Photosynthesis Flashcards
1
Q
How does photosynthesis benefit organisms that are not plants?
A
- It produces organic molecules that other organisms use as food.
- It produces oxygen that can be used for aerobic respiration.
2
Q
The process by which plants capture light energy and use it to synthesize carbohydrates is called __.
A
photosynthesis or Calvin cycle
3
Q
Photosynthesis is divided into two stages: the __ reactions and the __ cycle.
A
Blank 1: light or light-dependent
Blank 2: Calvin
4
Q
Which of the following types of organisms can conduct photosynthesis?
- Fungi
- Animals
- Bacteria
- Plants
- Algae
A
- Bacteria
- Plants
- Algae
5
Q
What is the general equation for photosynthesis?
A
CO2 + 2H2O + light energy → CH2O + O2 + H2O
6
Q
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.
A
Blank 1: glucose, sugars, sugar, or carbohydrates
Blank 2: oxygen, O2, O, 0xygen, or 02
7
Q
How might you summarize what happens during photosynthesis?
A
Plants capture energy from sunlight and use it to synthesize organic molecules.
8
Q
During photosynthesis in green plants, what molecule is oxidized?
A
Water
9
Q
What are the two stages of photosynthesis?
- Calvin cycle
- Krebs cycle
- Oxygen reactions
- Cellular respiration
- Light reactions
A
Calvin cycle
Light reactions
10
Q
In photosynthesis, carbon dioxide is reduced and H2O is oxidized. What type of chemical reaction is this?
A
A redox reaction
11
Q
True or false: Plants are the only living organisms that can conduct photosynthesis.
A
False
12
Q
According to the general equation for photosynthesis, CO2+ 2H2O + light energy → __ + __ + __
A
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
13
Q
Autotrophs sustain themselves by producing organic molecules from:
A
inorganic molecules
14
Q
What is the source of energy for photoautotrophs?
A
Light
15
Q
What molecule is reduced during the process of photosynthesis?
A
CO2
16
Q
Photosynthesis is a redox reaction where ______ is reduced and ______ is oxidized.
A
CO2; H2O
17
Q
Organisms that acquire energy by consuming organic molecules from the environment are called __
A
heterotrophs or heterotrophic
18
Q
Which of the following types of organisms can conduct photosynthesis?
- Bacteria
- Animals
- Fungi
- Plants
- Algae
A
Bacteria
Plants
Algae
19
Q
Organisms that are able to make organic molecules from inorganic sources, such as carbon dioxide and water, are called __
A
autotrophs
20
Q
Organisms that synthesize organic molecules using light as a source of energy are called:
A
photoautotrophs
21
Q
Which of the following are chloroplast membranes?
- The lumen membrane
- The stroma membrane
- An inner membrane
- An outer membrane
- The thylakoid membrane
A
An inner membrane
An outer membrane
The thylakoid membrane
22
Q
During photosynthesis in green plants, what molecule is oxidized?
A
Water
23
Q
Heterotrophs gain energy by:
A
consuming organic molecules from the environment
24
Q
True or false: Plants are the only living organisms that can conduct photosynthesis.
A
False
25
Within a chloroplast, where is the stroma located?
Between the thylakoid membrane and the inner membrane
26
The stroma of the chloroplast is the site where the ______ takes place.
Calvin cycle
27
What molecule is reduced during the process of photosynthesis?
CO2
28
Where do the light reactions occur?
In the thylakoid membrane
29
Organisms that acquire energy by consuming organic molecules from the environment are called __.
heterotrophs or heterotrophic
30
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
31
The fluid-filled region of the chloroplast between the thylakoid membrane and the inner membrane is known as the __.
stroma
32
The light reactions of photosynthesis produce three chemical products: __, __, and __.
Blank 1: ATP or adenosinetriphosphate
Blank 2: NADPH
Blank 3: O2, oxygen, or 02
33
The reactions of the Calvin cycle occur in the:
stroma
34
What molecule is used as an electron carrier during photosynthesis?
NADPH
35
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
36
The thylakoid membrane is the location of the __ reactions of photosynthesis.
light
37
What is the purpose of the light reactions of photosynthesis?
Conversion of light energy to chemical energy
38
Which of the following are products of the light reactions?
- CO2
- ATP
- O2
- Carbohydrates
- NADP+
- NADPH
ATP
O2
NADPH
39
Light is a type of ______ radiation because it consists of energy in the form of electric and magnetic fields.
electromagnetic
40
During photosynthesis, __ serves as an electron carrier that can accept two high-energy electrons.
NADPH, NADP+, or ferredoxin
41
True or false: Light has properties of both a particle and an elastic spring.
False
42
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
43
What is a photon?
A discrete particle of light
44
Where do the light reactions occur?
In the thylakoid membrane
45
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.
46
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
47
A molecule that can absorb light energy is called a(n):
pigment
48
Why is light considered a form of electromagnetic radiation?
Because it consists of both electric and magnetic energy
49
Why are leaves green?
They reflect green light.
50
A photon of light has properties of both
a particle and a wave.
51
After absorbing energy, an electron is said to be in a(n):
excited state
52
A discrete particle of light is called a(n) __
photon
53
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
54
What is the function of chlorophyll during photosynthesis?
It absorbs light energy.
55
A pigment is a molecule that can:
absorb light
56
Leaves appear green because they __ green light.
reflect or reject
57
When an electron absorbs energy, it becomes __.
excited, unstable, excited state, or energized
58
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.
59
What is a photon?
