What is the function of Granum?
The Correct Answer and Explanation is:
Correct Answer:
The function of a granum (plural: grana) is to capture light energy and convert it into chemical energy during photosynthesis in plant cells.
Detailed Explanation (300+ words):
A granum is a stack of thylakoid membranes found within the chloroplasts of plant cells and algae. These stacks are critical structures in the process of photosynthesis, which is how plants convert light energy from the sun into chemical energy stored as glucose.
Each thylakoid membrane within a granum contains chlorophyll and other pigments that absorb light, primarily in the blue and red wavelengths. Chlorophyll is the green pigment responsible for capturing light energy. The grana increase the surface area available for light absorption, maximizing the chloroplast’s ability to capture sunlight efficiently.
The primary function of the granum is to facilitate the light-dependent reactions of photosynthesis. During these reactions, light energy is absorbed by chlorophyll molecules and used to split water molecules (H₂O) into oxygen (O₂), protons (H⁺), and electrons. This process is called photolysis. The electrons move through an electron transport chain embedded in the thylakoid membranes, creating a flow of energy that is used to produce two key energy-carrying molecules: ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).
ATP and NADPH generated in the granum provide the necessary energy and reducing power for the light-independent reactions (Calvin cycle), which take place in the stroma of the chloroplast. In the Calvin cycle, carbon dioxide (CO₂) is fixed into organic molecules such as glucose.
Thus, the granum’s role is fundamental: it captures and converts solar energy into chemical energy, supports the generation of ATP and NADPH, and drives the photosynthetic process that sustains plant growth and oxygen production — a cornerstone for life on Earth.
In summary, without the granum’s function in the light-dependent reactions, plants would not be able to convert sunlight into usable energy, which would halt the entire photosynthesis process and disrupt the food chain
.