Biology Exam 2 photosynthesis
NADPH
A key role of PSI is to produce high-energy electrons that are used to make _______.
ATP
A major purpose of the electrochemical gradient generated in the light reactions of photosynthesis is to synthesize _____________.
pigment
A molecule that can absorb light energy is called a(n) ________.
absorb light
A pigment is a molecule that can ______.
glucose
A product of the Calvin cycle is used to produce _________ molecules that may be linked together to form a polysaccharide called starch.
light energy
Electrons in the pigment molecules of photosystems I and II are excited by _________.
decreases
As water is oxidized during photosynthesis, the pH of the thylakoid lumen ______.
Homologous
Genes that are derived from the same ancestral gene, and thus are similar to each other, are termed ______ genes.
Chlorophyll
Plants appear green because they contain _______,
energy
Sunlight enables the synthesis of glucose from carbon dioxide by providing the ________ that is necessary for the process.
water temperature
The Calvin cycle is affected by certain environmental conditions, including light intensity, ______availability, and ___________.
ATP electrons
The calvin cycle uses energy from ______, and high- energy ____ supplied by NADPH.
electrons
The light reactions of photosynthesis require water to supply two _______ that are transferred to P680+.
pigment
The light-harvesting complex is composed of several dozen ________ molecules that are anchored to transmembrane proteins.
Z
The model for photosynthesis that incorporates two photoactivation events and shows the series of energy changes during the light reactions of photosynthesis is called the ___ scheme.
carotenoids
The pigment molecules that cause autumn leaves to appear yellow and orange are called ____________.
NADPH and ATP
The products of the light reactions that are used by the Calvin cycle to make carbohydrates are ________.
stroma
The reactions of the Calvin cycle occur in the ______.
directly absorb photons of light
The role of light- harvesting complex is to ______,
O2, NADPH, ATP
The steps of the light reactions of photosynthesis yield three major products: _________, ________, and __________.
Light energy is converted to electrochemical energy, which is converted to chemical energy.
What energy conversion occurs during photosynthesis?
Rubisco attaches O2 to RuBP and CO2 is produced
What happens during photorespiration?
Plants capture energy from sunlight and use it to synthesize organic molecules.
What happens during photosynthesis?
It enters an electron transport chain in the thylakoid membrane
What happens to a pair of electrons after it reaches QB?
Atmosphere carbon dioxide is fixed into a five carbon sugar.
Which of the following summarizes the events of the first phase of the Calvin cycle?
the reaction center
Which of the following will remove a high energy electron from P680* and transfer it to a more stable molecule?
Reduction and carbohydrate production
Which phase of the Calvin cycle will require both ATP and NADPH?
Because it consists of both electric and magnetic energy.
Why is light considered a form of electromagnetic radiation?
To replace the electrons lost from P680
Why is water required for the light reactions of photosynthesis?
true
water is oxidized during the light reactions of photosynthesis
oxidation of water in photosystem II
O2 is produced in the thylakoid lumen via the _______.
P680 Cytochrome complex plastocyanin P700 NADP+
Order of electron flow during photosynthesis. beginning with the location of electrons first excited in noncyclic electron flow
1. Autotrophs 2. Heterotrophs
Organisms that can synthesize organic molecules from inorganic molecules are called ______, while those that must consume food to obtain organic molecules are termed _____________.
chemiosmotic
Similar to ATP synthesis in mitochondria, ATP synthesis in chloroplasts is achieved by a(n) _______ mechanism called photophosphorylation.
heterotroph
must consume food to obtain organic molecules
Autotroph
produces organic molecules from inorganic molecules
Photoautotrophs
use light energy to drive the synthesis of organic molecules from inorganic molecules
rubisco
what enzyme is responsible for carbon fixation?
Glyceraldehyde-3-phosphate
what is a primary output of the Calvin cycle?
2
Based on the Z scheme, how many photoactivation events occur during photosynthesis?
RuBP
In the last phase of the Calvin cycle, what molecule is regenerated so that the next cycle can occur?
Chemiosmosis
In the light reactions, ATP is generated via
false
In the reduction phase of the Calvin cycle, ATP is the source of electrons used to reduce a C-O bond to a C-H bond.
1. electron 2. H+
NADP+ reductase generates NADPH by transferring two ______ and one _________ ion to NADP+.
carbon fixation
Carbon dioxide is incorporated into a molecule of ribulose biphosphate to form an unstable 6-carbon intermediate that immediately splits into two 3-carbon molecules. This process is called ______ _______.
thylakoid
Chlorophylls a and b are found bound to integral membrane proteins in the _________ membrane of the chloroplast.
photosystem II, then to photosystem I, and ultimately are transferred to NADP+
During noncyclic electron flow, electrons flow from water to ______.
photosystem I
During photosynthesis, NADPH is synthesized by ______.
removal of electrons from water in PSII
During photosynthesis, oxygen is produced by the _______.
oxidized
During photosynthesis, water is _____.
NADPH ATP
During the Calvin cycle, high-energy electrons are provided by ______, and the source of energy for the reactions is ______.
3-phosphoglycerate
What is the product of the carbon fixation reaction catalyzed by rubisco in the Calvin cycle?
It transfers a high-energy electron to another molecule.
What is the role of the reaction center in a photosystem?
