Chapter 8 Flashcards
What are the important molecules that are reduced or oxidized during
photosynthesis?
Water Oxidized to O2
CO2 reduced to C6H12O6
What are the inputs and outputs of the Calvin Cycle?
Inputs: CO2, ATP, and NADH
Outputs: triose phosphate, ADP, NADP+, and sugars.
What are the two ways plants deal with extra light?
Create antioxidants, red pigment, detox reactive O2
Xanthophylls, yellow, slow formation of O2 species by converting light to heat
Action spectra
Wavelengths that drive photosynthesis
Absorption spectra
Wavelengths absorbed or the light that is harvested
Which molecule has the greatest potential energy?
NADH
How would you explain the need for fermenting cells to acquire more food than equivalent cells using cellular respiration?
The energetic gain by fermentation is relatively small
Isocitrate dehydrogenase is a key allosteric enzyme in the citric acid cycle. What effect do you think a high level of NAD+ has on this enzyme?
Enzymatic activity would increase
Why does a plant absorb more wavelengths of light compared to an isolated chlorophyll molecule in a lab
because the plant produces accessory pigments
The wavelengths of light emitted by fluorescence is ______ the wavelength of light absorbed by the fluorescing pigment.
higher than
Is fluorescence or FRET an example of a chemical reaction
no
Most of the chlorophyll in the photosystems is used ______
to gather light
What would happen if a plant was exposed to a toxin that made the thylakoid membranes permeable to protons.
The proton gradient across the thylakoid membrane would be eliminated.
Is the order of NADH, FADH2, ATP the most to least amount of energy sources or the least to most
most to least
True or False the electron carriers that are reduced during glycolysis must be reoxidized to take part in glycolysis again
True
NADH converts back to NAD+ to be used again
Where does fermentation occur
cytosol
What are the products of lactic acid fermentation and ethanol fermentation
Lactic Acid, 2 ATP
Ethanol, 2 ATP
Organisms that carry out lactic acid fermentation and ethanol fermentation
Lactic acid - animals, microorganisms
Ethanol - yeast, bacteria
What produces more energy than ATP
Fats (triglycerides)
Fatty acids are broken down into what?
acetyl coA used for beta oxidation
What is beta oxidation?
two carbons are broken off a fatty acid and made into acetyl coA
What is the breakdown process if we do not eat?
glycogen (liver, muscle), fats, proteins
Chemoheterotrophs example and what it does
energy by eating
eats to get carbon
humans
Chemoautotrophs example and what it does
energy by eating
produces own carbon
heliobacteria
Photoheterotrophs example and what it does
energy from sun
eats to get carbon
sulfur-oxidizing bacteria
Photoautotrophs example and what it does
energy from sun
produces own carbon
plants
What is a B6F cytochrome
pumps electrons from stroma to lumen, apart of the ETC
Light Reaction Process
Light enters PS2, splits H2O to O2, go through ETC, pumps protons from stroma to lumen, PSI gets light, reduces NADH to NADPH, reduce ATP to ADP
Where does the light reaction take place
thylakoid membrane
oxidation of ____ is needed to start up the ETC
H2O
Water is the ____________
reducing agent
The main purpose of the photosynthetic ETC is to convert light energy into ____ and ____
ATP, NADPH
_________ absorbs light energy and supplies electrons at the beginning of the ETC
chlorophyll in PS2
Electrons come from _____, and _____ is released
water, oxygen
What is oxidized and what is reduced: PS1, PS2
PS1 is reduced
PS2 is oxidized
What is the final electron acceptor
NADP+
The oxidation of water releases ____ into the lumen
H+
Cytochrome B6F acts as a __________
proton pump
What drives the synthesis of ATP
Electrochemical gradient
What is the cause for plants structure?
CO2
Is the excited state more or less reactive than the ground state
more
Energy from _____ boosts an electron into another shell
photon
Accessory Pigments
plants use to increase access to wavelengths of visible light that chlorophylls can’t absorb.
Excitation energy is passed between pigments and ends up in the _________ pigment
reaction center
Z-Scheme
energy diagram for electron transfer in the “light reactions” of plant photosynthesis
The main purpose of the cavin cycle is to do what?
Reduce CO2 into sugar
What are the three main steps of the Calvin Cycle?
Carboxylation, reduction, regeneration
In carboxylation CO2 is added to sugar called
RuBP
Carboxylation is catalyzed by the enzyme
rubisco
What is photorespiration?
metabolic pathway that releases carbon dioxide and consumes oxygen, bad for plants
________ is the reducing agent of the Calvin cycle
NADPH + ATP
Reduction transfers the energy and electrons that allow _____ to be synthesized from CO2
G3P
ATP is required in order to ____________
phosphorlyate
Carbohydrates are made during what stage in the Calvin Cycle
reduction
The regeneration of _____ requires ______
RuBP, ATP
What are two restrictions of extra light in the Calvin cycle
-proton pumping into thylakoids increases the stroma pH which favors the activation rubisco
-electron flow from photosystem 1 reduces disulfide bonds to activate Calvin cycle enzymes
What is the problem with cyclic electron transport?
Run out of ATP to make ADP
What is the function of water?
splits from the energy of sunlight into O2 and H ios which create an ion gradinent
Where is the proton gradient found
Lumen
What is the difference between cyclic and noncyclic electron transport
Non - NADPH and ATP are the products
Cyclic - ATP is the only product
What happens when there are reactive oxygen species produced in the plant
Photorespiration
What step does ethanol fermentation have that lactic acid fermentation does not?
pyruvate converted to acetaldehyde
