during respiration. Two thermos flasks are used: one with soaked seeds and another with boiled seeds. Thermometers are placed in both flasks. The temperature increases in the flask with germinating seeds, indicating that heat is produced during respiration.
Experiment 6. [49:30]
This experiment demonstrates anaerobic respiration. A test tube filled with mercury is inverted over a beaker with mercury, and peeled pea seeds are introduced. After a few days, the mercury level drops, indicating gas production. Introducing potassium hydroxide absorbs the gas, confirming it is carbon dioxide.
Question [52:42]
The energy currency of the cell is ATP. Oxidative breakdown of carbohydrates to release energy is respiration. An organism that respires throughout life aerobically is fungus. A common phase in both aerobic and anaerobic respiration is glycolysis, which occurs in the cytoplasm.
Photosynthesis Vs Respiration [53:47]
Photosynthesis and respiration are opposite processes. Photosynthesis occurs in the presence of chlorophyll and light, using carbon dioxide and water to produce glucose and oxygen. Respiration occurs in all living cells, using oxygen and glucose to release carbon dioxide, water, and energy. Photosynthesis is an anabolic process, while respiration is a catabolic process.
Respiration Plants Vs. Animals [57:21]
In plants, there is no specific gaseous transport system; gases move through cell-to-cell diffusion. In animals, gases are transported through tubes and blood. The end product of anaerobic respiration in plants is ethanol, while in animals, it can be lactic acid. Plants produce a little heat during respiration, whereas animals produce a lot of heat.