BIO131 #4
How many NADH are produced by glycolysis? 5 4 2 1 3
2 (Two NADH molecules are produced by glycolysis.)
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
"Conservation of energy" refers to the fact that _____. A.if you conserve energy you will not be as tired B. energy cannot be created or destroyed but can be converted from one form to another C.no chemical reaction is 100 percent efficient D.the net amount of disorder is always increasing E.the entropy of the universe is always increasing.
B. energy cannot be created or destroyed but can be converted from one form to another
An enzyme _____. A.increases the EA of a reaction B.is a inorganic catalyst C.can bind to nearly any molecule D.is a source of energy for endergonic reactions E.is an organic catalyst
B. is an organic catalyst (Enzymes are proteins that behave as catalysts.)
True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain. True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain. True False
False (The chemiosmotic hypothesis states that the flow of electrons through an electron transport chain generates a proton gradient that leads to the synthesis of ATP)
True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane. True False
False (The region of ATP synthase that catalyzes ATP production protrudes out of, but does not span, the chloroplast membrane; the region that spans the membrane is an ion channel through which protons can pass.)
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? The light-independent reactions turn glucose, a sugar, into CO2 gas. The light-independent reactions use CO2 to make ATP. The light-independent reactions turn sugar into ATP for energy. The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
The light-independent reactions turns CO₂, a gas, into a usable carbon in the form of sugars. -CO₂ is unusable until plants have "fixed" this carbon into sugar.
Calvin Cycle
The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO₂ fixation and reduction of the fixed carbon into carbohydrate.
Which of the following particles can pass through ATP synthase channel?
Protons
Which of the following particles can pass through the ATP synthase channel?
Protons
Which of the following particles can pass through the ATP synthase channel? Which of the following particles can pass through the ATP synthase channel? ADP ATP Protons Inorganic phosphate
Protons (The channels formed by ATP synthase are specific for protons.)
Photosynthesis and respiration in plants Drag the labels from the left to their correct locations in the concept map on the right. Not all labels will be used.
a) SUNLIGHT b) PHOTOSYNTHESIS c) CHLOROPLAST d) OXYGEN & SUGAR e) CHLOROPHYLL f) CARBON DIOXIDE & ATP g) CELLULAR RESPIRATION h) MITOCHONDRIA SUNLIGHT provides energy for PHOTOSYNTHESIS PHOTOSYNTHESIS occurs in CHLOROPLASTS CHLOROPLAST contains the pigment CHLOROPHYLL PHOTOSYNTHESIS produces OXYGEN & SUGAR OXYGEN & SUGAR are inputs for CELLULAR RESPIRATION CELLULAR RESPIRATION produces CARBON DIOXIDE & ATP CARBON DIOXIDE provides carbon for PHOTOSYNTHESIS CELLULAR RESPIRATION occurs in MITOCHONDRIA A mutually dependent relationship exists between chloroplasts and mitochondria in the plant cell. Photosynthesis, which occurs in chloroplasts, generates the sugars and oxygen gas that are used in mitochondria for cellular respiration. Cellular respiration generates carbon dioxide, which in turn is used as a carbon source for the synthesis of sugars during photosynthesis. Cellular respiration also generates ATP and water, which are used in various chemical reactions in the plant cell.
photosystem I
the oxidation of the electron transport chain between the two photosystems and the reduction of NADP+ happens in this one
photosystem II
the oxidation of water and reduction of the electron transport chain between the two photosystems happens in this one
Chlorophyll is ...which gives leaves their colour
the pigment which gives leaves their green colour, resides in the thylakoid membrane
Photosynthesis is
the process that converts solar energy into chemical energy
The electromagnetic spectrum
the range of wavelengths of electromagnetic radiation.
Earth's supply of fossil fuels was formed from
the remains of organisms that died hundreds of millions of years ago
The overall chemical change during photosynthesis is
the reverse of the one that occurs during cellular respiration
In most plants (C3 plants), initial fixation of CO2, via rubisco, forms a
three-carbon compound (3-phosphoglycerate)
Photosystem II and the cytochrome complex are located in the
thylakoid membraine
The Calvin cycle, like the citric acid cycle, regenerates its starting material after
molecules enter and leave the cycle
Which of the following does not occur during the Calvin cycle?
release of oxygen
which of the following does not occur during the calvin cycle?
release of oxygen
O2 is _______as a by-product of this reaction
released
Which process is most directly driven by light energy?
removal of electrons from chlorophyll molecules
Photosynthesis reverses the direction of electron flow compared to
respiration
Many eucarytoic organelles are connected via a flow of membrane. Which of the organelles listed below is not part of this membrane flow? nucleus lysosome golgi complex ribosome ER
ribosome
The CO2-fixing enzyme is called
ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco).
In a sense, fossil fuels represent stores of
solar energy from the distant past
Where does the Calvin cycle take place?
stroma of the chloroplast
What name is given to the reactants in an enzymatically catalyzed reaction? products EA substrate reactors active sites
substrate
In the light-capturing reactions, excited electrons are used to produce
the electron carrier NADPH or are donated to an electron transport chain, which results in the production of ATP via chemiosmosis.
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6
During glycolysis alone which of the following molecules is/are required? FAD ATP NADH + H+ Acetyl-CoA Pyruvic Acid
ATP
Glycolysis results in the production of ATP NADH + H+ Pyruvic Acid ATP and NADH + H+ NADH + H+ and Pyruvic Acid ATP, NADH + H+ and Pyruvic Acid
ATP, NADH + H+ and Pyruvic Acid
Chemical energy is a form of _____ energy. A.motion B.potential C.heat D.entropic E.kinetic
B. potential
Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5. The solution is then adjusted to pH 8. Which of the following conclusions can be drawn from these experimental conditions? A. ATP will be produced because the proton gradient favors proton movement through the ATP synthase channels. B. Protons will not diffuse toward the outside of the vesicles. C. ATP will not be produced because there is no ADP and inorganic phosphate in the solution. D. The change in the solution's pH results in a gradient across the chloroplast membranes such that there is a lower concentration of protons inside the vesicles and a higher concentration outside.
C. ATP will not be produced because there is no ADP and inorganic phosphate in the solution. (This statement is true; although the proton gradient is present, ADP and inorganic phosphate are required to make ATP and were not added to the reaction.)
What occurs during the Calvin Cycle?
CO2 is reduced
Chemical energy
Energy stored in the chemical bonds of molecules; a form of potential energy.
True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to the electron flow through an electron transport chain.
False
True or false? During active transport through the sodium-potassium pump, ATP hydrolysis provides the energy to pump three sodium ions into the cell for every two potassium ions pumped out of the cell. True False
False (The sodium-potassium pump maintains a state in which the concentration of sodium is low inside the cell relative to the outside and the concentration of potassium is high inside the cell relative to the outside; thus, three sodium ions are pumped out of the cell and two potassium ions are pumped into the cell against the electrochemical gradient.)
In both respiration and photosynthesis, the potential energy of a(n) __ ________ ______ is tapped to drive the phosphorylation of ADP to ATP. As H+ diffuses back through ___ ______ (an enzyme complex embedded in the membrane) ATP is produced.
H+ concentration gradient.. ATP synthase..
In photosynthesis, the electrons come from water and end up in ______.
NADPH
What transports electrons from the light reactions to the Calvin cycle?
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
Which of the following products of the light reactions of photosynthesis is consumed during the Calvin cycle?
NADPH
Photorespiration consumes __ and ______ ____ and releases ___ without producing ___ or _______.
O2 organic fuel CO2 ATP sugar
Light Reactions Outputs
O2, ATP, NADPH
Which of the following is a product of the light reactions of photosynthesis?
Oxygen, ATP, and NADPH
The reaction-center chlorophyll a of PS I is called
P700
Some organisms such as purple sulfur bacteria have
PS I but not PS II
Current evidence indicates that the process of photosynthesis arose more than three billion years ago Its origin had a huge impact on existing organisms and on the physical characteristics of the biosphere. Which major physical change could be attributed to photosynthesis?
Photosynthesis drastically increased the oxygen content of the atmosphere.
Photosynthesis contrasts with cellular respiration because:
Photosynthesis is endergonic (consumes energy). Reduces CO2 to sugar Cellular respiration is exergonic (releases energy). Oxidizes sugar to CO2
_____ splits water into 1/2 O2, H+, and e-
Photosystem 2
cyclic photophosphorylation
Photosystem I occasionally transfers electrons to photosystem II's electron transport chain to increase ATP production, instead of using them to reduce NADP+.
Summary of Photosystems I and II
Photosystem II produces a proton gradient that drives the synthesis of ATP. Photosystem I yields reducing power in the form of NADPH. Although several groups of bacteria have just one of the two photosystems, the cyanobacteria, algae, and plants have both.
A photosystem consists of what structures?
Reaction-center complex, Primary electron acceptor, chlorophyll molecules, light-harvesting complexes
Oxidation
The loss of electrons from a substance involved in a redox reaction.
Which of the following is usually NOT true about active transport? The molecules being moved can cross the phospholipid bilayer easily. The process of phagocytosis is not a form of active transport. The movement of material requires cellular energy. The movement of material is from a lower concentration to a higher concentration.
The molecules being moved can cross the phospholipid bilayer easily.
Carbon Fixation
The part of the Calvin Cycle in which carbon atoms are extracted from atmospheric carbon dioxide and used to make simple organic compounds that eventually become glucose.
Chlorophyll can be found in _____.
The photosystems contain chlorophyll.
Why are most autotrophs referred to as the producers of the biosphere?
They are the ultimate sources of organic compounds for all nonautotrophic organisms.
Which of these enters the citric acid cycle? NADH + H+ acetyl CoA pyruvate glucose G3P
acetyl CoA (Acetyl CoA is a reactant in the citric acid cycle.)
Energy is transferred inside the
antenna complex, from one molecule to the next, until it reaches the reaction center
Thylakoids are
connected sacs in the chloroplast which composes a third membrane system
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.
Cyclic electron flow is thought to have evolved before
linear electron flow.
P680+ is the strongest known biological _________ agent
oxidizing
In cyclic electron flow no _______ is released.
oxygen
In respiration, the electrons come from the oxidation of organic molecules, and ______ is the final electron acceptor.
oxygen
which of the following is a product of the light reactions of photosynthesis?
oxygen, ATP and NADPH
Directly or indirectly
photosynthesis nourishes almost the entire living world
The energy transformation of the light-dependent reactions and the carbon dioxide reduction of the Calvin cycle are two separate but linked processes in
photosynthesis.
Chlorophyll molecules work together in groups (+ carotenoids, proteins), forming a complex called a
photosystem
Electrons in the electron transport chain participate in
redox reactions and are gradually stepped down in potential energy.
Photons may be absorbed, transmitted, or reflected when they
strike an object.
The _____ is the site of ATP production because the proton gradient established by photosystem II drives protons into the _____.
stroma
c02 to G3P
the electrons derived from oxidation of NADPH to NADP+ in the calvin cycle are used to reduce _ to _
NADP+ to NADPH
the electrons derived from oxidation of h20 to 02 in light reactions are used to reduce _ to _
Linear electron flow is
the primary pathway, involves both photosystems and produces ATP and NADPH using light energy
Identify the chloroplast
A
__ splits water into half O2, H +, and e
A Photosystem II
Chlorophyll can be found in__.
A and C Photosystems
Chloroplast
A chlorphyll-containing organelle in plant cells, in which photosynthesis occurs.
