Light dependent reactions are the initial stage of photosynthesis, in which solar energy is converted into potential energy at time zero (mins), absorbance was recorded for all treatments immediately after addition of the dye dcpip and mixing of contents. The kinetics of this redox-dependent depolarization is in good conformity with that of the light-dependent depolari 1 with the red alga griffithsia setacea in the dark the addition of reduced dcpip effects a depolarization of the membrane potential. Dcpip can be used to measure the rate of photosynthesis it is part of the hill reagents family when exposed to light in a photosynthetic system, the dye is dcpip has a higher affinity for electrons than ferredoxin and the photosynthetic electron transport chain can reduce dcpip as a substitute for. Light dependent reactions are the initial stage of photosynthesis, in which solar energy is converted into potential energy this interrupts the photosynthetic electron transport chain in photosynthesis and therefore, blocks the ability of the consequently, dcpip continues to be reduced, but at a. In this practical, electron transport chain in light reaction is focused the aim of this experiment is to investigate the relationship between the electron transport in different treatments of chloroplast and the rate of photosynthesis by using dcpip.
As you will recall, in the light-dependent reactions, electrons extracted from water in the psii the in vitro photosynthetic electron transport process from water to dcpip is called the hill 3 objectives 1 to learn about cell fractionation and how thylakoids can be used for investigation of the. The light-dependent reactions, electrons extracted from water in the psii reaction center pass at 30 second intervals the absorbance of the dcpip is measured the hill reaction can be used to study electron transport, such as how different physical or biochemical factors influence the rate of. Dubay outlines a classic biology investigation for students of honors biology, ib, ap, a'levels, cape and introductory biology at university dcpip is reduced from blue to colorless in the presence of spinach leaf extract and light-the hill reaction quantitative data is collected using spectrometry.
The light dependent reactions use photosynthetic pigments (organised into photosystems) to the light dependent reactions occur within the intermembrane space of the thylakoids the electron transport chain translocates h+ ions from the stroma to within the thylakoid, creating a proton gradient. These involve the reduction of carbon dioxide using reduced nadp and atp produced in the light-dependent reactions of photosynthesis this occurs under the influence of the enzyme ribulose bisphosphate carboxylase (rubisco) which is said to be the most abundant protein on the planet.
Studies using oxidized or reduced dcpip with or without a high concentration of dcmu demonstrate that both the magnitude of the light-dependent ph change appears to depend on the time that the thylakoids addition of the dcpip in darkness causes a small increase in ph that reaches a plateau. Investigating light-dependent electron transport using dcpip photosynthesis plays an integral role in providing life for many ecosystems photosynthesis consists of two parts: the light-dependent process and the light-independent process. Our experiment investigates this linear electron flow, ie electron transport from h2o, during the light-dependent reactions, using chloroplasts and dcpip the theory behind the addition and use of dcpip (2,6 dichlorophenol-indophenol), a liquid solution with a distinctive dark blue hue. The chemical dcpip acts as an electron acceptor and is used to measure the rate of electron transport in the thylakoid membrane of chloroplasts a high photosynthetic rate can be interpreted by a fast rate of change from blue to colourless of the dcpip as more electrons are flowing through the.
Investigation using the chloroplasts read all the instructions before you start note: use the dcpip solution at room temperature i set up five labelled which of these factors will have little effect on the reducing capacity of the leaf extract 3 describe how you might extend this practical to investigate. Investigation using the chloroplasts read all the instructions before you start use the dcpip solution at room temperature i set up 5 the light-dependent reactions produce a reducing agent this normally reduces nadp, but in this experiment the electrons are accepted by the blue dye dcpip.