Photosynthesis Flashcards
How does photosynthesis benefit organisms that are not plants?
- It produces organic molecules that other organisms use as food.
- It produces oxygen that can be used for aerobic respiration.
The process by which plants capture light energy and use it to synthesize carbohydrates is called __.
photosynthesis or Calvin cycle
Photosynthesis is divided into two stages: the __ reactions and the __ cycle.
Blank 1: light or light-dependent
Blank 2: Calvin
Which of the following types of organisms can conduct photosynthesis?
- Fungi
- Animals
- Bacteria
- Plants
- Algae
- Bacteria
- Plants
- Algae
What is the general equation for photosynthesis?
CO2 + 2H2O + light energy → CH2O + O2 + H2O
Living organisms that are not plants depend on photosynthesis because photosynthesis produces: (1) organic molecules such as __ that can be used for nourishment; and (2) the __ gas that makes up a large portion of the Earth’s atmosphere.
Blank 1: glucose, sugars, sugar, or carbohydrates
Blank 2: oxygen, O2, O, 0xygen, or 02
How might you summarize what happens during photosynthesis?
Plants capture energy from sunlight and use it to synthesize organic molecules.
During photosynthesis in green plants, what molecule is oxidized?
Water
What are the two stages of photosynthesis?
- Calvin cycle
- Krebs cycle
- Oxygen reactions
- Cellular respiration
- Light reactions
Calvin cycle
Light reactions
In photosynthesis, carbon dioxide is reduced and H2O is oxidized. What type of chemical reaction is this?
A redox reaction
True or false: Plants are the only living organisms that can conduct photosynthesis.
False
According to the general equation for photosynthesis, CO2+ 2H2O + light energy → __ + __ + __
Blank 1: CH2O, CH20, glucose, Carbohydrate, C6H12O6, or C6H1206
Blank 2: O2, 02, o2, oxygen, or 6O2
Blank 3: H2O, H20, h20, water, 6H2O, or 6H20
Autotrophs sustain themselves by producing organic molecules from:
inorganic molecules
What is the source of energy for photoautotrophs?
Light
What molecule is reduced during the process of photosynthesis?
CO2
Photosynthesis is a redox reaction where ______ is reduced and ______ is oxidized.
CO2; H2O
Organisms that acquire energy by consuming organic molecules from the environment are called __
heterotrophs or heterotrophic
Which of the following types of organisms can conduct photosynthesis?
- Bacteria
- Animals
- Fungi
- Plants
- Algae
Bacteria
Plants
Algae
Organisms that are able to make organic molecules from inorganic sources, such as carbon dioxide and water, are called __
autotrophs
Organisms that synthesize organic molecules using light as a source of energy are called:
photoautotrophs
Which of the following are chloroplast membranes?
- The lumen membrane
- The stroma membrane
- An inner membrane
- An outer membrane
- The thylakoid membrane
An inner membrane
An outer membrane
The thylakoid membrane
During photosynthesis in green plants, what molecule is oxidized?
Water
Heterotrophs gain energy by:
consuming organic molecules from the environment
True or false: Plants are the only living organisms that can conduct photosynthesis.
False
Within a chloroplast, where is the stroma located?
Between the thylakoid membrane and the inner membrane
The stroma of the chloroplast is the site where the ______ takes place.
Calvin cycle
What molecule is reduced during the process of photosynthesis?
CO2
Where do the light reactions occur?
In the thylakoid membrane
Organisms that acquire energy by consuming organic molecules from the environment are called __.
heterotrophs or heterotrophic
The light reactions convert __ energy into __ energy stored in covalent bonds.
Blank 1: solar, light, radiant, sun, sunlight, electromagnetic, or photon
Blank 2: chemical, potential, or bond
The fluid-filled region of the chloroplast between the thylakoid membrane and the inner membrane is known as the __.
stroma
The light reactions of photosynthesis produce three chemical products: __, __, and __.
Blank 1: ATP or adenosinetriphosphate
Blank 2: NADPH
Blank 3: O2, oxygen, or 02
The reactions of the Calvin cycle occur in the:
stroma
What molecule is used as an electron carrier during photosynthesis?
NADPH
Which of the following are chloroplast membranes?
- The thylakoid membrane
- The lumen membrane
- The stroma membrane
- An inner membrane
- An outer membrane
The thylakoid membrane
An inner membrane
An outer membrane
The thylakoid membrane is the location of the __ reactions of photosynthesis.
light
What is the purpose of the light reactions of photosynthesis?
Conversion of light energy to chemical energy
Which of the following are products of the light reactions?
