Bio Chem 2 Exam 3

ethanol lactate

can be formed by reactions that include NADH

acetyl CoA

a two-carbon unit from pyruvate ca be coupled to coenzyme A to form this

acetyl CoA

in the Citric Acid Cycle (CAC) pyruvate enters the mitochondria where it is converted into this under aerobic conitions

Acetyl CoA

is the fuel for the citric acid cycle, which processes the two-carbon acetyl unit to 2 molecules of CO2 while generating high energy electrons that can be used to form ATP

citric acid cycle (CAC)/ krebs cycle/ tricarboxylic acid cycle (TAC)

oxidizes two carbon-units, producing two molecules of CO2, one molecule of ATP ot GTP, and high-transfer-potential electrons

pyurvate dehydrogenase

is irreversible and will not go through gluconeogenesis

light energy

makes glucose and O2 (from aerobic) to go into the mitchondria which generates CO2 and water

matrix of mitochondria

the citric acid cycle takes place here

mitchondria matrix

is the innermost part of the mitochondria; contains enzymes and mitochondrial DNA

matrix

pyruvate is converted into acetyl CoA here

mitochondrions

have a double membrane (inner membrane and outer membrane)

matrix

oxidative decarboxylation of pyruvate and the sequence of reactions in the citric acid cycle take place here

mitochondria

there are more enzymes here than any other orangelle

pyruvate

is important in the link between glycolysis and the citric acid cycle because it is produced by glycolysis and converted into acetyl CoA which is the fuel for the citric acid cycle

faat acid degradation

other than pyruvate what is another important source of acetyl CoA for the citric acid cycle

pyruvate dehyrogenase complex

converts pyruvate, CoA, and NAD+ to acetyl CoA, CO2, NADH, and a proton

2, 8, 1

the citric acid cycle releases ___ CO2, ___ eletrons, and ___ ATP

carboxyl group; CO2

in the first step of oxidaiton of pyruvate, a ____ is removed from pyruvate, releasing ____

NAD+; NADH

in the second step of oxidation of pyruvate, ___ is reduced to ____

acetyl; acetl CoA

in the last step of oxidation of pyruvate, an ___ group is transfered to coenxyme A, resulting in ____

pyruvate dehydrogenase complex

is an irreversible reaction converting pyruvate to acetyl CoA

Pyruvate dehydrogenase component (E1)

dihydrolipoyl transacetylase (E2)

dihydrolipoyl dehydrogenase (E3)

what are the 3 enxymes required for pyruvate dehydrogenase reaction:

pyruvate dehydrogenase component (E1)

has 24 chains, its prothetic group is TPP, and catalyzes oxidative decarboxylation of pyruvate

dihydrolipoyl transacetylase (E2)

has 24 chains, its prosthetic group is lipoamide, and catalyzes transfer of acetyl group to CoA

dihydrolipoyl dehydrogenase (E3)

has 12 chains, its prosthetic group is FAD, and catalyzes regeneration of the oxidized form of lipoamide

TPP, Lipoic acid, and FAD

3 catalytuc enzymes (not altered):

NAD and CoA

2 stoichiometric enzymes (act as substrates):

FADH2

carries electrons, vitamin precursor is riboflavin (vitamin B2)

Coenzyme A

carries Acyl, vitamin precursor is pantothenate (vitamin B5)

lipoamide

carries Acyl and has no vitamin precursor

thiamine pyrophosphate

carries aldehyde, vitamin precursor is thiamine (vitamin B1)

decarboxylation

oxidation

transfer to CoA

3 steps of synthesis of acetyl CoA (2C) from pyruvate (3C):

pyruvate dehyrdogenase (E1)

catalyzes the decarboxylation of pyruvate

coenzyme thiamine pyrophosphate (TPP)

in the decaroxylation step, pyruvate combines with ionized form of this

Beri Beri

lack of TPP causes this; a neuromusclar and cardiovascular disorder

thiamine

thiamine pyrophosphate is derived from this vitamine

TPP

if this is not absorbed then pyruvate cant be made to acetyl CoA because there is no thymine

lactate

if TPP is not being absorbed then ____ will be made instead because the body needs energy (creates weakness and fatigue)

acetyllipoamide

the two carbon fargment is oxidized and trnsferred to dihydrolipoamide to form ____ an E2 in a reaction also catalyzed by E1

