Photosynthesis Flashcards

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1
Q

the source of energy

A

the sun

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2
Q

autotrophs

A

organisms that can make their own food

all green plants, some bacteria, some protists

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3
Q

what form of energy do autotrophs use to produce food

A

light energy from the sun

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4
Q

what form is light energy produced as food

A

glucose or sugar

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5
Q

heterotrophs

A

organisms that cannot make their own food

all animals and all fungi

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6
Q

how do heterotrophs gain energy

A

by consuming food

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7
Q

what form does energy enter the ecosystem

A

sunlight

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8
Q

what do plants use the suns energy to make

A

glucose

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9
Q

photosynthesis

A
  • converting radiant energy (from the sun) into chemical energy (as glucose)
  • convert water & carbon dioxide into high-energy sugar molecules
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10
Q

Name & Energy Level

ATP

A
  • Adenosine Triphosphate
  • Energy Rich
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11
Q

Name & Energy Level

ADP

A
  • Adenosine Diphosphate
  • Energy Poor
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12
Q

Structure of ATP

A
  • Adenine, a nitrogen base
  • Ribose, a 5-carbon sugar
  • A chain of three phosphate groups
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13
Q

ADP -> ATP

A

Adding a phosphate
* when a cell has energy available it can store small amounts by adding a phosphate group

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14
Q

Storing Energy

A

Add a phosphate

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15
Q

ATP -> ADP

A

Removing a phosphate
* when a cell needs energy, the third phosphate will be removed

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16
Q

Releasing Energy

A

Removing a phosphate

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17
Q

What does ATP power?

A
  • Photosynthesis
  • Protein Synthesis
  • Muscle Contractions
  • Active Transport
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18
Q

Basic Energy Source

A

ATP

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19
Q

How much ATP is consumed & regenerated in a second?

A

10,000,000

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20
Q

waste product of photosynthesis

A

oxygen

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21
Q

What is life on earth dependent on photosynthesis for?

A

food & oxygen

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22
Q

The Photosynthesis Equation

A

6CO2 + 6H2O + Sunlight = C6H12O6 + 6O2

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23
Q

How do plants take in CO2?

A

Through their leaves

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24
Q

How do plants take in H2O?

A

Through their roots

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25
Q

What does photosynthesis require?

A
  • water
  • carbon dioxide
  • light energy
  • chlorophyll
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26
Q

electromagnetic spectrum

A

the range of energy radiated outward from the sun

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27
Q

what does the atmosphere act as?

A

a selective window that allows visible light to pass through while screening out a substantial fraction of other radiation

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28
Q

What drives photosynthesis?

A

the visible light from radiation

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29
Q

the colors of the visible spectrum are

A

red, orange, yellow, green, blue, indigo, violet

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30
Q

pigment

A

any substance that absorbs light

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31
Q

how do plants absorb the suns energy?

A

via pigments (light absorbing)

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32
Q

different pigments…

A

…absorb light of different wavelengths

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33
Q

what happens to the absorbed wavelengths?

A

they disappear

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34
Q

is there an alternate to absorbing wavelengths?

A

yes, reflecting them

the colors we see are being reflected by a pigment

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35
Q

principal photosynthetic pigment

A

chlorophyll

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36
Q

chlorophyll

A

a green pigment contained in chloroplasts

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37
Q

What can chlorophyll absorb?

A

All colors of the visible spectrum except for green. It reflects green.

So, its green to us

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38
Q

What wavelengths of light are best absorbed by chlorophyll?

A

~425nm and ~660nm

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39
Q

What wavelengths of light are least absorbed by chlorophyll?

A

~450nm and ~650nm

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40
Q

chlorophyll-a

A

blue-green

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41
Q

chlorophyll-b

A

yellow-green

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42
Q

what happens when chlorophyll absorbs light?

A

energy transfers directly to electrons

these high-energy electrons make photosynthesis work

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43
Q

major organ of photosynthesis

A

leaves

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44
Q

what are leaves the major organ of

A

photosynthesis

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45
Q

how many chloroplasts per sqmillimeter of leaf?