A discrete particle of light
60
Green plants utilize __ a and b to absorb light energy in photosynthesis.
chlorophyll or chlorophylls
61
The __ membrane of the chloroplast contains two independent, light capturing complexes of proteins and pigments called photosystems I and II.
thylakoid
62
A molecule that can absorb light energy is called a(n):
pigment
63
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
64
Why are leaves green?
They reflect green light.
65
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.
66
The pigment molecules that cause autumn leaves to appear yellow and orange are called
carotenoids or carotenoid
67
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
68
Photosystems I and II are located in:
the thylakoid membrane
69
During photosynthesis, water is:
oxidized
70
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
71
__ excite(s) electrons in pigment molecules in photosystems I and II
Light, Photons, Sunlight, Light energy, A photon of light, or Photons of light
72
A key role of PSI is to produce high-energy electrons that are used to make
NADPH
73
The synthesis of ATP using light as the ultimate energy source is called:
photophosphorylation
74
True or false: Water is oxidized during the light reactions of photosynthesis.
True
75
The electrochemical gradient generated in the light reactions of photosynthesis is used primarily to:
generate ATP via ATP synthase
76
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
77
The products of the light reactions of photosynthesis are __, __, and __.
Blank 1: NADPH
Blank 2: ATP
Blank 3: oxygen, O2, 02, or o2
78
During photosynthesis, NADPH is synthesized by:
photosystem I
79
Why is water required for the light reactions of photosynthesis?
To replace the electrons lost from P680
80
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
81
What is photophosphorylation?
Synthesis of ATP powered by light energy
82
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
83
A major purpose of the electrochemical gradient generated in the light reactions of photosynthesis is to synthesize __.
ATP
84
Which of the following are major chemical products of the light reactions of photosynthesis?
- oxygen
- ATP
- NADP+
- NADPH
- water
oxygen
ATP
NADPH
85
The light reactions of photosynthesis require water to supply two __ that are transferred to P680+.
electrons, e-, or low-energy electrons
86
During photosynthesis, oxygen is produced by:
the removal of electrons from water in PS2
87
What molecule is produced by photosystem II?
Oxygen
88
During the light reactions of photosynthesis, ATP is produced via the protein ATP __ that uses an H+ electrochemical gradient.
synthase or synthetase
89
The electrochemical gradient generated in the light reactions of photosynthesis is used primarily to:
generate ATP via ATP synthase
90
Which of the following are products of the light reactions that are used by the Calvin cycle?
NADPH and ATP
91
The products of the light reactions of photosynthesis are __, __, and __.
Blank 1: NADPH
Blank 2: ATP
Blank 3: oxygen, O2, 02, or o2
92
Plants take CO2 from the atmosphere via the ______ in order to synthesize carbohydrates.
Calvin cycle
93
The splitting of water in photosystem II results in the production of __ gas.
oxygen, O2, 02, or 0xygen
94
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
95
NADPH is produced in the stroma of the chloroplast when ______ are transferred to NADP+.
two high-energy electrons and one H+
96
Carbohydrates are very important to plant cells because they:
form the building block for many organic macromolecules
can be used as an energy reserve
97
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
98
What is the origin of the carbons in a carbohydrate generated by photosynthesis?
Carbon dioxide in the atmosphere
99
True or false: Glucose is the primary output of the Calvin cycle.
False
100
During photosynthesis, oxygen is produced by:
the removal of electrons from water in PS2
101
The glucose that is made by plant cells can be converted to other carbohydrates, including:
sucrose
starch
102
Why are carbohydrates critical for plant cells?
They provide a source of energy and form the precursors for most organic macromolecules
103
Which of the following are products of the light reactions that are used by the Calvin cycle?
NADPH and ATP
104
What is carbon fixation?
Incorporation of carbon into an organic molecule that is not a gas
105
What is the main product of the Calvin cycle?
Glyceraldehyde-3-phosphate
106
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
107
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
108
What chemical reaction is catalyzed by the enzyme rubisco?
Carbon fixation
109
What are the three phases of the Calvin cycle?
Regeneration of ribulose bisphosphate
Reduction and carbohydrate production
Carbon fixation
110
RuBP carboxylase/oxygenase, also known as __, is the most abundant protein in chloroplasts.
rubisco
111
The incorporation of carbon from CO2 in the atmosphere into an organic molecule is called carbon __.
fixation or fixing
112
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
113
True or false: Glucose is the primary output of the Calvin cycle.
False
114
The Calvin cycle uses energy from __, and high-energy __ supplied by NADPH.
Blank 1: ATP, adenosine triphosphate, or adenosinetriphosphate
Blank 2: electrons or e-
115
The glucose that is made by plant cells can be converted to other carbohydrates, including:
sucrose
starch
116
What enzyme is responsible for carbon fixation?
Rubisco
117
What molecule is reduced in the Calvin cycle?
CO2
118
What is the most abundant protein found in chloroplasts?
Rubisco
119
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
120
During the Calvin cycle, high-energy electrons are provided by ______, and the source of energy for the reactions is ______.
NADPH; ATP
121
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
122
In the Calvin cycle, CO2 is:
reduced
123
RuBP carboxylase/oxygenase, also known as __, is the most abundant protein in chloroplasts.
rubisco
124
The Calvin cycle uses energy from __, and high-energy __ supplied by NADPH.
Blank 1: ATP, adenosine triphosphate, or adenosinetriphosphate
Blank 2: electrons or e-
125
What molecule is reduced in the Calvin cycle?
CO2
126
What is the most abundant protein found in chloroplasts?
Rubisco
