Tag: historical events in photosynthesis

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Questions Related to historical events in photosynthesis

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Who proposed the cycle of events leading to the fixation of $CO _{2}$ in mesophyll and its reduction in bundle sheath?

  1. Emerson

  2. Melvin Calvin

  3. Hatch and Slack

  4. Hill and Bendall
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hatch and Slack pathway is a metabolic pathway for carbon-dioxide translocation occurring in $C _4$ plants. The overall effect of the pathway is to carry $CO _2$ from the mesophyll cells, which are in contact with air, to the bundle-sheath cells, which are the major sites of photosynthesis.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Which of the following reveals the role of air in the growth of green plants?

  1. Joseph Priestley

  2. Jan Ingenhousz

  3. T. W. Engelman

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Joseph Priestley conducted experiments in 1774 showing that plants restore the air that has been 'injured' by burning candles or breathing animals, demonstrating the role of plants in gas exchange.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Photosynthesis (nourishment in light) was discovered by

  1. Stephan Hales

  2. Priestley

  3. Ingenhousz

  4. Van Mayer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photosynthesis is a process by which green plants manufacture their food with the help of carbon dioxide and water in the presence of sunlight. It was discovered by Jan Ingenhousz. Through his experiments, he showed that sunlight is essential for the plant process that helps to somehow purify the air fouled by the breathing mouse and the burning candle in Priestley's bell jar experiment. In another experiment with an aquatic plant (Hydrilla), he showed that in bright sunlight, small bubbles were formed around the green parts of the plant while in dark, no bubbles were formed. He identified those bubbles to be of oxygen. Thus, the correct answer is option C.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Two pigment system theory of photosynthesis was proposed by

  1. Hill

  2. Blackman

  3. Emerson

  4. Arnon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Emerson effect is the increase in rate of photosynthesis after exposure to light of wavelength 670 nm far red light and 700 nm, red light respectively. When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of red light and far red light photosynthesis rates. The effect was early evidence, that photosystems processing different wavelengths cooperate in photosynthesis. 

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Most of the plants contain a green colouring pigment which is responsible for photosynthesis. This pigment was named chlorophyll by 

  1. Melvin Calvin

  2. Jean Senebier

  3. Julius Robert Mayer

  4. Pelletier and Caventou
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chlorophyll is the liquid substance in a plant cell, which is responsible for its colour. Plants make food when sunlight strikes chlorophyll. Pelletier and Caventou discovered chlorophyll in 1818.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

The term dephlogisticated air was given by

  1. Von Mayer

  2. Van Helmont

  3. Warburg

  4. Priestely
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The term dephlogisticated air was given by Priestely. He performed the experiment to prove that the plants are responsible for the recycling of the gas present in the air which is used during burning and respiration. 
The experiments which were performed are as follows:
1) There was a bell-shaped jar placed upon a burning candle and a live mouse.
2) When the mouse and the candle were placed under the bell jar, the mouse used all the oxygen from the air. This resulted in the extinguishing of the candle due to the absence of oxygen in the air.  The mouse also dies after some time due to the absence of oxygen. 
3) Then a mint plant was placed in the bell jar along with a live mouse and the burning candle. 
4) The plant help in recycling the oxygen in the air by using carbon dioxide. This causes the replenishing of the oxygen in the air which is lost by the respiration by mouse and the burning of the candle.

Thus, the plant can perform photosynthesis and replenish the oxygen in the air which is used by the animals for breathing. 
Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Sunlight is essential to the plant process is shown by the

  1. T. W. Engelman

  2. Jan Ingenhousz

  3. Von Mayer

  4. Blackman
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Jan Ingenhousz demonstrated that sunlight is essential to the plant process by showing that aquatic plants produce bubbles in the presence of light but not in the dark.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Action spectrum of photosynthesis was first studied by

  1. Blackman

  2. Van Mayer

  3. Engelmann

  4. Boussingault
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

T. W. Engelmann experimented on Cladophora. Using a prism, he split light into its spectral components and then he illuminated a green alga, Cladophora, placed in a suspension of aerobic bacteria. The bacteria were used to detect the sites of oxygen evolution. He found that the bacteria accumulated mainly in the region of blue and red light of the split spectrum. Thus, action spectrum of photosynthesis was first studied by Engelmann.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

The first scientist to find out the role of light in photosynthesis was

  1. Ingenhousz

  2. Senebier

  3. Priestley

  4. Sachs
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photosynthesis is a process by which green plants manufacture their food with the help of carbon dioxide and water in the presence of sunlight. It was discovered by Jan Ingenhousz. Through his experiments, he showed that sunlight is essential for the plant process that helps to somehow purify the air fouled by the breathing mouse and the burning candle in Priestley's bell jar experiment. In another experiment with an aquatic plant (Hydrilla), he showed that in bright sunlight, small bubbles were formed around the green parts of the plant while in dark, no bubbles were formed. Thus, the correct answer is option A.

Multiple choice botany living world of plants - plant physiology historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Action spectrum of photosynthesis was discovered in 1883 by

  1. Engelmann

  2. Calvin

  3. Arnon

  4. Hill.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Theodor Wilhelm Engelmann was a German scientist. In 1883, he performed his famous action spectrum experiment to learn which wavelengths or colour of light were the most effective in carrying out photosynthesis in the green alga.

So the correct option is 'Engelmann'.