Connect Ch 8-Photosynthesis
During the electron transport stage of the thylakoid reactions electrons are shuttled along a series of electron carrier molecules, eventually reaching the final acceptor. This final acceptor is
NADP+
The ATP needed in the Calvin cycle comes from
both cyclic and noncyclic photophosphorylation
The first two stages of photosynthesis require light and are commonly known as the light- ___reactions.
dependent
The light- ___ reactions of photosynthesis occur on membranes.
dependent
The ATP synthases of chloroplasts and mitochondria are
evolutionary related
In a leaf, the thick layer of cells that are rich in chloroplasts is called the ___.
mesophyll
The removal of electrons from certain molecules by a beam of light is also known as the ___ effect.
photoelectric
Which photosystem's main function is to generate high-energy electrons for the synthesis of ATP?
photosystem
Photosynthetic pigments in the chloroplast are organized into distinct clusters known as
photosystems
Pigment molecules capturing photons in the chloroplast are organized in distinct structures called ___.
photosystems
Molecules that can absorb light in the visible range are called ___.
pigments
In bacteria, light-dependent reactions take place in which of the following?
plasma membrane
When light strikes a pigment, some wavelengths are absorbed and some are reflected. For instance, a leaf that appears green to the eye ___ green wavelengths of light.
reflects
A Z diagram illustrates how many electron-energizing steps?
two
What is split during photosynthesis in plants resulting in the production of oxygen?
water
The __ diagram describes the energy transitions of electrons as they move through the __ reactions.
Z diagram light reactions
Why is the Calvin cycle also known as C3 photosynthesis?
Because the first molecule in the cycle has 3 carbon atoms.
Why are the cyclic reactions in carbon fixation also referred to as light-independent reactions?
Because they can occur whether or not light is present.
In which type of plant does carbon dioxide capture occur at night, and decarboxylation occur during the day?
CAM plants
What does the stroma of the chloroplast contain?
Enzymes needed for carbon fixation.
Glyceraldehyde 3-phosphate formed during the Calvin cycle is an important compound in which of the following stages of cell respiration?
Glycolysis
In van Niel's generalized equation of photosynthesis, which of the following is the donor of electrons?
H2A
Where do the light-dependent reactions of photosynthesis occur in the chloroplast?
In the thylakoid membrane.
In the equation that summarizes photosynthesis, if 6 carbon dioxide + 12 water + light are the reactants, what are the products?
-6 water -6 oxygen -glucose
Which of the following are chloroplast membranes?
-An inner membrane -An outer membrane -The thylakoid membrane
Which of the following are used by green plants to absorb light energy?
-Chlorophyll b -Chlorophyll a
Which of the following plants are C4 plants?
-Sorghum -Corn -Sugarcane
Which of these statements are true about the relationship between photosynthesis and cell respiration?
-The products of cell respiration are the reactants of photosynthesis. -The products of photosynthesis are the reactants of cell respiration.
NADP reductase accepts two electrons from two molecules of __ and catalyzes the production of __.
-ferredoxin -NADPH
In the reaction center, excited ___(is)are transferred out of the photosystem.
electrons
Sequence the phases of the Calvin cycle from first (on top) to last.
1. carbon fixation 2. reduction and carbohydrate production 3. regeneration of ribulose bisphosphate
___molecules of G3P made during the Calvin cycle can be used to make one molecule of ___.
2 G3P glucose
The following diagram represents light absorption as a function of wavelength of various pigments. The pigment represented by the dotted line will absorb most strongly light with which of the following wavelengths?
470 nm
How many molecules of CO2 need to be bound to molecules of RuBP to produce 12 molecules of PGA in the Calvin cycle?
6
When added to light in photosynthesis, how many molecules of carbon dioxide and water are needed to make one molecule of glucose?
6 CO2 and 12 H2O
Photophosphorylation produces ____ , which stores chemical energy that can be used for the Calvin cycle. Carbon fixation also requires reducing power, which is provided by ____ produced by photosystem I.