- CO2
- ATP
- O2
- Carbohydrates
- NADP+
- NADPH
ATP
O2
NADPH
Light is a type of ______ radiation because it consists of energy in the form of electric and magnetic fields.
electromagnetic
During photosynthesis, __ serves as an electron carrier that can accept two high-energy electrons.
NADPH, NADP+, or ferredoxin
True or false: Light has properties of both a particle and an elastic spring.
False
Similar to a mitochondrion, a(n) __ contains an outer and inner membrane, with an intermembrane space between the two. Unlike a mitochondrion, it also contains chlorophyll-containing membranes called __ membranes.
Blank 1: chloroplast
Blank 2: thylakoid
What is a photon?
A discrete particle of light
Where do the light reactions occur?
In the thylakoid membrane
What three things may happen to light when it strikes an object?
It may pass through the object.
It may be absorbed.
It may change direction.
The light reactions convert __ energy into __ energy stored in covalent bonds.
Blank 1: solar, light, radiant, sun, sunlight, electromagnetic, or photon
Blank 2: chemical, potential, or bond
A molecule that can absorb light energy is called a(n):
pigment
Why is light considered a form of electromagnetic radiation?
Because it consists of both electric and magnetic energy
Why are leaves green?
They reflect green light.
A photon of light has properties of both
a particle and a wave.
After absorbing energy, an electron is said to be in a(n):
excited state
A discrete particle of light is called a(n) __
photon
When light strikes an object, the light may pass through the object, have its direction changed by the object (reflected), or be __ by the object.
absorbed or absorb
What is the function of chlorophyll during photosynthesis?
It absorbs light energy.
A pigment is a molecule that can:
absorb light
Leaves appear green because they __ green light.
reflect or reject
When an electron absorbs energy, it becomes __.
excited, unstable, excited state, or energized
Which of the following statements are true of carotenoids?
- They are more abundant in leaves than chlorophyll pigments.
- They are invisible.
- They may appear yellow, orange, or red.
- They are abundant in flowers and fruits.
- They may appear yellow, orange, or red.
- They are abundant in flowers and fruits.
What is a photon?
A discrete particle of light
Green plants utilize __ a and b to absorb light energy in photosynthesis.
chlorophyll or chlorophylls
The __ membrane of the chloroplast contains two independent, light capturing complexes of proteins and pigments called photosystems I and II.
thylakoid
A molecule that can absorb light energy is called a(n):
pigment
In the light reactions, both photosystems absorb and capture light energy in the form of excited electrons; however PSII is able to oxidize __, which results in the production of oxygen.
water, H2O, h20, water molecules, or H2O molecules
Why are leaves green?
They reflect green light.
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.
The pigment molecules that cause autumn leaves to appear yellow and orange are called
carotenoids or carotenoid
Excited electrons are moved out of photosystem II by a carrier called __. These electrons enter a cytochrome complex, and then finally are transferred to a small protein called __, which carries the electrons to photosystem I.
Blank 1: plastoquinone or QB
Blank 2: plastocyanin or Pc
Photosystems I and II are located in:
the thylakoid membrane
During photosynthesis, water is:
oxidized
The electron transport chain directly associated with PSII is used to generate ______, while the electron transport chain directly associated with PSI is used to generate ______.
ATP; NADPH
__ excite(s) electrons in pigment molecules in photosystems I and II
Light, Photons, Sunlight, Light energy, A photon of light, or Photons of light
A key role of PSI is to produce high-energy electrons that are used to make
NADPH
The synthesis of ATP using light as the ultimate energy source is called:
photophosphorylation
True or false: Water is oxidized during the light reactions of photosynthesis.
True
The electrochemical gradient generated in the light reactions of photosynthesis is used primarily to:
generate ATP via ATP synthase
In the light reactions, both photosystems absorb and capture light energy in the form of excited electrons; however PSII is able to oxidize __, which results in the production of oxygen.
water, H2O, h20, water molecules, or H2O molecules
The products of the light reactions of photosynthesis are __, __, and __.
Blank 1: NADPH
Blank 2: ATP
Blank 3: oxygen, O2, 02, or o2
During photosynthesis, NADPH is synthesized by:
photosystem I
Why is water required for the light reactions of photosynthesis?
To replace the electrons lost from P680
Excited electrons are moved out of photosystem II by a carrier called __. These electrons enter a cytochrome complex, and then finally are transferred to a small protein called __, which carries the electrons to photosystem I.
Blank 1: plastoquinone or qb
Blank 2: plastocyanin or Pc
What is photophosphorylation?
Synthesis of ATP powered by light energy
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, H2O, H20, or water molecules
A major purpose of the electrochemical gradient generated in the light reactions of photosynthesis is to synthesize __.
ATP
Which of the following are major chemical products of the light reactions of photosynthesis?
