bio photosynthesis
Regeneration (3rd stage)
A series of chemical reactions uses energy from ATP to rearrange the atoms in the five G3P molecules (15 carbons total), forming three RuBP molecules (15 carbons)
Reduction (2nd stage)
A series of two chemical reactions uses energy from ATP and electrons donated from NADPH to produce six molecules of the energy-rich three-carbon sugar, G3P
how does light interact with pigments in photosystems of the light reactions, and why are certain wavelengths of light not helpful for photosynthesis
Light energy enters the process of photosynthesis when pigments absorb the light. In plants, pigment molecules absorb only visible light for photosynthesis. green is the least helpful light - The main reason why green light is purportedly not useful to plants is because it is poorly absorbed by chlorophyll.
what molecules are used to link the two processes(Light + Dark reactions) together
NADP+/NADPH and ADP + P/ATP
Refer to Figure 7.8 on page 118 in your textbook. What molecules do the two people at the top of the platforms represent?
They represent primary electron acceptors.
discuss the three main facets of the Calvin cycle
carbon fixation, reduction, and regeneration
the three main facets of the Calvin cycle
carbon fixation, reduction, and regeneration
What links photosystem I with photosystem II?
electron transport chain
A plant's leaves are the primary site of photosynthesis. A plant's leaves would be expected to have a large amount of .
chloroplasts (A student could also make an argument for chlorophyll.)
the overall reaction of photosynthesis
6CO2 + 6H2O ------> C6H12O6 + 6O2 (Sunlight + Carbon dioxide + water = glucose + Oxygen
Inputs of Calvin Cycle
3 CO2
C4 plants
A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, which then supplies CO2 for the Calvin cycle.
CAM plants
A plant that uses an adaptation for photosynthesis in arid conditions in which carbon dioxide entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed.
C3 plants
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
The Calvin cycle is also referred to as the light-independent reactions. Briefly explain why referring to the chemical reactions of the Calvin cycle as the light-independent reactions is only partially accurate.
Although the chemical reactions of the Calvin cycle do not directly depend on solar energy, the reactions do depend on the products produced by the light reactions.
describe and give an example of two alternate evolutionary Calvin cycle pathways
C4 and CAM
Briefly explain what would happen to the levels of NADPH and ATP within the stroma if the passage of electrons to the primary electron acceptor of photosystem I were inhibited.
Because the continuous passing of electrons along the electron transport chain powers the production of ATP, ATP production would stop. Additionally, because the electron transport chain links photosystem II to photosystem I, any interruption in the transport chain would also halt NADPH production.
photosynthesis no's
C6H12O6 becomes oxidized in this process. --> NO Overall, this process is exergonic. --> NO
List all molecules which enter the Calvin cycle
CO2, ATP, NADPH
A toxin is found to inhibit the uptake of CO2 into plant leaves. This toxin would most directly affect the _____
Calvin cycle
Which substances provide most of the atoms that make up the sugar produced by photosynthesis?
Carbon dioxide
A student has been shrunk to fit inside the thylakoid space of a granum. How many layers of phospholipids would he or she need to cross through to get completely out of the mesophyll cell?
Eight layers of phospholipids.
True or false: A photoautotroph is a type of heterotroph that uses solar energy to produce sugars. If false, make it a correct statement.
False, a photoautotroph is not a heterotroph. Of course, it would be an autotroph.
True or false: Each turn of the Calvin cycle produces one molecule of glucose. If false, make it a correct statement.
False, one turn of the Calvin cycle makes a 3-carbon sugar called G3P. It would take two turns of the Calvin cycle to make a 6-carbon glucose.
True or false: During photosynthesis, CO2 is split to release oxygen gas. If false, make it a correct statement.
False. O2 gas is created as a result of splitting H2O.
True or false: Red wavelengths of light have more energy than purple wavelengths of light. If false, make it a correct statement. Refer to Figure 7.6A on page 116 in your textbook for help to answer this question
False. Red wavelengths of light have less energy than violet (purple) wavelengths
Outputs of Calvin Cycle
G3P
Photorespiration
In a plant cell, a metabolic pathway that consumes oxygen, releases CO2, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry days, when stomata close, O2 accumulates in the leaf, and rubisco fixes O2 rather than CO2. Photorespiration produces no sugar molecules or ATP.
A botanist discovers a new plant species in the Amazon rain forest that has blue leaves. Briefly explain what can be inferred about the pigments in the leaves of this plant.
It can be assumed that the pigments in this plant absorb all wavelengths of the visible light spectrum except blue.
Figure 7.7A on page 117 clearly depicts the events that occur when a pigment absorbs a photon of light. If a substance somehow kept the boosted electron from falling back to its ground state, would light and heat still be released in the same amount? Briefly explain your answer.
No, if an electron were kept from falling back to its ground state, the energy would not be given off as light and heat in that moment.
_______ is the process by which a plant adds O2 to RuBP instead of CO2.
Photorespiration
Comparing Photosynthesis and Cellular Respiration
Photosynthesis removes carbon dioxide from the atmosphere, and the cellular respiration puts it back. Photosynethesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food
identify each of the major parts of the light reactions of photosynthesis and the order in which the are used
Photosystem 2 is the first one ETC Photosystem 1 the enzyme that makes NADPH ATP Synthase
The Calvin cycle is cyclic because
RuBP is regenerated in the final chemical reaction
list all molecules which are produced during the Calvin cycle and where does it go.
Sugar goes to the mitochondria, NADP+ and ADP + P go back to light reactions
A new bacterium is discovered in Lake Superior. Scientists are able to determine that these bacteria produce oxygen gas. What is likely to be true about these organisms?
The bacteria are likely photoautotrophs and perform photosynthesis.
carbon fixation (1st stage)
The enzyme Rubisco combines CO2 with the five-carbon sugar RUBP. The product splits into three-carbon intermediate molecules. For three CO2 entering, six three-carbon molecules result.
If a scientist removes the pair of chlorophyll a molecules from the reaction-center complex, then which of the following consequences would be most likely to occur?
The primary electron acceptor would capture boosted electrons from the light-harvesting complex.
Briefly explain what links the two stages of photosynthesis with each other
The two stages of photosynthesis are linked by the ATP and NADPH produced in the light reactions. ATP and NADPH are used in the dark reactions to power the synthesis of sugar.
two major processes involved in photosynthesis
light reactions and dark reactions
The two complexes of pigments that constitute a photosystem include ______ and the _______
light-harvesting complex, reaction-center complex
Where is the Calvin Cycle located?
stroma
list all molecules which enter the light reactions
sunlight and water from outside NADP+ and ADP + P from the Calvin cycle
Where are light reactions located?
thylakoid
photosynthesis yes's
yes: CO2 is reduced in this process. Yes: Overall, this process is endergonic.