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Cellular Respiration and Photosynthesis
Terms in this set (37)
6 CO2 + 6 H2O + energy --> C6H12O6 + 6 O
What is the primary function of photosynthesis?
The primary function of photosynthesis is to capture light energy from the sun, convert some of this light energy into chemical energy, and store this chemical energy in molecules of carbohydrates (such as glucose, or starch).
A chloroplast is?
The light dependent reactions occur in the proteins embedded
in the thylakoid membranes - the ETC pumps protons out from the stroma into the thylakoids. The light independent reactions occur in the stroma.
Name a gas released as by-product of the light dependent reactions of photosynthesis. Name the molecule that is the source of this gas.
Oxygen is released as a by-product (=
"waste material") of photosynthesis.
The oxygen atoms are removed from
water as the water is broken down
during the light reactions. Water is broken down to provide hydrogen atoms (which, in turn, provide electrons to replace electrons that are lost from chlorophyll). At this point, oxygen is of no value to the system and, consequently, is released from the chloroplast and from the leaf into the surrounding air.
Name two molecules that are produced during the light dependent reactions of photosynthesis and serve as temporary sites for energy storage.
Two high-energy molecules that are produced during the light reactions are ATP and NADPH. These two molecules temporarily store energy; they transfer energy into carbohydrates being produced during the light independent reactions (Calvin cycle). The carbohydrates (PGAL, glucose, starch) can store energy for much longer periods of time.
When chlorophyll absorbs sunlight, what subatomic particle experiences a change in energy? (electron or proton or neutron)
When chlorophyll absorbs light energy, an electron gains the energy.
What happens to an electron in chlorophyll when the electron absorbs light energy?
The electron gains so much energy (by absorbing photons of light) that the electron leaves the chlorophyll molecule. The electron is now described as a "high-energy electron" and can provide energy for the formation of molecules of ATP and NADPH.
When chlorophyll loses an electron, from what molecule does the chlorophyll receive a replacement electron?
When chlorophyll loses an electron, it is replaced with an electron taken from an atom of hydrogen, which has come out of a molecule of water. (Review: a hydrogen atom consists of one proton and one electron. If the electron is removed, only the proton remains. The proton will be used later to join with in the formation of NADPH, one of products of the light-dependent reactions.)
Name the molecule that is taken from the air and that provides the carbon for the production of sugars during the Calvin cycle.
Carbon dioxide, in the form of a gas, is removed from the environment of a plant (either from the surrounding air or water), taken into leaves and chloroplasts, and used as a carbon source during the manufacture of carbohydrates (such as PGAL, glucose, and starch) in the Calvin cycle.
True or False: The Calvin cycle (= light-independent reactions) can occur in a plant that is in dark room so long as the materials CO2, ATP, and NADPH are present.
True. The Calvin cycle requires the input of CO2 (as a source of carbon for building carbohydrates) and the availability of ATP and NADPH to provide energy to reduce the carbon dioxides and construct high-energy carbohydrates. If these materials (CO2, ATP, and NADPH) are available, the Calvin cycle can occur, even in darkness.
Summarize, in one sentence, what happens during the light dependent reactions of photosynthesis.
Light energy is absorbed by electrons that supply energy for the formation of molecules of ATP and NADPH, which are used as temporary energy storing molecules.
Summarize, in one sentence, what happens during the light independent reactions of photosynthesis.
Molecules of carbon dioxide enter the Calvin cycle where high-energy carbon molecules, such as glucose, are constructed using energy from ATP and NADPH (from the light dependent reactions).
Why is it accurate to say that (almost) all life on the planet relies on photosynthesis?
With the exception of certain organisms utilizing chemosynthesis, all plants and animals are ultimately dependent on the sugars and carbohydrates produced by plants through photosynthesis.
Cellular Respiration equation
C6H12O6 + 6O2---> 6CO2 + 6H2O + ATP
In what part of the cell does glycolysis take place?
Glycolysis takes place in the cytoplasm.
What is a Chloroplast's structure?
