Chapter 10
What comes out of Light Reaction?
ATP (goes to Calvin Cycle) NADPH (goes to Calvin Cycle) O2 (oxygen released from plant into environment)
Light reaction (the photo part)
Converts light energy to chemical energy Occurs during the day
What goes into Light Reaction?
Light energy H2O ADP NADP+
Calvin cycle (synthesis part)
Uses products from light reaction to produce G3P sugar Occurs during day or night
Regeneration
(of CO2 acceptor) phase
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
Visible light falls in the wavelength range of _____ - _____. These are the colors of the rainbow: red, orange, yellow, green, blue, indigo, and violet (ROY G BIV)
380-750 nm
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6
What comes out of the Calvin Cycle?
9 ADP, 6 NADH+, and a G3P (a 3 carbon sugar) One goes toward building sugar or starch The other 5 recycle back to RuBP in the regeneration phase
What goes into the Calvin Cycle?
9 ATP, 6 NADPH, 3 CO2
_____ splits water into 1/2 O2, H+, and e- .
A
Chlorophyll can be found in _____.
A and C Photosystems I and II
The Calvin cycle could not occur without the light reactions. Which of the following statements describes why this is the case?
ATP and NADPH produced in the light reactions provide the energy for the production of sugars in the Calvin cycle.
The light reactions of photosynthesis supply the Calvin cycle with __________.
ATP and NADPH.
When is the Clavin Cycle?
After Light Reaction
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
B
Energized electrons from ____ are used to reduce NADP+.
C
Who is the main player in the Calvin Cycle?
CO2
(carbon) Fixation phase
Catalyzed by rubisco
Photosystem II
Chlorophyll a (P680)
Photosystem I
Chlorophyll a (P700)
Plants contain what several different photosynthetic pigments? *Each pigment absorbs light of a different wavelength
Chlorophyll a, Chlorophyll b, and carotenoids.
What property of the pigment chlorophyll makes it appear green?
Chlorophyll absorbs all of the visible spectrum of light except green, which it reflects.
Chlorophyll Photosystems
Chlorophyll molecules in plant cells are surrounded by other chlorophyll molecules. Each molecule absorbs light energy from the sun Electrons jump up/fall back, give off energy Energy given off is transmitted to another chlorophyll molecule - Causes an electron in that molecule to jump up/fall back In plants, we call these light harvesting complexes Photosystems.
Which of these phosphorylates ADP to make ATP?
E ATP synthase Phosphorylates ADP
When does Light Reaction happen?
First phase
What are the three sub-phases of the Calvin Cycle?
Fixation, Reduction, Regeneration
Which of the following processes occurs during the second phase, the reduction phase, of the Calvin cycle?
G3P production
Where does the Calvin Cycle occur?
In the stroma of the chloroplast
Why does all of this happen in Light Reaction?
It converts light energy to chemical energy (ATP) and electron carrier NADPH
Two stages of Photosynthesis
Light Reaction (Photo part) Calvin Cycle (Synthesis part)
Photosynthesis equation
Light energy + 6CO2 + H2O --> C6H12O6 + 6O2
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
Photosystem I reduces NADP+ to _____.
NADPH *This is linear electron flow
The light reactions of photosynthesis generate high-energy electrons, which end up in __________. The light reactions also produce __________ and __________.
NADPH; ATP; oxygen
In the light reactions of photosynthesis, ATP is produced by photophosphorylation. Which of the listed processes is most similar to photophosphorylation?
Oxidative phosphorylation in cellular respiration
Which process produces oxygen?
Photosynthesis
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
RuBP
Where does the Calvin cycle of photosynthesis occur?
Stroma
Who is the main player in Light Reaction?
Sunlight
________ is solar energy in the form of electromagnetic waves; these are photons of light that are traveling in a wave
Sunlight
Both ATP and NADPH are made in the stroma of the chloroplast. What would happen if they were trapped within the thylakoid space?
The Calvin Cycle would shut down
During the Calvin cycle, what happens during the carbon fixation phase?
The Calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five-carbon sugar named ribulose bisphosphate.
Which set of reactions uses H2O and produces O2?
The light-dependent reactions
Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
How does carbon dioxide enter the leaf?
Through the stomata
Where are Chlorophyll Photosystems located?