Hydroxyehtyl-TPP (ionized form) + lipoamide → carbanion of TPP + Acetyllipoamide

equation of the second step (oxidation) of the synthesis of acetyl CoA from pyruvate

Carbanion of TPP + Pyruvate + 2H+ → hydroxethyl-TPP

equation of the first step (decarboxylation) of the synthesis of acetyl CoA from pyruvate

E2

during the formation of acetyl CoA, ___ cataylzes the transfer of the acetyl group from acetyllipoamide to coenzyme A to form acetyl CoA

Coenzyme A + Acetyllipoamide → acetyl CoA + dihydrolipoamide

the last equation in the synthesis of acetyl CoA from pyruvate

reoxidized

after synthesis of acetyl CoA from pyruvate, dihydrolipamide must be ____ to participate in another eaction cycle

dihydrolipoamide dehydrogenase (E3)

the reoxidation of dihydrolipoamide is catalyzed by this

dihydrolipoamide + FAD → lipoamide + FADH2 + NAD+ → FAD + NADH + H+

the reaction equeation for reoxidizing dihydrolipomade

ATP, Acetyl CoA, and NADH

these 3 inhibit the synthesis of acetyl CoA by the pyruvate dehydrogenase complex

ADP and Pyruvate

the 2 simulate the synthesis of acetyl CoA from pyruvate

metabolism of glucose

the synthesis of acetyl CoA by the pyruvate dehydrogenase complex is a key irreversible step in the ____

NAD

makes energy through the electron transport chain; high level of this will deactivate pyruvate dehydrogenase

beta oxidation

when there are high levels of acetyl CoA it will be made into fatty acid but can be changed back into acetyl CoA through this

feedfoward activation mechanism

something that is upstream activates something that is downstream

PDH complex (pyruvate dehydrogenase)

is regulated to respond to the energy charge of the cell

PDH complex (pyruvate dehydrogenase)

the complex is inhibited by its immediate products, NADH and acetyl CoA, as well as the ultimate product of cellular respiration, ATP (high energy)

PDH complex (pyruvate dehydrogenase)

the complex is activated by pyruvate and ADP (low energy)

PDH kinase

this is associated with the PDH complex and phosphorylates and inactivates E1, uses ATP

PDH phosphatase

is associated with the PDH complex; it removes the phosphate and thereby activates the enzyme; activates the dehydrogenase by removing the phosphoryl group

kinase and phophatase

are highlt regulated enzymes in the pyruvate dehydrogenase complex

ADP and Calcium

as these levels go up it activates PDH phosphatase which activates PDH (cause muscle contractions)

lactic acid

pyruvate dehydrogenase deficiency is charactered by the buildup of this chemical in the body and a variety of neurological problems

pyruvate dehydrogenase deficiency

signs and symptoms of this condition usually first appear shortly after birth, and they can vary widely among affected indiviuals

lactic acidosis

the most common feature of PDH deficiency is a potentially life threatening buildup of lactic acid called _____, which can cause nausea, vomiting, server breathing problems, and an abnormal heartbeat

neurological problems

people with pyruvate dehydrogenase deficiency uasually have ______ some examples are having delayed development of mental abilities and motor skills such as sitting and walking

corpus callosum

when an individual has abnormal brain structures, such as underdevelopment of the tissue connecting the let ans right halves of the brain called ______

atrophy

wasting away

hypotonia

weak muscle tone

cerebral cortex

exterior part of the brain

lesions

patches of damaged tissue

citric acid cycle

is the biochemical hub of the cell, oxidizing carbon fuels, usually in the form of acetyl CoA, and serving as a source of precursors for biosynthesis