Cellular Respiration
A common and efficient pathway to produce ATP, which involves a transfer of electrons from a reduced compound to an electron transport chain, and ultimately to an electron acceptor.
photosystem
A complex of molecules and enzymes in plant chloroplasts that takes part in photosynthesis. 1. photosystem 1 (NADPH) 2. photosystem 2 (ATP)
Which of these equations best summarizes photosynthesis? Which of these equations best summarizes photosynthesis? A. 6 CO2 + 6 H2O → C6H12O6 + 6 O2 B. H2O → 2 H+ + 1/2 O2 + 2e- C. 6 CO2 + 6 O2 → C6H12O6 + 6 H2O D. C6H12O6 + 6 O2 → 6 CO2 + 12 H2O E. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A. 6 CO2 + 6 H2O → C6H12O6 + 6 O2
What is the fate of the phosphate group that is removed when ATP is converted to ADP? A.It is acquired by a reactant in an endergonic reaction. B.It is broken down into one phosphorus and four oxygen atoms. C.It is acquired by a reactant in an exergonic reaction. D.It is used to convert an ATP into an AQP. E.It is acquired by a reactant in a spontaneous reaction.
A.It is acquired by a reactant in an endergonic reaction. (By acquiring the phosphate group the reactant acquires energy.)
In glycolysis, what starts the process of glucose oxidation? ADP hexokinase FADH2 ATP NADPH
ATP (Some ATP energy is used to start the process of glucose oxidation.)
Chloroplast membrane vesicles are equilibrated any simple solution of pH 5. The solution is then adjusted to P88. Which of the following conclusions can be drawn from the experimental conditions?
ATP will not be produced because there is no ADP and inorganic phosphate in the solution.
Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5 . The solution is then adjusted to pH 8 . Which of the following conclusions can be drawn from these experimental conditions?
ATP will not be produced because there is no ADP and inorganic phosphate in the solution.
__Releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment
B The energy released as electrons are passed along the electron transport chain is used to pump protons into thylakoid compartment
Which of the following clues would tell you if a cell is prokaryotic or eukaryotic? A.whether or not the cell carries out cellular metabolism B.whether or not the cell is partitioned by internal membranes C.the presence or absence of ribosomes D.whether or not the cell contains DNA E.the presence or absence of a rigid cell wall
B. whether or not the cell is partitioned by internal membranes (Prokaryotic cells lack any internal membranous compartmentalization.)
A(n) _____ reaction occurs spontaneously. A.endergonic B.exergonic C.kinetic D.chemical E.anabolic
B.exergonic (In exergonic reactions the products have less potential energy than the reactants.)
In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain? A. The advantage of the respiratory electron transport chain is that oxygen is the final electron acceptor. B. The advantage of an electron transport chain is the production of a large number of reduced, high-energy intermediates. C. The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.
C. The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates. (As the electrons "fall" down the electron transport chain, the energy released is used to actively transport protons into the inner-membrane space. Read about the respiratory electron transport chain.)
What is energy coupling? A. the use of an enzyme to reduce EA B. a barrier to the initiation of a reaction C. the use of energy released from an exergonic reaction to drive an endergonic reaction D.a description of the energetic relationship between the reactants and products in an exergonic reaction E.the hydrolysis of ATP to ADP + P
C. the use of energy released from an exergonic reaction to drive an endergonic reaction
A reaction involving an increase in Enthalpy and an increase in Entropy will always be? A.Spontaneous B.Non-Spontaneous C.It can be either depending on the exact values
C.It can be either depending on the exact values
Identify all correct statements about the basic function of fermentation. Select all that apply. A.The basic function of fermentation is the production of additional ATP by further oxidation of the products of glycolysis. B.The basic function of fermentation is the production of ethyl alcohol or lactic acid. C.The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis.
C.The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis. (Fermentation occurs in the absence of oxygen and does not yeild as much ATP. Read about fermentation.)
In _____ plants, CO2 is first fixed into a four-carbon compound, which moves into bundle-sheath cells and releases CO2 to the Calvin cycle.
C4
Photosynthesis Outputs
C6H12O6 (glucose), 6O2
In _____ plants, stomata are open at night, and CO2 is first fixed into a four-carbon compound, which releases CO2 to the Calvin cycle during the day.
CAM
Mechanisms for Increasing CO2 Concentration
CAM and C4 Plants
What is the basic role of CO2 in photosynthesis? CO2 is taken in by plants as a form of inverse respiration, in which carbon dioxide is "breathed in" and oxygen is "breathed out." CO2 is a source of electrons in the formation of organic molecules. CO2 is fixed or incorporated into organic molecules.
CO2 is fixed or incorporated into organic molecules.
Of the following, which occurs during the Calvin cycle?
CO2 is reduced.
C4 photosynthesis and CAM function as
CO2 pumps. They minimize photorespiration when stomata are closed and CO2 cannot diffuse in directly from the atmosphere.
The discovery of the Calvin cycle clarified how the ATP and NADPH produced by light-capturing reactions allow cells to reduce
CO2 to carbohydrate
Calvin Cycle Inputs
CO2, ATP, NADPH
Fixation
Calvin Cycle's first Phase: CO2 reacts with ribulose bisphosphate (RuBP), producing two 3-phosphoglycerate molecules. The attachment of CO2 to an organic compound is called carbon fixation.
What property of the pigment chlorophyll makes it appear green?
Chlorophyll absorbs all of the visible spectrum of the light except green, which it reflects
In which of the organelles does photosynthesis take place?
Chloroplast
True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
False
Who or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
False
In photorespiration, rubisco adds
O2 instead of CO2 in the Calvin cycle, producing a two-carbon compound
Photorespiration occurs when rubisco reacts RuBP with
O2.
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
Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle.
Oxidized; Reduced -During the light reactions of photosynthesis, water is oxidized, and during the Calvin cycle, carbon is reduced.
Which of the following particles could diffuse easily through a cell membrane? Hydrogen ion (H+) Oxygen (O2) Glucose Sodium ion (Na+)
Oxygen (O2) (Small nonpolar molecules such as oxygen can diffuse across cell membranes.)
One of the important waste products of photosynthesis is oxygen gas. Where does this oxygen gas come from?
Oxygen is released when water is broken down to extract electrons and protons for use in the light reactions.
C4 photosynthesis, carbon fixation and the Calvin cycle occur in separate types of cells. This occurs in a three-step process:
PEP carboxylase fixes CO2 in mesophyll cells. The 4-carbon organic acids produced travel to bundle-sheath cells. The four-carbon organic acids release a CO2 molecule, which rubisco uses to form 3-phosphoglycerate, thus initiating the Calvin cycle.
P700+ (P700 that is missing an electron) accepts an electron passed down from _____via the electron transport chain
PS II
The Z scheme explains the enhancement effect
Photosynthesis is more efficient when both 680-nm and 700-nm wavelengths are available (hence the names of the pairs of reaction-center chlorophyll molecules), allowing both photosystems to run at maximum rates.
The light reactions of photosynthesis use chemiosmosis to produce ATP that will be used in the calvin cycle. The electrochemical gradient that drives this chemiosmosis is formed across which structure(s)?
Thylakoid membrane
Chlorophyll molecules are in which part of the chloroplast?
Thylakoid membranes
Which two things worked in conjunction to make CFCs harmful to the ozone?
chlorine and sunlight
True or false? Active transport differs from passive transport in that active transport does not require an input of energy. True False
false (Active transport requires the input of energy, whereas passive transport is primarily driven by the gradient.Active transport requires energy, whereas passive transport does not.)
photorespiration
favors conditions in hot arid climates that is considered wasteful
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.
Photosystem II is much more abundant in the
interior, stacked membranes of grana.
Photosynthesis consists of two linked sets of reactions:
light-dependent reactions produce O2 from H2O, and Calvin cycle reactions produce sugar from CO2.
Cyclic electron flow may protect cells from
light-induced damage
Which of the following organelles would be expected to contain DNA? Mitochondrion Flagellum Intermediate filament Lysosome Peroxisome
mitochondrion
Pigments
molecules that absorb only certain wavelengths of light.
The ultimate acceptor of all electrons flowing down the electron transport chain is: ATP ADP Glucose Water NADH + H+ Oxygen
oxygen
the final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorlayion is
oxygen
The final electron acceptor of cellular respiration is _____. NADH FADH2 CO2 oxygen water
oxygen Oxygen is combined with electrons and hydrogen to form water.
Photosystem II "splits" water to replace its lost electrons and in the process produces
oxygen (oxygenic photosynthesis)
Which of the following is a product of the light reactions of photosynthesis?
oxygen, ATP, and NADPH
The light reactions produce _____.
oxygen, NADPH, and ATP
Cellular respiration and photosynthesis are similar in that both involve __________.
oxygen-reduction (redox) reactions
There are two types of reaction centers:
photosystem I and photosystem II
Cyclic electron flow uses only
photosystem I and produces ATP, but not NADPH
The light-harvesting complexes aka:
pigment molecules bound to proteins
Thylakoid membranes contain large quantities of
pigments. The most common pigment is chlorophyll.
why are plants classified as producers?
plants are classified as producers because they fix inorganic carbon into organic molecules
The fluid-filled space between the thylakoids and the inner membrane is the
stroma
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________.
water
the electrons stripped from glucose in cellular respiration end up in which compound?
water
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
The light reactions of photosynthesis use _____ and produce _____.
water; NADPH -NADPH is a reactant in the Calvin cycle.
which of the following products of the light reactions of photosynthesis is consumed during the calvin cycle?
NADPH
Can you tell from the absorption spectra whether red light is effective in driving photosynthesis?
One cannot tell from the graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.
Can you tell from these absorption spectra whether red light is effective in driving photosynthesis?
One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.
Where was the thinning of ozone initially discovered?
Over the Antartic
Photosynthesis occurs in
in plants, algae, certain other unicellular eukaryotes, and some prokaryotes
Which of these is NOT a product of glycolysis? ATP NADH FADH2 pyruvate
FADH2 FADH2 is a product of the citric acid cycle
Carrier proteins and channel proteins are both involved in? Phagocytosis Facilitated diffusion Exocytosis Receptor-mediated endocytosis Osmosis
Facilitated diffusion
The amount of ATP produced via substrate level phosphorylation would be expected to increase. True False
False
The hydrogen ion concentration in the space between the mitochondrial membranes would be expected to increase. True False
False
True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain.
False
In photosynthesis, ______ ______ drives electrons from low-energy state in water to a high-energy state.
light energy
Photosynthesis converts
light energy to the chemical energy of food
The thylakoid membranes bring together the components necessary to carry out the _____.
light reactions
Photorespiration limits damaging products of
light reactions that build up in the absence of the Calvin cycle
Like other electromagnetic energy,
light travels in rhythmic waves
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
What is the biological significance of the light-independent reactions of photosynthesis? They convert ATP to sugar. They generate ATP and NADPH. They make oxygen. They convert carbon dioxide to sugar.
They convert carbon dioxide to sugar.
C4 plants differ from C3 and CAM plants in that C4 plants__.
Transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria. True False
True (Glycolysis takes place in the cytoplasm, whereas the Krebs cycle and the electron transport chain, which generate the largest amounts of ATP during cellular respiration, take place in the mitochondria.)
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups. True False
True (The three phosphate groups in an ATP molecule carry negative charges that strongly repel each other and give ATP a large amount of potential energy.)
sugar NADP+ ADP
outputs of calvin cycle
NADPH ATP 02
outputs of light dependent reactions
In cellular respiration, most ATP molecules are produced by _____. cellular respiration photophosphorylation photosynthesis oxidative phosphorylation substrate-level phosphorylation
oxidative phosphorylation (This process utilizes energy released by electron transport.)
Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle.
oxidized...reduced
How Does Photosystem II Obtain Electrons?
oxidizes water to replace electrons used during the light reactions. When excited electrons leave and enter the ETC, the photosystem becomes so electronegative that enzymes can remove electrons from water, leaving protons and oxygen.
In photosynthesis
plants use carbon dioxide, water, and light energy to produce sugar and other complex molecules. Oxygen is released as a by-product.
Photosynthesis is a
redox process in which H2O is oxidized and CO2 is reduced
plastoquinone (PQ)
shuttles electrons from pheophytin across the thylakoid membrane to a cytochrome complex.
On hot, dry days, plants close ________.
stomata
In plants, CO2 enters photosynthetic tissue through
stomata. The CAM and C4 pathways increase CO2 concentrations inside the leaves of some species and make photosynthesis more efficien
A photosystem consists of
a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes
Carbon enters the cycle as CO2 and leaves as
a sugar named glyceraldehyde 3-phospate (G3P)
Light is
a type of energy electromagnetic radiation that acts both particle-like and wave-like.
After Pyruvic Acid enters the mitochondrion it is converted into _____ prior to entering the Citric Aciod Cycle ATP Lactic Acid Acetyl-CoA Water FADH2
Acetyl-CoA
If the concentration of phosphate in the cytosol is 2.0 mM and the concentration of phosphate in the surrounding fluid is 0.1 mM, how could the cell increase the concentration of phosphate in the cytosol? passive transport diffusion active transport osmosis facilitated diffusion
active transport (For the cell to accumulate phosphate, it must move calcium against the concentration gradient. This process requires energy.)
Lactose transport by membrane proteins occurs under conditions in which the concentration of lactose inside the cell is higher than the concentration outside the cell. What type of transport is used to move lactose into the cell? Simple diffusion Osmosis Active transport Facilitated diffusion
active transport (Under these conditions, lactose moves against its concentration gradient, so its transport will require energy.)
How can one increase the rate of a chemical reaction? add a catalyst increase the entropy of reactants decrease the concentration of reactants cool the reactants
add a catalyst
Active transport moves molecules ____________ their concentration gradients and ____________ energy. against, uses against, uses no with, uses with, uses no none of the above
against, uses
These organisms feed not only themselves but
also most of the living world
Leaves are
are the major locations of photosynthesis
Both mitochondria and chloroplasts _____.
use an H+ gradient to produce ATP
Reduction
Calvin Cycle's second phase: The 3-phosphoglycerate molecules are phosphorylated by ATP and reduced by NADPH to produce glyceraldehyde 3-phosphate (G3P).
ATP and NADPH are produced on the side facing the stroma, where the ______ ______ takes place
Calvin cycle
A strong concentration gradient favoring entry of CO2 is maintained by the
Calvin cycle, which constantly uses up the CO2 in chloroplasts
The most important role of pigments in photosynthesis is to
Capture light energy
Both mitochondria and chloroplasts __________.
use chemiosmosis to produce ATP
Which of the following is/are inputs required for photosynthesis? Oxygen Carbon Dioxide NADH + H+ Glucose more than one of the above
Carbon Dioxide
Chloroplasts and mitochondria generate ATP by
chemiosmosis, but use different sources of energy
As a wave, light can be characterized by its
wavelength - the distance between two successive wave crests.
By closing the stomata in a plant the plant ...
conserves H2O but also limits photosynthesis
What does the chemiosmotic process in chloroplasts involve?
establishment of a proton gradient across the thylakoid membrane.
Which of the following molecules represent outputs from the Citric Acid Cycle (alone)? NAD+ FAD ADP Carbon Dioxide more than one of the above
Carbon Dioxide
Chlorophylls have a long
"tail" made of isoprene subunits, and a "head" consisting of a large ring structure with a magnesium atom in the middle. Light is absorbed in the head
3 co2 - 1 g3p
# of c02 input # of g3p output calvin cycle
RuBP is also known as
(Ribulose Bisphosphate carboxylase-oxygenase
A spontaneous reaction occuring at 250K and with a 2.0Kcal decrease in entropy can have which of the following changes in enthalpy? -600Kcal -250Kcal -100 Kcal 100Kcal 250Kcal 600Kcal
-600Kcal
Light Reactions
-Are carried out by molecules in the thylakoid membranes -Convert light energy to the chemical energy of ATP and NADPH -Split H2O and release O2 to the atmosphere
A photosystem consists of which of the following structures?
-Chlorophyll molecules -Primary electron acceptor -Reaction-center complex -Light-harvesting complexes
G3P is used in which of the following processes?
-Production of cell walls in growing plants -Production of starch -Production of glucose -Production of cellulose -Production of sucrose
Calvin Cycle Reactions
-Take place in the stroma -Use ATP and NADPH to convert CO2 to the sugar G3P -Return ADP, inorganic phosphate, and NADP+ to the light reactions
Light-Dependent Reactions
-The light dependent reactions of photosynthesis occur within the thylakoid membranes inside the chloroplast. -Light dependent reaction have two photosystems. In photosystem 1, excited electrons are used to produce NADPH. In photosystem 2 they are used to produce ATP.
The Calvin cycle has three phases:
1) Carbon fixation (catalyzed by rubisco) 2) Reduction 3) Regeneration of the CO2 acceptor (RuBP)
After the cycle takes place three times it fixes _ molecules of ___
3 CO2
Calvin cycle (3 phases)
1. The fixation phase 2. The reduction phase 3. The regeneration phase -Can occur with or without light and occurs in the stroma.
Two set of reaction of Photosynthesis?
1.) Light dependent reaction: transform the energy in sunlight to chemical energy in the form of electrons with high potential energy. These reactions result in the production of OXYGEN from water. 2.) Light independent reaction: uses ATP and NADPH to reduce carbon dioxide from the atmosphere to sugar, through a set of reactions called CALVIN CYCLE.
Beginning with 10 molecules of pyruvic acid, in the presence of Oxygen , and assuming a normal mitochondrion how many molecules of ATP would be expected to be produced via substrate level phosphorylation. I am looking for total production, not net production. 1 5 10 20 40 100
10
For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle. 0 5 1 2 4
2 (Each glucose produces two pyruvates, each of which is converted into acetyl CoA.)
In glycolysis there is a net gain of _____ ATP. 4 3 2 5 1
2 (It takes 2 ATP to produce 4 ATP.)
The Importance of Rubisco in the Reduction phase
3-Phosphoglycerate is phosphorylated by ATP and then reduced by electrons from NADPH. The product is the phosphorylated sugar glyceralaldehyde-3-phosphate (G3P). Some of the G3P that is synthesized is drawn off to manufacture glucose and fructose.
Each mesophyll cell contains
30-40 chloroplasts
Beginning with 1 moleucle of glucose, in the presence of Oxygen , and assuming a normal mitochondrion how many molecules of ATP would be expected to be produced via oxidative level phosphorylation. I am looking for total production, not net production. 16 24 34 40
34
Approximately what wavelength of light is best absorbed by chlorophyll a, the pigment that participates directly in the light reactions?
435 nm
Which wavelength of light is best absorbed by chlorophyll b.
455 nm
Which wavelength of light is best absorbed by chlorophyll b?
455 nm
In many plants, photorespiration is a problem because on a hot, dry day it can drain as much as
50% of the carbon fixed by the Calvin cycle
For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle. 6 2 3 0 3 to 6
6 (3 NADH + H+ are produced per each acetyl CoA that enters the citric acid cycle.)
The overall reaction when glucose is the carbohydrate can be written as:
6 CO2 + 12 H2O + light energy ---> C6H12O6 + 6 O2 + 6 H2O
The photosynthesis equation
6 CO2 + 6 H2O + Light Energy >>> Glucose + 6 O2
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O --> C6H12O6 + 6 O2
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
The equation that represents photosynthesis
6 CO2+6 H2O > C6H12O6 + 6 O2
Photosynthesis Inputs
6H2O, 6CO2, (light) energy
There are _ _____ in linear electron flow
8 steps
Thylakoid
A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.
thylakoid
A flattened, membrane-bound disk inside a plant chloroplast. A stack of thylakoids is called a granum.
Chlorophyll
A green pigment located within the chloroplasts of plants. Chlorophyll a can participate directly in the light reactions, which convert solar energy to chemical energy.
Chlorophyll
A green pigment molecule found in plant cells that absorbs light energy to power photosynthesis.
mesophyll cell
A loosely arranged photosynthetic cell located between the bundle sheath and the leaf surface.
photorespiration
A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.
Pheophytin
A molecule, very similar to chlorophyll, that acts as an electron acceptor in photosynthesis.
Step 1:
A photon hits a pigment and its energy is passed among pigment molecules until it excites P680
Chemiosmosis
A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.
photolysis
A reaction taking place in the thylakoid membranes of a chloroplast during light-dependant reactions where two molecules of water are split to form oxygen, hydrogen ions, and electrons.
Photosynthesis
A series of chemical reactions and electron transfers that covert the energy of light into the chemical energy stored in glucose.
plastocyanin
A small protein that shuttles electrons at the end of photosystem II's ETC to photosystem I during photosynthesis. Carries the electron back across the thylakoid membrane and donates it to photosystem I, thus physically linking the two photosystems.
Plastocyanin
A small protein that shuttles electrons from photosystem 2 to photosystem 1 during photosynthesis.
Plastoquinone
A small, hydrophobic molecule that carries electrons across the thylakoid membrane during photosynthesis.
chloroplasts
A structure in the cells of plants and some other organisms that captures energy from sunlight and uses it to produce food.
The following reaction A --> B + C + heat is a(n) _____ reaction. A.exergonic B.exchange C.dehydration synthesis D.endergonic E.anabolic
A.exergonic (Energy has been released.)
Which option properly summarizes the inputs and outputs of the Calvin cycle?
ATP + NADPH + 3CO2 > G3P
The light reactions of photosynthesis supply the Calvin cycle with
ATP and NADPH
The light reactions of photosynthesis supply the Calvin cycle with __________.
ATP and NADPH
ATP
Adenosine triphosphate, a molecule consisting of adenine, a sugar, and three phosphate groups that can be hydrolyxed to release free energy. Universally used by cells to store and transfer energy.
Even though plants cells photosynthesize, they still use their mitochondria for oxidation of pyruvate. This will occur in _____. photosynthesizing cells in the light and in other tissues in the dark all cells all the time cells that are storing glucose only photosynthetic cells in the light, while photosynthesis occurs concurrently
All cells all the time
What property of dishwashing liquid (detergent) makes it useful to wash grease from pans? Solubility in water Amphipathic nature Permeability Hydrophobic nature
Amphipathic nature (detergents form micelles around the grease, which are then washed away because the polar head groups facing outward on the micelle are water-soluble.)
ATP (Adenosine triphosphate)
An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bond are hydrolyzed. This energy is used to drive endergonic reactions in cells.
What connects the two photosystems in the light reactions?
An electron transport chain
Step 2:
An excited electron from P680 is transferred to the primary electron acceptor (we now call it P680+)
Chloraplasts
An organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
Based on current findings about climate change, the following statement is true . . .
As climate change speeds up, there will be an increase in the number of strong storms, in turn causing an increased amount of ozone depletion.
What is a correct distinction between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Autotrrophes, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
Active and passive transport of solutes across a membrane typically differ in which of the following ways? A. Active transport is usually down the concentration gradient of the solute, whereas passive transport is always against the concentration gradient of the solute. B. Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy. C. Active transport is always faster than passive transport. D. Active transport uses protein carriers, whereas passive transport uses carbohydrate carriers. E. Active transport is used for ions, passive transport is used for uncharged solutes.
B. Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy. (Active and passive transport can be distinguished by whether or not they use cellular energy.)
Generation of proton gradients across membranes occurs during
Both PHOTOSYNTHESIS and RESPIRATION.
In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during
Both photosynthesis and respiration
Energized electrons from ___enter an electron transport chain and are then used to reduce NADP+
C Photosystem I
The most important role of pigments in photosynthesis is to __________.
CAPTURE LIGHT ENERGY
Which gas contributes to both global warming and the deterioration of the ozone layer?
CFCs
The closing of stomata reduces access to
CO2 and causes O2 to build up
Carbon fixation is favored over photorespiration when a cell's
CO2 concentration is high and O2 concentration is low.
Closing the stomata causes
CO2 delivery, and thus photosynthesis, to stop.
What is the basic role of CO2 in photosynthesis?
CO2 is fixed or incorporated into organic molecules
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration? Carbon dioxide Water NADH ATP
Carbon Dioxide (All of the carbon atoms in glucose are incorporated into carbon dioxide: Two molecules are formed as pyruvate is converted to acetyl CoA, and four molecules are formed during the Krebs cycle.)
In photosynthesis, plants use carbon from _____ to make sugar and other organic molecules
Carbon dioxide
What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? Carbon dioxide (CO2)
Carbon dioxide (CO2)
NADPH Is an Electron
Carrier that can donate electrons to other compounds and thus reduce them. Photosystem I produces NADPH, which is similar in function to the NADH and FADH2 produced by the citric acid cycle.
ATP Synthesis in both chloroplast and mitochondria involves a process called_________.
Chemiosmosis
What property of the pigment chlorophyll makes it appear green?
Chlorophyll absorbs all of the visible spectrum of light except green, which it reflects.
In C4 and CAM plants carbon dioxide is fixed in the__on the mesophyll cells.
Cytoplasm
Identify a thylakoid
D
In cells, what is usually the immediate source of energy for an endergonic reaction? A. ADP B.. as spontaneous reactions, endergonic reactions do not need an addition of energy C. sugar D. ATP E. glucose
D. ATP (The hydrolysis of ATP provides the energy needed for an endergonic reaction.)
Which of the following statements about the electron transport chain is true? A. Water is the last electron acceptor. B. The electron transport chain is the first step in cellular respiration. C. Electrons gain energy as they move down the chain. D. NADH and FADH2 donate their electrons to the chain.
D. NADH and FADH2 donate their electrons to the chain. (The electrons lose energy as they move down the chain, and this energy is used to create a proton gradient that drives the synthesis of ATP.)
Which statement correctly describes the nuclear envelope of a eukaryotic cell? A.The nuclear envelope is a single membrane, consisting of a phospholipid bilayer. B.Plasmadesmosomes in the nuclear envelope permit the exchange of macromolecules between the nucleus and the cytoplasm. C.All of the proteins of the cell are synthesized on ribosomes bound on the nuclear envelope. D.The nuclear envelope is continuous with the endoplasmic reticulum. E.The outer layer of the nuclear envelope is coated with laminin.
D. The nuclear envelope is continuous with the endoplasmic reticulum.
Which of these is exhibiting kinetic energy? an archer with a flexed bow A.a person sitting on a couch while watching TV B.the high-energy phosphate bonds of a molecule of ATP C.a rock on a mountain ledge D.a space station orbiting Earth
D. a space station orbiting Earth (Kinetic energy is energy of motion)
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis? A. up to 30 ATP B. four ATP C. none, because in the absence of oxygen, no ATP can be made D. two ATP E. none, because all of the available energy remains in either lactate or ethanol
D. two ATP (Four ATP are made, but two ATP are consumed to start the process of glycolysis.)
Which one of the following statements about the endomembrane system is correct? A.Most of the phospholipids of the endomembrane system are synthesized in the mitochondria. B.The endoplasmic reticulum is continuous with the plasma membrane. C.Mitochondria function in the modification and sorting of lipids and proteins. D.Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system. E. Ribosomes move lipids and proteins among the different organelles of the endomembrane system.
D.Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system. (Proteins that will be secreted are always enclosed by some membrane of the endomembrane system until they are secreted.)
Which of the following best describes the structure of a biological membrane? A.a fluid structure in which phospholipids and proteins move freely between sides of the membrane B.two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins C.a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot D.two layers of phospholipids with proteins either crossing the layers or on the surface of the layers E.two layers of phospholipids with proteins embedded between the two layers
D.two layers of phospholipids with proteins either crossing the layers or on the surface of the layers (The membrane proteins can be found either embedded in or attached to the surface of the phospholipid bilayer)
__________ of H+ (protons) across the membrane drives ATP synthesis.
Diffusion
Step5:
Energy released by the fall drives the creation of a proton gradient across the thylakoid membrane
CAM Plants
During the night, CAM plants take in CO2 and temporarily fix it into organic acids. During the day, CO2 is released from the stored organic acids and used by the Calvin cycle, thus minimizing the effects of photorespiration.
Identify the stroma
E
Which of these Phosphorylates ADP to make ATP?
E ATP synthase Phosphorylates ADP
The proximate (immediate) source of energy for oxidative phosphorylation is _____. A. ATP B. NADH and FADH2 C. ATP synthase D. substrate-level phosphorylation E. kinetic energy that is released as hydrogen ions diffuse down their concentration gradient
E. kinetic energy that is released as hydrogen ions diffuse down their concentration gradient (Concentration gradients are a form of potential energy.)
Which of the following functions is NOT associated with the cytoskeleton in eukaryotic cells? A.maintaining the position of the nucleus in the cell B.the contraction of muscle cells in animals C.determining the shape of animal cells D.the beating of cilia or flagella E.Movement of RNA molecules from the nucleus to the cytoplasm
E.Movement of RNA molecules from the nucleus to the cytoplasm (RNA molecules exit the nucleus via nuclear pores.)
Step7:
Each electron "falls" down an electron transport chain from the primary electron acceptor of PS I to the protein ferredoxin (Fd)
Step4:
Each electron "falls" down an electron transport chain from the primary electron acceptor of PS II to PS I
A cell containing the following structures, ribosomes, plasma membrane and flagella, but without a nucleus, ER, or mitochnodria could be? Procaryotic Eucaryotic Either procaryotic or eucaryotic
Either procaryotic or eucaryotic
Which stage of glucose metabolism produces the most ATP? Glycolysis Krebs cycle Electron transport and chemiosmosis Fermentation of pyruvate to lactate
Electron transport and chemiosmosis (Electron transport and chemiosmosis (oxidative phosphorylation) can yield around 26 molecules of ATP.)
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment
Electron transport chain -The energy released as electrons are passed along the electron transport chain is used to pump protons into the thylakoid compartment.
Which statement regarding the light reactions is true?
Electrons are supplied to chlorophyll P680 as it reduces the primary electron acceptor.
Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.
Energized electrons from photosystem I are used to reduce NADP+
The energy for an endergonic reaction comes from a(n) _____ reaction. exergonic glucose + glucose --> maltose anabolic ADP + P --> ATP synthesis
Exergonic (The energy released by an exergonic reaction can be used to drive an endergonic reaction.)
Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell? Fermentation Glycolysis Electron transport chain Krebs cycle
Fermentation (Fermentation is an alternate pathway used when oxygen levels are low.)
The Calvin cycle has three phases:
Fixation Reduction Regeneration
Calvin Cycle Outputs
G3P
select the correct molecule that is the main product of the calvin cycle
G3P
Select the correct molecule that is the main product of the Calvin cycle. Glucose NADPH G3P
G3P (Glucose is discussed as the product of photosynthesis primarily for convenience. In fact, very little free glucose is produced by or transported from photosynthetic cells. Read about the Calvin cycle.)
What occurs during the second phase, the reduction phase, of the Calvin cycle?
G3P Production
The Fate of Sugar Produced by Photosynthesis
G3P molecules produced by the Calvin cycle are often used to make glucose and fructose, which can be combined to form sucrose. In rapidly photosynthesizing cells where sucrose is abundant, glucose is temporarily stored in the chloroplast as starch. Because starch is not water soluble, it is broken down at night and used to make more sucrose for transport throughout the plant.
Which of the following processes occurs during the second phase, the reduction phase, of the Calvin cycle?
G3P production
Which molecule is metabolized in a cell to produce energy for performing work? Phosphate ADP ATP Glucose
Glucose (Glucose is used to produce high-energy ATP in a cell.)
Based on your knowledge of cellular respiration, which is the correct ranking the following molecules from highest to lowest in terms of the amount of energy that they contain. Hint: think about the fact that all the reactions in cellular respiration are spontaneous. Pyruvic Acid, NADH + H+, ATP, Acetyl-CoA, Glucose Glucose, NADH + H+, ATP, Acetyl-CoA, Pyruvic Acid ATP, NADH + H+, Acetyl-CoA, Pyruvic Acid, Glucose Glucose, Pyruvic Acid , Acetyl-CoA, NADH + H+, ATP
Glucose, Pyruvic Acid , Acetyl-CoA, NADH + H+, ATP
Which step of the cellular respiration pathway can take place in the absence of oxygen? Glycolysis Krebs cycle Electron transport chain Fermentation
Glycolysis (Glycolysis can take place in the absence of oxygen; its product, pyruvate, enters the cellular respiration pathway or undergoes fermentation depending on the availability of oxygen.)
The process of transferring an electron to NADP+ also removes an ___ from the stroma
H+
What provides electrons for the light reactions?
H2O
Step 3:
H2O is split by enzymes, and the electrons are transferred from the hydrogen atoms to P680+, thus reducing it to P680
The oxidized form of FAD is reduced by adding Hydrogen protons neutrons Oxygen none of the above
Hydrogen
If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell? Isotonic Hypotonic Hypertonic Osmotic
Hypotonic (The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.)
The Regeneration Phase (CC)
If the Calvin Cycle did not go through a regeneration phase, the chloroplast would run out of the RuBP molecules required to make glucose. To make a single molecule of glucose and to regenerate RuBP, the cycle must run SIX times.
Step6:
In PS I (like PS II), transferred light energy excites P700, which loses an electron to an electron acceptor
pheophytin
In photosystem II, a molecule that accepts excited electrons from a reaction center chlorophyll and passes them to an electron transport chain.
The Fixation Phase (CC)
In the fixation phase, carbon dioxide from the atmosphere combines with a 5-carbon molecule called ribulose-bis-phosphate, or RuBP. This process, in which carbon dioxide is made usable to life by incorporating it into an organic molecule called carbon fixation. The product of the initial reaction is an unstable 6-carbon compound that splits to yield two 3 carbon molecules of 3 phosphoglycerate.
Which does the Calvin cycle occur?
In the stroma
Part A - Inputs and outputs of the light reactions From the following choices, identify those that are the inputs and outputs of the light reactions. (Recall that inputs to chemical reactions are modified over the course of the reaction as they are converted into products. In other words, if something is required for a reaction to occur, and it does not remain in its original form when the reaction is complete, it is an input.) Drag each item to the appropriate bin. If the item is not an input to or an output from the light reactions, drag it to the "not input or output" bin.
Input: light, water, NADP+, ADP Output: O2, ATP, NADPH not input or output: glucose, CO2,G3P In the light reactions, the energy of sunlight is used to oxidize water (the electron donor) to O2 and pass these electrons to NADP+, producing NADPH. Some light energy is used to convert ADP to ATP. The NADPH and ATP produced are subsequently used to power the sugar-producing Calvin cycle.
Part B - Inputs and outputs of the Calvin cycle From the following choices, identify those that are the inputs and outputs of the Calvin cycle. Drag each item to the appropriate bin. If the item is not an input to or an output from the Calvin cycle, drag it to the "not input or output" bin.
