Chapter: Life Sciences
The green plants in a terrestrial ecosystem absorbs sunlight that falls on their leaves and convert it into food energy. The percentage of solar radiation absorbed by all green plants for the process of photosynthesis is about
Explanation: Green plants utilize approximately 1% of the solar radiation they absorb through their leaves for the process of photosynthesis. This critical reaction relies on the absorption of sunlight. Carbon dioxide is taken in by the plant through stomata, commonly found on the underside of the leaves, while water is absorbed through its roots. The fraction of solar radiation utilized for photosynthesis is approximately 1%.
Leaves of most plants appear green because the chlorophyll present in it:
The green appearance of leaves is primarily due to chlorophyll, utilizing the principles of light absorption and reflectance.
Chlorophyll is a pigment that plays a crucial role in photosynthesis. It has two main forms: chlorophyll a and chlorophyll b, both predominantly found in plant leaves.
Chlorophyll absorbs light in the following wavelengths:
However, chlorophyll does not absorb green light (approximately 495-570 nm), which is instead reflected, making leaves appear green to our eyes.
Option B is incorrect; chlorophyll does not absorb green light. Option C is inaccurate as it states chlorophyll absorbs green light. Option D is also wrong; chlorophyll reflects red light instead of absorbing it.
Remember: "Green reflects, blue and red attract." This can help recall chlorophyll's light absorption properties.
A diagram showing the chlorophyll absorption spectrum, including wavelengths absorbed (red and blue) and reflected (green), visualizing the process of photosynthesis in leaves.
Verified against NCERT Class XI Biology, Chapter on Plant Physiology.
In a dicot pot herb, vaseline/vegetable oil was applied on the upper surface of one leaf (Experimental leaf 1) and on the lower surface of another leaf (Experimental leaf 2). Vaseline/ Vegetable oil was not applied on the control leaf. The plant was deliberately not watered for several days. Which leaf will dry up last?
Transpiration is the process through which water vapor is lost from the aerial parts of the plant, primarily through stomata. In dicot leaves, stomata are predominantly found on the lower surface.
When vaseline or vegetable oil is applied on the leaves, it blocks the stomata:
Tip: Remember that "Stomata on the bottom, water stays in." Leaves with blocked stomata retain moisture longer.
Illustrate a cross-section of a leaf showing the location of stomata, highlighting the impact of vaseline application and its effect on transpiration rates.
[Verified against NCERT Class XI Biology, Chapter 11 (Transport in Plants)]
Which one of the following statements about the process of photosynthesis is correct?
Photosynthesis is a biochemical process where light energy is converted into chemical energy, facilitating the conversion of carbon dioxide and water into glucose and oxygen.
The overall equation for photosynthesis can be summarized as:
During the light-dependent reactions, which occur in the thylakoid membranes, water molecules are split (photolysis) into oxygen, protons, and electrons:
This reaction harnesses light energy to facilitate the splitting of water molecules.
Option A: Incorrect. Chemical energy is generated, not converted to light energy.
Option B: Incorrect. Carbon dioxide is reduced, not oxidized, to form carbohydrates.
Option C: Incorrect. Water is split into oxygen and hydrogen ions, not oxidized as a standalone compound.
Remember: "Light Splits, Water Lifts!" to recall that light energy drives the splitting of water during photosynthesis.
A flowchart depicting the photosynthesis process can enhance understanding. Show how light energy converts into chemical energy, highlighting the split of water into oxygen and hydrogen ions.
Verified against NCERT Class 11 Biology, Chapter 13 (Photosynthesis in Higher Plants).
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