Photosynthesis Flashcards
C6H12O6 + 6 O2 —> 6 CO2 + 6H2O + energy
Which statement describes the results of this reaction?
C6H12O6 is oxidized and O2 is reduced
The oxygen consumed during cellular respiration is involved directly in which process or event?
Accepting electrons at the end of the electron transport chain (becomes water)
The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only 2 molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?
Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of 1 molecule of pyruvate?
2 carbon atoms
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?
Energy released from movement of protons through ATP synthase
Carbon dioxide is released during which of the following stages of cellular respiration?
Oxidation of pyruvate to acetyl CoA and the citric acid cycle
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide and water?
Oxidative phosphorylation (chemiosmosis)
Approximately how many molecules of ATP are produced from the complete oxidation of 1 molecule of glucose (C6H12O6) in cellular respiration?
38 or 36
Which of the following most accurately describes what is happening along this chain? (Electron transport chain)
Each electron carrier alternates between being reduced and being oxidized
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of:
ATP, CO2, and ethanol (ethyl alcohol)
When oxygen is released as a result of photosynthesis, it is a by-product of which of the following?
Splitting the water molecules
What did Engelmann conclude about the congregation of bacteria in the red and blue areas?
Bacteria congregated in these areas because these areas had the most oxygen being released
An outcome of the Engelmann experiment was to help determine:
The relationship between wavelengths of light and the oxygen released during photosynthesis
Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
Other pigments (antenna pigments) absorb light in addition to chlorophyll a
Which statement describes the functioning of photosystem II?
The electron vacancies in P680 are filled by electrons derived from water (splitting water)
Which of the following statements best represents the relationships between the light reactions and the calvin cycle?
The light reactions provide ATP and NADPH to the calvin cycle
Cycle returns ADP, Pi, and NADP+ to the light reactions
What is the primary function of the calvin cycle?
Synthesize simple sugars from carbon dioxide
The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which relationship would you expect to find?
The pH within the thylakoid is less than that of the stroma
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they:
Fix CO2 into organic acids during the night
Endergonic =
Anabolic
Exergonic =
Catabolic
Define hydrolysis
Adding water to break bond and extract energy
Exergonic is _______ energy
Extracting
Endergonic _______ and ______ energy
Requires and absorbs
Catabolic processes are almost always…
Hydrolysis reactions
Anabolic process are almost always…
Dehydration syntheses
The ______ the concentration of enzyme, the ______ the rate of reaction
Higher/higher, lower/lower
A pH change in an enzyme can prevent…
A polyphenol reaction
How would you change the salinity in an enzyme?
Adding ions
If hydrophobic/hydrophilic, structure might break
Define an acid
They liberate hydronium ions in aqueous solution
Donate a proton
How do enzyme speed up the rate of reaction?
Lowering the activation energy that is required to drive reaction
What does + delta G mean?
Spontaneous in the opposite direction
Define the active site
The groove in the surface of a 3D protein molecule
What do competitive inhibitors do?
Bind to the active site so the substrate/reactant can’t react
List all the possible names of things that activate enzymes
Coenzyme, cofactor, prosthetic group
What is the role of catalase in a reaction?
Working as a catalyst
All enzymes can…
Catalyze things
What can cause changes in protein configuration of an enzyme?
Heat, pH, or salinity
When heat, pH, or salinity changes the protein configuration of an enzyme, the enzyme is said to be…
Denatured and no longer functions as it should
What is an example of changing the pH of an enzyme to denature it?
Adding like or lemon juice to guacamole and fruit salad
Anabolic processes:
Build syntheses
Require energy
Endergonic
Glu + glu + glu —> starch
Condensation or dehydration reaction/synthesis
Catabolic processes:
Break and decompose
Generate energy
Exergonic
Polypeptide —> pep + pep + pep
Hydrolysis reaction
Proteins and carbs = how many calories?
4
Fats = how many calories?
