Grade 12 ATP-ADP Cycle PDF

ATP-ADP Cycle Week 11  J. Williard Gibbs He is a professor at Yale (1878), proposed the idea of Gibbs free energy or simply free energy, of a system which is symbolized by the letter G.  Free Energy It refers to the portion of a system’s energy that can perform work when t...

ATP-ADP Cycle Week 11  J. Williard Gibbs He is a professor at Yale (1878), proposed the idea of Gibbs free energy or simply free energy, of a system which is symbolized by the letter G.  Free Energy It refers to the portion of a system’s energy that can perform work when temperature and pressure are constant throughout the system, an example of this is the living cell.  Exergonic “energy outward” ΔG is negative and the reactions occur spontaneously.  Endergonic “energy inward” It refers to reactions that absorbs free energy from the surrounding.  Coupled Reaction Process It refers to the type of chemical reactions that involves the transfer of energy from one side of the reaction to the other side with the involvement of some specific intermediates.  Work involvement of ATP Chemical work - which includes the pushing of endergonic reactions that are non- spontaneous such as the synthesis of polymers from monomers  Work involvement of ATP Transport work - the propelling of substances across membranes against the direction of spontaneous movement  Work involvement of ATP Mechanical work - such as the whipping of cilia, the contraction of muscle cells, and the movement of chromosomes during cellular division. The Structure and Hydrolysis of ATP  ATP (adenosine triphosphate) It contains the sugar ribose, with the nitrogenous base adenine and a chain of three phosphate groups bonded to it  Hydrolysis It refers to the reaction which involves water.  adenosine diphosphate or ADP It is when the inorganic phosphate or ℗i leaves the ATP thus the resulting structure  Involvement of ATP in Cellular Works The cell’s proteins have alternatives on how to connect the energy released during the hydrolysis of ATP to perform the three types of cellular work.  Chemical Work Conversion of glutamic acid to glutamine. Glutamine synthesis from glutamic acid (Glu) by itself is endergonic (ΔG is positive), so it is not spontaneous.  Chemical Work Conversion of glutamic acid to glutamine with energy coupling. Glutamine synthesis in the cell, occurs in two steps, ATP phosphorylates glutamic acid forming the phosphorylated intermediate, making it less stable. Then, ammonia displaces the phosphate group, forming glutamine.  Chemical Work Observe the free-energy change for coupled reaction. ΔG for the glutamic acid conversion to glutamine (+3.4 kcal/mol) plus ΔG for ATP hydrolysis (–7.3 kcal/mol) gives the free-energy change for the overall reaction (–3.9 kcal/mol). Thus, the overall process is exergonic (net ΔG is negative), and occurs spontaneously.  The ATP Cycle ATP synthesis mostly occurs in the mitochondria and is catalyzed by the enzyme ATP synthase. ATP is a renewable energy supply, which can be regenerated by the process of phosphorylation or the addition of phosphates to the ADP.  Importance of Chlorophyll and Other Pigments  Importance of Chlorophyll and Other Pigments Chlorophyll which is the green pigment that gives the usual green color of most leaves, is located in the thylakoid membrane of the chloroplast. This major pigment play a crucial role in the conversion of light energy to chemical energy in photosynthesis.  Importance of Chlorophyll and Other Pigments Pigments - refer to substances that have the ability to absorb visible light. Different pigments absorb different wavelengths.  Three Types of Pigments in Chlorophyll Chlorophyll a Chlorophyll b carotenoids.  Three Types of Pigments in Chlorophyll Chlorophyll a - is the pigment which participates directly in the light reaction  Three Types of Pigments in Chlorophyll Chlorophyll b and carotenoids - regarded as accessory pigments Difference between Chlorophyll a and Chlorophyll b The main difference between chlorophyll a and chlorophyll b is found in their molecular structures. This minor structural difference between them is enough to cause the two pigments to absorb different wavelengths in the red and blue parts of the spectrum which results to chlorophyll a having a blue green appearance while chlorophyll b is olive green.  Carotenoids These are hydrocarbons that are in different shades of yellow and orange. They protect the plants from the damages caused by light by absorbing and dispersing the excessive light energy, which could bring potential harm to the main pigment, chlorophyll.