Energy Transfer Flashcards

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1
Q

what happens to energy stored within covalent bonds

A
  • can be released through hydrolysis
  • stored in carrier molecules
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2
Q

what is the pathway of energy of sunlight to energy useful for cells

A
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3
Q

what is the energy currency of cells

A

ATP (adenosine triphosphate)

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4
Q

how does ATP form energy

A
  • terminal phosphate is easily hydrolyzed
  • energy released through hydrolysis can be used to fuel cellular processes
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5
Q

what happens when ATP goes to ADP

A
  • energy released through hydrolysis can be used to fuel cellular processes
  • released phosphate may be transferred to another molecule (which can change the shape and function of that molecule)
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6
Q

where do the three stages of catabolism of food take place

A
  • stage 1 outside of the cell
  • stage 2 mostly in cytosol
  • stage 3 mitochondria
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7
Q

what happens in stage 1 of food catabolism

A
  • food is broken down into simple subunits
  • proteins to AA
  • polysaccharides to simple sugars
  • fats to fatty acids + glycerol
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8
Q

what happens in stage 2 of food catabolism

A
  • simple subunits are converted to acetyl CoA (glucose to pyruvate to acetyl CoA via glycolysis)
  • limited amounts of ATP and NADH produced
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9
Q

what happens in stage 3 of food catabolism

A
  • acetyl CoA is converted to H2O and CO2 (oxidative phosphorylation)
  • large amounts of ATP produced
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10
Q

what are the inputs and outputs of glycolysis

A
  • input
  • 2ATP
  • output
  • 2 NADH, 4 ATP, 2 pyruvate
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11
Q

what is the net result of glycolysis

A
  • 2 NADH
  • 2 ATP
  • 2 pyruvate
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12
Q

what is substrate-level phosphorylation

A

glycolysis

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13
Q

what is the NADH produced in glycolysis used for

A

used later in oxidative phosphorylation

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14
Q

what is gluconeogenesis

A
  • process to store and increase available glucose
  • builds glucose molecules from pyruvate
  • essentially the reverse of glycolysis
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15
Q

what are the 3 main steps in glycolysis

A
  1. energy investment to be recouped later
  2. cleavage of 6C sugar to 3C sugar
  3. energy generation
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16
Q

what is the input and output of gluconeogenesis

A
  • input
  • 4 ATP, 2GTP, 2 pyruvate, 2NADH, 6H2O
  • output
  • glucose, 4ADP, 2GDP, 2NAD+, 2H+
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17
Q

how is gluconeogenesis driven

A

through feedback regulation of two enzymes: phosphofructokinase and fructose 1,6-biphosphatase

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18
Q

what activates/ inhibits glycolysis and gluconeogenesis

A
  • ADP, AMP, and phosphate activate glycolysis and inhibit gluconeogenesis
  • ATP inhibits glycolysis and activates gluconeogenesis
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19
Q

what do phosphofructokinase and fructose 1,6-biphosphatase do

A
  • phosphofructokinase catalyzes the phosphorylation of fructose 6-phosphate to form fructose 1, 6-bisphosphate in step 3 of glycolysis
  • fructose 1,6-bisphosphatase removes the phosphate from fructose 1,6-bisphosphate in gluconeogenesis
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20
Q

how is glucose stored in animal cells vs plant cells

A
  • animal cells glycogen
  • plant cells starch
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21
Q

Glycogen is synthesized by _______ and broken down into glucose by ________

A
  • glycogen synthase
  • glycogen phosphorylase
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22
Q

how is glycogen synthesized

A

by glycogen synthase

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23
Q

how is glycogen broken down into glycose

A

by glycogen phosphorylase

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24
Q

what is the primary source of ATP in oxygen-limited conditions

A

glycolysis

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25
Q

what is the primary source of ATP in anaerobic organisms

A

glycolysis

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26
Q

how can pyruvate be broken down, and where

A
  • via fermentation
  • in the cytosol
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27
Q

what can pyruvate be broken down into

A
  • lactate
  • ethanol
28
Q

what are the inputs and outputs of fermentation in a vigorously active muscle cell

A
  • inputs
  • pyruvate
  • 2NADH from glycolysis
  • outputs
  • lactate
  • 2NAD+
29
Q

what are the inputs and outputs of fermentation in yeast

A
  • inputs
  • pyruvate
  • 2NADH from glycolysis
  • H+
  • outputs
  • ethanol
  • 2NAD+
  • CO2
30
Q

what is the matrix of the mitochondria

A
  • high [ ] mixture of many enzymes
  • (including those needed for oxidation of pyruvate and fatty acids for the citric acid cycle)
31
Q

what is the inner membrane of the mitochondria

A
  • folded into many cristae
  • contains proteins that carry out oxidative phosphorylation
  • (including electron-transport chain and ATP synthase)
  • contains transport proteins that move select molecules in and out of the matrix
32
Q

what is the outer membrane of the mitochondria

A

contains large channel-forming proteins (porins), making it permeable to all molecules 5000Da or less

