Exam #4 - Photosynthesis Flashcards Preview

BSC 2010 - Biology I > Exam #4 - Photosynthesis > Flashcards

Flashcards in Exam #4 - Photosynthesis Deck (119):
1

Photosynthesis is the synthesis of _______.

sugar

2

Just as cellular respiration releases energy, photosynthesis _______ energy.

requires

3

In photosynthesis, we ______ energy to make sugar.

harvest

4

How do we store energy? Within....?

Electrons

5

Biochemically speaking, what is needed to make sugar?

1) Carbon source - raw material
2) Energy - sun
3) Electrons - store energy

6

We need a source of carbon to _____ those electrons to store that energy.

carry

7

Carbon fixation means making carbon _______.

organic

8

What does that mean? Making carbon "organic"?

Making carbon bonded to Hydrogen

9

Plants take carbon from the ___ and make it organic.

air. THAT'S THE SOURCE!

10

What is the process of photosynthesis?

6CO2 + 6H20 + Light energy ---> CH2O + O2

11

What is the delta G of this process?
Endothermic or exothermic?

+ 686 kcal/mol
Endothermic, requires energy

12

Is photosynthesis the reverse of cellular respiration?

NO. It's not the same process backwards

13

_______ is not the immediate product of photosynthesis . You can make glucose from the sugar product, but it is not the actual product.

Glucose

14

Only ___ CO2 is fixed at a time in the calvin cycle.
In other words, CO2 is metabolized ___ at a time.

one

15

6CO2 + 6H20 + Light energy --->CH2O + O2

Which reactant is oxidized?

H20

16

If you lose hydrogen, you're ________.
If you gain hydrogen, you're ________.

oxidized
reduced

17

6CO2 + 6H20 + Light energy ---> CH2O + O2

Which reactant is reduced?

CO2

18

What is CH2O?

A symbol for sugar.
A carbohydrate, CH2O

19

What do all organisms require?

Organic compounds

20

Who MAKES organic compounds from CO2?

Autotroph

21

What does autotroph mean?

Self feeder. You make your own food.

22

Who must OBTAIN organic compounds from other organisms?

Heterotrophs

23

Animals are ________.

heterotrophs

24

Photosynthesis is making _____ from the energy of ______.

sugar, light

25

It's an energy transformation, from light energy into ______ energy stored in sugar.

chemical

26

In eukaryotes, photosynthesis occurs in _________.

chloroplasts

27

Do prokaryotes do photosynthesis? If so, which ones?

Cyanobacteria are photosynthetic, but they don't do photosynthesis because they don't have chloroplasts

28

Eukaryotes do photosynthesis in _______, and in plants, it happens in _______.

chloroplasts, leaves

29

Are there any non-plant eukaryotes that can do photosynthesis?

The protist Euglena - photosynthetic

30

The leaf absorbs ___ from the atmosphere.

CO2

31

CO2 is the source of ______ to make sugar.

carbon

32

It is the leaf that releases _______. We said it's one of the byproducts of photosynthesis.

oxygen

33

That leaves us with water...where does water come from?
Water comes from the ______ which the plants brings up through vessels known as _____ vessels into the leaf where it can be used to make sugar.

ground, xylem

34

Why do plants need water?
We need CARBON...we need energy (SUNLIGHT), we need to store the energy....ELECTRONS. Where do you get electrons?

HYDROGEN. H20, water, is a source of electrons!

35

Leaves have pores called ______.

stomata

36

What are the leaf cells where photosynthesis happens?

Mesophyll cells

37

What is located within the mesophyll cells?

Chloroplast

38

Mesophyll cells are loaded with ________...that's the whole purpose! To do photosynthesis!

Chloroplast

39

The chloroplast is a complex organelle, bounded by ___ membranes

two

40

Does the inter membrane space of chloroplast have any significance?

No significance

41

What is important is the fluid filled space bounded by the inter membrane, and this is called the ______.

stroma

42

The _____ is where the soluble biochemistry happens.

stroma

43

Where does the calvin cycle occur?

