Chapter 3 Flashcards by Jessica Gayle

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)

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bond between the phosphate in ATP are ________: their hydrolysis is accompanied by a large decrease in free energy

high energy bonds

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for ATP hydrolysis delta G is how much (kcal/mol)?

-12kcal/mol

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Alternatively, ATP can be hydrolyzed to AMP plus

pyrophosphate (PPi)

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the pyrophosphate is then rapidly hydrolyzed, and the total free- energy change is about ____ that from hydrolysis of ATP to ADP

twice

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ATP hydrolysis can drive other reactions? True or false?

true

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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

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Glycolysis reaction equation: complete it:

glucose+ATP —.>

glucose-6-phospate+ADP

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energy yielding reactions within the cell are coupled to ____

ATP synthesis

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energy-requiring reactions are coupled to ___

ATP hydrolysis

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the complete oxidation breakdown of glucose to CO2 and H2O yields a large amount of energy:

delta G = -686 kcal/mol

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complete the reaction for the oxidative breakdown of glucose:

C6H12O6 +O2 —>

6CO2+6H2O

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to harness the free energy, glucose is oxidize in a series of steps coupled to

ATP synthesis

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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

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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

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in ___ the NADH is reoxidized to NAD+ by the conversion of pyruvate to lactate or ethanol

anaerobic conditions

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in ________ the NADH donates electrons to the electron transport chain

aerobic condtions

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glycolysis takes place in the

cytosol

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in eukaryotic cells, pyruvate is then transported in to __________ where it is completely oxidized

mitochondria

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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

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______ enters the citric acid cycle

Acetyl CoA

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in the citric acid cycle the 2 carbon acetyl group

combines with oxaloacetate (4 carbons) to yield nitrate (6 carbons)

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in the citric acid cycle the remaining involve the 2 carbons of citrate

being completely oxidized to CO2 , where oxaloacetate is regenerated

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2 carbons of citrate makes ??

2 CO2
1 oxaloacetate
1 GTP
3 NADH 
1 FADH2

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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

the proton gradient is an

electrochemical gradient

the phospholipid bilayer is impermeable to ions, so protons can cross the membrane only through ________________-

protein channels

both the ________ and the _______ drive the protons back into the matrix, they combine to form an _________ across the inner membrane

pH gradient and the electric potential for an electrochemical gradient

protons can cross the membrane only through a ______________

protein channel

The protein channel allows energy in the electrochemical gradient to be harnessed and converted to ATP in complex V , also called __________

ATP synthase

ATP is generated as protons move with the concentration gradient through ______________ which is ____________

complex V | ATP synthase

ATP synthase consists of two components:

F0 forms a spinning channel through which protons pass F1 spins and harvests the free energy by catalyzing the synthesis of ATP

_____ converts the energy of sunlight to a usable form of chemical energy

photosynthesis. note it is ultimately the source of all metabolic energy in biological systems

What is the overall equation for photosynthesis

6CO2+6H2O---> C6H12O6+6O2

the process takes place in two stages: ___ reactions and _____ reactions

light and dark

light reactions: sunlight energy drives synthesis of ____ and ___ coupled to the oxidation of H2O to ____

ATP and NADPH | oxidation of H2O to O2

Dark reactions: the ATP and NADPH drive synthesis of carbohydrates from

CO2

in eukaryotic cells both light and dark reactions occur in what organelle?

chloroplast

sunligh is absorbed by ______ pigments, such as chlorophylls

photosynthetic

Absorption of light excites an ____ to a higher energy state, thus converting the energy of sunlight to the potential chemical energy

electron

the pigments are organized into _____ in the chloroplast membrane

photocenters

hundreds of pigment molecules absorb photons and transfer energy to _______________

reaction center chlorophyll

excited electrons are then transferred to an acceptor in the ______--

electron transport chain

in light reactions, energy from sunlight is used to split

H2O to O2

in light reactions, the resulting high energy electrons are then transported through a series of carriers and used to convert NADP + to _________

NADPH

in light reactions, the energy from the electron transport reactions also drive __________-

ATP synthesis

chloroplast have an internal membrane system, the _____________-

thylakoid membrane

the thylakoid membrane divides chloroplast into three internal compartments

stroma, intermembrane space, thylakoid lumen

four proteins complexes in the ___________ function in electron transport and synthesis of _____ and ________

thylakoid membrane, synthesis of ATP and NADPH

photons of light energy are absorbed by photosystems __ and ___

photosystems I and II

in the first electron transport pathway: at photosystem _____, H2O is split and the resulting electrons enter the transport chain

photosystem II

in the first electron transport pathway photo-system _____ generates NADPH, which is required for converting CO2 to carbohydrates

photosystem I

in the first electron transport pathway: photosystem ____and _______ complex generates a proton gradient that drives synthesis of ATP

Photosystem II and cytochrome bf complex

in a second electron transport pathway, cyclic electron flow, light absorbed at photosystem ____ is used to ____ instead of NADPH

cyclic electron flow, ligh absorbed at photosystem I is used to generate ATP instead of NADPH

in a second electron transport pathway, high energy electrons are transported back to the ____ complex and coupled to establishment of proton gradient

cytochrome bf complex

the energy in the proton gradient is almost entirely ______?

chemical

the thylakoid membrane is impermeable to other _____, particulary Mg+2 and Cl-

other ions

free passage of these ions neutralizes the voltage component of the _________

proton gradient

the difference in PH units between the stroma and the thylakoid lumen can be more then ?