9
Catalyzed reactions can only increase in rate if…
The enzymes occupied process the substrate/reactants faster
(Slight increase in temp)
OR
Increase the amount of enzyme
If you reduce the amount of enzyme in a reaction or cool the reaction…
The rate of reaction will slow
If all enzymes are occupied then…
Rate of reaction can’t be increased
If you add to much heat to the reaction when trying to increase rate of reaction, the enzyme might…
Be denatured
How do enzymes increase the rate of reaction by lowering the activation energy required to drive the reaction?
Holding substrate/reactants in their active site, reducing the energy for them to gain proximity for bond formation
Define activation energy
Energy required to bring reactants together to promote bond formation of breaking of a bond
Describe the calvin cycle
Light capture/dependent reactions
Ps II - split water, generate electrons
Ps 1 - Use those electrons to produce NADH+H+
NADH + H+ goes into calvin cycle which synthesizes simple sugars from CO2
In exposure of fruit to air, like a cut apple or avocado, flesh undergoes a color change resulting from…
A catalyzed reaction
Describe the preparatory step of the citric acid cycle after pyruvate feeds 2 carbons to it
1 of the carbons is broken free as the carboxyl group, forming a CO2
We generate most of ATP from:
Oxidative phosphorylation/Chemiosmosis/Chemiosmotic synthesis/ATP synthesis
C3 plants keep…
Their stomates open in the day, causing desiccation
C4 cycle attaches…
CO2 as a carboxyl to molecule temporarily
Define a catalyst
Molecules that function to speed up chemical reactions
What type of light do antenna pigments absorb?
Chlorophyll b and c and beta-carotene
Most ATP is produced by oxidative phosphorylation (chemiosmosis) in the…
Mitochondrian when glucose is completely oxidized to carbon dioxide and water
Describe what happens in photosystem II
Splitting of the water molecule as electrons are shifted to electron vacancies in p680
Describe what happens in photosystem I
Electrons are further energized by light energy absorbed by p700 and transferred to NADPH+H+
Some ATP is generated as a result of…
Elevated energy from photosystem I
Engelmann concluded bacteria congregated in these areas because these areas had the most oxygen being released. We know now that…
That is the effect of splitting the water molecule in photosystem II to generate O2 as waste
What are the products of lactic acid fermentation in muscle tissue?
ATP, CO2, and lactate
What are the products of glycolysis?
ATP, NADH, and pyruvate
What happens to the CO2 generated as waste from most organic reactions?
It breaks free as a carboxyl group from an organic acid to generate the CO2 and transfer the H to NADH+H+
Acetyl CoA is shuttled into the…
Citric acid cycle in the matrix of the mitochondrian to generate more ATP, NADH+H+, FADH2, and CO2 as waste
The most immediate product of the calvin cycle is glycerate, but the carboxyl group is converted to form…
Glyceraldehyde that can be used to make glucose, frutose, and starch
Which step shows a split of one molecule into two smaller molecules?
B (frustose-1, 6-biphosphate —> 2 glyceraldehyde-3-phosphate)
What does letter a represent in the reaction of A+B?
Energy of catalyzed reaction
What does letter e represent in the reaction of A+B?
Energy of uncatalyzed reaction
What does letter b represent in the reaction of A+B?
Activation energy of catalyzed reaction
What does letter c represent in the reaction of A+B?
Activation energy of uncatalyzed reaction
What does letter d represent in the reaction of A+B?
Change in free energy
Delta G
Assume that the reaction has delta G of -5.6 kcal/mol. Which of the following would be true?
The reaction would result in an increase in entropy (S) and a decrease in the total energy content (H) of the system
What is the mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway?
Feedback inhibition
If ATP used by this plant is labeled with radioactive phosphorus, in which molecules will the radioactivity be measurable after one turn of the cycle?
B, C, D, E
if the carbon atom of the incoming CO2 molecule is labeled with a radioactive isotope of carbon, where will the radioactivity be measurable after one turn of the cycle?
A, B, C
Which molecules of the Calvin cycle are most like molecules found in glycolysis?
C and D only
In metabolic processes of cell respiration and photosynthesis, which prosthetic groups are encountered?
Heme and iron-sulfur complexes
They both oxidize and reduce during electron transport