A

~500,000

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46
Q

Cuticle

A

A waxy covering on the upper & lower surface of a leaf that helps prevent water loss

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47
Q

Mesophyll

A
  • central middle area
  • contains palisade cells & spongy cells (both of many chloroplasts)
  • the palisade layer is the primary photosynthetic layer
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48
Q

Stomata

A
  • pores in the leaf (for CO2 to enter and oxygen to exit)
  • the opening into the leaf
  • guard cells found on either side (they’re like the doors)
  • source of water loss
  • usually found on the lower surface (to help reduce water loss)
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49
Q

vascular bundles

A
  • contains xylem and phloem
  • xylem carries water up the plant, brings water to the leaf
  • phloem carries food down the plant, glucose will exit through the phloem and get carried to other parts of the plant
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50
Q

chloroplast membrane

A

double membrane - there is a space between them

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51
Q

thylakoids affect on the chloroplast

A
  • make a third membrane system
  • big stacks of thylakoids are called grana
  • they contain chlorophyll
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52
Q

What is surrounding of the thylakoid?

A

a dense solution called, the stroma

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53
Q

What are Thylakoids

A

the structural unit of photosynthesis

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54
Q

what form do thylakoids take

A

the form of flattened sacs or vesicles

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55
Q

What molecules are built into the thylakoid membrane

A

chlorophyll molecules

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56
Q

what do chlorophyll molecules do?

A

capture light energy

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57
Q

where does photosynthesis take place??

A

in the chloroplast

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58
Q

What happens to pigments in the thylakoid membrane?

A

They are clustered together

59
Q

What are clusters of pigments called?

A

Photosystems

60
Q

Photosystems

A
  • clusters of pigments
  • light collecting units
61
Q

what is the light collecting unit of the chloroplast?

A

photosystems

62
Q

what happens when sunlight hits chlorophyll

A

the electrons in chlorophyll become very excited

63
Q

excited electrons

A

electrons that have a LOT of energy

64
Q

what do high energy electrons need?

A

a carrier

65
Q

an electron carrier

A

a compound that can accept a pair of high energy electrons

without draining the electrons energy

66
Q

electron carriers are also known as

A

the electron transport chain

67
Q

what is the process of transporting high energy electrons called?

A

electron transport

68
Q

example of an electron carrier

A

NADP+

69
Q

NADP+

A

accepts and holds 2 high energy electrons alongside a hydrogen ion

when that happens NADP+ becomes NADPH

70
Q

NADPH

A

NADP+ when it has 2 high energy electrons and a hydrogen ion

71
Q

where do the high energy electrons go?

A

elsewhere in the chloroplast for chemical reactions & to build glucose molecules

72
Q

where do light dependent reactions occur?

A

thylakoid membranes

73
Q

where do light INdependent reactions occur?

A

in the stroma - region outside of the thylakoids

74
Q

example of a light independent reaction

A

calvin cycle

75
Q

Which photosystem comes first?

A

Photosystem II

76
Q

What is a photosystem?

A

a collection of pigment molecules that serve as the light collecting unit

embedded in the thylakoid membranes

77
Q

what do pigments in photosystem II do?

A

absorb light

78
Q

what does the light energy absorbed by the electrons do?

A

increase their energy level

79
Q

what happens when electrons are lost?

A

they get replaced

80
Q

what do enzymes break apart in the thylakoid membrane?

A

water molecules into 2 electrons, 2 H+ ions, and 1 oxygen atom

81
Q

what is considered a waste product?

photosystems

A

oxygen

82
Q

what is responsible for nearly all the oxygen in our atmosphere?

A

the splitting apart of water

83
Q

what ion is released into the thylakoid?

A

hydrogen

84
Q

protein molecules use the energy from high-energy electrons to create what?

A

ATP

85
Q

what does chlorophyll do in photosystem I?

A

absorb energy and use it to re-energize the electrons

86
Q

What is the purpose of light dependent reactions?

A

produce ATP and NADPH for the light independent reactions

87
Q

Where do light dependent reactions take place?

A

Thylakoid membrane

88
Q

What do light dependent reactions do?

A

pass electrons from water to NADPH

89
Q

The two photosystems work together to produce what?

A

ATP and NADPH

90
Q

Where are thylakoids found?

A

inside the chloroplasts

91
Q

what are big stacks of thylakoids called?

A

grana

92
Q

what are grana?

A

big stacks of thylakoids

93
Q
A
94
Q

what is the thylakoid space

A

the middle of the thylakoid

95
Q

what is in the middle of the thylakoid?

A

the thylakoid space

96
Q

what is a collection of chlorophylls and carotenoids called?

