Plant Physiology: I. Photosynthesis

Chlorophyll's primary function is to capture light energy from the sun. This light energy is then used to drive the process of photosynthesis, where plants convert carbon dioxide and water into glucose (a sugar) and oxygen. Chlorophyll is the "antenna" that absorbs light, initiating the chain of reactions that leads to the production of food.

Chlorophyll is a porphyrin derivative, meaning it has a ring structure with a central magnesium atom. There are different types of chlorophyll, including chlorophyll a and chlorophyll b. Chlorophyll a is the main pigment involved in photosynthesis, while chlorophyll b acts as an accessory pigment, absorbing light at different wavelengths. Other types of chlorophyll, like chlorophyll c, d, and e, are found in algae.

DNA carries the long-term genetic instructions, while RNA plays a more active role in various cellular processes, including the initiation of DNA replication. DNA polymerase, the enzyme responsible for synthesizing new DNA strands, cannot initiate the synthesis of DNA without a primer. RNA primers are short sequences of RNA molecules that provide the necessary free 3' hydroxyl group (3'-OH) that DNA polymerase can attach to and start building a new DNA strand. The use of RNA primers is essential because DNA polymerase can only add nucleotides to the 3' end of an existing strand, and the RNA primers provide this necessary starting point.

While both water and carbon dioxide are involved in photosynthesis, water is the source of the oxygen released into the atmosphere. During the light-dependent reactions of photosynthesis, water is split into hydrogen ions (H+), electrons, and oxygen molecules (O₂). The hydrogen ions and electrons from the split water are then used to convert carbon dioxide into glucose in the light-independent reactions (Calvin cycle). Experiments using radioactive isotopes have confirmed that the oxygen produced in photosynthesis originates from water, not carbon dioxide.

Photosynthesis is the physicochemical process by which green plants, algae, and some bacteria synthesise organic compounds in the presence of sunlight using components such as carbon dioxide and water. In this process, light energy is converted to chemical energy in the form of sugars and Oxygen as a byproduct. Photosynthesis by green plants and other photoautotrophs is the basis of life as it is the primary source of all food on Earth.

Photosynthesis takes place in the chloroplast organelle of plant cells. It is a double-membrane organelle having its own DNA, mitochondria, and ribosomes. It also contains a third inner membrane, called thylakoid.

Thylakoid membranes: They look like stacks of coins. It contains chlorophyll.
The membrane system is responsible for trapping the light energy for the synthesis of ATP and NADPH.

Stroma: The space between the thylakoid and the chloroplast membranes is called the stroma. Within the stroma, enzymatic reactions occur to synthesize sugar, subsequently leading to the formation of starch.

Photosynthesis is the physicochemical process by which green plants, algae, and some bacteria synthesise organic compounds in the presence of sunlight using components such as carbon dioxide and water. In this process, light energy is converted to chemical energy in the form of sugars and Oxygen as a byproduct. Photosynthesis by green plants and other photoautotrophs is the basis of life as it is the primary source of all food on Earth.

Photosynthesis takes place in the chloroplast organelle of plant cells. It is a double-membrane organelle having its own DNA, mitochondria, and ribosomes. It also contains a third inner membrane, called thylakoid.

Thylakoid membranes: They look like stacks of coins. It contains chlorophyll.
The membrane system is responsible for trapping the light energy for the synthesis of ATP and NADPH.

Stroma: The space between the thylakoid and the chloroplast membranes is called the stroma. Within the stroma, enzymatic reactions occur to synthesize sugar, subsequently leading to the formation of starch.