In the Calvin cycle, how many ATP ..
Photosynthesis is a process where by energy from light is harvested and used to drive synthesis of organic carbohydrates from carbon dioxide and water. Photosynthesis takes place in chloroplasts and can be divided into two steps: light reactions which require light and dark reactions which do not require light. During light reaction, light energy is captured by photosystems and electrons are transferred among the electron receptors. ATP and NADPH are generated. During dark reactions, CO2 is fixed using ATP and NADPH generated by the light reactions and organic carbohydrates are synthesized via the Calvin Cycle. When the CO2 is first fixed into a 3 carbon compound 3PGA, it is called C3 pathways and these plants are called C3 plants. The disadvantage of C3 plants is that they undergo photorespiration and thus waste some energy gained in light reactions. C4 cycle is the pathway adopted by C4 plants to bypass photorespiration.
Using the ATP and NADPH produced by the light-dependent reactions, ..
E. Summary of some key points in photosynthesis
1. Photosynthesis is the major energy-storing process of life (light energy stored as chemical energy in organic compounds)
2. CO2 and H2O are raw materials
3. Products are sugar and oxygen
4. Light energy is absorbed by pigments and drives the reactions of photosynthesis
5. ATP and NADPH2 are formed during the light reactions
6. Oxygen of water is liberated as a gas
7. Steps of Calvin Cycle are controlled by enzymes
8. Light reactions occur in the grana
Dark reactions occur in the stroma
The Light Independent Reactions are a series of reactions referred to as the Calvin Cycle. They all occur in the stroma of the chloroplast. The chemical energy stored in ATP and NADPH powers the formation of glucose, using carbon dioxide (CO2) and the H+ from the NADPH+. The light independent reactions can occur in the light or in the dark.
The energy in ATP is needed for the Calvin cycle
For thefirst step of the light-independent reaction (Calvin cycle), the enzyme attaches a molecule of carbon dioxide to amolecule of a sugar which contains 5 carbon atoms.
H2O > NADPH > Calvin cycle Q 2 Photosynthesis is a ..
Dark reaction – Calvin cycle
Second step of photosynthesis is called Calvin’s cycle. Because it does not require light, so it is called dark reaction. During dark reaction, the ATP and NADPH generated by light reaction are consumed to fix carbon dioxide into organic carbohydrates. The first fixed carbohydrate is a three carbon compound 3-phosphoglycerate (3PGA). The final product is a high-energy 3 carbon compound glyceraldehyde-3-phosphate (G3P) which can be used to synthesize a broad range of organic molecules. An important intermediate molecule for carbon dioxide fixation is ribulose bisphosphate (RuBP), and the enzyme catalyzing the CO2 fixation is Rubisco.
Calvin Cycle The light reactions are only half of photosynthesis
Light reaction and photophosphorylation
Pigments embedded on thylakoid membranes form photosystems. There are of two types: PS I P700, PS II P680. Components of photosystem I and II transfer the electrons from water to NADP via cyclic electron transfer or non-cyclic electron transfer. During electron transfer, the light energy captured by the photosynthetic organisms is transformed into the phosphate bond energy of ATP. This is called photophosphorylation. NADPH is generated during non-cyclic electron transfer.
In the Calvin cycle, how many ATP …
Photosynthesis converts these energy- depleted compounds (ADPand NADP+) back to the high energy forms (ATP and NADPH) and theenergy thus produced in this chemical form is utilized to drivethe chemical reactions necessary for synthesis of sugars andother carbon containing compounds (e.g., proteins, fats). Theproduction of high energy ATP and NADPH in plants occurs in whatis known as Light Phase Reactions (Z Scheme) (requiressunlight). The energy releasing reactions which converts themback to energy-depleted ADP and NADP is known as Dark PhaseReactions (Calvin Cycle) (does not require light) in whichthe synthesis of glucose and other carbohydrates occurs.