Metabolism Flashcards
(98 cards)
1
Q
Autotrophs
A
organisms that obtain their carbon from in an inorganic form (such as CO2)
2
Q
Photosynthesis
A
using solar energy to convert inorganic carbon into organic carbon
3
Q
Chemosynthesis
A
Using chemical energy to convert inorganic carbon into organic carbon
4
Q
Heterotrophs
A
Organisms that take in carbon already in an organic form from other organisms
5
Q
Metabolism
A
All enzyme catalyzed reactions in a cell
6
Q
Catabolism
A
Degrading reactions, typically release energy
7
Q
Anabolism
A
Building reactions, typically requires energy
8
Q
ATP
A
Adenosine Triphosphate, an energy carrier or transmitter, not an energy store. A nucleoside triphosphate with Adenine as the nucleoside base.
9
Q
Nucleoside triphosphate
A
A class of molecule to which ATP belongs. A nucleoside base, attached to a ribose molecule bonded to a chain of three phosphate molecules. The bonds between phosphate molecules have lots of energy.
10
Q
ADP
A
Adenosine Diphosphate
11
Q
Energy released in going from ATP to ADP
A
30.5Kj
12
Q
phosphorylation
A
A reaction where phosphate is added to something, for example to ADP to make ATP
13
Q
Substrate level Phosphorylation
A
Phosphate moves from one substrate to another
14
Q
NAD+ and FAD
A
nicotinamide adenine dinucleotide and Flavin adenine dinucleotide respectively, they act as electron acceptors
15
Q
Aerobic Respiration
A
Fuel is completely oxidized to CO2 and ATP is generated through both substrate level Phosphorylation and oxidative phosphorylation
16
Q
What form of NAD+ and FAD is oxidized
A
NAD+ and FAD
17
Q
what form of NAD+ and FAD is reduced
A
NADH and FADH2
18
Q
Glycolysis
A
the first stage of ATP generation of any kind in which glucose is converted through a 10 step process to pyruvate
19
Q
1st step of glycolysis
A
glucose is phosphorylated to glucose-6-phosphate, consuming 1 ATP
20
Q
2nd step of glycolysis
A
glucose-6-phosphate is isomerised to fructose-6-phosphate
21
Q
3rd step of glycolysis
A
fructose-6-phosphate is phosphorylated to fructose-1,6-bisphosphate, this consumes 1 ATP
22
Q
4th step of glycolysis
A
fructose-1,6-bisphosphate is cleaved to produce dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P)
23
Q
DHAP
A
dihydroxyacetone phosphate
24
Q
G3P
A
glyceraldehyde-3-phosphate
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5th step of glycolysis
DHAP is isomerised to G3P, there are now two G3P molecules that proceed through the reaction
26
6th step of glycolysis
G3P is oxidized to 1,3-bisphosphoglycerate, this reduces one NAD+ and consumes one phosphate
27
7th step of glycolysis
1,3-bisphosphoglycerate is dephosphorylated to 3-phosphoglycerate generating 1 ATP
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8th step of glycolysis
3-phosphoglycerate is converted to 2-phosphoglycerate
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9th step of glycolysis
2-phosphoglycerate is converted to phosphoenolpyruvate
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10th step of glycolysis
phosphoenolpyruvate is dephosphorylated to pyruvate generating 1 ATP
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Overall reaction of glycolysis
glucose + 2ADP + 2Pi + 2NAD+ -> 2pyruvate + 2ATP + 2NADH
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Fermentation
A process of breaking down pyruvate that serves to oxidize NADH such that the cell does not run out of NAD+ required for glycolysis
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where does ethanol fermentation occur
The cytoplasm of yeast cells
34
what is the process of ethanol fermentation
pyruvate gives off CO2 making acetaldehyde which further converts to ethanol. NADH is oxidized in the process
35
what is the overall reaction of ethanol fermentation and glycolysis
glucose + 2ADP + 2Pi -> 2ethanol + 2CO2 +2ATP
36
where does lactic acid fermentation occur
in the cytoplasm of muscle cells and microbes
37
what is the process of lactic acid fermentation
pyruvate converts to lactate and NADH is oxidized
38
what is the overall reaction of lactic acid fermentation and glycolysis
glucose + 2ADP + 2Pi -> 2lactate + 2ATP
39
TCA Cycle
The section of ATP generation after glycolysis where pyruvate is oxidized to CO2. Also called the krebs cycle or the citric acid cycle
40
TCA Cycle
The section of ATP generation after glycolysis where pyruvate is oxidized to CO2. Also called the krebs cycle or the citric acid cycle
41
CoA
Co-enzyme A, an enzyme that activates pyruvate allowing it to enter into the mitochondria and the TCA Cycle
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TCA
tricarboxylic acid