NADPH
What is the source of electrons used to reduce the C-O bond of 3-phosphoglycerate during the Calvin cycle?
Oxygen
What molecule is produced by photosystem II?
CO2
What molecule is reduced in the Calvin cycle?
electron
When a pigment molecule absorbs a photon of light, a(n) _______ is boosted to a higher energy level.
In the thylakoid membranes
Where are photosystems I and II located?
In the thylakoid membrane
Where do the light reactions occur?
Thylakoid membrane
Which of following best describes the location of chlorophyll a and b within the chloroplasts of green plants?
A light-harvesting complex A reaction center
Which of the following are components of both PSI and PSII? NADP+ reductase A light-harvesting complex ATP synthase A reaction center
oxygen, NADPH, ATP
Which of the following are major chemical products of the light reactions of photosynthesis? Water NADPH Oxygen ATP NADP+
ATP, NADPH
Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle? Carbohydrates ATP CO2 NADPH O2
it is immediately split into two more stable three- carbon molecules.
Which of the following happens to the molecule formed by the addition of carbon dioxide to ribulose bisphosphate?
To create a new 5 carbon sugar for the next Calvin cycle
Which of the following is the purpose of phase 3 of the Calvin cycle?
1) They are abundant in flowers and fruits. 2) They may appear yellow, orange, or red. 3) They are found in chloroplasts.
Which of the following statements are true of carotenoids?
Absorption spectrum
A diagram that depicts the wavelengths of electromagnetic radiation that are absorbed by a pigment is termed a(n) ________ ___________.
absorption spectrum
A graph that represents the wavelengths of light absorbed by a given pigment is called a(n) ______.
chlorophyll
Green plants absorb light energy is photosynthesis using _________ a and b.
derived from the same ancestral gene
Homologous genes have similarity to one another because they are ______.
Light excites an electron in a pigment found in the light-harvesting complexes of the photosystems.
How does an electron located in the pigment of the light-harvesting complexes become excited?
NADP+ reductase adds two electrons and a H+ to NADP+
How is NADPH formed in PSI?
four carbon molecules
In C4 plants, the first product of carbon fixation is
oxygen
In PSII, water is "split" and the electrons are used to replenish excited electrons that are lost from the photosystem. The loss of electrons during the oxidation, or "splitting" of water, results in the formation of ______ gas.
1) Chlorophyll 2) Carotene
In comparison to a leaf that appears yellow, a leaf that appears green has more of the pigment _________. A leaf may appear more yellow due to the presence of pigments called ___________.
photorespiration
In hot dry conditions, rubisco can attach O2 to RuBP in a process called ______. which ultimately produces CO2.
1)electrochemical 2)chemical
In photosynthesis, light energy is converted to _______ energy, which in turn is converted to ________ energy in a sugar molecule.
Glucose
In plants, which of the following is polymerized to form starch?
1. carbon fixation 2. reduction and carbohydrates production 3. regeneration of ribulose bisphosphate
Levels of Calvin Cycle
H+
Along their journey from PSII to PSI, electrons release energy as they pass from one electron carrier to the next. This energy is used to pump ____________ ions into the thylakoid lumen.
declines, unmasking the carotenoids
In the Fall, aspen leaves change from a green color to a lovely yellow color. Seasonal color changes in a leaf happen because ______.
Calvin Cycle
In the first phase of the _____, atmospheric carbon dioxide is fixed into a five carbon sugar.
electromagnetic
Light is a type of ______ radiation because it consists of energy in the form of electric and magnetic fields.
Light reaction
PSI and PSII have two main components: a(n) _________-harvesting complex and a(n) __________ center.
to regenerate ribulose bisphosphate to make glucose or other carbohydrates
The G3P produced at the end of the second phase of the Calvin cycle is directly used for which of the following?
generate ATP via ATP synthase
The electrochemical gradient generated in the light reactions of photosynthesis is used primarily to ____.
H2O
The electrons that exit PSII are replenished by electrons from oxidized _________, which yields oxygen gas that can be used by plant cells or released to the environment.
carbohydrates RuBP
The end product of phase 2 of the Calvin cycle is G3P. This molecule is used to synthesize _____ and to regenerate the starting material ________ bisphosphate.
pump H+ establish an electrochemical gradient
The energy released as electrons pass from an electron carrier to another in the electron transport chain between photosystem II and photosystem I is used to ______.
sunlight
The energy required for the synthesis of glucose from carbon dioxide ultimately comes from _________.
linear
The flow of electrons from PSII to PSI involves a direct movement, thus electrons end up at a different destination from where they started. This is called ________ electron flow.
water
The formation of oxygen gas and the replenishment of electrons lost from PSII are the result of the oxidation of ______.
Chlorophyll
The green color of plants is due primarily to the absorptive properties of the pigment ________ found in the chloroplasts.
carbon fixation
The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon _____.
An electron is boosted in a higher level.
What happens when a photon of light is absorbed by a pigment molecule?
The incorporation of carbon into an organic molecule that is not a gas
What is carbon fixation?
Glyceraldehyde 3-phosphate
What is produced at the end of the second phase of the Calvin cycle?
Linear electron flow
What is the flow of electrons from PSII to PSI called?
It absorbs light energy
What is the function of chlorophyll during photosynthesis?