Stroma (fluid in the interior), Thylakoia (Photosynthetic pigments (chlorophyll) embedded in membranes), & Granum (Stack of Thylakoias)
What is the Stroma?
fluid in the interior of the Chloroplast
-where calvin cycle happens
What is the Thylakoia
Photosynthetic pigments (chlorophyll) embedded in membranes of the Chloroplast
-where light reactions happen
What is the Granum?
Stack of Thylakoias
What happens within the light dependent reaction?
produces energy from solar power (photons) in the form of ATP and NADPH
What happens within the light independent reaction
-uses energy ATP and NADPH form light reaction to make sugars (glucose)
Where does the Calvin cycle occur?
What does the Calvin cycle use?
uses ATP and NADPH from light reactions as energy
uses CO2 to produce glucose
What does it take in Photosynthesis to make one Glucose?
it takes 6 turns (cycles) and 18 ATP and 12 NADPH to produce on glucose
where/what is photosynthesis?
it takes energy (sunlight) to combine CO2 with H2O to make glucose. in plants, this energy is absorbed and used by a substance called Chlorophyll in an organelle called a Chloroplast.
What are the reactants and products of Glycolysis? How much ATP is made?
During Glycolysis, one glucose breaks down into two pyruvates. Two ATP are made.
What does the phrase "it takes energy to make energy"?
Two ATP are consumed to initiate glycolysis but four ATP are produced during glycolysis, netting two ATP per glucose. It takes energy to initiate the reactions, but more energy is produced than consumed.
Describe the event that occurs when pyruvate enters the mitochondria?
An intermediate step (between glycolysis and the Krebs cycle) converts pyruvate to acetyl coenzyme A (acetyl-CoA ) when pyruvate enters the mitochondria.
Where does most of the Krebs cycle take place?
The Krebs cycle occurs in the matrix of the mitochondrion.
What are the reactants and products of the Krebs Cycle? How much ATP is made?
The Krebs cycle is a series of nine reactions that oxidize acetyl- CoA, yielding NADH and FADH2. Two ATP are made per glucose molecule.
What are NADH and FADH2? What purpose do they serve?
NADH and FADH2 are "electron carriers." NAD+ is a coenzyme
that is reduced to NADH when it picks up two electrons and one
hydrogen ion in the Kreb cycle. In the Electron Transport Chain, NADH is oxidized back to NAD+, donating its electrons to another molecule (O2 for instance). Passage of electrons between donor and acceptor molecules releases energy, which is used to generate a H+ gradient across the mitochondrial membrane by pumping H+ out of the matrix. Similar story for FAD+ and FADH2.
Where does the Electron Transport Chain take place?
The ETC takes place across the inner-mitochondrial membrane in the mitochondria.
What sub atomic particle in transferred to the Electron Transport System the Krebs Cycle
NADH and FADH2 transfer electrons from the Krebs cycle to the ETC.
What reactant molecule from outside the cell is essential for electron transport to occur?
O2 is essential for both the Kreb Cycle and the Electron Transport Chain.
Describe two main functions of the Electron Transport Chain.
The Electron Transport Chain moves electrons through a series of reactions that are regulated by proteins embedded in the inner-mitochondrial membrane. These reactions use the energy released by the electrons to pump H+ ions out of the matrix. The return of these H+ into the matrix via ATP synthase generates ATP (~34 molecules of ATP per glucose molecule). And the electrons are "caught" by O2 to make H2O.
What is the relationship between breathing and respiration?
You breathe in order to bring O2 into your body for cellular respiration. You release CO2 and H2O, the waste products of cellular respiration, when you exhale. These reactants and products are transported between your cells and lungs via the bloodstream.
Steps of Light Dependent Reaction
a. Light Absorption: pigments absorb light energy (photons) and excite e- of chlorophyll
b. Electron Transport: electrons are transferred along a series of proteins embedded in the thykaloid membrane. NADPH serves as the final electron receptor.
c. Oxygen Production: Water is split in order to replace the electrons lost by chlorophyll to NADPH. Oxygen gas is a waste product.
d. ATP Formation: H+ is pumped out of stroma through ETC and decomposition of water . . . chemiosmosis powers ATP synthesis
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