- oxygen
- ATP
- NADP+
- NADPH
- water
oxygen
ATP
NADPH
The light reactions of photosynthesis require water to supply two __ that are transferred to P680+.
electrons, e-, or low-energy electrons
During photosynthesis, oxygen is produced by:
the removal of electrons from water in PS2
What molecule is produced by photosystem II?
Oxygen
During the light reactions of photosynthesis, ATP is produced via the protein ATP __ that uses an H+ electrochemical gradient.
synthase or synthetase
The electrochemical gradient generated in the light reactions of photosynthesis is used primarily to:
generate ATP via ATP synthase
Which of the following are products of the light reactions that are used by the Calvin cycle?
NADPH and ATP
The products of the light reactions of photosynthesis are __, __, and __.
Blank 1: NADPH
Blank 2: ATP
Blank 3: oxygen, O2, 02, or o2
Plants take CO2 from the atmosphere via the ______ in order to synthesize carbohydrates.
Calvin cycle
The splitting of water in photosystem II results in the production of __ gas.
oxygen, O2, 02, or 0xygen
Excited electrons are moved out of photosystem II by a carrier called __. These electrons enter a cytochrome complex, and then finally are transferred to a small protein called __, which carries the electrons to photosystem I.
Blank 1: plastoquinone, QB
Blank 2: plastocyanin or Pc
NADPH is produced in the stroma of the chloroplast when ______ are transferred to NADP+.
two high-energy electrons and one H+
Carbohydrates are very important to plant cells because they:
form the building block for many organic macromolecules
can be used as an energy reserve
Which of the following are products of the light reactions of photosynthesis that are used as reactants in the Calvin cycle?
- ATP
- CO2
- Carbohydrates
- O2
- NADPH
ATP
NADPH
What is the origin of the carbons in a carbohydrate generated by photosynthesis?
Carbon dioxide in the atmosphere
True or false: Glucose is the primary output of the Calvin cycle.
False
During photosynthesis, oxygen is produced by:
the removal of electrons from water in PS2
The glucose that is made by plant cells can be converted to other carbohydrates, including:
sucrose
starch
Why are carbohydrates critical for plant cells?
They provide a source of energy and form the precursors for most organic macromolecules
Which of the following are products of the light reactions that are used by the Calvin cycle?
NADPH and ATP
What is carbon fixation?
Incorporation of carbon into an organic molecule that is not a gas
What is the main product of the Calvin cycle?
Glyceraldehyde-3-phosphate
After glucose molecules are synthesized, they can be linked together to form a polymer called __, which is stored, or used to make the disaccharide __, which can be transported to other parts of the plant.
Blank 1: starch
Blank 2: sucrose
Excited electrons are moved out of photosystem II by a carrier called __. These electrons enter a cytochrome complex, and then finally are transferred to a small protein called __, which carries the electrons to photosystem I.
Blank 1: plastoquinone, QB
Blank 2: plastocyanin or Pc
What chemical reaction is catalyzed by the enzyme rubisco?
Carbon fixation
What are the three phases of the Calvin cycle?
Regeneration of ribulose bisphosphate
Reduction and carbohydrate production
Carbon fixation
RuBP carboxylase/oxygenase, also known as __, is the most abundant protein in chloroplasts.
rubisco
The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon __.
fixation or fixing
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.
Blank 1: carbohydrates, glucose, sugar, sugars, carbohydrate, or carbs
Blank 2: ribulose, Ru, or RuBP
True or false: Glucose is the primary output of the Calvin cycle.
False
The Calvin cycle uses energy from __, and high-energy __ supplied by NADPH.
Blank 1: ATP, adenosine triphosphate, or adenosinetriphosphate
Blank 2: electrons or e-
The glucose that is made by plant cells can be converted to other carbohydrates, including:
sucrose
starch
What enzyme is responsible for carbon fixation?
Rubisco
What molecule is reduced in the Calvin cycle?
CO2
What is the most abundant protein found in chloroplasts?
Rubisco
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
During the Calvin cycle, high-energy electrons are provided by ______, and the source of energy for the reactions is ______.
NADPH; ATP
After glucose molecules are synthesized, they can be linked together to form a polymer called __, which is stored, or used to make the disaccharide __, which can be transported to other parts of the plant.
Blank 1: starch
Blank 2: sucrose
In the Calvin cycle, CO2 is:
reduced
RuBP carboxylase/oxygenase, also known as __, is the most abundant protein in chloroplasts.
rubisco
The Calvin cycle uses energy from __, and high-energy __ supplied by NADPH.
Blank 1: ATP, adenosine triphosphate, or adenosinetriphosphate
Blank 2: electrons or e-
What molecule is reduced in the Calvin cycle?
CO2
What is the most abundant protein found in chloroplasts?
Rubisco