In the stroma

44

Floating within the stroma is this third extended membrane, and it's called the _______.

thylakoid

45

Again, the thylakoid is an extended membrane. In some regions they're organized into these columns. These columns are called _______.

grana

46

What is a singular column called ?
What are multiple columns called ?

Granum
Grana

47

Where does the membrane biochemistry happen?

Grana

48

Where is the chlorophyll found?

In the thylakoid membrane

49

The thylakoid is an enclosed space. There is a lumen within, and it's called the thylakoid ______.

lumen

50

Photosynthesis has ___ stages.

two

51

What are the two stages called?

1) Light reactions
2) Light independent-reactions

52

Light reactions use the energy of light to energize ________.

electrons

53

Whose electrons?

Water's electrons

54

Water's electrons are energy _____.
We're going to get those electrons and in order to energize them...we need to rip them away from the oxygen!

poor.

55

Once we take those electrons (hydrogens) away, we need to transfer them to an electron carrier. An electron carrier is called a ________.

coenzyme.

56

What is the coenzyme that's going to carry the electrons from hydrogen?

NADP+

57

How is NADP+ different from NAD?

It has a phosphate on it

58

We have a dedicated coenzyme for photosynthesis, which is called ____.

NADP+ (You can think "NADP+, P for photosynthesis"

59

How many electrons and protons does NADP+ carry?

2e and 1p

60

What is the reduced coenzyme of NADP+?

NADPH

61

That's the whole point of the light reactions...to get those high energy electrons in the form of ______.

NADPH

62

The NADPH will then _____ the electrons to the next stage (light-independent reactions).

carry

63

NADPH will reduce ___ to make sugar.

CO2

64

Light reactions take electrons from H2O, give it to _____, then we get NADPH.
NADPH takes the electrons and reduces ___. So we get sugar.

NADP+, CO2

65

It's at this stage where we oxidize NADPH and we get _____ again.

NADP+

66

But we also need some ____ to run this light-independent reaction.

ATP

67

Where do we get the ATP?

It's a product of the light reactions

68

Light enters the leaf, enters the mesophyll cell, enters the chloroplast and strikes the ______.

Granum

69

The _____ is where the light is harvested. And that's where the ______ must be obtained.

granum, electrons

70

When you take electrons away from water, what are you left with?

Oxygen

71

Who do you give the electrons to?

The NADP+ and you get NADPH

72

How is the ATP made?

From ADP and inorganic phosphate. Reattach them and you get ATP

73

What are the two products of the light reactions?

NADPH and ATP.
They're going to feed into the calvin cycle.

74

Light has properties of ______ and _______.

waves and particles

75

The particle is called a _______.

photon

76

Photons are ______ particles with fixed amounts of energy.

discrete

77

There is a relationship between the amount of energy and the wavelength.
The shorter the wavelength, the ______ the energy.
The lower the energy, the ______ the wavelength.

greater
longer

78

We can see light between (approximately) ___ nm - ___ nm

400-800nm

79

It is that portion, ______ light, that also fuels photosynthesis.

visible

80

When light strikes matter, what three things can happen?

1) reflected
2) transmitted - passes through the matter
3) ABSORBED

81

It is only light _______ that can do any work.

absorbed

82

How is light harvested?
Light is absorbed by the ________ of the chloroplast.

thylakoids

83

What do thylakoids have in order to absorb light?

Pigments

84

Pigments are the chemical that ______ light.

absorb

85

What is the main pigment for photosynthesis?

Chlorophyll a

86

The photosystem is the light harvesting unit of the _________.

chloroplast.

87

These photosystem units have three components.
What are the three units?

1) Antenne complex
2) Reaction center chlorophyll
3) Primary electron acceptor - accepts the excited electron so that it doesn't drop down to the ground state.

88

What is that called, when you pass an electron from molecule to another?

Redox

89

Which photosystem operates first in the light reactions?

Photosystem II

90

What's the difference between the two photosystems?

