Revision: 11th Std >> Plant Growth and Development MAH-MHT CET (PCM/PCB) Plant Growth and Development

Photosynthesis is the process by which living plant cells, containing chlorophyll, produce food substances (glucose and starch) from carbon dioxide and water by using light energy. Plants release oxygen as a byproduct during photosynthesis.

Releasing electrons and dividing the water molecule (H2O) into its two components (Hydrogen and Oxygen). Photolysis is the term used to describe this reaction, which is characterised by the fracturing of molecules by light (photo = light, lysis = breaking).

Thylakoids are indeed very small compartments that are present within chloroplasts. They are the locations where the light-dependent reactions of photosynthesis take place and contain chlorophyll. Nevertheless, the response could be simplified to enhance its clarity.

Chloroplasts are indeed miniature ovoid structures that are encased in a double membrane. Nevertheless, the response could offer a more succinct definition: Chloroplasts are the cellular organelles that are responsible for the process of photosynthesis in plant cells. They are the sites where photosynthesis occurs and contain thylakoids.

The branch of optics that is based on rectilinear propagation of light and deals with mirrors, lenses, reflection, refraction, etc. is called ray optics.

The branch of optics that considers light as a wave which can bend around objects, diffract and interfere, etc. is called wave optics.

Coupled time-varying electric and magnetic fields that propagate in space are called electromagnetic waves.

The phenomenon that is based on the fact that light waves are transverse electromagnetic waves is called polarisation.

In the presence of chlorophyll, photosynthesis is the process by which green plants and certain other organisms convert carbon dioxide and water into glucose (a form of sugar) using light energy, typically from the sun. As a byproduct, this process generates oxygen.

Photolysis occurs in the grana of a chloroplast and is defined as the splitting of H₂O molecules into hydrogen ions and oxygen in the presence of light.

Photophosphorylation is the process of converting ADP into energy-rich ATP by adding an inorganic phosphate (Pi), using energy from light (photons).

Most green plants use glucose as soon as it occurs during photosynthesis to make starch. Polymerisation is the process by which several glucose molecules are turned into one starch molecule.

The process by which monomer molecules combine together to form a polymer is called polymerisation.

The process by which monomer molecules combine together to form a polymer is called polymerisation.

The process of conversion of many simpler and smaller molecules into a complex, bigger molecule is termed as polymerisation. For example, conversion of several glucose molecules into a starch molecule. 

The balanced chemical equation is: \[6\mathrm{CO}_{2}+12\mathrm{H}_{2}\mathrm{O}\frac{\text{light energy}}{\text{chlorophyll}}\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6}+6\mathrm{H}_{2}\mathrm{O}+6\mathrm{O}_{2}\uparrow\]

1. Plastids are present only in plant cells and are of several types—chloroplasts, leucoplasts, and chromoplasts.
2. They are double-membraned organelles with a proteinaceous matrix and contain DNA.
3. Chloroplasts (green) contain chlorophyll in thylakoids and perform photosynthesis.
4. Leucoplasts are colourless, store starch, and have no pigment.
5. Chromoplasts are variously coloured, contain pigments like xanthophyll and carotene, and help in pollination by attracting pollinators.

1. Chlorophyll is the green pigment in plants, found in chloroplasts.
2. It is located in the thylakoid walls inside the chloroplasts.
3. Chloroplasts are mainly present in mesophyll cells of leaves.
4. There are nine types of chlorophyll, but chlorophyll a and chlorophyll b are the most common.
5. Chlorophyll absorbs blue and red light for photosynthesis and reflects green light.

1. Photosynthesis mainly occurs in mesophyll cells (palisade and spongy) of leaves, using chlorophyll to trap sunlight.
2. Carbon dioxide enters the leaf via stomata by diffusion down a concentration gradient.
3. Water is absorbed by roots, transported via the stem to mesophyll cells of the leaves.
4. Using light energy, chlorophyll helps synthesize glucose (C₆H₁₂O₆) from CO₂ and H₂O, releasing O₂ as a by-product.
5. The balanced chemical equation is: \[6\mathrm{CO}_{2}+12\mathrm{H}_{2}\mathrm{O}\frac{\text{light energy}}{\text{chlorophyll}}\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6}+6\mathrm{H}_{2}\mathrm{O}+6\mathrm{O}_{2}\uparrow\]