33
Q

what is the intermembrane space of the mitochondria

A
  • contains enzymes that use ATP passing out of the matrix to phosphorylate other nucleotides
  • contains proteins released during apoptosis
34
Q

how is acetyl CoA formed

A
  • pyruvate is pumped into the mitochondrial matrix
  • rapidly decarboxylated into CO2, NADH, and acetyl CoA
  • this is done by the pyruvate dehydrogenase complex
35
Q

what are the components of the pyruvate dehydrogenase complex

A
  • pyruvate dehydrogenase removed CO2 from pyruvate
  • dihydrolipoyl transacetylase turns coenzyme A into acetyl CoA
  • dihydrolipoyl dehydrogenase turns NAD+ into NADH
36
Q

how is fat an energy source

A
  • fatty acids can be converted into acetyl CoA in the mitochondrial matrix
  • fatty acyl CoA oxidized in a cycle
37
Q

what are the inputs and outputs of the fatty acyl CoA being oxidized

A
  • inputs
  • fatty acyl CoA, FAD, H2O, NAD+,
  • outputs
  • acetyl CoA, NADH, FADH2
38
Q

what are the other names for the citric acid cycle

A
  • krebs cycle
  • tricarboxylic cycle
39
Q

what does the citric acid cycle do

A

catalyzes the oxidation of carbon atoms of the acetyl groups in acetyl CoA, converting them to CO2

40
Q

what are the inputs and outputs of the citric acid cycle

A
  • inputs
  • 2 acetyl CoA molecules
  • outputs
  • 3 NADH, 1 GTP, 1 FADH2, 2 CO2
41
Q

cells obtain most of their ATP how

A

via membrane-based mechanisms using energy generated from food or sunlight

42
Q

what are the two stages in which ATP is generated

A
  1. energy released by electron transport is used to pump protons across membrane
  2. energy stores in the proton gradient is harnessed by ATP synthase to make ATP
43
Q

what does the energy from NADH do

A
  • NADH donates its high eng electrons to the electron transport chain
  • this enables the movement of H+ across the inner membrane to maintain the electrochemical gradient
44
Q

what is the electron transport chain

A
  • comprise over 40 proteins organized into 3 large complexes
  • each complex contains metal ions w incrasing affinity for electrons
45
Q

which complexes are involved in the ETC

A
  • NADH dehydrogenase complex
  • cytochrome c reductase complex
  • cytochrome c oxidase complex
46
Q

what are the mobile carriers in the ETC

A
  • ubiquinone
  • cytochrome c
47
Q

what drives enzymatic activity of ATP synthase

A

proton gradient

48
Q

how does ATP synthase make ATP

A
  • acts like a motor to convert the energy of protons flowing down their electrochemical gradient to chemical-bond energy in ATP
  • the rotating part of the synthase spins really fast as a result of the proton gradient
  • this causes Pi and ADP to merge and form ATP
49
Q

describe the structure of ATP synthase

A
  • has a stationary head (F1 ATPase)
  • rotating portion (F0 rotor), which has a rotor ring and a central stalk
50
Q

what can the F1 ATPase do

A

can convert ATP to ADP and Pi when not attached to the F0 rotor

51
Q

can ATP synthase work in either directions and why

A
  • yes!
  • because its dependent on the proton gradient
52
Q

when is ATP synthase used to maintain the H+ gradient

A

in bacteria capable of both aerobic and anaerobic growth, under O2 limited conditions

53
Q

what are the 2 primary stages in photosynthesis

A
  1. light reactions chlorophyll captures energy from light and transfers it to produce ATP and NADH
  2. light-independent reactions ATP and NADH are used to manufacture sugars from CO2
54
Q

what is a photosystem

A

a reaction center surrounded by chlorophyll-containing antenna complexes

55
Q

what happens when light reaches a photosystem

A
  • light energy will excite a chlorophyll molecule in the antenna complex
  • it will pass from one molecule to another until it reaches the reaction center
  • within the reaction center, the energy will be trapped in a chlorophyll special pair
  • the energy trapped in the special pair will transfer electrons to an electron carrier right next to it
56
Q

what happens when electrons are transferred to plastoquinone in photosystem II

A

the electrons will then be transferred to a proton pump (cytochome b6-f complex) to generate the electrochemical gradient needed for ATP synthesis

57
Q

what is photosystem II used for

A

creating the H+ gradient to drive ATP synthase

58
Q

what is photosystem I used for

A

to reduce NADP+ to NADPH

59
Q

which electron carrier is in photosystem II

A

plastoquinone

60
Q

which electron carrier is in photosystem I

A

ferredoxin

61
Q

what happens once electrons are transferred to ferredoxin in photosystem I

A

high energy electrons will be transferred to an enzyme (FNR) to reduce NADP+ to NADPH

62
Q

what happens in the calvin cycle

A
  • ATP and NADPH are used in carbon fixation to produce sugar
  • CO2 from the atmosphere combines w ribulose to produce G3P
63
Q

what are the inputs and outputs of the calvin cycle

A
  • input
  • 3CO2, 9ATP, 6NADPH
  • output
  • 1G3P, 9ADP, 6NADP+
64
Q

what does G3P stand for

A

glyceraldehyde 3-phosphate

65
Q

what works in plants to supply it w metabolites and ATP

A
  • mitochondria
  • chloroplasts
66
Q

ATP and NADPH are used to do what

A

manufacture sugars in carbon fixation

67
Q
A