Photosynthesis Flashcards

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1
Q

C6H12O6 + 6 O2 —> 6 CO2 + 6H2O + energy
Which statement describes the results of this reaction?

A

C6H12O6 is oxidized and O2 is reduced

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2
Q

The oxygen consumed during cellular respiration is involved directly in which process or event?

A

Accepting electrons at the end of the electron transport chain (becomes water)

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3
Q

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only 2 molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

A

Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis

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4
Q

How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of 1 molecule of pyruvate?

A

2 carbon atoms

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5
Q

In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?

A

Energy released from movement of protons through ATP synthase

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6
Q

Carbon dioxide is released during which of the following stages of cellular respiration?

A

Oxidation of pyruvate to acetyl CoA and the citric acid cycle

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7
Q

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide and water?

A

Oxidative phosphorylation (chemiosmosis)

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8
Q

Approximately how many molecules of ATP are produced from the complete oxidation of 1 molecule of glucose (C6H12O6) in cellular respiration?

A

38 or 36

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9
Q

Which of the following most accurately describes what is happening along this chain? (Electron transport chain)

A

Each electron carrier alternates between being reduced and being oxidized

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10
Q

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of:

A

ATP, CO2, and ethanol (ethyl alcohol)

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11
Q

When oxygen is released as a result of photosynthesis, it is a by-product of which of the following?

A

Splitting the water molecules

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12
Q

What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

A

Bacteria congregated in these areas because these areas had the most oxygen being released

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13
Q

An outcome of the Engelmann experiment was to help determine:

A

The relationship between wavelengths of light and the oxygen released during photosynthesis

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14
Q

Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

A

Other pigments (antenna pigments) absorb light in addition to chlorophyll a

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15
Q

Which statement describes the functioning of photosystem II?

A

The electron vacancies in P680 are filled by electrons derived from water (splitting water)

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16
Q

Which of the following statements best represents the relationships between the light reactions and the calvin cycle?

A

The light reactions provide ATP and NADPH to the calvin cycle
Cycle returns ADP, Pi, and NADP+ to the light reactions

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17
Q

What is the primary function of the calvin cycle?

A

Synthesize simple sugars from carbon dioxide

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18
Q

The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which relationship would you expect to find?

A

The pH within the thylakoid is less than that of the stroma

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19
Q

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they:

A

Fix CO2 into organic acids during the night

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20
Q

Endergonic =

A

Anabolic

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21
Q

Exergonic =

A

Catabolic

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22
Q

Define hydrolysis

A

Adding water to break bond and extract energy

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23
Q

Exergonic is _______ energy

A

Extracting

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24
Q

Endergonic _______ and ______ energy

A

Requires and absorbs

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25
Q

Catabolic processes are almost always…

A

Hydrolysis reactions

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26
Q

Anabolic process are almost always…

A

Dehydration syntheses

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27
Q

The ______ the concentration of enzyme, the ______ the rate of reaction

A

Higher/higher, lower/lower

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28
Q

A pH change in an enzyme can prevent…

A

A polyphenol reaction

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29
Q

How would you change the salinity in an enzyme?

A

Adding ions
If hydrophobic/hydrophilic, structure might break

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30
Q

Define an acid

A

They liberate hydronium ions in aqueous solution
Donate a proton

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31
Q

How do enzyme speed up the rate of reaction?

A

Lowering the activation energy that is required to drive reaction

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32
Q

What does + delta G mean?

A

Spontaneous in the opposite direction

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33
Q

Define the active site

A

The groove in the surface of a 3D protein molecule

34
Q

What do competitive inhibitors do?

A

Bind to the active site so the substrate/reactant can’t react

35
Q

List all the possible names of things that activate enzymes

A

Coenzyme, cofactor, prosthetic group

36
Q

What is the role of catalase in a reaction?

A

Working as a catalyst

37
Q

All enzymes can…

A

Catalyze things

38
Q

What can cause changes in protein configuration of an enzyme?

A

Heat, pH, or salinity

39
Q

When heat, pH, or salinity changes the protein configuration of an enzyme, the enzyme is said to be…

A

Denatured and no longer functions as it should

40
Q

What is an example of changing the pH of an enzyme to denature it?

A

Adding like or lemon juice to guacamole and fruit salad

41
Q

Anabolic processes:

A

Build syntheses
Require energy
Endergonic
Glu + glu + glu —> starch
Condensation or dehydration reaction/synthesis

42
Q

Catabolic processes:

A

Break and decompose
Generate energy
Exergonic
Polypeptide —> pep + pep + pep
Hydrolysis reaction

43
Q

Proteins and carbs = how many calories?

A

4

44
Q

Fats = how many calories?