ATP NADPH
The electron transport chain directly associated with photosystem II is used to generate __, while the electron transport chain directly associated with photosystem I is used to generate __.
ATP NADPH
Why do hot and dry conditions favor photorespiration?
Because plants close their stomata, inhibiting CO2 uptake and increasing O2
Plants that only fix carbon using the Calvin cycle are also known as ___ plants.
C3
The Calvin cycle is also known as ___ photosynthesis because the first intermediate of the cycle contains three carbon atoms.
C3
In which type of plant does carbon dioxide capture occur in one cell, and decarboxylation occur in an adjacent cell?
C4
___plants avoid water loss by closing their stomata during the day and opening them at nigh
CAM
According to the generalized equation for photosynthesis proposed by van Niel, CO2 + 2H2A + light energy yields which of the following?
CH2O + H2O + 2A
Which of the following is an accurate description of carotenoids?
They are made of carbon rings connected to carbon chains with alternating single and double bonds.
Which of the following (choose all that apply) are necessary for carbon fixation in the Calvin cycle?
NADPH and ATP
A beam of light can remove electrons from certain molecules, creating electrical current. What is this phenomenon called?
Photoelectric effect
In the Calvin cycle CO2 is attached to an organic molecule abbreviated as ___
RuBP
Which of the following statements about radiation is TRUE?
Shorter-wavelength radiation carries more energy per unit of time than longer-wavelength radiation.
The following diagram represents light absorption as a function of wavelength of various pigments. Which of the three pigments might reflect a yellow or red color?
The pigment represented by the gray line
What is the function of the b6-f complex?
To pump protons in the thylakoid space
A particle of light that acts as a discrete bundle of energy is called
a photon
The formation of organic molecules from carbon dioxide is called
carbon fixation
The Calvin cycle begins with
carbon fixation using Rubisco
During the fourth stage of the thylakoid reactions, known as ___ , protons flow across the membrane down their gradient and in the process ATP is synthesized.
chemiosmosis
Green plants utilize ___ a and b to absorb light energy in photosynthesis.
chlorophyll
Where is rubisco located?
chloroplast stroma
The electron that is transferred out of the chlorophyll in the reaction center is restored from a nearby weak electron ___.
donor
True or false: The light-dependent reactions of photosynthesizing bacteria take place in the chloroplasts.
false
True or false: Glucose is the primary output of the Calvin cycle.
false The primary output of the Calvin Cycle is G3P. Two molecules of G3P can then be used to make glucose.
Longer wavelength radiation contains ___ energy per unit time than shorter wavelength radiation.
less
The cyclic reactions in carbon fixation do not require which of the following?
light
The role of the ___ light-harvesting complex is to directly absorb photons of light
light
Similar to other pigments, carotenoids assist photosynthesis by capturing energy from ___ , however, they absorb wavelengths that are not efficiently absorbed by ___ . In addition, they scavenge ___radicals.
light chlorophylls free radicals
In chloroplasts, electrons ejected from the photosystems do not return to them, which is known as
noncyclic photophosphorylation.
The abbreviation, RuBP, stands for ___ 1,5-bisphosphate.
ribulose
What is the name of the enzyme that incorporates CO2 into organic matter during the Calvin cycle?
rubisco
The range and efficiency of photons that a pigment molecule is capable of absorbing constitute its characteristic absorption ___.
spectrum
The chloroplast's ___ contains enzymes needed to assemble organic molecules from CO2.
stroma
The energy used by most living cells comes ultimately from the ___and is captured through the process of ___.
sun and photosynthesis
As protons pass through the ATP ___ channels, ADP is phosphorylated to ATP and released into the ____ of the chloroplast.
synthase stroma
Once a photon is captured by the light harvesting complex, the pigments in it transfer
the energy of excited electrons but not electrons themselves
What is ultimately the main source of energy for almost all living cells on Earth?
the sun
How are the equation for photosynthesis in plants and the equation for cellular respiration related?
they are reverse
In a chloroplast, chlorophyll molecules that capture light energy are found in the internal, or inner membrane, which is also called the ___ membrane.
thylakoid
The ___ membrane contains pigment molecules, including chlorophyll.
thylakoid
The function of the b6-f complex is to pump protons into the ___ space.
thylakoid
The ATP synthase enzymes of chloroplasts are located in the
thylakoid membrane.