Thylakoid membrane
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True
Calvin cycle
Uses ATP and NADPH from Light Reaction to reduce CO2 to G3P
Where do the electrons entering photosystem II come from?
Water
Chlorophyll excitation
When a molecule of chlorophyll absorbs a photon of light, it goes from a stable state to an excited state.
Evaluate the accuracy of the following statement: "ATP Synthase takes electrons from the electron transport chain and makes ATP." a. Actually, ATP Synthase uses the H+ gradient produced by the electron transport chain to make ATP, it does not use the electrons themselves. b. Actually, ATP Synthase takes electrons from the electron transport chain to break down ATP and release energy for plants c. Actually, ATP synthase doesn't depend on the electron transport chain, it functions independently. d. The statement is accurate.
a. Actually, ATP Synthase uses the H+ gradient produced by the electron transport chain to make ATP, it does not use the electrons themselves.
In the Light Reaction, when light strikes the chlorophyll pigments (P700 or P680) what is the immediate result? a. Excited electrons are passed to electron acceptors b. Electrons are fused to form ATP c. Glucose is produced d. Carbon fixation occurs
a. Excited electrons are passed to electron acceptors
How is Photosystem II recharged? a. Splitting water provides electrons to Photosystem II b. Oxygen provides electrons to Photosystem II c. Photosystem I provides electrons to Photosystem II d. NADP+ provides electrons to Photosystem II
a. Splitting water provides electrons to Photosystem II
What happens to photosynthesis in the absence of sunlight? a. The Light Reaction cannot take place b. The Calvin Cycle cannot take place c. NADPH and ATP continue to be produced but G3P cannot be produced d. The plant switches to the Dark Reaction
a. The Light Reaction cannot take place
The light reaction takes place in the ____________ a. Thylakoid membrane b. Granum c. Photosystem d. Photon
a. Thylakoid membrane
Is the Calvin cycle anabolic or catabolic?
anabolic
Since plants make their own food, we call them __________.
autotrophs
During which stage of photosynthesis are ATP & NADPH converted to ADP + Pi & NADP+? a. Light dependent b. Calvin Cycle c. Both of the above d. None of the above
b. Calvin Cycle
As the Light Reaction progresses, the pH in the thylakoid space a. Increases (becomes more basic) b. Decreases (becomes more acidic) c. Stays the same
b. Decreases (becomes more acidic)
T or F. Light-driven electron transport in the thylakoid pumps H+ into the intermembrane space between the outer & inner membranes. a. True b. False
b. False
T or F. Plants absorb green light waves used for photosynthesis. a. True b. False
b. False
T or F. The Calvin Cycle is the light dependent reaction involved in photosynthesis. a. True b. False
b. False
Where in the chloroplast is the H+ ion concentration gradient built up? a. In the stroma b. In the thylakoid space c. In the intermembrane space d. In the cytosol
b. In the thylakoid space
Which of the following statements is correct? a. Plants use their mitochondria for photosynthesis and animals use their mitochondria for respiration b. Plants produce waste oxygen that animals use in their mitochondria for cellular respiration c. Animals produce waste oxygen that plants use in their mitochondria to make energy d. Animals and plants both produce waste oxygen
b. Plants produce waste oxygen that animals use in their mitochondria for cellular respiration
____________ must be regenerated at the end of the Calvin Cycle. a. G3P b. RuBP c. ATP d. CO2
b. RuBP
During what stage of photosynthesis is O2 produced? a. Cyclic photophosphorylation b. The light dependent reactions involving photosystem II & I c. Carbon fixation d. The Krebs cycle
b. The light dependent reactions involving photosystem II & I
Photosynthesis is a(n)__________ pathway & is therefore a __________ process. a. Anabolic, exergonic b. Catabolic, exergonic c. Anabolic, endergonic d. Catabolic, endergonic
c. Anabolic, endergonic
Which of the following occurs in the stroma of the chloroplast? a. Light reaction b. Electron transport chain c. Calvin cycle d. Glycolysis
c. Calvin cycle
Select the correct sequence for the movement of electrons during the light dependent reaction of plants. I. Photosystem I II. Photosystem II III. Water IV. NADP+ a. I, II, III, IV b. I, IV, III, II c. III, II, I, IV d. I, III, II, IV
c. III, II, I, IV
The Calvin Cycle requires the input of each of the following except... a. ATP b. NADPH c. O2 d. CO2
c. O2
How is Photosystem I recharged? a. Splitting water provides electrons to Photosystem II b. Oxygen provides electrons to Photosystem II c. Photosystem II provides electrons to Photosystem I d. NADP+ provides electrons to Photosystem II
c. Photosystem II provides electrons to Photosystem I
The main purpose of photosynthesis is to: a. Consume CO2 b. produce ATP c. Produce G3P d. Convert light energy into kinetic energy
c. Produce G3P
Photosystem II... a. Uses light energy to transfer electrons to water b. Takes electrons from water and passes them to ATP Synthase c. Takes electrons from water, energizes them, and passes them to an electron transport chain d. Absorbs light energy to energize electrons and make NADPH
c. Takes electrons from water, energizes them, and passes them to an electron transport chain
The Light Reaction needs NADP+ and ADP, where does it get these molecules? a. They are produced in the chloroplast b. Plant mitochondria produce them c. They are a byproduct of the Calvin Cycle d. They are produced from splitting H2O.
