Question

Which of the following scientists concluded by his experiments that green plant parts play a role in purifying the noxious air only in the presence of sunlight? (a) Priestley (b) Ingenhousz (c) Sachs (d) Engelmann

Short answer

The correct answer is (b) Ingenhousz, who concluded that green plant parts purify air only in the presence of sunlight.

Step-by-step solution

- Identifying the Scientist

First, we need to recognize the contribution of each scientist listed in the choices. Joseph Priestley discovered that plants release oxygen, which is part of the process of purifying air. Jan Ingenhousz expanded on Priestley's work, discovering that sunlight is necessary for this purification process to occur. Julius von Sachs contributed to our understanding of photosynthesis through his work on plant nutrition. Theodor Engelmann used bacteria to demonstrate the action spectrum of photosynthesis. For the specific role of green plant parts in purifying noxious air in the presence of sunlight, we should identify the scientist who found the connection between sunlight and the purification process.

- Finding the Connection with Sunlight

By analyzing the contributions, we can deduce that Jan Ingenhousz is the scientist who specifically concluded that green plant parts could purify the air, and that this process only occurs in the presence of sunlight. Thus, the correct answer is (b) Ingenhousz.

Key concepts

Ingenhousz Photosynthesis

The discoveries of Jan Ingenhousz are fundamental for our understanding of photosynthesis. After Joseph Priestley uncovered that plants were capable of replenishing oxygen in the air, it was Ingenhousz who took this knowledge further.

He conducted experiments by placing submerged plants in sunlight and observed the production of oxygen bubbles. Ingenhousz found that this process only happened in the presence of sunlight, leading to his conclusion that the green parts of the plant were essential for purifying the air. This purification is actually the photosynthesis process, where carbon dioxide is absorbed and oxygen is released. Important to note is that Ingenhousz’s research underscored that sunlight acts as the energy source for this incredible transformation, thereby laying the groundwork for future studies in the field of plant biology.

Priestley Oxygen Discovery

Joseph Priestley's experiments played a pivotal role in the discovery of oxygen and its relationship to living organisms. Priestley demonstrated that a candle burning in a closed container would eventually extinguish due to the lack of 'good air', which we now know is oxygen.

He further observed that placing a live plant in the container seemed to 'restore' the air, allowing the candle to be lit again. This experiment was crucial as it showed that plants produce oxygen, which is vital for the respiration of animals and the burning of candles. Priestley, therefore, uncovered the symbiotic relationship between plants and animals with respect to air purification.

Photosynthesis Process

Photosynthesis is a complex biological process through which green plants convert light energy, usually from the sun, into chemical energy stored in glucose. This process occurs in the chloroplasts, primarily in leaf cells. The overall chemical reaction is represented by:6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Light energy is captured by the pigment chlorophyll, and water is split into hydrogen and oxygen. The hydrogen joins with carbon dioxide from the air to produce glucose, which serves as an energy source for the plant, while oxygen is released as a byproduct. Upgrading textbook material on this topic can include a focus on the light-dependent reactions and the Calvin cycle for advanced students.

Plant Purification Role

Plants play a critical role in purifying the atmosphere. They absorb carbon dioxide, a major greenhouse gas, and release oxygen back into the environment during photosynthesis. This not only helps to stabilize Earth's climate but also provides the oxygen necessary for animal life.

Furthermore, plants can remove toxins and pollutants from the air, soil, and water, a process known as phytoremediation. In indoor spaces, plants are capable of reducing levels of certain pollutants like benzene, trichloroethylene, and formaldehyde. Understanding the full scope of plants’ vital purification role highlights why it is crucial to protect and conserve plant life on our planet.