How many types of photosystems are found in chloroplasts?
two
In photosynthesis, CO2 is reduced to glucose using electrons from the oxidation of ___ ; in respiration, ___is oxidized to CO2 using O2 as the final electron acceptor.
water and glucose
What molecule is released during photorespiration?
carbon dioxide
In C4 plants PEP carboxylase is only active in ___ cells.
mesophyll
Which are the two most important kinds of pigments in chloroplasts?
Chlorophylls and carotenoids
What is transferred out of the reaction center?
Excited electrons
During photosynthesis, a chlorophyll in the reaction center loses its excited electron. How is that electron restored?
From a nearby weak electron donor.
Which of the following statements best describes the properties of light?
Light has properties of both a particle and a wave.
The synthesis of NADPH is catalyzed by which of the following?
NADP+ reductase
Which of the following is made during the light-dependent stages of photosynthesis?
NADPH
A leaf that appears to be green to the human eye contains pigment molecules that are
reflecting green light
Pigments are molecules that
absorb light in the visible range
A graph depicting the efficiency of photon absorption by a pigment molecule as a function of photon wavelength is known as the
absorption spectrum of the pigment
A photosystem consists of two components, a(n) ___ complex and a(n) ___center.
antenna complex and reaction center
A C3 plant
can only fix carbon using the Calvin cycle
___ are accessory photosynthetic pigments that consist of carbon rings linked to chains with alternating single and double bonds.
caotenoids
A photon of light has properties of both
particle and a wave
The energy content of a is inversely proportional to the wavelength of the light.
photon
The enzyme rubisco has more than one activity. Because of this, most plants also perform ____ , which consumes oxygen and liberates carbon dioxide. This process can lower the net benefit from photosynthesis.
photorespiration
How many molecules of G3P are needed to make one molecule of glucose?
2
Typically, it is considered that the net gain of the Calvin cycle is(are) ____ molecule(s) of G3P.
2
In the Calvin Cycle, ___ molecules of CO2 are bound to the same number of RuBP molecules to produce 12 molecules of PGA
6
What happens during the chemiosmosis stage of the thylakoid reactions?
ATP is synthesized.
How do carotenoids assist in the photosynthetic process?
By capturing light wavelengths that are not efficiently absorbed by chlorophylls.
The synthesis of ATP during the light reactions in anoxygenic bacteria is achieved as the electron that was transferred out of the photosystem returns to the chlorophyll molecule in the reaction center; this is also known as ___ photophosphorylation.
cyclic
In anoxygenic bacteria, excited electrons that are transferred out of the photosystem eventually return back to the chlorophyll in the reaction center; this process is known as
cyclic photophosphorylation
Protons are pumped across the thylakoid membrane of the chloroplast during the ___ ___ stage of the thylakoid (or light-dependent) reactions.
electron transport
In the reaction center which of the following excited subatomic particles are transferred to an acceptor?
electrons
In the light-harvesting complex of the chloroplast, it is excitation ___ , not the electrons themselves, that pass from one pigment molecule to the next. Listen to the complete question
energy
True or false: The mechanism of ATP synthesis in the ATP synthase of chloroplasts is fundamentally different from the one used in the ATP synthase of mitochondria.
false the 2 enzymes use basically the same mechanism
The process in which electrons from water move through PSII and PSI and ultimately to NADPH is also known as ___ photophosphorylation.
noncyclic
In a green plant, the majority of photosynthesis takes place in __.
the leaves
The oxygen produced by plants during photosynthesis comes from the splitting of ___molecules.
water
Which of the following are the two components of a photosystem?
-reaction center -antenna complex
Which of the following are parts of the chloroplast?
-thylakoids -stroma -grana -inner membrane