A. What is the process of photosynthesis? How does it allow plants to convert solar energy into chemical energy? Photosynthesis is an anabolic process by which green plants, algae, and some bacteria use chlorophyll pigment molecules to trap and convert solar energy from the sun into chemical energy , using water and carbon di oxide. The energy is stored in the form of glucose or other carbohydrates andoxygen is released int he process. This process takes place in the chloroplasts of plant cells and involves several stages. Overall process can be summarised as follows- Light Dependent reactions -Takes place in the thylakoid (grana) of the chloroplasts and require continuous presence of Light energy. Light Absorption: Photosynthesis begins with the absorption of light by pigments, primarily chlorophyll found in the chloroplasts of plant cells. Chlorophyll absorbs light in the visible spectrum, particularly in the red and blue wavelengths. Light-Dependent Reactions (Photophosphorylation): Light energy is used to split water molecules into oxygen, protons (H⁺ ions), and electrons in a process called photolysis. The electrons generated in photolysis are used to create an electron transport chain (ETC) within the thylakoid membrane of the chloroplast. As electrons move through the ETC, energy is released and used to actively pump protons into the thylakoid space, creating a proton gradient. ATP Formation: The proton gradient generated in the thylakoid space creates a potential energy difference. Protons flow back into the stroma through ATP synthase, a protein complex embedded in the thylakoid membrane. This flow of protons powers the synthesis of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate (Pi). NADPH Formation: Simultaneously, electrons released from the photolysis of water are captured by the electron carrier molecule nicotinamide adenine dinucleotide phosphate (NADP⁺), reducing it to form NADPH. Light-Independent Reactions (Calvin Cycle): Carbon Fixation: The Calvin Cycle, also known as the light-independent reactions, occurs in the stroma of the chloroplast. Carbon dioxide from the atmosphere is captured by a five-carbon sugar molecule, ribulose bisphosphate (RuBP), through a process called carbon fixation. This is catalyzed by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Reduction Phase: ATP and NADPH generated in the light-dependent reactions provide the energy and reducing power needed for the Calvin Cycle. Carbon molecules are rearranged and reduced, leading to the formation of glucose and other carbohydrates. Regeneration of RuBP: Some molecules in the Calvin Cycle regenerate RuBP, ensuring that the cycle can continue. This regeneration phase prepares the system for the next round of carbon fixation. Overall Equation for Photosynthesis: The overall chemical equation for photosynthesis can be represented as: 6CO2+6H2O+light energy→C6H12O6+6O2​ This equation summarizes the conversion of carbon dioxide and water into glucose and oxygen using solar energy. Significance: Photosynthesis is crucial for life on Earth, as it is the primary process through which solar energy is converted into chemical energy. Plants, algae, and certain bacteria serve as the foundation for most ecosystems by producing organic molecules that serve as food for other organisms. Additionally, photosynthesis is responsible for the oxygen released into the atmosphere, which is essential for the respiration of most living organisms.

A. What is the role of DNA in genetic inheritance and how does it determine the individual’s traits? DNA, the Deoxyribonucleic acid is a double helical molecule comprising of two chains of polynucleotides.The nucleotides consist of– nitrogenous bases- Adenine, guanine,cytosine and thymine in combination with deoxyribose sugar and phosphate groups. It is found in the chromosomes. DNA carries the codes for proteins. Small, functional segments of DNA form a gene which is the basic physical and functional unit of heredity. Each gene codes for a specific protein, which undergoes modifications in various ways and forms certain traits. Genes are transcribed and translated by the cell to make proteins. The proteins create visible phenotypes. Codes from DNA are read by the messengers that break it open into single-stranded polynucleotide chains and are copied into messenger RNA. RNA forms opposite bases from that present in the DNA. For example, G on the DNA forms C on the RNA strand. Each of the bases gets together in a combination of three and forms particular amino acids. There are 20 such amino acids known. The amino acids are also known as the building blocks of proteins. Linkage of codes to proteins: The basic steps include: Transcription The first step that occurs is a process known as transcription. Here the information on the DNA is written down onto a different molecule called the RNA. This molecule acts as a messenger to carry the information to other parts of the cell. Translation The next step is called translation. In this step, the cell organelles called ribosomes act as translators by translating the messenger's code into the proper protein format or a chain of amino acids that form the building blocks of the protein. Each amino acid is formed by combining three bases on the RNA. Modification and folding The third step is the modification folding and structuring of the final protein and sending it to the required areas in the body. Coding for proteins DNA is read by the messengers that break it open into single-stranded polynucleotide chains and is copied into RNA. RNA forms opposite bases from that present in the DNA. For example, G on the DNA forms C on the RNA strand. Each of the bases gets together in threes and these form particular amino acids. There are 20 such amino acids. These are also known as the building blocks of proteins. Thus DNA contains all the information needed to build your body. Our DNA determines things such as your eye colour, hair colour, height, and even the size of your nose and all the traits The DNA in your cells is responsible for all the physical attributes.