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Flashcards in Photosynthesis Deck (107):
1

What does photosynthesis do?

Maintain oxygen levels in the atmosphere

2

What is the photosynthesis equation?

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

3

What type of reaction is photosynthesis?

Endergonic

4

What are the products of photosynthesis?

Oxygen and glucose

5

What does photosynthesis use to create food molecules?

Solar energy

6

What is the relationship between Cellular Respiration and Photosynthesis?

The reactants for photosynthesis are the products for cellular respiration and the reactants for the cellular respiration are the products of photosynthesis.

7

Pigment that give a plant its green color and is used by the plant to complete the process of photosynthesis.

Chlorophyll

8

The gas that a plant released into the atmosphere as a product of the process of photosynthesis.

Oxygen

9

The gas that a plant takes in to use in the process of photosynthesis.

Carbon dioxide

10

The part of the plant where most of the photosynthesis process occurs.

Leaf

11

The part of the plant that supports the leaves and transports water through the plant.

Stem

12

Energy from the sun that is used by plants to produce their own food by the process of photosynthesis

Solar energy

13

Tiny holes in the leaves of the plant where gases like carbon dioxide and oxygen enter and exit

Stomata

14

A type of sugar that is produced by the plant during photosynthesis; this is the material that makes the plant grow and is also its food

Cellulose

15

An organism that makes its own food by converting inorganic molecules to complex organic molecules

Autotroph

16

A membrane system found within chloroplasts that contains the pigments for photosynthesis.

Thylakoid

17

The solution that surrounds the thylakoids in a chloroplast.

Stroma

18

A stack of thylakoids within a cholorplast.

Granum (grana for plural)

19

Reaction in thylakoids in which light and water are used to produce oxygen, ATP, and reduced NADP

Light dependent reaction

20

Uses products from the light dependent reaction to convert carbon dioxide to an organic molecule (usually sugar)

Light independent reaction

21

These cells change shape to open or close the stoma

Guard cells

22

They use energy from light to transform carbon dioxide and water into sugar (glucose) and oxygen.

Choroplasts

23

In C3 and CAM plants, _________ cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis.

Mesophyll

24

Their membranes contain molecular "machinery" used to convert light energy to chemical energy.

Thylakoids

25

What are the two stages of photosynthesis?

light dependent and light independent

26

The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate.

Calvin cycle

27

Temporarily stores energized electrons produced during the light reactions.

NADP

28

The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis.

Photophosphorylation

29

The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).

Carbon fixation

30

An accessory pigment, either yellow or orange, in the chloroplasts of plants and in some prokaryotes. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.

Caroteins

31

A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes

Photosystem

32

They absorb light best at different wavelengths.

Photosystems

33

A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor.

Reaction-center complex

34

Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis.

Reaction-center complex

35

Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain.

Reaction-center complex

36

One of two light-capturing units in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P680 chlorophyll a at its reaction center.

photosystem II

37

A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P700 chlorophyll a at its reaction center.

Photosystem I

38

A complex of proteins associated with pigment molecules (including chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.

Light harvesting complex

39

In the thylakoid membrane of a chloroplast or in the membrane of some prokaryotes, a specialized molecule that shares the reaction-center complex with a pair of chlorophyll a molecules and that accepts an electron from them.

Primary electron acceptor

40

A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis.

Glyceraldehyde 3-phosphate (G3P)

41

What are the 3 phases of Calvin cycle?

Carbon Fixation
Energy Consumption and Redox
Release of G3P; Regeneration of RuBP

42

A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.

C3 plants

43

A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output.

Photorespiration

44

A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle.

C4 plants

45

In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.

Bundle-sheath cells

46

What is the flow of electrons during photosynthesis?

H2O → NADPH → Calvin cycle

47

No release of oxygen during this phase.

Calvin cycle

48

The light reactions of photosynthesis supply the Calvin cycle with ______ & _______.

ATP and NADPH

49

How is photosynthesis similar in C4 plants and CAM plants?

Rubisco is not used to fix carbon initially.

50

Three molecules of carbon dioxide are added to three molecules of a five-carbon sugar abbreviated RuBP. These molecules are then rearranged to form six molecules called 3-PGA, which have three carbons each.

Carbon fixation in the calvin cycle

51

Photoelectric effect is used to ..

Convert the light energy to bond energy

52

What is the equation for carbon fixation?

CO2 ----> glucose

53

Overall photosynthesis is ____.

Anabolic

54

What are accessory pigments?

Pigments other than CHLOROPHYLL A

55

Lipid-type molecules that absorb visible light; examples Chlorophyll a chlorophyll b, carotene etc

Pigments

56

Where is the chlorophyll located?