A

pigments

97
Q

what do pigments do?

A

absorb light energy from the sun

98
Q

what strikes the surface of the leaf?

A

sunlight

99
Q

what increases the energy level of electrons in chlorophyll?

A

light energy

100
Q

What is the energy from high energy electrons used for?

A

to transport hydrogen ions from the stroma into the thylakoid space

101
Q

what gets released inside the thylakoid

A

hydrogen ions

102
Q

what gets released into the air?

A

oxygen

103
Q

what does photosystem I receive from photosystem II?

A

electrons

104
Q

What is the energy absorbed from the sun by chlorophyll molecules in photosystem I used for?

A

re-energizing electrons

105
Q

What does NADP+ join with in light dependent reactions?

A

1 hydrogen atom and 2 electrons

106
Q

NADPH is formed when?

A

NADP+ joins with 1 hydrogen ion and two electrons

107
Q
A
108
Q

what is the area outside the thylakoid called?

A

the stroma

109
Q

what is the stroma?

A

a dense liquid surrounding the thylakoids

110
Q
A
111
Q

from where to where do hydrogen ions move in the chloroplast?

A

flow from high concentration (in the thylakoid) to low concentration (in the stroma)

112
Q

what is hydrogen flowing through?

A

ATP synthase, a protein enzyme

113
Q

What does ATP synthase do when hydrogen flows through it?

A

Rotates like a turbine

114
Q

What does ATP synthase do while rotating?

A

Binds a phosphate to ADP (forms ATP from ADP)

115
Q

How does the concentration of hydrogen stay high inside the thylakoid?

A

Hydrogen ions are actively pumped back into it

116
Q

What is formed for use in the Calvin Cycle?

A

NADPH & ATP

117
Q

What is the purpose of light dependent reactions?

A

Produce high-energy compounds

118
Q

What are high-energy compounds?

A

ATP & NADPH

119
Q

What are high-energy compounds used for?

A

Calvin Cycle

120
Q

The Calvin Cycle is also known as…

A

the Light Independent Reactions

121
Q

Where does the Calvin Cycle occur?

A

In the Stroma

122
Q

What is the purpose of the Calvin Cycle?

A

to take CO2 and high-energy products of the light dependent reaction to make glucose

123
Q

How does the Calvin Cycle obtain CO2?

A

via the atmosphere

124
Q

What does CO2 enter leaves through?

A

the stomata

125
Q

5-carbon sugar called

A

RuBP or ribulose biphosphate

126
Q

carbon fixation

A

carbon (from CO2) combining with 5-carbon sugar (RuBP)

127
Q

What does Carbon Fixation form?

A

An unstable 6-carbon compound

128
Q

What does the unstable 6-carbon compoud break apart into?

A

2 molecules of PGA (a three-carbon compound)

129
Q

how does PGAL form?

A

a series of reactions involving ATP & NADPH convert PGA into PGAL

130
Q

What could happen to the PGAL?

A
  1. the two PGAL molecules combine and form glucose
  2. the PGAL is converted into RuBP for the reaction to occur again
131
Q

What is the number one problem land plants face?

A

Dehydration

132
Q

Why is dehydration a problem?

A

Plants must open their stomata, to let in CO2, which causes excessive water loss

133
Q

What do plants do on a hot dry day?

A

Close the stomata to conserve water

134
Q

Consequences of having the stomata closed?

A

Slows down photosynthesis

135
Q

What are the 2 pathways for carbon fixation?

A
  1. the four-carbon pathway
  2. the CAM pathway
136
Q

What is special about the C4 Pathway?

A

Prefaces the Calvin Cycle with an additional step

137
Q

Additional step of C4 Pathway

A

converts CO2 into a 4-carbon compound to save it until it is needed

REVERSABLE

138
Q

C4 Plant Examples

A

Corn, Sugar Cane, Crab Grass

139
Q

What is special about the CAM pathway?

A

Stomata is only open at night

140
Q

CAM Pathway Plant examples

A

Cacti & Pineapples

141
Q

What is REQUIRED in light dependent reactions?

A

water

…and light

142
Q

how is water obtained for photosynthesis?

A

via the roots of plants

143
Q

what does a shortage of water do?

A

slow or stop photosynthesis

144
Q

what is done to prevent water loss?

A

plants are covered with a waxy cuticle