In 1966, André Jagendorf and Ernest Uribe directly tested whether artificial proton gradients in isolated chloroplasts could support the generation ofATP without redox energy or light. Chloroplasts were suspended in the dark in low-pH buffer and allowed to equilibrate. When the buffer waschanged to a higher pH and ADP and radiolabeled phosphate (32P) were added, 32p-labeled ATP accumulated in the stroma. Answer the followingquestions on the basis of the results of this experiment:pH 4++Ko comuneOpH1117!!!o↓Measure amount ofsip.ATP synthesizedAllow toequilibrateOC. 8OD. 6Add ADPand pChoose one:ⒸA. 16OB. 12Which of the following is a true representation of the experimental design and results?B.Choose one:A. In order for ATP to be synthesized, the concentration of protons must be higher in the lumen than in thesurrounding chloroplast solution.OB. ATP was used as an energy source to pump protons from the lumen into the stroma.OC. The proton-motive force dissipates in the presence of light.OD. ATP synthase was functioning in reverse.Choose one:AC.How many 32P-ATPs would be produced if 48 H* were transported through the ATP synthase complex in the thylakoid membrane?D.If ADP +P; were completely converted to ATP, and then you continued the experiment to "Step 5° by turning on the lights, what wouldyou predict would be the next picture in the sequence?111Lumen111wwH!!!pH 4www78.8.4Changebufferto pH 8pH 8111the4848pH 4WHAT

Low pH means a higher concentration of H+ ions. The experiment was conducted to determine whether…

Answered: Which of the following is a true…

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter20: The Protists

Section: Chapter Questions

Problem 4CT: Melvin Calvin and Andrew Benson determined the steps in the light-independent reactions of...