Thylakoid membrane of chloroplast

57

It shows the range and efficiency of photons it is capable of absorbing.

Absorption spectrum

58

Captures light energy in the absence of chloroplasts

Chlorophyll

59

Site of photosynthesis is in ______ layer.

Mesophyll

60

How are chloroplasts organized?

1. Intermembrane space
2. Stroma (calvin cycle)
3. Thylakoid space (inside a thylakoid disk)

61

one stack of thylakoid membranes

granum

62

What does the inner thylakoid membrane contain?

Photosystem II and I

63

Captures light energy by exciting chlorophyll molecules.

Photosystems II and I

Light reaction (light dependent RXN)

64

Fixes carbon (converts CO2 to G3P)

Calvin cycle (light independent RXN)

65

What does a photosystem consist of (3 things)?

1. Antenna complex (accessory pigments)
2. Reaction center (chlorophyll a)
3. ETC

66

-Reaction center P680
-ETC makes ATP
-Final electron acceptor is reaction center of PS I

PS II

67

-Reaction center P700
-ETC makes NADPH
-Final electron acceptor is NADP+

PS I

68

Transfers light energy through the accessory pigments.

Antenna complex

69

Photons of light excite electrons on pigments, creating an electrical current known as the _________.

Photoelectric effect

70

In which photosystem does photoelectric effect occur?

PS II antenna complex

71

Where does photolysis occur?

PS II

72

What is photolysis?

Water is split releasing oxygen and hydrogen ions in PS II

73

How does ETC of PS II make ATP?

Photophosphorylation and ATP synthase

74

What does ETC of PS I make?

NADPH

75

Where does light independent reaction occur?

Stroma

76

Cyclical pathway in photosynthesis

Calvin cycle

77

What is the key enzyme in Calvin cycle?

Rubisco

78

What does the Calvin cycle regenerate?

RuBP

79

What does light independent reaction oxidize and recycle?

Oxidizes NADPH
Recycles NADP+ and ADP

80

What is RuBP?

5C substrate in Calvin cycle that binds to carbon dioxide

81

1. Carbon fixation
2. Reduction to produce G3P (3C sugar)
3. Requires RuBP to bind to CO2

Calvin cycle

82

RUBISCO enzyme catalyzes C-fixation

ok

83

What do cells need to build carbs?

1. energy (ATP from light dependent)
2. reduction potential (NADPH from PS I)
3. carbon dioxide from environment

84

RuBP + CO2 ----> 2 molecules PGA

Carbon fixation

85

PGA reduced to G3P

Reduction to sugar

86

1 G3P devoted to glucose synthesis
5 G3P used to regenerate RuBP

Regeneration of RuBP

87

The carbon fixation reaction is catalyzed by the enzyme ______.

Rubisco

88

____ turns needed to make 1 glucose and 5 RuBP.

6 turns

89

Total of 1 G3P generated per ___ turns of Calvin.

3 turns

90

__ G3P are recycled to make RuBP

5

91

What happens to the one G3P that is not recycled to make RuBP?

Leaves chloroplast to be used to make 6C sugar.

92

What enters the Calvin cycle?

ATP
NADPH
CO2

93

What leaves the Calvin cycle?

G3P, ADP, NADP+

94

For every 6 CO2 entering Calvin, it requires:
- ___ ATP
- ___ NADPH

to generate ___ G3P

18 ATP
12 NADPH
6 G3P

95

In warmer temps, rubisco enzyme more likely binds oxygen instead of carbon dioxide. What is the name of this process?

Photorespiration

96

When does stomata close?

At night, on hot dry days

97

What happens when stomata closes?

No access to carbon dioxide and oxygen builds up

98

In photorespiration O2 competes with CO2 for the active site in the enzyme rubisco.

ok

99

_____ adds O2 to the Calvin cycle instead of CO2

Rubisco

100

Which plant can avoid photorespiration?

C4 plants

101

Why can C4 plants avoid photorespiration?

They can use an enzyme other than rubisco for the initial C-fixation

102

What other enzyme could be used for the initial carbon fixation?

PEP carboxylase to fix CO2 to become a 4C molecule called oxaloacetate

103

The C4 uses 2 cells separating carbon fixation from light reactions. What are they?

Mesophyll cell (c-fixation)
Bundle Sheath cell (Calvin)

104

What happens in the C4 mesophyll cell?

PEP carboxylase captures CO2
Makes a 4-carbon product which is moved into a bundle sheath cell

105

What happens in the bundle sheath cell?

1. The 4C is cleaved to 3C sending the CO2 to the Calvin cycle
2. The 3C returns to Mesophyll cell

106

What do CAM plants do?

Open stomata at night and close during the day

107

Give an example of a CAM plant.

Desert plants