3 Ph units

the total free energy stored across the thylakoid membrane is similar to that stored across the inner mitochondrial membrane? (true or false)

true

for each pair of electrons transported, ______ protons are transferred at photosystem II and _____ protons at cytochrome bf complex

2 protons are transferred at photosystem II 2-4 protons at cytochrome bf complex

since ___ protons are needed for synthesis of 1 ATP each pair of electrons yeilds ___ to ___ ATP

4 protons are needed for synthesis of 1 ATP each pair of electrons yields 1 to 1.5 ATP

cyclic electron flow yields____ ATP per pair of electrons

1 ATP per pair of electrons

in the dark reactions, the ATP and NADPH produced in the light reactions drive _________ from _________-

reactions drive synthesis of carbohydrates from | Co2 and H2O

one molecule of Co2 at a time is added to a cycle of reactions, the ______ cycle which leads to the formation of carbohydrates

calvin cycle

the calvin cycle consumes________ for each glucose produced

18 ATP and 12 NADPH

____ electrons are needed to convert each molecule of NADP+ to NADPH

two electrons

these electrons come from the conversion of ____ to ____

H20 to O2

energy from the breakdown of organic molecules (catabolism) drives synthesis of other components in the cell (true or false?)

true

____ pathways involve oxidation of organic molecules coupled to generation of ATP and reducing power (NADH)

catabolic pathways

____________ pathways use ATP and reducing power (NADH or NADPH) for the production for new organic compounds

anabolic or you can call it biosynthetic pathway an example would be dark reactions`

in animal cells, glucose synthesis (____________) usually starts with ??????????

gluconeogenesis this can usually start with: - lactate (from anaerobic glycolysis) - amino acids (From breakdown of protiens - glycerol (from breakdown of lipids)

plant cells can synthesize glucose from _______

fatty acids

in seed germination: energy stored as fats must be converted to carbohydrates for growth of the new plant. This is why it is important that plant cells can synthesize glucose from fatty acids. (true or false)

true

in ________ pyruvate is converted to glucose

gluconeogenesis

Gluconeogenesis is not simply the reversal of glycolysis pathways, it requires more energy to drive the pathway in direction of _______

biosynthesis

glucose is stored in the form of ___________

starch and glycogen

the dehydration reaction that ______ is energetically unfavorable, and must be coupled to an energy yielding reaction this is accomplished by the use of __________

joins two sugar molecules nucleotide sugars as intermediates

glucose is phosphorylated, then reacts ________, yielding _________

glucose is phosphorlyated the nreacts with UTP (uridine triphosphate) yeilding UDP glucose

____ glucose is and activated intermediate that then donates its glucose to a growing polysaccharide chain

UDP- glucose

proteins and nucleic acids contain ______. different organisms use different sources of _____

nitrogen

some bacteria uses atmospheric N2 by a process called _______, in which N2 is reduced to NH3. ATP is required

nitrogen fixation

most bacteria, fungi and aplants can use ____ which is common constituent of soil, by reducing it to NH3

nitrate NO3-

all organisms are able to incorporate _____ into organic compounds

ammonia

NH3 is incorporated during synthesis of the amino acids _____________

glutamate and glutamine these amino acids then donate amino groups to other amino acids, which are derived from intermediates in glycolysis and the citric acid cycle

bacteria and plants can synthesize all ____ amino acids

humans and other mammals can make only about half of the required _______, the remainder must be obtained from dietary sources

amino acids

synthesis of protiens also require energy? (true or false?)

true

unlike polysaccharide synthesis, amino acids are incorporated into protiens in a ____ order, specified by the order of nucleotide bases in a gene

unique order

what type of RNA acts as a template for protien synthesis?

messenger RNA, mRNA

each amino acid is attached to a specific __________ molecule in a reaction coupled to ATP hydrolysis

transfer RNA (tRNA)

__________ then align on the mRNA template, and each amino acid is added to the peptide chain is also coupled to the hydrolysis of _________-

the aminoacyl-tRNAS hydrolysis of ATP and GTP

nucleotides can come from dietary sources or from nucleic acid break down or be synthesized from ____________

carbohydrates and amino acids

synthesis of starts with ________. different pathways lead to synthesis of purine and pyrimidine ribonucleotides

ribose-5 phosphate