NADH, FADH2 (8 electrons), ATP, 2 CO2

the citric acid cycle releases two of each of these molecules:

citric acid cycle

oxidizes teo carbon units, producing two molecules of CO2, one molecule of ATP, and high energy electrons in the form of NADH and FADH2

acetyl fragment; CO2

in the citric acid cycle ____ of acetyl CoA is oxidizes to ____

NADH and FADH2

in the citric acid cycle high energy electrons are saptured in the form of ______

high energy electrons

a key function of the citric acid cycle is to harvest _____ from carbon fuels

succinyl CoA

the high energy molecule that releases ATP

citric acid cycle

constitutes the first stage in cellular respiration, the removal fo high energy electrons from carbon fuels

proton gradient

the electrons removed from carbon fuels in the citric acid cycle reduce O2 to generate a ____, which is used to synthesize ATP

oxidative phosphorylation

the reduction of O2 and the synthesis of ATP consitute ____

proton production

the electron transport chain is coupled to this

8

16 carbons will make ___ acetyl CoA

citrate synthase

in the first step of the citric acid cycle ____ catalyzes the condensation of acetyl CoA (2C) and oxaloacetate (4C) to form citrate (6C)

energy rich electrons

in the stage 1 of the citric acid cycle oxidation of two carbon atoms gather ____

aconitase

in stage 1 of the CAC ____ catalyzes the formation of isocitrate from citrate to be follwoed by decarboxylation because the streochemistry has to change in order to remove to CO2

isocitrate dehydrogenase

in stage 1 of the CAC ____ (an allosteric enzyme) catalyzes the oxidative decarboxylation of isocitrate, formaion alpha-ketoglutarate and capturing high-energy electrons as NADH

alpha-ketogluctarate dehydrogenase complex

in the stage 1 of CAC ____ (an allosteric enzyme) catalyzes the synthesis of succinyl CoA from alpha-ketoglutarate, generating NADH can CO2

pyruvate dehydrogenase complex

alpha-ketoglutarate dehydrogenase complex and the reactions are strucurally and mechanistically similar to the _____

succinyl CoA + CO2 + NADH

the products of this reactions are:

alpha-ketoglutarate + CoA + NAD+ → ( Alpha-ketoglutareate dehydrogenase)

acetyl CoA + CO2 + NADH H+

the products of this reactions are:

pyruvate + CoA + NAD+ → (pyruvate dehydrogenase)

regeneration of oxaloacetate and harvesting of energy-rich electrons

stage 2 of the citric acid cycle consitst of:

succinyl CoA synthetase

in stage 2 of the CAC ___ cataylyzes the cleavage of a thioester linkage and concomitantly forms GTP/ATP

GTP/ATP

cleavage of the tioester of succinyl CoA powers the formation of ____

substrate-level phosphorylation

the formation of GTP/ATP by succinyl coenzyme A synthetase is an example of a _____ because succinyl phosphate, a high phosphoryl transfer potential compound, donates a phosphate to ADP

histidine

in the reaction of succinyl CoA synthetase this acts as a base and an acid form; it grabs onto a phosphate and donates it to ATP

oxaloacetate

can condense with another acetyl CoA to initate another CAC

malate dehydrogenase

can make pyruvate into oxaloacetate (a reversble reaction)

2CO2 + 3NADH + FADH2 + ATP + 2H+ + CoA

the products of the CAC are

Acetyl CoA + 3NAD+ + FAD + ADP + Pi + 2H2O

2.5

the elctrons NADh will generate ___ ATP when used to reduce oxygen in the electron-transport chain

1.5

the electrons FADH2 will power the synthesis of ___ ATP with the reduction of oxygen in the electron transport chain

10

the CAC makes about ___ molecules of ATP per cycle

symmetric molecule

since succinate is a ____, the identity of carbon atoms from the acetyl unit is lost