Input:ATP, NADPH, CO2 Output:ADP, NADP+, G3P not input or output:light, glucose, O2 In the Calvin cycle, the energy outputs from the light reactions (ATP and NADPH) are used to power the conversion of CO2 into the sugar G3P. As ATP and NADPH are used, they produce ADP and NADP+, respectively, which are returned to the light reactions so that more ATP and NADPH can be formed.
What is the potential benefit of photorespiration in plants?
It allows plant cells to reduce the buildup of oxygen gas without opening stomata
Which of the following is generally true about the stratosphere?
It is very dry.
Light Reactions Inputs
Light (energy), ADP, Pi, NADP, H2O
Which of the events listed below occurs in the light reactions of photosynthesis?
Light is absorbed and funneled to reaction-center chlorophy 2 a.
The reactions that produce sugar from carbon dioxide in the Calvin cycle are
Light-independent These reactions require the ATP and NADPH produced by the light-dependent reactions.
How can a lipid be distinguished from a sugar? Lipids are mostly saturated. A lipid is made up of only hydrocarbons. A lipid dissolves in water. Lipids are mostly nonpolar.
Lipids are mostly nonpolar. (Lipids are nonpolar molecules, whereas sugars are polar)
The overall function of the Calvin cycle is _____.
Making Sugar -Using the ATP and NADPH made during the light reactions, carbon is reduced in the Calvin cycle and sugar is made.
In a respiring mitochondrion the lowest hydrogen ion concentration would be expected to be found in the: Mitochondrial matrix Mitochondiral membrane space
Mitochondrial matrix
You are the CEO of a major manufacturing company that decides to use CFCs in production of your products. What are you failing to abide by?
Montreal Protocol
The energy used to produce ATP in the light reactions of photosynthesis comes from
Movement of H+ through a membrane
Oxygen is the final electron acceptor for cellular respiration. What is the final electron acceptor in the light reactions of photosynthesis?
NADP+
After 3-PGA is Phosphorylated, it is reduced by__.
NADPH
Which of the following molecules is the primary product of photosystem I? Oxygen Carbon dioxide NADPH ATP
NADPH The NADPH produced by photosystem I is used to supply energy for the production of sugars during photosynthesis.
Which of the following products of the light reactions of photosynthesis is consumed during the Calvin cycle?
NADPH -During the Calvin cycle electrons stored in NADPH are used to reduce carbon.
Which of the following molecules is the primary product of photosystem I?
NADPH -The NADPH produced by photosystem 1 is used to supply energy for the production of sugars during photosynthesis.
The light reactions of photosynthesis generate high-energy electrons, which end up in ______. The light reactions also produce ______ and _______.
NADPH; ATP; oxygen
The light reactions of photosynthesis generate high-energy electrons, which end up in __________. The light reactions also produce __________ and __________.
NADPH; ATP; oxygen
In the cyclic electron flow process no __ is released.
O2
When such plants close their stomata on hot, dry days to conserve water, ___ builds up in the leaf and is added to RuBP in place of CO2. A two-carbon product of this reaction is broken down to CO2, consuming ATP and generating no sugar.
O2
OIL RIG
Oxidation is Loss (of electron), Reduction is Gain (of electron)
In the light reactions of photosynthesis, ATP is produced by photophosphorylation. What process is the most similar to photophosphorylation?
Oxidative phosphorylation in cellular respiration
The reaction-center chlorophyll a of PS II is called
P680
Which term describes ATP production resulting from the capture of light energy by chlorophyll?
Photophosphorylation
Which term describes ATP production resulting from the capture of light energy by chlorophyll? Which term describes ATP production resulting from the capture of light energy by chlorophyll? Dephosphorylation Oxidative phosphorylation Substrate-level phosphorylation Photophosphorylation
Photophosphorylation (The excitation of chlorophyll by light energy initiates a chain of events that leads to ATP production.)
In C3 plants the conservation of water promotes__.
Photorespiration
Which process produces oxygen?
Photosynthesis
Which process produces oxygen?
Photosynthesis -Oxygen is a by-product of the photosynthesis process.
Which process produces oxygen?
Photosynthesis -Oxygen is a by-product of the photosynthetic process
How Does Photosystem I Work?
Pigments in the antenna complex absorb photons and pass the energy to the reaction center. Excited electrons from the reaction center of photosystem I are passed down an ETC of iron- and sulfur-containing proteins to ferredoxin. The enzyme NADP+ reductase transfers a proton and two electrons from ferredoxin to NADP+, forming NADPH. The photosystem itself and NADP+ reductase are anchored in the thylakoid membrane.
Hydrogen is a leading candidate in the search for a petroleum replacement. However, the hydrogen-generating reaction requires more energy than it produces. Why are plants considered to be one step ahead in the utilization of hydrogen as an alternative fuel source?
Plant cells possess water splitting enzymes
G3P is used in what processes?
Production of cell walls in growing plants, production of sucrose, production of glucose, production of starch, and production of cellulose
What is the biological significance of the light independent reactions of photosynthesis?
They convert carbon dioxide to sugar
The rough ER is the site of the production of: Proteins to be exported from the cell Enzymes to be used in the cytoplasm Lipids Microtubules
Proteins to be exported from the cell
According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis? According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis? Osmotic gradient Electrons Temperature gradient Proton gradient
Proton Gradient (A proton gradient across chloroplast and mitochondrial membranes drives ATP synthesis by the enzyme ATP synthase.)
According to the chemiosmotic hypothesis, What provides the energy that directly drives ATP synthesis?
Proton gradient
According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?
Proton gradient
_____ has a longer wavelength than _____.
Red ... green
_____ has a longer wavelength than _____.
Red has a longer wavelength than Green
__has a longer wavelength then__.
Red...Green
Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose?
Regeneration of RuBP -the regeneration of RuBP ensures that the Calvin Cycle can proceed indefinitely, since RuBP fixes carbon dioxide into an organic molecule that is used to produce sugar.
Which of the following reactions ensure that the Calvin cycle can make it continuous supply of glucose?
Regneration of RuBP
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
Carbon fixation involves the addition of carbon dioxide to__.
RuBP
Which of the following transporters does not use passive transport to move molecules across a membrane? Sodium-potassium pump Gramicidin ion channel Valinomycin GLUT-1 glucose transporter
Sodium-potassium pump (This pump uses the energy provided by ATP hydrolysis to transport sodium and potassium ions across the membrane.)
The light reactions (in the thylakoids)
Split H2O Release O2 Reduce the electron acceptor NADP+ to NADPH Generate ATP from ADP by photophosphorylation
Carbon dioxide and oxygen enter and exit a leaf by diffusion. Which structure(s) on a leaf allow(s) this process to happen?
Stomata
The Calvin Cycle occurs in the Stroma Matrix Cytoplasm
Stroma
Where does the Calvin cycle occur?
Stroma
Where does the Calvin cycle of photosynthesis occur?
Stroma
Where do the enzymatic reactions of the Calvin cycle take place?
Stroma of the chloroplast
Where does the Calvin cycle take place?
Stroma of the chloroplast
What is the primary function of the Calvin cycle?
Synthesize simple sugars from carbon dioxide.
If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm) be effective in driving photosynthesis?
The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective.
The Importance of Rubisco in the Fixation phase
The Calvin cycle begins when CO2 reacts with RuBP. This phase fixes carbon and produces two molecules of 3-phosphoglycerate.
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle depends on products of the light reactions.
Select the correct statement about the Calvin cycle
The Calvin cycle has three phases carbon fixation, reduction, and regeneration of RuBP.
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.
Where does the Calvin cycle occur?
The Calvin cycle occurs in the stroma.
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle requires products only produced when the photosystems are illuminated
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle requires products only produced when the photosystems are illuminated.
Reduction
The addition of electrons to a substance involved in a redox reaction.
Carbon fixation
The attachment of CO2 to an organic compound
Photosynthesis (def)
The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes.
wavelength
The distance between crests of waves, such as those of the electromagnetic spectrum.
Which statement describes the functioning of photosystem II?
The electron vacancies in P680+ are filled by electrons derived from water.
Step8:
The electrons are then transferred to NADP+ and reduce it to NADPH
Radiation
The emission of electromagnetic waves by all objects warmer than absolute zero
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.
Elecromagnetic spectrum
The entire spectrum of radiation ranging in wavelength from less that a nanometer to more than a kilometer.
What correctly describes the difference in carbon fixation between C3 and C4 plants?
The first product of carbon fixation in C4 plants is a four-carbon compound instead of a three-carbon compound
Which of the following statements correctly describes the difference in carbon fixation between C3 and C4 plants?
The first product of carbon fixation in C4 plants is a four-carbon compound instead of a three-carbon compound.
Stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
Which set of reactions uses H2O and produces O2?
The light-dependent reactions
thylakoids:
The internal membranes of chloroplasts that form flattened, vesicle-like structures grana:
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.
Which set of reactions uses H2O and produces O2?
The light dependent reactions.
What is the importance of the light- independent reactions in term of carbon flow in the biosphere?
The light independent reactions turn CO2, gas, unused carbon in the form of sugars.
The reactions that produce molecular oxygen (O2) take place in
The light reactions alone.
During which process is molecular oxygen produced in photosynthesis?
The light reactions by linear electron flow
Which set of reactions uses H2O and produces 02?
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 carbon dioxide, which is then used by the light-independent reactions. The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions. The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions. The light-independent reactions release energy, and the light-dependent reactions require energy.
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
Which set of reactions uses H₂O and produced O₂
The light-dependent reactions.
The Regulation of Photosynthesis
The rate of photosynthesis is finely tuned, to reflect changes in environmental conditions and use resources efficiently. For example, light triggers synthesis of photosynthetic proteins, and high sugar levels inhibit synthesis of photosynthetic proteins and stimulate production of proteins required for sugar processing and storage.
The Reduction Phase (CC)
The reduction phase begins when 3 phosphoglycerate is phosphorylated by ATP and concludes when it has been reduced by electrons from NAPDH. The product of the phosphorylated sugar glyceraldehyde 3 phosphate (G3P). Two G3P molecules are used to manufacture glucose.
Regeneration
The remaining G3P is used in reactions that regenerate RuBP.
The Importance of Rubisco in the Regeneration phase
The rest of the G3P keeps the cycle going by serving as the substrate for the third phase in the cycle: reactions that result in the regeneration of RuBP.
A red chemical dye known as phenol red changes to yellow when CO2 is present. A small green plant seedling is placed in phenol red and then placed in the dark. Which of the following is most likely to occur?
The solution is red to begin with, and it will turn yellow because respiration is occurring.
Light reactions
The steps in photosynthesis that occur on the thylakoid membranes of the chloroplast and that convert solar energy to the chemical energy of ATP and NADPH, evolving oxygen in the process.
When chloroplast pigments absorb light
Their electrons become excited
An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of about 490 nm is effective in driving photosynthesis. Based on this information and the absorption spectra shown at left, what role may chlorophyll b and carotenoids play in photosynthesis?
These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.
You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?
They absorb blue/green light and reflect yellow and red wavelengths of light.
Why are most autotrophs referred to as the producers of the biosphere?
They are the ultimate sources of organic compounds for all nonautotrophic organisms
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar. -All organisms use the sugars produced by photosynthesis to generate energy.
Over the course of one week you measure the amount of Carbon in the food consumed and absorbed by a person. You also measure the amount of Carbon in the CO2 that they exhale. During this time period the person loses 1.5 kgs of mass. Based on this you would expect. They exhaled less Carbon than they consumed/absorbed. They exhaled more Carbon than they consumed/absorbed. They exhaled the same amount of Carbon that they consumed/absorbed.
