Chapter 8 Photosynthesis
A pigment is a molecule that can
Absorb light
What molecule is reduced in the Calvin cycle?
CO2
Sunlight provides the _____ that is necessary for the synthesis of glucose from carbon dioxide
Energy
True or False: Glucose is the primary output of the Calvin cycle.
False
What molecule is produced by photosystem II?
Oxygen
In hot dry conditions, rubisco can attach O2 to RuBP in a process called _______, which ultimately produces CO2
Photorespiration
The process by which plants capture light energy and use it to synthesize glucose and other organic molecules is called
Photosynthesis
During photosynthesis, NADPH is synthesized by
Photosystem I
A molecule that can absorb light energy is called a(n)
Pigment
The light-harvesting complex is composed of several dozen _______ molecules that are anchored to transmembrane proteins.
Pigment
What happens during photosynthesis?
Plants capture energy from sunlight and use it to synthesize organic molecules
Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle.
ATP, NADPH
Which of the following are major chemical products of the light reactions of photosynthesis?
ATP, Oxygen, NADPH
What happens when a photon of light is absorbed by a pigment molecule?
An electron is boosted to a higher level
Which of the following summarizes the events of the first phase of the Calvin cycle?
Atmospheric carbon dioxide is fixed into a five carbon sugar.
A(n) _____ can synthesize organic molecules from inorganic molecules, while a(n) ____ must consume food to obtain organic molecules
Autotroph, heterotroph
Why is light considered a form of electromagnetic radiation?
Because it consists of both electric and magnetic energy
In some plants, carbon fixation yields a four-carbon molecule instead of G3P as the first product. Such plants are known as ______ plants
C4
________ plants avoid water loss by closing their stomata during the day and opening them at night
CAM
How do CAM plants avoid water loss?
CAM plants close their stomata during the day and open them at night.
In the first phase of the _______, atmospheric carbon dioxide is fixed into a five carbon sugar.
Calvin cycle.
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.
Carbohydrate, RuBP
What are the three phases of the Calvin cycle?
Carbon fixation, reduction and carbohydrate production, regeneration of ribulose bisphosphate
Sequence the phases of the Calvin cycle from first (on top) to last:
Carbon fixation, reduction and carbohydrate production, regeneration of ribulose bisphosphate.
In the light reactions, ATP is generated via
Chemiosmosis
Similar to ATP synthesis in mitochondria, ATP synthesis in chloroplasts is achieved by a(n) _____ mechanism called phosphorylation
Chemiosmosis
Green plants utilize _____ a and b to absorb light energy in photosynthesis.
Chlorophyll
Plants appear green because they contaim
Chlorophyll
The green color of plants is due primarily to the absorptive properties of the pigment ____ found in the chloroplasts
Chlorophyll
In photosynthesis, light energy is converted to _____ energy, which in turn is converted to _____ energy in a sugar molecule.
Electrochemical, chemical
Light is a type of _____ radiation because it consists of energy in the form of electric and magnetic fields.
Electromagnetic
When a pigment molecule absorbs a photon of light, a(n) _______ is boosted to a higher energy level.
Electron
After a pair of ______ reach QB, each enters a transport chain in the thylakoid membrane.
Electrons
NADP+ reductase transfers two _____ and one _____ to NADP+ to generate NADPH
Electrons, H+
During resonance energy transfer, what is transferred from one molecule to another?
Energy
The incorporation of carbon from CO2 in the atmosphere into an organic molecule called carbon ________
Fixation
After ______ molecules are made, they may be linked together in a polysaccharide called starch.
Glucose
In plants, which of the following is polymerized to form starch?
Glucose
Which of the following is the primary output of the Calvin cycle?
Glyceraldehyde-3-phosphate
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
Pump H+, establish an electrochemical gradient
In the Calvin cycle, CO2 is
Reduced
The energy of an excited electron can be transferred from one pigment molecule to another via ______ energy transfer.
Resonance
In the last phase of the Calvin cycle, what molecule is regenerated so that the next cycle can occur?
Ribulose bisphosphate
What happens during photorespiration?
Rubisco attaches O2 to RuBP, and CO2 is produced.
The reactions of the Calvin cycle occur in the
Stroma
The energy required for the synthesis of glucose from carbon dioxide ultimately comes from
Sunlight
Photosystems I and II are located in
The thylakoid membrane
Homologous genes are similar to one another because
They are derived from the same ancestral gene
The ____ membrane of the chloroplast contains two independent, light capturing complexes of proteins and pigments called photosystems I and II
Thylakoid
Which of the following is the purpose of phase 3 of the Calvin cycle?
To create a new 5-carbon sugar for the "next" Calvin cycle.
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.
Water
Which of the following conditions affect the way the Calvin cycle operates in photosynthetic organisms?
Water availability, light intensity, temperature
The Calvin cycle is affect by certain environmental conditions, including light intensity, _______ availability, and _______.
Water, temeprature
The model for photosynthesis that incorporates two photo activation events and shows the series of energy changes during the light reactions of photosynthesis is called the _______ scheme.
Z
What happens to a pair of electrons after it reaches QB?
It enters an electron transport chain in the thylakoid membrane
Several dozen pigment molecules anchored to transmembrane proteins make up the ______ -harvesting complex of a photosystem.
Light
______ excite(s) electrons in pigment molecules in photosystems I and II.
Light
What energy conversion occurs during photosynthesis?
Light energy is converted to electrochemical energy, which is converted to chemical energy
Which of the following are components of both PSI and PSII?
A reaction center, a light harvesting complex
Where do the light reactions occur?
In the thylakoids membrane
What is carbon fixation?
Incorporation of carbon into an organic molecule that is not a gas
A key role of PSI is to produce high-energy electrons that are used to make
NADPH
Which of the following are products of light reactions that are used by the Calvin cycle to make carbohydrates?
NADPH and ATP
The flow of electrons from PSII to PSI is called _______ electron flow because the electrons move linearly from PSII to PSI.
Noncyclic
The products of the light reactions of photosynthesis are
O2, NADPH, and ATP
In C4 plants, the first product of carbon fixation is
A four-carbon molecule
According to the Z scheme, how many photo activation events occur during photosynthesis?
2
Match each term with the correct description
Heterotroph- must consume food to obtain organic molecules, Autotroph- produces organic molecules from inorganic molecules Photoautotroph- uses light energy to drive the synthesis of organic molecules from inorganic molecules
_______ genes are similar to each other because they are derived from the same ancestral gene.
Homologous
The energy that is released as electrons pass from one electron carrier to the next is used to pump _______ ions into the thylakoid lumen
Hydrogen
What is the function of chlorophyll during photosynthesis?
It absorbs light energy
How does an electron present in the pigment of the light-harvesting complexes become excited?
Light excites an electron in a pigment found in the light-harvesting complexes of the photosystems.
PSI and PSII have two main components: a(n) ______ harvesting complex and a(n) _____ center.
Light, reaction
The flow of electrons from PSII to PSI is considered to be
Linear electron flow
The G3P produced at the end of the second phase of the Calvin cycle is directly used for which of the following?
Make glucose or other carbohydrates, regenerate ribulose bisphosphate
How is NADPH formed in PSI?
NADP+ reductase adds two electrons and a H+ to NADP+