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Step 1 of the TCA Cycle
Pyruvate (3C) is decarboxylated to acetyl CoA (2C) realising 1 CO2 and producing 1 NADH
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Step 2 of the TCA Cycle
Acetyl CoA (2C) is combined with oxaloacetate (4C) to produce citrate (6C)
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Step 3 of the TCA Cycle
Citrate (6C) is isomerised to isocitrate (6C)
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Step 4 of the TCA Cycle
Isocitrate (6C) is oxidized to alpha-ketoglutarate (5C) producing 1CO2 and 1NADH
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Step 5 of the TCA Cycle
alpha-ketoglutarate (5C) is oxidized to succinyl CoA (4C) producing 1CO2 and 1NADH, at this stage the pyruvate has been completely oxidized
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Step 6 of the TCA Cycle
Succinyl CoA is converted to Succinate producing 1GTP through substrate level Phosphorylation
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GTP
Guanosine triphosphate, basically just ATP
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Step 7 of the TCA Cycle
Succinate is oxidized to fumerate, producing 1 FADH2
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Step 8 of the TCA Cycle
fumarate is converted to malate
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Step 9 of the TCA Cycle
malate is oxidized to oxaloacetate, producing 1 NADH. Oxaloacetate then goes to step 2.
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Glycerol Phosphate shuttle
In the presence of oxygen NADH from glycolysis is oxidized alongside dihydroxyacetone phosphate reducing to 2-glycerol-3-phosphate. 2-glycerol-3-phosphate can travel into the mitochondria and oxidized back to dihydroxyacetone phosphate allowing FAD to oxidize to FADH2. The dihydroxyacetone phosphate then leaves the mitochondria and continues through glycolysis.
54
How many moles of ATP are produced from 1 mol of glucose
36, 2 from glucose, 30 from TCA/ETC and 4 from the G3P shuttle
55
The overall reaction of ATP generation
glucose + 6O2 + 36ADP + 36Pi -> 6CO2 +6H2O + 36ATP
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How much energy is released from glucose, trapped in ATP and what is the efficiency
2870Kj released, 1098Kj trapped. efficiency is 38%
57
Electron Transport Chain
A series of redox reactions resulting in the reduction of O2 to H2O that serves to re-oxidise electron acceptors and generate ATP
58
Cytochrome
general name for proteins that contain iron ions that van be either oxidized (Fe3+) or reduced (Fe2+)
59
what is the sequence of chemicals in the electron transport chain
NADH -> NADH oxidoreductase -> coenzyme q -> cytochrome b -> cytochrome c1 -> cytochrome c -> cytochrome (a+a3) -> O2 to H20
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at what step does FADH2 enter the chain
FADH2 passes it's electron to coenzyme q
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How much ATP is released from NADH and FADH2
3 ATP from NADH and 2 ATP from FADH2
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Why does NADH not just immediately react to H20
Thos would be less efficient as the energy released would only have the potential to be captured by one ATP instead of 3
63
Where does oxidative Phosphorylation/ETC occur
in the intermembrane space of the mitochondria/in the inner membrane of the mitochondria
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Respiratory Control
regulation of oxidative Phosphorylation by ADP levels, preventing the coupled process of ETC occurring hence preventing he unnecessary catabolism of fuel
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Chemiosmotic theory
Energy released during the ETC forve H+ ions across the inner mitochondrial membrane into the intermembrane space, the resulting electrochemical gradient causes H+ ions to flow back across the membrane through ATP synthase, the gradient's energy is hence used by ATP synthase to synthesize ATP
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ATP Synthase
a protein imbeded in the inner mitochondrial membrane that is used to synthesize ATP in line with the chemiosmotic theory
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What reaction does ATP synthase make use of
ATP + H2O ADP + Pi + H+
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Translocase proteins
proteins that allow ADP and Pi to enter the mitochondria and ATP to exit the mitochondria
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2,4-dinitrophenol
a chemical that uncouples ETC and oxidative phosphorylation by shuttling protons across membranes