They exhaled more Carbon than they consumed/absorbed.
Why are C4 plants able to photosynthesize with no apparent photorespiration?
They use PEP carboxylase to initially fix CO₂
Plants are photoautotrophs. What does this mean?
They use light energy to drive the synthesis of organic molecules from inorganic materials.
How does carbon dioxide enter the leaf?
Through the stomata
The light reactions of photosynthesis use chemiosmosis to produce ATP that will be used in the Calvin cycle. The electrochemical gradient that drives this chemiosmosis is formed across which structure(s)?
Thylakoid membrane
In a plant cell, where are the ATP synthase complexes located?
Thylakoid membrane and inner mitochondrial membrane
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True -The water molecules are split to replenish electrons in photosystem 2, leaving behind protons, which are used to generate a proton gradient for the formation of ATP, and oxygen, which is released as a by product.
Both mitochondria and chloroplasts
Use chemiosmosis to produce ATP
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from
Water
Where do the electrons entering photosystem II come from?
Water
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?
While it did have access to light before you left, the plant stored energy in the form of sugars or starch, and it was able to derive energy from those during your vacation.
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?
While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.
Photosynthesis is a
a complex series of reactions
Electromagnetic radiation is
a form of energy.
An absorption spectrum is
a graph plotting a pigment's light absorption versus wavelength
When a pigment absorbs light, it goes from
a ground state to an excited state, which is unstable
The Z scheme
a model of how photosystems I and II interact.
Part D - Chloroplast structure and function In eukaryotes, all the reactions of photosynthesis occur in various membranes and compartments of the chloroplast. Identify the membranes or compartments of the chloroplast by dragging the blue labels to the blue targets. Then, identify where the light reactions and Calvin cycle occur by dragging the pink labels to the pink targets. Note that only blue labels should be placed in blue targets, and only pink labels should be placed in pink targets.
a) stroma- the dense fluid surrounded between the inner envelope membrane and the thylakoid membranes b) thylakoid membrane- the third membrane system; surrounds the thylakoid; chrorophyll resides in the thylakoid membrane c)cytosol- the fluid portion of cytoplasm surrounding (outside) the chloroplast d) location of Calvin Cycle- the calvin cycle occurs in the stroma e) thylakoid space- the space within the thylakoid sacs f)location of light reactions- the light reactions occur in the thylakoids of the chloroplast g) envelope membranes- the inner and outer membranes of the chloroplast The chloroplast is enclosed by a pair of envelope membranes (inner and outer) that separate the interior of the chloroplast from the surrounding cytosol of the cell. Inside the chloroplast, the chlorophyll-containing thylakoid membranes are the site of the light reactions. Between the inner envelope membrane and the thylakoid membranes is the aqueous stroma, which is the location of the reactions of the Calvin cycle. Inside the thylakoid membranes is the thylakoid space, where protons accumulate during ATP synthesis in the light reactions.
The carotenoids
absorb blue and green light and reflect and transmit yellow, orange, and red light.
The chlorophylls (chlorophyll a and chlorophyll b)
absorb red and blue light and reflect and transmit green light.
Biologists use a graph called an ________ to study pigments.
absorption spectrum This spectrum plots the wavelength of light absorbed by pigment molecules.
The Oxygen consumed during cellular respiration is directly involved in: the phosphorylation of ADP the Calvin Cycle the reduction of NAD+ accepting electrons at the end of the Electron Transport Chain the Kreb's Cycle Glycolysis
accepting electrons at the end of the Electron Transport Chain
Which of these is NOT a product of the citric acid cycle? NADH + H+ FADH2 acetyl CoA ATP CO2
acetyl CoA (Acetyl CoA enters the citric acid cycle)
Electrons from Pheophytin Enter
an ETC in the thylakoid membrane. This ETC is similar in structure and function to the ETC in mitochondria.
A photosystem consists of two major elements:
an antenna complex and a reaction center, as well as proteins that capture and process excited electrons.
When a photon strikes chlorophyll, its energy can be transferred to
an electron in the chlorophyll head. The electron becomes excited, raised to a higher energy state.
A chloroplast has
an envelope of two membranes surrounding a dense fluid
stroma is
an envelope of two membranes surrounding a dense fluid
ferredoxin
an iron sulfur protein that acts as another mobile electron carrier of the pathway; then transfers to the NADP+ reductase
If illuminated
an isolated solution of chlorophyll will fluoresce, giving off light and heat
Chloroplasts are structurally similar to
and likely evolved from photosynthetic bacteria
Purple non-sulfur and purple sulfur bacteria, with their single photosystem, cannot oxidize water and thus perform
anoxygenic photosynthesis.
In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary?
autotrophs
redox reactions result in protons
being pumped from one side of the membrane to the other. Proton concentration inside the thylakoid increases1000-fold.
Autotrophs are the producers of the ________producing organic molecules from CO2 and other inorganic molecules
biosphere
Generation of proton gradients across membranes occurs during
both photosynthesis and respiration.
Chlorophyll b
broaden the spectrum used for photosynthesis
Compared to C3 plants, C4 plants
can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations.
Based on size and charge which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? Insulin (a protein) Starch An amino acid Carbon Dioxide Glucose
carbon dioxide
Calvin Cycle Input: G3P Glucose ADP Carbon Dioxide NADP+
carbon dioxide
In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.
carbon dioxide
In crassulacean acid metabolism (CAM) plants,
carbon fixation and the Calvin cycle are separated in time. These plants, which also live in hot, dry habitats, keep their stomata closed all day and open them only at night.
The Calvin cycle begins with
carbon fixation, incorporating CO2 into organic molecules
Sugar made in the chloroplasts supplies chemical energy and
carbon skeletons to synthesize the organic molecules of cells
Carotenoids are classified into two groups:
carotenes and xanthophylls.
Accessory pigments called _________ absorb excessive light that would damage chlorophyll
carotenoids
In the Calvin cycle, the enzyme rubisco
catalyzes the addition of CO2 to a five-carbon compound. Subsequent reactions use the ATP and NADPH synthesized in the light reactions, yielding a molecule required for carbohydrate production.
Chloroplasts are found mainly in
cells of the mesophyll
Which of the following correctly matches an organelle with its function? central vacuole ... storage lysosome ... movement mitochondrion ... photosynthesis ribosome ... manufacture of lipids nucleus ... cellular respiration
central vacuole ... storage (But remember, plant cells have a central vacuole, whereas most animal cells have several smaller vacuoles located throughout the cytoplasm.)
The energy entering chloroplasts as sunlight gets stored as
chemical energy in organic compounds
Chloroplasts are solar-powered
chemical factories
Accessory pigments, such as
chlorophyll b
There are two major classes of pigments in plant leaves:
chlorophylls and carotenoids.
The photosynthetic membranes are found in the _____ in plant cells.
chloroplasts
The photosynthetic membranes are found in the _____ in plant cells.
chloroplasts - An elaborate system of interconnected thylakoid membranes segregates the stroma from the thylakoid space in the chloroplast.
Spatial organization of chemiosmosis differs between _________ and __________ but also shows ______.
chloroplasts mitochondria similarities
the photosynthetic membranes are found in the ____ in plant cells
choroplasts
what is the basic role of co2 in photosynthesis?
co2 is fixed or incorporated into organic molecules
violet-blue and red
colors most effective in driving photosynthesis
The photosystem's antenna complex is
composed of accessory pigment molecules. resonance-When a red or blue photon strikes a pigment molecule in the antenna complex, the energy is absorbed and an electron excited. This energy is passed to another chlorophyll molecule, exciting another electron.
The protons transported by plastoquinone result in a large
concentration of protons in the thylakoid lumen.
Photosynthesis is the
conversion of light energy to chemical energy stored in the bonds of carbohydrates. It consists of two linked sets of reactions.
Which of the following are photo autotrophs?
corn stalks just before harvest
The complementary process of cellular respiration
coverts oxygen and sugar into carbon dioxide and water. In the process some energy is released to make ATP, and the rest is lost as heat.
In cyclic electron flow the electrons
cycle back from Fd to the PS I reaction center
During the light reactions, there are two possible routes for electron flow:
cyclic and linear
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
cytoplasm
Stomata are normally open during the
day and closed at night.
Beginning with 1 molecule of glucose, in the presence of Oxygen , and assuming a mitochondrion with two fewer hydrogen ion pumps in the electron transport chain what would happen to the oxidative level phosphorylation production Decrease Stay the same Increase
decrease
Pigments that absorb blue and red photons are the most effective at
driving photosynthesis. Chlorophylls absorb these wavelengths - they are the main photosynthetic pigments.
Excited electrons in chloroplasts may
drop back down to a low energy state, causing fluorescence. excite an electron in a nearby pigment, inducing resonance. be transferred to an electron acceptor in a redox reaction.
protons diffuse down their
electrochemical gradient.
In both cellular respiration and photosynthesis, a(n)______ ______ _____ built into a membrane pumps H+ across the membrane as electrons are passed from one electron carrier to the next in a series of redox reactions. electron transport chain
electron transport chain
In cyclic electron flow
electrons cycle back from Fd to the PS I reaction center.
Photosynthetic reactions are linked by
electrons, which are released in the light-dependent reactions then uses these electrons and the potential energy in ATP to reduce CO2 to produce carbohydrates in the Calvin Cycle
Photosynthesis is an
endergonic process; the energy boost is provided by light
Photosynthesis is an _____ process in which carbon is _____, whereas cellular respiration is an _____ process in which carbon is _____ .
endergonic, reduced, exergonic, oxidized
How Does Photosystem II Work?
energy reaches the reaction center of the photosystem, the reaction center chlorophyll is oxidized a high-energy electron is donated to the electron acceptor pheophytin The electron is passed to an electron transport chain (ETC) in the thylakoid membrane, producing a proton gradient and driving ATP production via ATP synthase. This triggers chemiosmosis and ATP synthesis in the chloroplast.
Each photon and wavelength has a specific amount of
energy. The energy of a photon of light is inversely proportional to its wavelength. Shorter wavelengths such as ultraviolet light have more energy than longer wavelengths such as infrared light.
Photosystems I and II work together to produce an
enhancement effect, in which photosynthesis increases dramatically when cells are exposed to both red and far-red light.
rubisco
enzyme that catalyzes calvin cycle reaction
A primary electron acceptor in the reaction center accepts
excited electrons and is reduced as a result
Incoming photons of light energy initiate photosynthesis by _____.
exciting electrons in pigment molecules within the photosystems, raising them to a higher energy level
Select the INCORRECT association. exergonic ... uphill kinetic energy ... motion potential energy ... positional energy exergonic ... spontaneous enzyme ... protein
exergonic ... uphil (Exergonic reactions release energy.)
Photosystem I and ATP synthase are much more common in the
exterior, unstacked membranes
When excited electrons
fall back to the ground state, photons are given off, an afterglow called fluorescence
A researcher isolates a chloroplast and decreases the pH inside the individual thylakoids. Assuming that there is abundant light energy and CO2 and that there are no other changes to this chloroplast indicate whether the following statement if True or False. This chloroplast will produce more G3P or glucose than a control chloroplast under the same light and CO2 conditions True False
false
Based on the observations of the chemical reaction in the question above indicate whether the following statement is true or false. The products would be contain less heat energy than the reactant. True False
false
Based on the observations of the chemical reaction in the question above indicate whether the following statement is true or false. This reaction will be spontaneous. True False
false
Mitochondria transfer chemical energy from
food to ATP
Light is a
form of electromagnetic energy, from the light travels in the rythmic
the redox reactions that occur in the ETC result in protons being pumped
from one side of an internal membrane to another. The proton gradient that builds up drives ATP production via ATP synthase.
