Chapter 10 Flashcards B
Autotroph
"Self-feeders," they sustain themselves without eating anything derived from other living beings.
In the Calvin cycle, we start with ___ carbons distrusted in 3 RuBPs. After fixing 3 CO2s using the enzyme ____, the Calvin cycle forms 6 G3Ps with ___ carbons. The net gain of carbons is now ___, or one G3P molecules.
15, rubisco, 18, 3
Each turn of the Calvin cycle fixes one molecules of CO2; therefore, it will take ___ turns of the Calvin cycle to net one G3P.
3
PSII's special pair of chlorophyll is called P_______.
680
What is the chemical formula for photosynthesis?
6CO2 + 6H2O + Light Energy -> C6H12O6 + 6O2
PSI's special pair of chlorophyll is called P_______.
700
The net production of one G3P molecule requires ___ ATP, and ___ NADPH.
9,6
The newly built proton gradient between PS I and II is used in chemiosmosis to produce ____.
ATP
Light reactions store energy in the form of ____ and ____, which shuttle the energy to the carbohydrate producing ____ cycle.
ATP; NADPH; Calvin
Compare and contrast C4 plants with CAM plants.
Both live in arid environments, they both use PEP carbozylase to fix CO2. In CAM plants the two stages of photosynthesis are separated temporally.
How is chemiosmosis similar in photosynthesis and cellular respiration?
Both use H+ gradient, ATP is produced, there is an ETC, and ATP synthase is used
Explain what occurs in the Calvin cycle.
CO2 from the air is incorporated into organic molecules. This is called carbon fixation. The fixed carbon is used with the NADPH and the ATP to form G3P.
Explain the important events that occur in the carbon fixation stage of the Calvin cycle.
CO2 is incorporated into the 5 carbon sugar RuBP. This is catalyzed by rubisco. Thus, a 6 carbon intermediate is formed that splits into 2, forming 2 molecules of 3-phosphoglycerate.
Reaction center complex
Energy from the light-harvesting complex is transferred to the reaction center complex where a water molecule is split and the electron from that water molecule moves to the primary electron acceptor.
How is chemiosmosis different in photosynthesis and cellular respiration?
Energy is obtained from food in cellular respiration, while in photosynthesis energy is obtained from the sun. In cellular respiration the electrons are extracted from food while in photosynthesis they are taken from H2O.
Describe how Englemann was able to form an action spectrum long before the invention of a spectrophotometer.
Englemann illuminated a filament of algae through different wavelengths of light. Then, aerobic bacteria were used to see where they would clump and grow the most. They were more populated where more oxygen was released. By analyzing these results, it was obvious what the action spectrum was.
The Carbohydrate produced directly from the Calvin cycle is not glucose, but the three-carbon compound _____.
G3P
The cytochrome complex uses the energy to pump ____ ions.
H+
List three places in the light reactions where a proton-motive force is generated.
H+ from H2O; H+ pumped across membrane by cytochrome complex; removal of H+ from stroma when NADP+->NADPH
What compound is the source of electrons for linear electron flow?
H2O
What is the source of energy that requires the electron in PSII?
Light.
What is the relationship between wavelength and energy?
Longer wavelength -> less energy; shorter wavelength -> higher energy
In phase two, the reduction stage, the reducing power of ____ will donate electrons to 1,3-bisphosphoglycerate to form ____.
NADPH, G3P
In PSII, the exited electron is eventually used by NADP+ reductase to join NADP+ and an H+ to form ____.
NADPH.
In cyclic electron flow there is no production of ______, and no release of ______.
NADPH; O2
Using O18 as the basis of your discussion, explain how we know that the oxygen released in photosynthesis comes from water.
O18 is a heavy isotope that was used as a tracer. When the O18 was in the H2O that went in, the O2 that was produced was marked with the O18 heavy isotope. If O18 was used for the CO2, the O18 was not present in the O2.
H2O is the source of ____ in the atmosphere.
O2
Explain the role of PEP carboxylase in C4 plants.
PEP catalyzes the first step in the C4 pathway when CO2 is added to PEP, thus forming oxaloacetate.
Explain how photorespiration can be bad.
Photosynthetic output is decreased; plants cannot make food.
Explain what is meant by C3 Plants.
Plants that use the Calvin cycle to incorporate CO2 into organic material, forming a 3-carbon compound as the first stable intermediate.
A photosystem is composed of a protein complex called a _____-_____ complex surrounded by several ____-_____ complexes.
Reaction-center; light-harvesting
What are the colors of the visible spectrum?
Red, orange, yellow, green, blow, indigo, violet; ROY G BIV.
The enzyme responsible for carbon fixation in the Calvin cycle, and the most abundant protein on earth is _____.
Rubisco
What happens when a plant undergoes photorespiration?
Rubisco binds O2, thus no sugar is generated.
Explain what occurs in the light reactions.
Solar energy is converted to chemical energy. Light is absorbed and drives the transfer of electrons from water to NADP+ to form NADPH and in the process creating ATP by going through an ETC. Oxygen is released.
Explain what is meant by a C4 plant.
The Calvin cycle is preceded by reactions that incorporate CO2 first into a 4 carbon compound, the end products of which supply CO2 to the Calvin cycle.
Explain how changes in leaf architecture help isolate rubisco in high CO2 areas but low O2 areas.
The Calvin cycle occurs in the bundle sheath cells and that is also where most of the CO2 is also stored, thus encouraging photosynthesis vs respiration.
Explain how regeneration of RuBP is accomplished.
The carbon skeletons of 5 molecules of G3P are rearranged in the last step of the Calvin cycle to form 3 molecules of RuBP. To do this an investment of 3 ATP is needed.
Explain the correlation between an absorption spectra and an action spectrum.
The light that is absorbed is that same light that is used in photosynthesis. Also, chlorophylls have a larger input than do karatynoids.
Primary electron acceptor
The primary electron acceptor accepts the electrons from the reaction center complex and shuttles them to the ETC.
Light-harvesting complex
When chlorophyll absorbs light energy in the form of photons, one of the molecule's electrons is raised to an orbital of higher potential energy. The chlorophyll is then said to be in an excited state.
Heterotroph
organisms that get energy from compounds produced by other organisms.