70
How are other saccharides metabolized
They are cleaved into monosaccharides (in the digestive track/inside bacteria/by enzymes excreted by bacteria) and then reactes into a chemical used in glycolysis, resulting in the same ATP output as glucose
71
amylase
an enzyme that breaks down starch and glycogen
72
cellulase
an enzyme that breaks down cellulose
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How are triglycerides metabolized
glycerol proceds through glycolysis (with a net gain of 1 ATP) and the fatty acid chains are split into acetyl CoA and procced through the TCA Cycle
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how are proteins metabolized
the a NH2 groups of amino acids are removed through deamination and the the left over bits are fed into the TCA Cycle
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Gluconeogenesis
synthesis of glucose from non-carbohydrate precursors mostly occuring in the liver and kidneys
76
Where do precursors feed in to gluconeogenesis
lactate and some amino acids are converted to pyruvate, other amino acids are converted straight to oxaloacetate
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pyruvate kinase
enzyme associated with the reaction of phosphoenolpyruvate to pyruvate
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phosphofructokinase
enzyme associated with the reaction of fructose-6-phosphate to fructose-1,6-bisphosphate
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hexokinase
enzyme associated with the reaction of glucose to glucose-6-phosphate
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4 essential enzymes for gluconeogenesis and their location
pyruvate carboxylase (mitochondria), phosphoenolpyruvate carboxykinase (cytoplasm), fructose-1,6-bisphosphatase (cytoplasm), glucose-6-phosphatase (endoplasmic reticulum)
81
step 1 of gluconeogenesis
pyruvate is carboxylated to oxaloacetate in the mitochondria requiring one ATP and using pyruvate carboxylase
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step 2 of gluconeogenesis
oxaloacetate is temporarily converted to malate so it can leave the mitochondria before being oxidized back, NAD+ is used as an electron acceptor
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step 3 of gluconeogenesis
oxaloacetate is decarboxylated and phosphorylated to phosphoenolpyruvate requiring one GTP and using phosphoenolpyruvate carboxykinase
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step 4 of gluconeogenesis
phosphoenolpyruvate is converted to 2-phosphoglycerate
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step 5 of gluconeogenesis
2-phosphoglycerate is converted to 3-phosphoglycerate
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step 6 of gluconeogenesis
3-phosphoglycerate is phosphorylated to 1,3-bisphosphoglycerate requiring 1 ATP
87
step 7 of gluconeogenesis
1,3-bisphosphoglycerate is reduced and dephosphorylated to glyceraldehyde-3-phosphate, oxidizing one NADH to NAD+
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step 8 of gluconeogenesis
half the G3P is converted to DHAP
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step 9 of gluconeogenesis
one G3P and DHAP are combined to make fructose-1,6-bisphosphate
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step 10 of gluconeogenesis
fructose-1,6-bisphosphate is dephosphorylated to fructose-6-phosphate using phosphofructokinase
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step 11 of gluconeogenesis
fructose-6-6-phosphate is isomerised to glucose -6-phosphate
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step 12 of gluconeogenesis
glucose-6-phosphate is dephosphorylated to glucose using hexokinase
93
Overall formula for gluconeogenesis
2pyruvate + 4ATP + 2GTP + 2NADH -> glucose + 4ADP + 2GDP +6Pi + 2NAD+
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Photosynthesis
A series of reactions converting CO2 to organic sugars using solar energy
95
where does photosynthesis occur
chloroplasts, a type of plastid
96
what are the two phases photosynthesis
energy transduction (converting light to chemical energy-light dependent) carbon assimilation (carbon is converted to organic sugars-light independent)
97
describe energy transduction
light passes through leaves, hitting the thylakoid where membrane bound proteins use light to oxidize water creating an energy gradient with protons going from the stroma to the thylakoid lumen. the ETC makes NADPH and ATP synthase makes ATP
98
equation for carbon assimilation
6CO2 + 12H2O -> C6H12O6 + 6H20 + 6O3 this uses ATP and NADPH