Heterotrophs obtain their organic material
from other organisms
Photosystem II (PS II)
functions first (the numbers reflect order of discovery) and is best at absorbing a wavelength of 680 nm
which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
Thylakoids form stacks called
grana
Integral proteins (those embedded in the membrane) would be expected to: have hydrophobic regions lack tertiary structure have no known functions in membranes be loosely bound to the bilayer exit and re-enter the membrane
have hydrophobic regions
chemiosmosis
how do chloroplasts create atp
9
how many molecules of atp consumed in calvin cycle
6
how many molecules of nadph consumed in calvin cycle
What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule? entropic dehydration synthesis anabolism hydrolysis dehydration decomposition
hydrolysis (Hydrolysis involves breaking bonds with the addition of water.)
h20 to 02
in the light reactions, light energy is used to oxidize _ to _
There are two types of photosystems
in the thylakoid membrane
In chloroplasts, the split of water and oxygen are
incorporating the electrons of hydrogen into sugar molecules and releasing oxygen as a by-product
The electron transport chain is part of the thylakoid membrane inner mitochnodrial membrane chloroplast membrane outer mitochnodrial membrane
inner mitochnodrial membrane
ATP NADPH co2
inputs of calvin cycle
light water NADP+ ADP
inputs of light dependent reaction
Photosystem I (PS I)
is best at absorbing a wavelength of 700 nm
As a result of its involvement in a reaction, an enzyme _____. loses a phosphate group loses energy is used up is unchanged permanently alters its shape.
is unchanged (Enzymes are not changed as a result of their participation in a reaction.)
Rubisco is 'inefficient' because although it does catalyze the addition of CO2 to RuBP,
it also catalyzes the addition of O2 to RuBP. Oxygen and carbon dioxide compete at the enzyme's active sites, which slows the rate of CO2 reduction.
which of the following describes the process of glycosis?
it represents the first stage in the chemical oxidation of glucose by a cell
chlorophyll a
key light capturing pigment, directly participates in light reactions
In muscle cells, fermentation produces _____. lactate and NAD+ carbon dioxide, ethanol, and NAD+ lactate, NADH, and ATP carbon dioxide, ethanol, NADH, and ATP pyruvate
lactate and NAD+ (these are the products)
Stomata are
leaf structures where gas exchange occurs. They consist of two guard cells that change shape to open or close. When a leaf's CO2 concentration is low during photosynthesis, stomata open to allow atmospheric CO2 to diffuse into the leaf and its cells' chloroplasts.
both I and II
light absorbtion and the reduction of primary electron acceptor happens in this photosystem
stroma
location of calvin cycle
thylakoid membrane
location of light dependent reaction
White blood cells known as macrophages, consume and digest foreign cells. The organelle involved in digesting the foreign cells is? Ribosomes Lysosme Peroxisome Nucleus ER
lysosme
The overall function of the Calvin cycle is _____.
making sugar
the overall function of the calvin cycle is ____
making sugar
The energy used to produce ATP in the light reactions of photosynthesis comes from __________.
movement of H+ through a membrane
In summary, light reactions generate ATP and increase the potential energy of electrons by
moving them from H2O to NADPH
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
neither photosynthesis nor respiration
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
neither photosynthesis nor respiration.
A molecule which is bound to a site other than the active site of an enzyme and causes a decrease in the rate of the reaction would be best described as a Non-competitive inhibitor Co-factor Competitive inhibitor Co-enzyme Allosteric activator
non-competitive inhibitor
The C4 pathway
occurs mostly in plants from hot, dry habitats, limits the damaging effects of photorespiration by spatially separating carbon fixation and the Calvin cycle. During carbon fixation, C4 plants incorporate CO2 into 4-carbon (C4) organic acids instead of 3-phosphoglycerate (performed by C3 plants).
Fluorescence
occurs when a pigment absorbs a photon and the electron gets excited, but then falls back to its ground state. Some of the absorbed energy is released as heat and the rest is released as electromagnetic radiation (light).
Heterotrophs are the consumers
of the biosphere
One turn of the Calvin cycle fixes
one molecule of CO2.
three turns of the Calvin cycle are required to produce
one molecule of glyceraldehyde 3-phosphate (G3P)
The most abundant lipids in most membranes are phospholipids triglycerides cholesterol glycolipids sterols
phospohlipids
Almost all heterotrophs, including humans, depend on
photoautotrophs for food and O2
Almost all plants are
photoautotrophs, using the energy of sunlight to make organic molecules
As a particle, light exists in discrete packets called
photons
The capture of light energy by photosystem II to produce ATP is called
photophosphorylation
In C3 plants the conservation of water promotes _____.
photorespiration
The apparently wasteful process described above is called _____ .
photorespiration
The ETC includes
plastoquinone (PQ), which shuttles electrons from pheophytin across the thylakoid membrane to a cytochrome complex.
Linear electron flow is the
primary pathway, involves both photosystems and produces ATP and NADPH using light energy
An action spectrum
profiles the relative effectiveness of different wavelengths of radiation in driving a process
In general, enzymes are what kinds of molecules? lipids carbohydrates proteins minerals nucleic acids
proteins
long wavelength low energy
red and orange colors are what wavelength and energy
In chloroplasts, protons are
pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma
In mitochondria, protons are
pumped to the intermembrane space and drive ATP synthesis as they diffuse back into the mitochondrial matrix
short wavelength high energy
purple and blue colors are what wavelength and energy
In fermentation _____ is reduced and _____ is oxidized. pyruvate ... NADH NAD+ ... pyruvate lactate ... NADH NADH ... lactate lactate ... ethanol
pyruvate ... NADH (The pyruvate from glycolysis is reduced to either lactate or ethanol, and NADH is oxidized to NAD+.)
An action spectrum shows the
rate of photosynthesis vs. wavelength.
The NADPH required for the Calvin cycle comes from
reactions initiated in photosystem 1
Carbon fixation is catalyzed by...
rubisco
In all three types of plants, the enzyme _____ brings CO2 into the Calvin Cycle.
rubisco
Photorespiration may be an evolutionary relic because
rubisco first evolved at a time when the atmosphere had far less O2 and more CO2
In C4 plants, the reactions catalyzed by PEP carboxylase and rubisco are separated in
space
Chloroplasts
split H2O into hydrogen and oxygen
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting of water molecules
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules.
When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.
splitting water; -The electrons removed from water are transferred to P680.
Thylakoids may be ______ in columns.
stacked
Grana are ...
stacks of of thylakoids in column
Plants store excess sugar as
starch in structures such as roots, tubers, seeds, and fruits
CO2 enters and O2 exits the leaf through microscopic pores called
stomata
In the citric acid cycle, ATP molecules are produced by _____. cellular respiration photosynthesis oxidative phosphorylation photophosphorylation substrate-level phosphorylation
substrate-level phosphorylation (A phosphate group is transferred from GTP to ADP.)
In glycolysis, ATP molecules are produced by _____. photophosphorylation oxidative phosphorylation substrate-level phosphorylation photosynthesis cellular respiration
substrate-level phosphorylation (A phosphate group is transferred from glyceraldehyde phosphate to ADP.)
The Calvin cycle (in the stroma) forms
sugar from CO2, using ATP and NADPH
The ultimate source of energy to support most life on Earth is _____.
sunlight
Photosynthesis requires
sunlight, carbon dioxide, and water, and produces oxygen as a by-product.
The electrons of NADPH are available for the reactions of ___ ______ _____.
the Calvin cycle
In C3 photosynthesis, the reactions that require ATP take place in
the Calvin cycle alone
Reactions that require CO2 take place in
the Calvin cycle alone.
Rubisco is found in all photosynthetic organisms that use
the Calvin cycle to fix carbon, and is thought to be the most abundant enzyme on Earth.
In addition to food production, photosynthesis produces
the O2 in our atmosphere
in cellular respiration a series of molecules forming an electron transport chain alternately....what is the advantage of such an electron transport chain?
the advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates
NADPH to NADP +
the calvin cycle oxidizes the light reactions product _ to _
chloroplasts transform light energy into
the chemical energy of ATP
Chloroplasts thylakoids transform light energy into
the chemical energy of ATP and NADH
The structural organization of these organelles allows for
the chemical reactions of photosynthesis
which of the following statements about the chemiosmotic synthesis of ATP is correct?
the chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane
Photosynthesis occurs in
the chloroplasts of green plants, algae, and other photosynthetic organisms.
Solar-powered transfer of an electron from a chlorophyll a molecule to the primary electron acceptor is
the first step of the light reactions
Chemiosmosis results when
the flow of protons through ATP synthase causes a change in its shape, driving the phosphorylation of ADP.
Cells of the mesophyll are
the interior tissue of the leaf
which statement about the citric acid cycle is correct?
the last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle
Which set of reactions uses H2O and produces O2? The light-dependent reactions The light-independent reactions
the light dependent reactions
Photosynthesis consists of
the light reactions (the photo part) and Calvin cycle (the synthesis part)
Chlorophyll a is
the main photosynthetic pigment
The tail of chlorophylls keeps
the molecule embedded in the thylakoid membrane.
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
the stroma to the thylakoid space.
The Calvin Cycle occurs in
the stroma.
When chloroplast pigments absorb light, __________.
their electrons become excited
C4 plants occur more commonly in desert conditions because _____.
they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed
C4 plants occur more commonly in desert conditions because _____.
they can fix carbon at the lower CO₂ concentrations that develop when the stomata are closed. -To conserve water during hot, dry conditions, the stomata are fully or partially closed, preventing CO₂ from reaching high concentrations.
c4 plants occur more commonly in desert conditions because ____
they can fix carbon at the lower co2 concentrations that develop when the stomata are closed
For net synthesis of 1 G3P, the cycle must take place______ times.
three
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
The light-harvesting complexes
transfer the energy of photons to the reaction center
At the reaction center, excited electrons are
transferred to a specialized chlorophyll molecule that acts as an electron acceptor. When this electron acceptor becomes reduced, the electromagnetic energy is transformed to chemical energy.
NADP+ reductase
transfers a proton and two electrons from ferredoxin to NADP+, forming NADPH.
Which membrane protein would be used to move glucose across a membrane from a region of higher concentration to a region of lower concentration? Ion channel No protein is necessary. Transporter Pump
transporter (The GLUT-1 transporter assists the diffusion of glucose through the membrane.)
Based on the preceding two questions indicate whether the following statement is True or False. If the researcher also increased the concentration of NADPH +H+ in the stroma of the experimental chloroplast, but not the control, the experimental chloroplast would produce more G3P or glucose. True False
true
Based on the previous question indicate whether the following statement is True or False. The experimental chloroplast will produce more ATP than the control chloroplast. True False
true
During a chemical reaction you observe that there is an increase in enthalpy and a decrease in the entropy. Based on these observations please indicate whether the following statement about this reaction is true or false. The products of this reaction are more organized than the reactants. True False
true
You introduce cyanide to an actively respiring mitochondrion. Cyanide blocks the transfer of electrons from the last cytochrome in the ETC to Oxygen. Based on your understanding of cellular respiration would the following statements be true or false? The pumping of Hydrogen ions from the matrix to the space between the mitochondrial membranes would decrease. True False
true
True or false? Osmosis is a type of diffusion. True False
true (Osmosis is the diffusion of water across a selectively permeable membrane.)
True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group. True False
true (The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.)