They operate at different times in the light reactions and that is because their reaction center chlorophylls have slightly DIFFERENT ABSORBANCE PEAKS , so they're going to function in either this stage or that.

91

Light reactions have ____ parts.

four

92

What are the four parts of the light reactions?

1) Photosystem II - going to capture the excited electron
2) Electron transport chain - use the excited electron and to create a proton gradient
- use the proton gradient to make ATP
-at this point, the energy of the electron is low, need to re-energize it.
3) Photosystem I - re-energizes the electron, then passes it
4) Electron transport chain - short chain, then passes it to NADP+, and we got the electron.
DONE.

93

All of this is happening in the _______ membrane.

thylakoid

94

Steps of the light reactions...

1) Photosystem II absorbs _____.
-electron is transferred to the _______ _______ _______.
-reaction center is oxidized/reduced?
-primary electron center is oxidized/reduced?
(FIRST REDOX OF photosynthesis)

light
primary electron acceptor
reaction center is oxidized
primary electron center is reduced

95

If this photosystem is ever going to function again, what do we have to do?

A source of electrons from water in order to keep this process going

96

Steps of the light reactions...

2) Obtain an electron from ___.
-This requires an ______ to split the water, removing its electrons, removing the protons and putting them into solution.
-highly ________ process.
-Where does the energy source come from to energize the electrons?

H2O
enzyme
endergonic

The energy to take electrons from water is coming from the SUNLIGHT . This allows us to oxidize the water.

97

At the end of the light reactions, the energy rich electrons will go to ______.

NADP+, then reducing it, making NADPH, which is the primary product of the light reactions.

98

Light-independent reactions is in the form of a cyclical pathway known as the ______ cycle.

Calvin

99

It is the Calvin cycle which will _______ NADPH. We use the electrons to _______ CO2, and we get sugar.

oxidize, reduce

100

Steps of the light reactions...

3) Excited electron is transferred to an E.T.C
-ATP is made by ___________.

chemiosmosis

101

Protons moving across the thylakoid membrane from the ______ to the _______ ______.

stroma to thylakoid lumen

102

Making ATP from ADP and an inorganic phosphate driven by light energy is called ____________.

photophosphorylation

103

In chloroplasts, we concentrate protons in the ________ ______.

thylakoid lumen

104

Protons flow back into the _______.

stroma

105

Where do the electrons go?

Electrons come off the chain and reduce photosystem I

106

Steps of the light reactions...

4) P.S I absorbs ______.
-It is Re-excited by another photon
-Transferred to a 2nd primary electron acceptor

light

107

Steps of the light reactions...

5) Excited electron is transferred to a 2nd ____.

E.T.C

108

Steps of the light reactions...

6) Electron passed to NADP+ ---> _______.

NADPH.

Done.

Goal of the light reactions: Make NADPH, make ATP

109

Steps of the light reactions...

1) P.S II absorbs _____
2) Obtain an _______.
3) Excited electron is transferred to an ____.
4) P.S I absorbs ____.
5) Excited electron is transferred to a 2nd ____.
6) Electron passed to NADP+ ---> _______

light
electron
E.T.C
light
E.T.C
NADPH

110

How many photons are required to make one NADPH?

4 photons

111

Stage 2 : ______ cycle.
Occurs in the ______.

Calvin cycle
stroma

112

The calvin cycle is what produces ______.

sugar

113

The Calvin cycle has __ parts.

3

114

The first part of the Calvin cycle is _______ _______.
The second part is ________.
The third part is the ___________ of the CO2 acceptor.

carbon fixation
reduction
regeneration

115

What is the CO2 acceptor?

RuBP.
When CO2 joins with RuBP, you get an organic product. Carbon fixation.

116

***What is the sugar product of photosynthesis?***

***G3P***

117

How many cycles generate ONE G3P?

***3***
You need 3 CO2 to make ONE 3 carbon sugar

118

What is the molecule used to "fix" CO2?

RuBP.

119

What is the enzyme that catalyzes carbon fixation?

Rubisco