Chapter 20: Photosynthesis

how can a plant produce more ATP without additional water splitting?

a plant can produce more ATP without additional water splitting by increasing the efficiency of ATP production, this can be achieved through various mechanisms, such as optimizing the activity of ATP synthase, enhancing the function of the electron transport chain, and absorbing more light

the carbon fixation step of the Calvin cycle produces... a. 3 phosphoglycerate that will be reduced b. glucose 1,6 bisphosphate that is split c. ribuloser1,5 biphosphate d. CO2

a. 3 phosphoglycerate that will be reduced

in the Calvin cycle a. 3-phosphoglycerate kinase uses __________ to produce 2,3BPG b. GAPDH uses _____________ to produce GAP c. ribulose-5P kinase uses ________ to regenerate _______ d. 2 GAP are used to make ____________ originating from ________

a. ATP b. NADPH c. ATP, ribulose-1,5-bisphosphate d. glucose-6-phosphate (G6P), the regeneration phase of the Calvin cycle

which of the following is the source of the carbon in the sugar that is produced by photosynthetic organisms during photosynthesis? a. carbon dioxide b. water c. RUBISCO d. ATP e. NADPH

a. carbon dioxide

in the light dependent reactions, when light strikes the pigments (P700 or P680) what is the immediate result? a. excited electrons are passed to electron acceptors b. electron are fused to form ATP c. glucose is produced d. carbon fixation occurs

a. excited electrons are passed to electron acceptors

the reaction NADP+ + 2 e- + 2 H+ --> NADPH+H+ has a ΔG°'= +220 kJ/mol... a. is this reaction favorable? b. why does this reaction happen in the plant cell?

a. no, this reaction is not favorable b. this reaction happens in the plant cell because it is coupled to the light-dependent reactions of photosynthesis, which provide the energy required to drive the reduction of NADP+ to NADPH

which step of the Calvin cycle does not require energy? a. the carbon fixation step b. the reduction step c. the regeneration step d. all of them require energy e. none of them require energy in the light

a. the carbon fixation step

in the Calvin cycle, more ATP than NADPH is used, how is this difference made up? a. the cyclic pathway creates more ATP b. the Calvin cycle occurs half as often as the light dependent reaction c. additional ATP is created from glucose d. excess NADPH is reused in the light reaction

a. the cyclic pathway creates more ATP

which statement(s) is/are correct about Rubisco? a. uses CO2 as a substrate b. uses O2 as substrate c. uses Ribulose1,5P2 as a substrate d. does not require input of energy e. is the most abundant protein on Earth

a. uses CO2 as a substrate c. uses Ribulose1,5P2 as a substrate e. is the most abundant protein on Earth

the electron donor for photosynthetic electron transport is _____ a. O2 b. H2O c. NADP + d. CO2 e. glucose

b. H2O

to monitor the rate of photosynthesis you would measure... a. oxygen consumed b. oxygen produced c. ADP consumed d. NAD+ consumed e. glucose produced

b. oxygen produced

the oxygen produced in photosynthesis comes from what molecule? a. glucose b. water c. P680 d. P700 e. ATP

b. water

why is chlorophyll green?

because it absorbs blue and red light, while reflecting green light

how does red and blue light differ with respect to energy?

blue light has a higher frequency and shorter wavelength, which results in each photon carrying more energy compared to red light

which of the following occurs in the stroma of the chloroplast? a. light dependent reactions b. electron transport chain c. calvin cycle d. photolysis e. pentose monophosphate pathway

c. calvin cycle

why are chemicals that block photosynthetic electron transport often used as herbicides?

chemicals that block photosynthetic electron transport are often used as herbicides because they inhibit the photosynthetic process in plants, leading to a disruption in the production of energy and organic compounds essential for plant growth

in 1804, Theodore de Saussure observed that the total weight of oxygen and dry organic matter produced by plants is greater than the weight of carbon dioxide consumed during photosynthesis, where does the extra weight come from? a. NO3- b. NADPH c. ATP d. H2O

d. H2O

which of the following is NOT a product of the light dependent reaction? a. oxygen b. ATP c. NADPH d. sugar

d. sugar

to determine which wavelengths of light is the most effective for photosynthesis Engelmann split white light with a prism into a rainbow of separate wavelengths, he then used this light to illuminate algae on a microscope slide and added aerobic bacteria, why did he add bacteria to the experiment? a. to provide food for the algae b. to provide shade for the algae by filtering the light c. to consume the sugar produced by the algae d. to serve an oxygen sensor in the experiment

d. to serve an oxygen sensor in the experiment

which of the following are produced during the light reactions of photosynthesis and are utilized in the Calvin cycle? a. CO2 and glucose b. electrons and H + c. ADP, P i, and NADP + d. H2O and O2 e. ATP and NADPH

e. ATP and NADPH

how many times does the calvin cycle need to run to produce one glucose molecule?

six

how much light is used in the Calvin cycle?

the Calvin cycle is not directly dependent on light, however it is indirectly dependent on light since the necessary energy carriers ( ATP and NADPH) are products of light-dependent reactions

water has an E°' = +0.820 V, why can the molecule serve as electron donor?

the positive E°' value of water indicates that it has a tendency to lose electrons and be oxidized, this means that it can donate electrons to other molecules that have a higher tendency to accept electrons

how can you show that the proton gradient can drive ATP synthesis in chloroplast even without light?

the proton gradient can drive ATP synthesis in chloroplasts even without light through the proton motive force generated by the electron transport chain, which is utilized by the ATP synthase complex to produce ATP

to study the role of different wavelengths of light on photosynthesis Engelmann split white light with a prism into a rainbow of separate wavelengths, he then used this light to illuminate algae on a microscope slide and added aerobic bacteria, could he have added anaerobic bacteria instead?

the purpose of adding these bacteria was to act as oxygen sensors by moving towards regions where oxygen was being produced by photosynthesis, indicating the wavelengths of light most effective for photosynthesis, this would not have worked with anaerobic bacteria

would you expect an uncoupler to affect both, the proton gradient in chloroplasts and in mitochondria?

yes, uncouplers are compounds that disrupt the coupling between electron transport and ATP synthesis by dissipating the proton gradient across membranes

describe the function of CO2 in the light reactions

CO2 does not play a role in the light dependent reactions, CO2 is actually fixed on in the light-independent reactions