A

9

45
Q

Catalyzed reactions can only increase in rate if…

A

The enzymes occupied process the substrate/reactants faster
(Slight increase in temp)
OR
Increase the amount of enzyme

46
Q

If you reduce the amount of enzyme in a reaction or cool the reaction…

A

The rate of reaction will slow

47
Q

If all enzymes are occupied then…

A

Rate of reaction can’t be increased

48
Q

If you add to much heat to the reaction when trying to increase rate of reaction, the enzyme might…

A

Be denatured

49
Q

How do enzymes increase the rate of reaction by lowering the activation energy required to drive the reaction?

A

Holding substrate/reactants in their active site, reducing the energy for them to gain proximity for bond formation

50
Q

Define activation energy

A

Energy required to bring reactants together to promote bond formation of breaking of a bond

51
Q

Describe the calvin cycle

A

Light capture/dependent reactions
Ps II - split water, generate electrons
Ps 1 - Use those electrons to produce NADH+H+

NADH + H+ goes into calvin cycle which synthesizes simple sugars from CO2

52
Q

In exposure of fruit to air, like a cut apple or avocado, flesh undergoes a color change resulting from…

A

A catalyzed reaction

53
Q

Describe the preparatory step of the citric acid cycle after pyruvate feeds 2 carbons to it

A

1 of the carbons is broken free as the carboxyl group, forming a CO2

54
Q

We generate most of ATP from:

A

Oxidative phosphorylation/Chemiosmosis/Chemiosmotic synthesis/ATP synthesis

55
Q

C3 plants keep…

A

Their stomates open in the day, causing desiccation

56
Q

C4 cycle attaches…

A

CO2 as a carboxyl to molecule temporarily

57
Q

Define a catalyst

A

Molecules that function to speed up chemical reactions

58
Q

What type of light do antenna pigments absorb?

A

Chlorophyll b and c and beta-carotene

59
Q

Most ATP is produced by oxidative phosphorylation (chemiosmosis) in the…

A

Mitochondrian when glucose is completely oxidized to carbon dioxide and water

60
Q

Describe what happens in photosystem II

A

Splitting of the water molecule as electrons are shifted to electron vacancies in p680

61
Q

Describe what happens in photosystem I

A

Electrons are further energized by light energy absorbed by p700 and transferred to NADPH+H+

62
Q

Some ATP is generated as a result of…

A

Elevated energy from photosystem I

63
Q

Engelmann concluded bacteria congregated in these areas because these areas had the most oxygen being released. We know now that…

A

That is the effect of splitting the water molecule in photosystem II to generate O2 as waste

64
Q

What are the products of lactic acid fermentation in muscle tissue?

A

ATP, CO2, and lactate

65
Q

What are the products of glycolysis?

A

ATP, NADH, and pyruvate

66
Q

What happens to the CO2 generated as waste from most organic reactions?

A

It breaks free as a carboxyl group from an organic acid to generate the CO2 and transfer the H to NADH+H+

67
Q

Acetyl CoA is shuttled into the…

A

Citric acid cycle in the matrix of the mitochondrian to generate more ATP, NADH+H+, FADH2, and CO2 as waste

68
Q

The most immediate product of the calvin cycle is glycerate, but the carboxyl group is converted to form…

A

Glyceraldehyde that can be used to make glucose, frutose, and starch

69
Q

Which step shows a split of one molecule into two smaller molecules?

A

B (frustose-1, 6-biphosphate —> 2 glyceraldehyde-3-phosphate)

70
Q

What does letter a represent in the reaction of A+B?

A

Energy of catalyzed reaction

71
Q

What does letter e represent in the reaction of A+B?

A

Energy of uncatalyzed reaction

72
Q

What does letter b represent in the reaction of A+B?

A

Activation energy of catalyzed reaction

73
Q

What does letter c represent in the reaction of A+B?

A

Activation energy of uncatalyzed reaction

74
Q

What does letter d represent in the reaction of A+B?

A

Change in free energy
Delta G

75
Q

Assume that the reaction has delta G of -5.6 kcal/mol. Which of the following would be true?

A

The reaction would result in an increase in entropy (S) and a decrease in the total energy content (H) of the system

76
Q

What is the mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway?

A

Feedback inhibition

77
Q

If ATP used by this plant is labeled with radioactive phosphorus, in which molecules will the radioactivity be measurable after one turn of the cycle?

A

B, C, D, E

78
Q

if the carbon atom of the incoming CO2 molecule is labeled with a radioactive isotope of carbon, where will the radioactivity be measurable after one turn of the cycle?

A

A, B, C

79
Q

Which molecules of the Calvin cycle are most like molecules found in glycolysis?

A

C and D only

80
Q

In metabolic processes of cell respiration and photosynthesis, which prosthetic groups are encountered?

A

Heme and iron-sulfur complexes
They both oxidize and reduce during electron transport