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen. True False
true (The water molecules are split to replenish electrons in photosystem II, leaving behind protons, which are used to generate a proton gradient for the formation of ATP, and oxygen, which is released as a by-product.)
in the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glucose?
two ATP
During the light reactions, there are
two possible routes for electron flow: cyclic and linear
In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
ultraviolet radiation and infrared radiation
in the electromagnetic spectrum, the type of radiation that we call visible light occurs between...
ultraviolet radiation and infrared radiation
In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
ultraviolet radiation and infrared radiation -Visible light is a narrow band of the electromagnetic spectrum that lies between ultraviolet radiation and infrared radiation.
The cycle builds sugar from smaller molecules by
using ATP and the reducing power of electrons carried by NADPH
Photosynthesis is the process of
using sunlight to produce carbohydrates.
The absorption spectrum of chlorophyll a suggests that
violet-blue and red light work best for photosynthesis
Electromagnetic radiation that humans can see is called
visible light.
Where do the electrons entering photosystem II come from?
water
Carotenoids absorb
wavelengths of light not absorbed by chlorophyll, thus extending the range of wavelengths that can drive photosynthesis. They also stabilize free radicals, protecting chlorophylls from damage.
yellows and greeens
what colors on are on the visible light wavelength
c02
what input of calvin cycle doesnt come from light reaction?
h+ (protons)
what is pumped across electron transport chain to make potential energy
02
what output of light reaction doesnt go to calvin cycle?
electron transport chain
where does chemiosmosis occur
Autotrophs sustain themselves
without eating anything derived from other organisms
What two molecules are produced by the light reactions and used to power the Calvin cycle?
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
the light reactions of photosynthesis supply the calvin cycle with
ATP and NADPH
Non-cyclic photophosphorylation produces (outputs)? NADPH + H+ G3P ATP and NADPH + H+ ATP all of the above
ATP and NADPH + H+
The Calvin cycle could not occur without the light reactions. Which of the following statements describes why this is the case?
ATP and NADPH produce in the light reactions provide the energy for the production of sugars in the Calvin cycle
The Calvin cycle could not occur without the light reactions. What 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.
Which of these phosphorylates ADP to make ATP?
ATP synthase phosphorylates ADP.
In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? A.redox B.cellular respiration C.potentiation D.anabolism E.digestion
B. cellular respiration
Part C - Redox reactions of photosynthesis In photosynthesis, a redox compound that is produced in the light reactions is required to drive other redox reactions in the Calvin cycle, as shown in this figure along with other components of photosynthesis. Drag the terms to the appropriate blanks to complete the following sentences summarizing the redox reactions of photosynthesis. Terms may be used once, more than once, or not at all.
1. In the light reactions, light energy is used to oxidize H2O to O2. 2. The electrons derived from this oxidation reaction in the light reactions are used to reduce NADP+ to NADPH. 3. The Calvin cycle oxidizes the light-reactions product NADPH to NADP+. 4. The electrons derived from this oxidation reaction in the Calvin cycle are used to reduce CO2 to G3P. In the light reactions, light energy is used to remove electrons from (oxidize) water, producing O2 gas. These electrons are ultimately used to reduce NADP+ to NADPH. In the Calvin cycle, NADPH is oxidized back to NADP+ (which returns to the light reactions). The electrons released by the oxidation of NADPH are used to reduce three molecules of CO2 to sugar (G3P), which then exits the Calvin cycle.
Cyclic electron flow uses only photosystem I and produces ___, but not _____.
ATP NADPH
Five dialysis bags, with membranes impermeable to sucrose, were filled with various concentrations of sucrose as follows: Bag #1 = 0.1 M sucrose Bag #2 =0.2 M sucrose Bag #3 = 0.3 M sucrose Bag #4 = 0.4 M sucrose Bag #5 = 0.5 M sucrose The bags were all weighed and then placed in separate beakers each containing an initial concentration of 0.6 M sucrose solution. After 30-minute the bags were removed weighed again and the percent change in mass of each bag was calculated. Which of the following statements would correctly reflect the outcome of this experiment? A. All the bags weighed less because they lost water. B. All the bags weighed less because they lost sucrose. C. All the bags weighed the same as at the start of the experiment. D. All the bags weighed more because they gained water. E. All the bags weighed more because they gained sucrose.
A. All the bags weighed less because they lost water.
Which of the following are common traits of chloroplasts and mitochondria? A. Both have their own DNA. B. Both reproduce by meiosis. C.Both are found in plant and animal cells. D. Both are surrounded by a single membrane. E.Proteins for both are synthesized on ribosomes in the rough ER.
A. Both have their own DNA. (Mitochondria and chloroplasts contain their own DNA and ribosomes.)
What distinguishes facilitated diffusion from simple diffusion? A.Membrane proteins help move molecules across the membrane. B.Molecules move from a region of lower concentration to a region of higher concentration. C.Molecules move from a region of higher concentration to a region of lower concentration. D.No energy is used to move molecules across the membrane.
A. Membrane proteins help move molecules across the membrane. (Membrane proteins facilitate the movement of molecules across the membrane)
Which of the following statements is true about the net movement of an ion across a membrane by passive diffusion through a membrane channel? A.The charge on the other side of the membrane is generally the opposite of the ion's charge. B.The cell expends energy as the ion passes through the membrane. C.For every ion that diffuses through the membrane, a different ion diffuses in the opposite direction. D.There is a higher concentration of ions on the side of the membrane toward which the ion diffuses.
A.The charge on the other side of the membrane is generally the opposite of the ion's charge. (Ions tend to move toward regions of unlike charge)
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is filled with a solution of 1 M sucrose and 1 M glucose. Side B is filled with 1 M sucrose and 2 M glucose. After the system reaches equilibrium, what changes are observed? A.The water level is unchanged B.The molarity of glucose is higher in side A than inside B. C.The molarity of sucrose is increased inside A. D.The water level is higher in side A than in side B. E.The molarity of sucrose equals the molarity of glucose on both sides
A.The water level is unchanged
The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following? A.cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis B.passive diffusion of the glucose through the lipid bilayer C.movement of glucose into the cell through a glucose channel D.receptor-mediated endocytosis E.facilitated diffusion of the glucose using a carrier protein
A.cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis (Movement of most solutes against their concentration gradient couples the movement of one solute down its concentration gradient to the movement of another (glucose in this case) against its concentration gradient.)
The reaction ADP + P --> ATP is a(n) _____ reaction. A.spontaneous B.endergonic C.hydrolysis D.exergonic E.chemical
B. Endergonic (Energy has been acquired from the surroundings.)
Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration? A. The function of the bonding of acetic acid to the carrier molecule CoA to form acetyl CoA is the reduction of glucose to acetyl CoA. B. The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP. C. The function of the citric acid cycle is the transfer of electrons from pyruvate to NADH to O2.
B. The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP. (Glycolysis is the first stage in cellular respiration and does not depend on the presence of oxygen.)
Which of the following factors does not affect membrane permeability? A.The saturation of hydrocarbon tails in membrane phospholipids B.Temperature C.The polarity of membrane phospholipids D.The amount of cholesterol in the membrane
C.The polarity of membrane phospholipids (Phospholipids contain both a polar head and a nonpolar hydrocarbon tail, both of which are necessary for their ability to form membrane bilayers.)
Which of these reactions requires a net input of energy from its surroundings? A.catabolic B.exergonic C.endergonic D.hydrolysis E. ATP --> ADP + P
C.endergonic (The products of endergonic reactions have more potential energy than the reactants.)
Which of these are by-products of cellular respiration? A. ATP and carbon dioxide B.carbon dioxide and water C.heat, carbon dioxide, and water D.glucose, carbon dioxide, and water E. ATP, carbon dioxide, and water
C.heat, carbon dioxide, and water
Enzymes work by _____. A.adding a phosphate group to a reactant B.decreasing the potential energy difference between reactant and product C.reducing EA D.increasing the potential energy difference between reactant and product E.adding energy to a reaction
C.reducing EA (EA= energy of activation)
In _____ plants, the first product of carbon fixation is the 3-carbon compound 3-PGA formed in the Calvin Cycle.
C3
During electron transport, energy from _____ is used to pump hydrogen ions into the _____. NADH ... intermembrane space acetyl CoA ... intermembrane space NADH and FADH2 ... intermembrane space NADH ... mitochondrial matrix NADH and FADH2 ... mitochondrial matrix
NADH and FADH2 ... intermembrane space (The energy released as electrons, which have been donated by NADH and FADH2, is passed along the electron transport chain and used to pump hydrogen ions into the intermembrane space.)
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose?
Regneration of RuBP
Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose? Carbon fixation Production of 3-phosphoglycerate Regneration of RuBP Production of G3P
Regneration of RuBP
Select the most accurate statement describing the basic function of the light reactions of photosynthesis. The basic function of the light reactions of photosynthesis is the trapping of light energy. The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy. The basic function of the light reactions of photosynthesis is the production of glucose.
The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy.
Select the most accurate statement describing the basic function of light reactions of photosynthesis
The basic function of light reactions of photosynthesis is the conversion of solar energy to chemical energy.
Which of the following statements best describes the relationship between the light-independent in the light independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
Calvin Cycle (occurs in the Stroma)
The light-independent component of photosynthesis, in which carbon dioxide is reduced to form sugars. The carbohydrates produced by the Calvin cycle are used in cellular respiration to make ATP for the cell.
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.
The light reactions of photosynthesis occur in the
Thylakoids
Plants Must Balance
Water Preservation and CO2 Delivery
Metabolic pathways are typically redox processes. In photosynthesis, what molecule is oxidized and what molecule is reduced?
Water is oxidized and carbon dioxide is reduced.
The light reactions of photosynthesis use __and produce ___.
Water...NADPH
oxygenic photosynthesis
When Photosystem II "splits" water to replace its lost electrons and in the process produces oxygen Photosystem II is the only known protein complex able to oxidize water in this way.
When O2 and RuBP react in rubisco's active site, one of the products undergoes a process called
photorespiration. Photorespiration "undoes" photosynthesis because it consumes energy and releases fixed CO2.
Dehydration is a problem for plants, sometimes requiring trade-offs with other metabolic processes, especially _______________.
photosynthesis
When photorespiration occurs, the rate of _____ declines drastically
photosynthesis
Which process produces oxygen? Cellular respiration Photosynthesis
photosynthesis
light energy - photosynthesis - organic molecules and o2 - cellular respiration - co2 and h20
photosynthesis flow in ecosystem
leaf - mesophyll cells - chloroplasts - thylakoid membranes - stroma
photosynthesis flow in plants
The photosystem itself and NADP+ reductase are anchored in the
thylakoid membrane.
Where are the molecules of the electron transport chain found in plant cells?
thylakoid membranes of chloroplast
The light reactions of photosynthesis occur in the __________.
thylakoids
Chloroplasts are surrounded by two membranes:
thylakoids: The internal membranes of chloroplasts that form flattened, vesicle-like structures grana: stroma: The fluid-filled space between the thylakoids and the inner membrane
The light reactions take place in the _________ and the Calvin cycle takes place in the _________.
thylakoids; stroma
In CAM plants the reactions catalyzed by PEP carboxylase and rubisco are separated in
time
The difference in the absorption spectrum between chlorophyll a and b is due
to a slight structural difference between the pigment molecules
The light reactions of photosynthesis use _____ and produce _____. The light reactions of photosynthesis use _____ and produce _____. carbon dioxide ... sugar water ... NADPH NADPH ... oxygen NADPH ... NADP+ carbon dioxide ... oxygen
water ... NADPH (NADPH is a reactant in the Calvin cycle.)