Table of Contents
- 1 Where does the reduction of NADP occur?
- 2 During which process is NADP+ reduced?
- 3 Which event occurs in photosystem 1?
- 4 How is reduced NADP formed in photosynthesis?
- 5 What is photophosphorylation and when does it occur?
- 6 What event occurs in photosystem?
- 7 How is nicotinamide adenine dinucleotide ( NAD + ) converted to NADP +?
- 8 Are there any NADP + dependent cytoplasmic enzymes in humans?
Where does the reduction of NADP occur?
After a photon hits the photosystem II (PSII) reaction center, energy from sunlight is used to extract electrons from water. The electrons travel through the chloroplast electron transport chain to photosystem I (PSI), which reduces NADP+ to NADPH (Figure 3).
During which process is NADP+ reduced?
NADP+ functions alongside many enzymes to provide energy to the many reactions in a cell. NADP+ is the used form of NADPH, and must be reduced with more electrons and a hydrogen. This is typically done during photosynthesis in plants, or as part of sugar digestion in animals.
What produces reduced NADP?
NADP is the reducing agent produced by the light reactions of photosynthesis and is consumed in the Calvin cycle of photosynthesis and used in many other anabolic reactions in both plants and animals.
Does reduction of NADP occurs in cyclic photophosphorylation?
Non-cyclic photophosphorylation involves both PS-1 and PS-11. Here electrons are not cycled back and are used in the reduction of NADP to NADPH,. Here water is utilized and O, evolution occurs. Whereas in cyclic photophosphorylation only PS-I is involved.
Which event occurs in photosystem 1?
High-energy electrons, which are released as photosystem I absorbs light energy, are used to drive the synthesis of nicotine adenine dinucleotide phosphate (NADPH). Photosystem I obtains replacement electrons from the electron transport chain.
How is reduced NADP formed in photosynthesis?
In photosystem II, chlorophyll within the chloroplasts of plant cells absorbs sunlight and transfers the energy to electrons. During these reactions, the NADP+ molecules are reduced by the addition of electrons. A hydrogen ion is added to NADP+ to form NADPH.
Is NADP reduced in cellular respiration?
The cellular respiration processes of all living cells make use of the coenzyme Nicotinamide adenine dinucleotide (NAD). The NAD+ is used in redox reactions in the cell and acts as a reducing agent. NADH contributes to oxidation in cell processes like glycolysis to help with the oxidation of glucose.
What role does RuBisCO play in Photorespiration?
Photorespiration (also known as the oxidative photosynthetic carbon cycle, or C2 photosynthesis) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis. Photorespiration also incurs a direct cost of one ATP and one NAD(P)H.
What is photophosphorylation and when does it occur?
In the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation. Cyclic photophosphorylation occurs in both aerobic and anaerobic conditions. All organisms produce ATP, which is the universal energy currency of life.
What event occurs in photosystem?
The light reaction occurs in two photosystems (units of chlorophyll molecules). Light energy (indicated by wavy arrows) absorbed by photosystem II causes the formation of high-energy electrons, which are transferred along a series of acceptor molecules in an electron transport chain to photosystem I.
Which event occurs in photosystem II?
Photosystem II obtains replacement electrons from water molecules, resulting in their split into hydrogen ions (H+) and oxygen atoms. The oxygen atoms combine to form molecular oxygen (O2), which is released into the atmosphere. The hydrogen ions are released into the lumen.
What is the role of NADPH in reductive biosynthesis?
Given the significant roles of NADPH in numerous pathways of reductive biosynthesis and in the maintenance of cellular redox status, in both the cytosol and the mitochondria, it is not surprising that there are multiple cytoplasmic and mitochondrial enzymes that have, as a product of their reactions, the reduced electron carrier, NADPH.
How is nicotinamide adenine dinucleotide ( NAD + ) converted to NADP +?
The details of the synthesis of nicotinamide adenine dinucleotide (NAD +) can be found in the Vitamins page. NAD + can be converted to NADP + through the action of cytoplasmic NAD + kinase (NADK) or mitochondrial NAD + kinase 2 (NADK2).
Are there any NADP + dependent cytoplasmic enzymes in humans?
Humans express three malic enzymes, one cytoplasmic that requires NADP + and two mitochondrial enzymes, one that requires NADP + and one that requires NAD +. The NADP + -dependent cytoplasmic enzyme is called malic enzyme 1 and is encoded by the ME1 gene.
Where is the NADP + dependent mitochondrial malic enzyme located?
The NADP + -dependent mitochondrial malic enzyme is called malic enzyme 3 and is encoded by the ME3 gene. The ME3 gene is located on chromosome 11q14.2 and is composed of 22 exons that generate four alternatively spliced mRNAs that all encode the same 604 amino acid protein.