See similar textbooks

Similar questions

For the following questions, choose one to discuss: chloroplast/photosynthesis State at the outset which one you will discuss. A) What role do proton gradients play in the process of photosynthesis proton gradients allow B) Where are proton gradients formed? Within what structures are they seen in chloroplasts How do the structures help them to maintain a gradient? C) Explain where and how the chloroplast or mitochondria uses passive transport and active transport to complete photosynthesis or cellular respiration.
Why is an isotonic buffered extraction medium used to isolate the chloroplasts? 1.To gently lyse the chloroplasts, leaving the electron transport membranes intact, whilst allowing DCPIP access 2.To maintain a constant acidic pH and favourable hyper-osmotic conditions, to ensure that the chloroplasts remained intact and functional during extraction 3.To gently separate the chloroplasts from each other, leaving the electron transport membranes intact, whilst allowing DCPIP access 4.To maintain a constant physiological pH and favourable iso-osmotic conditions, to ensure that the chloroplasts remained intact and functional during extraction.
Assume a pH gradient of 4.0 units across a thylakoid membrane, with the lumen more acidic than the stroma. What is the longest wavelength of light that could provide enough energy per photon to pump one proton against this gradient, assuming a 20% efficiency in photosynthesis and T = 25 °C?
In the photosynthesis lab, a group of students found that in the blue light condition, there was a change in absorbance (ΔA620) of 0.324 in extracted spinach chloroplasts. The students later went on a hike and located a plant they had never seen before and were interested in how the photosynthesis rates would compare to their experiment with spinach chloroplasts. They extracted chloroplasts of the unknown green-leaved plant and exposed them to the same experimental conditions as before. The students calculated the ΔA620 to be 0.100. Which plant (spinach or unknown) has the highest rate of photosynthesis? Explain your answer using evidence, being sure to demonstrate your understanding of the dependent variable.
You performed an experiment on photosynthesis on Elodea, using bromothymol blue as an indicator forpH. Your two light conditions were red light and blue light. You found that in blue light, your solutionturned a nice cobalt blue, and in red light it turned green.a. What can you conclude about the efficiency of photosynthesis in Elodea regarding those twowavelengths?b. What would your conclusion be if your negative control (no Elodea in white light) turned greenalso?
Thylakoids were isolated from chloroplasts and incubated in the dark in an acidic solution (pH 4) to equilibrate the pH. After 30 minutes, the thylakoids were transferred to a basic solution (pH 8) and kept in the dark. Will this system produce ATP? Explain. Will this system produce G3P? Explain.
Melvin Calvin and Andrew Benson determined the steps in the light-independent reactions of photosynthesis by exposing the green alga Chlorella to CO2 labeled with the radioisotope carbon 14. By looking at which compounds the C14 ended up in, they were able to identify all intermediates in this cyclic pathway. Why did they predict correctly that the same set of intermediates would be formed in the light reaction in land plants?
Identify the chemical basis for ApH and AY across the chloroplast thylakoid membrane by dragging the descriptions to their targets. Be sure to notice that the upper arrow iindicates ApH and the lower arrow indicates ΔΨ. ATP synthase complex H+ N ADP + P₁ Light energy ATP H*N Photosystem I/II- Chloroplast N side Aus PN ApH T + Thylakoid membrane HTp H+p Lumen Stroma P side Proton circuit A B High H concentration Low positive charge High positive charge Low H+ concentration Within the image, identify the types of proton translocation by dragging each label to its target. O XH₂ 2H+ + Z 2 H* ZH₂ O XH₂ Z 2H+ ZH₂ 2H+ C A B Proton pump Redox loop
In a photosynthetic investigation, a student measured the following pH of the stroma and the inner thylakoid compartments of spinach leaf cells at the conclusion of the experiment. Source of Fluid pH (mean) Standard Error of Mean (SEM) Stroma 8.2 0.75 Inner compartment of thylakoid 5.6 0.35 Describe the stages of photosynthesis. Explain the need for a constant supply of inorganic carbon dioxide.
Consider how the Hill Reaction might be used to investigate how the wavelength of light influences the rate electrons move in the electron transport chain of the chloroplast. a) Design an experiment to compare the effects of blue light and green light on the Hill Reaction. (Assume that you have filters that you can attach to your light source to control the wavelength of light.) b) Based on your knowledge of photosynthesis, how would you expect the color of the light to effect the movement of electrons? c) Draw a line graph of your expected results.
In chloroplasts, the light reactions power the creation of ATP via chemiosmosis. In relation to this process, which of the following is true? a) ATP synthase breaks ATP down into ADP, creating energy to fuel chemiosmosis. b) Oxygen is used as a source of electrons to replace those lost in photosystem II. c) Chemiosmosis during the light reactions is also used in the reduction of NADPH and FADH2. d) As excited electrons fall back down to a lower energy state, they create a proton gradient that is used to fuel the phosphorylation of ADP.
Daniel Arnon and coworkers carried out experiments with intact, salt- washed chloroplasts to study photophosphorylation. When the chloroplasts were illuminated in the presence of ADP +P, ATP was produced, but oxygen was not produced or nor consumed. ATP formation was not accom- panied by a measurable electron transport involving any external electron donor or acceptor. The overall reaction for this result is: ADP + P -", ATP When NADP+ was included in addition to the ADP + P, ilumination of the intact chloroplats again resulted in resulted in the photophosphorylation of ADP to ATP. In addition, the NADPpt was reduced to NADPH + H* and o, was produced. Moreover, the light-induced reduction of NADP* was greatly decreased if ADP + P; were ommitted. The equation for this reaction is: NADP* + H,0 + ADP + R -", NADPH + H + ATP + }02 Briefly describe the mechanism(s) of these two types of photophosphoryla- tion that explain all of these results.

SEE MORE QUESTIONS

Recommended textbooks for you

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

Biology

ISBN:

9781305967359

Author:

STARR

Publisher:

CENGAGE L

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

Biology

ISBN:

9781305967359

Author:

STARR

Publisher:

CENGAGE L

SEE MORE TEXTBOOKS