Chapter 3 Flashcards
GLycolysis generates
It generates a NET 2 ATP and 2 NADH, and 2 pyruvate molecules that can enter the citric acid cycle for more ATP synthesis
Please note that glycolysis DOES MAKE 4 ATPs total however it had to use up 2 to prepare the 6 carbon ring for cleavage (gotta spend some to make some)
bond between the phosphate in ATP are ________: their hydrolysis is accompanied by a large decrease in free energy
high energy bonds
for ATP hydrolysis delta G is how much (kcal/mol)?
-12kcal/mol
Alternatively, ATP can be hydrolyzed to AMP plus
pyrophosphate (PPi)
the pyrophosphate is then rapidly hydrolyzed, and the total free- energy change is about ____ that from hydrolysis of ATP to ADP
twice
ATP hydrolysis can drive other reactions? True or false?
true
The first step in glycolysis is ______ (delta G =3.3 kcal/mol)
but it is coupled to ATP hydrolysis (delta G = -7.3 kcal/mol) making delta G (-4 kcal/mol)
unfavorable
remember that the first step in glycolysis is unfavorable. This is why you have to spend 2 ATPs in the begging to make 4 ATPs (aka net gain of 2 ATPs)…. however it can be coupled with ATP hydrolysis and this is what makes the reactions still able to occur
Glycolysis reaction equation: complete it:
glucose+ATP —.>
glucose-6-phospate+ADP
energy yielding reactions within the cell are coupled to ____
ATP synthesis
energy-requiring reactions are coupled to ___
ATP hydrolysis
the complete oxidation breakdown of glucose to CO2 and H2O yields a large amount of energy:
delta G = -686 kcal/mol
complete the reaction for the oxidative breakdown of glucose:
C6H12O6 +O2 —>
6CO2+6H2O
to harness the free energy, glucose is oxidize in a series of steps coupled to
ATP synthesis
The first step of generating ATP is __________ please describe it
glycolysis
occurs in all cells in the absence of oxygen; it can provide all the metabolic energy of anaerobic organisms
glycolysis results in the breakdown of glucose into pyruvate, with a net gain of 2 ATP
The first part of the pathway consumes energy
the enzymes that catalyze these reactions are important regulatory points; when there is an adequate supply of ATP, glycolysis is inhibited
glycolysis also converts two molecules of the coenzyes
NAD+ to NADH…
NAD+ acts as an oxidzing agent that accepts electrons
NADH must be recycled by serving as an electron donor for other oxidation-reduction reactions
in ___ the NADH is reoxidized to NAD+ by the conversion of pyruvate to lactate or ethanol
anaerobic conditions
in ________ the NADH donates electrons to the electron transport chain
aerobic condtions
glycolysis takes place in the
cytosol
in eukaryotic cells, pyruvate is then transported in to __________ where it is completely oxidized
mitochondria
pyruvate undergoes oxidative decarboxylation in the presence of _______________ forming____ generation of ______
in the presence of COENZYME A (COA-SH) forming ACETYL COA generation of 2NADH
______ enters the citric acid cycle
Acetyl CoA
in the citric acid cycle the 2 carbon acetyl group
combines with oxaloacetate (4 carbons) to yield nitrate (6 carbons)
in the citric acid cycle the remaining involve the 2 carbons of citrate
being completely oxidized to CO2 , where oxaloacetate is regenerated
2 carbons of citrate makes ??
2 CO2 1 oxaloacetate 1 GTP 3 NADH 1 FADH2
The complete oxidation of glucose makes what?
6 Co2
4 ATP
10 NADH
2 FADH2
Note that makes a total of 38 ATPs because :
one FADH2 makes 2 ATPs
one NADH makes 3 ATPS
Give the total ATP yield of glycolysis
2 ATP+2NADH
Give total ATP yield for citric acid cycle
2ATP, 8 NADH, 2 FADH2
give total ATP yield for oxidative phophorylation
each NADH yields 3 ATP, each FADH2 yields 2 ATP
polysaccharides can be broken down to ___ which are metabolized by glycolysis and the Krebs cycle
sugars
oxidation of lipids yields (more or less) energy per weight of starting material
more energy
Fats are first broken down to ______ and ____
glycerol and free fatty acids
each fatty acids is joined to ___ yielding a ___ at the cost of one ATP
coenzyme A,,, fatty acyl CoA
The fatty acids are then degraded in a stepwise oxidative process, two carbons at a time. each round of oxidation also yields _____ NADH and _____ FADH2
one NADH
one FADH2
the acetyl coA then enters the ______. the net gain is ____ ATPs per molecules of 16 carbon fatty acid. (compared to net gain of 38 ATPs per molecule of glucose
enters the citric acid cycle
net gain of 130 ATPS per molecule
most of the energy from the breakdown of carboyhydrates or fats is dervided by ______ and ____
electron transport
oxidative phosphorylation
Electrons from NADH and FADH2 are transferred to O2 which is coupled to the formation of
34 ATP by oxidative phosphorylation
to harvest the free energy in a usuable formthe process is gradual as electrons pass through a series of carriers, which constitute the
electron transport chain
components of the ______ are organized into ____ complexes in the inner mitochondrial membrane
electron transport chain
four complexes
NOTE INNER MITOCHONDRIA MEMBRANE
NADH is produced in the krebs cycle in the ___ of the mitrochondria
matrix
electrons from NADH enter the electron transport chain at _____
complex I
electrons are transferred to _____ by Coenzyme _ (ubiquinone)`
(mitrochondria)
complex III by coenzyme Q
_____ then carries electrons to complex IV (______) where they are transferred to O2
(mitrochondria)
cytochrome c then carries electrons to complex IV cytochrome oxidase, where they are transferred to O2
Note the energy yielding electron transfers at each step are coupled to ATP synthesis
passage of electron through complexes I, III, and IV drives synthesis of ATP by
oxidative phosphorylation
the energy derived from _____ coupled to the generation of a _______ across the inner mitochondrial membrane
electron transport
protein gradient
electron transport through complexes I, III, and IV is coupled to the transport of protons out of the interior of the mitrochondrion, establishing a _______ across the mitochondrial membrane
proton gradient
In complex IV,
__ proton per pair of electron are pumed across
__ combine with O2 to form H2O in the matrix
thus ___ protons per pair of electrons are transported at each complex
2 protons
two
4 protons per pair of electrons