c. They are a byproduct of the Calvin Cycle
The most important role of pigments in photosynthesis is to __________.
capture light energy
In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.
carbon dioxide
Photosynthesis takes place in special organelles called _____________.
chloroplasts
chloroplast structure
contains a plant cell's thylakoids, stroma and grana, and chlorophyll
Photosystem I... a. Sends electrons to Photosystem II through the electron transport chain b. Makes NADPH that is used by ATP Synthase to make ATP c. Uses the H+ gradient to energize electrons to make ATP d. Absorbs light to energize electrons so they can be transferred to NADP+ to make NADPH
d. Absorbs light to energize electrons so they can be transferred to NADP+ to make NADPH
Which of the following is not a product of the Light Reaction? a. Oxygen b. ATP c. NADPH d. G3P
d. G3P
Which color below is reflected off the thylakoid? a. Red b. Blue c. Yellow d. Green
d. Green
What is the final electron acceptor of the electrons from Photosystems II and I? a. ATP b. CO2 c. O2 d. NADP+
d. NADP+
Chlorophyll a
dark green
When does the Calvin Cycle occur?
day and night (not light dependent)
Photosystem II recharges Photosystem I via ______ ______ _____.
electron transport chain
Photosynthesis is anabolic (it builds sugar) which means that it is _________ and requires energy.
endergonic
As electron falls back to its original orbital, it gives off ______.
energy
thylakoids are a membranous system that are stacked in columns called _______.
granum
Each pigment reflects light that is not used for photosynthesis (i.e., _____).
green
Organisms that ingest food from an outside source are called __________.
heterotrophs
Individual electrons in the chlorophyll absorb the light energy causing the electron to move to a _______ orbital.
higher
The space between the chloroplasts two membranes is called the ____________ space.
intermembrane
Photosynthesis uses these same wavelengths of ______.
light
Chlorophyll b
light green
The energy used to produce ATP in the light reactions of photosynthesis comes from __________.
movement of H+ through a membrane
carotenoids
orange
What are the chloroplasts two membranes called?
outer membrane and inner membrane
Plants are called _________ since they use light energy.
photoautotrophs
plants harness the energy in sunlight (plus CO2 and water) to create sugar, this is called ________________.
photosynthesis
Chloroplasts are present in large quantities in the leaves of _______.
plants
Photosynthesis is a _________ reaction in which CO2 is reduced to C6H12O6 and H2O is oxidized to O2.
redox
the membrane of the thylakoid separates the thylakoid space from the _________.
stoma
The space inside the inner membrane is called the ______ (this is analogous to the matrix of a mitochondria).
stroma
When chloroplast pigments absorb light, __________.
their electrons become excited
Where does Light Reaction happen?
thylakoid membrane
Inside a thylakoid is the ________ ________.
thylakoid space
Inside the stroma are _________.
thylakoids
Why is this happening in the Calvin Cycle?
to make G3P
Much like mitochondria, chloroplast have ____ membranes.
two
Photosystem II is ________ of Photosystem I.
upstream
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________.
water
The space between each crest of the wave is called the ____________.
wavelength