How do electrons move through the light reactions of photosynthesis?
How do electrons move through the light reactions of photosynthesis?
The light reactions of photosynthesis use energy from photons to generate high-energy electrons (Figure 19.2). These electrons are used directly to reduce NADP+ to NADPH and are used indirectly through an electron-transport chain to generate a proton-motive force across a membrane.
Where do electrons flow in photosynthesis?
The electrons must travel through special proteins stuck in the thylakoid membrane. They go through the first special protein (the photosystem II protein) and down the electron transport chain. Then they pass through a second special protein (photosystem I protein).
What acts as an electron shuttle in photosynthesis?
PSII is a large molecular complex that contains several proteins and light-absorbing pigment molecules. This molecule shuttles the excited electrons to the next complex in the photosynthetic electron-transport chain.
What is electron excitation in photosynthesis?
The excited electron is boosted to a higher energy state. Electrons are passed from a photosystem into a redox or electron transport chain, eventually attaching to a chlorophyll molecule in Photosystem I (P700). Light acts on chlorophyll in Photosystem I, causing an electron to be boosted to a still higher potential.
Which process of photosynthesis is linked to the production of ATP?
The Calvin cycle takes place in the stroma and uses the ATP and NADPH from the light-dependent reactions to fix carbon dioxide, producing three-carbon sugars—glyceraldehyde-3-phosphate, or G3P, molecules. The Calvin cycle converts ATP to ADP and Pi, and it converts NADPH to NADP+.
Which product is the result of light reactions in photosynthesis?
Essentially, oxygen is a waste product of the light reactions of photosynthesis. It is a ”leftover” from a necessary part of the process. All the oxygen that is necessary to maintain most forms of life just happens to come about during this process.
What is produced in cyclic electron flow?
Under certain conditions, the photoexcited electrons take an alternative path called cyclic electron flow, which uses photosystem I (P700) but not photosystem II (P680). This process produces no NADPH and no O2, but it does make ATP. This is called cyclic photophosphorylation.
What are the electron carriers in photosynthesis and cellular respiration?
There are two types of electron carriers that are particularly important in cellular respiration: NAD +start superscript, plus, end superscript (nicotinamide adenine dinucleotide, shown below) and FAD (flavin adenine dinucleotide). Chemical structures of NAD+ and NADH.
What are the two products of photosynthesis?
These two processes are responsible for the exchange of oxygen and carbon dioxide between living organisms and the environment. Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a by-product.
What is the first stable product of photosynthesis?
The first product of photosynthesis is a threecarbon compound called phosphoglyceric acid and phosphoglyceraldehyde. Almost immediately, two of these join to form a glucose molecule.
What are products of light reaction?
The NADPH and ATP obtained from the light reaction along with carbon dioxide is utilised to form glucose. Thus the correct answer is (A) NADPH and ATP are the products of light reaction.
Is carbon dioxide a product of light reaction?
During the first stage, the energy from sunlight is absorbed by the chloroplast. Water is used, and oxygen is produced during this part of the process. During the second stage, carbon dioxide is used, and glucose is produced. Energy from sunlight is absorbed by the pigment chlorophyll in the thylakoid membrane.