Biochem Exam 2 (3-4)

question

where does the Pentose Phosphate Shunt happen?
answer

cytoplasm
question

this is a product of PPP and it is necessary to make nucleotides and deoxynucleuotides
answer

Ribose-5-Phosphate
question

this product of the PPP is primarily involved in reduction reactions and is most prominent in making fatty acids and dealing with oxidative damage
answer

NADPH
question

in the liver, about ____% of liver glucose metabolism goes through the PPP but it is higher in places where you make ___________
answer

5-10 fatty acids (adipocytes)
question

what does NADPH stand for?
answer

nicotinamide adenine dinucleotide-phosphate (Derived from Niacin)
question

NADPH is prominent in synthesis of ______ and detoxification of
answer

fatty acid, cholesterol, neurotransmitter, nucleotide, reduction of oxidized glutathion e, cytochrome P450 monooxygenases
question

thiamine containing enzyme that moves 2 carbon units and has been used to measure thiamine concentrations in people by measuring enzyme activity
answer

transketolase
question

if you have a thiamine deficiency, you will develop ____________ which most often comes up in alcoholics and gives rise to ___________
answer

wernicke-korsakoff syndrome wet or dry beriberi
question

what is the function of transaldolase?
answer

move 3 carbons
question

the first committed step in the pathway, where regulation primarily occurs, is at _________
answer

glucose-6P to phosphogluconolactone by G6PDH
question

in PPP, G6PDH is activated by _________ and deactivated by __________
answer

insulin NADPH
question

since the kM of G6PDH is ______ than the concentration of [NADPH] in the committed step of PPP, this means that the reaction favors ___________ and must be inhibited
answer

less NADPH
question

what are the names of the steps, in order, of oxygens oxidation states?
answer

molecular oxygen superoxide radical ion hydrogen peroxide hydroxyl radical
question

what is the most reactive oxygen species? (can break DNA and lead to mutations in patients)
answer

hydroxyl radical
question

superoxide reacts with hydrogen peroxide to produce hydroxyl radical
answer

haber-weiss reaction
question

hydrogen peroxide reacts with iron to produce hydroxyl radical
answer

fenton reaction
question

this is caused by a deficiency in NADPH oxidase and it results in multiple fungal infections and problems fighting pathogenic infection
answer

Chronic Granulomatous Disease
question

hydrogen peroxide makes hydrochloric acid through ___________ which is also used to generate bleach
answer

myeloperoxidase
question

what are the diseases thought to be associated with free radical injury?
answer

atherogenesis, ischemia (reperfusion injury), alcoholism, ALS, acute renal failure, emphysema
question

this occurs after an ischemic attack and happens when the blood supply is restored suddenly, leading to a burst of oxygen and a shower of oxygen radicals
answer

reperfusion injury
question

this is a major problem caused by peroxides because it disrupts membrane structures
answer

lipid peroxidation
question

oxygen radicals can attack _____, _____, and ______
answer

lipids, carbs, proteins
question

what vitamins/bioflaivonoids that can be used to protect ourselves from free radical damage?
answer

vitamin a, vitamin c, vitamin e, green tea, turmeric, chocolate
question

this enzyme converts superoxide to hydrogen peroxide
answer

Superoxide Dismutase (SOD)
question

_________ reduces peroxides into water and at the same time, it is oxidized into _______
answer

glutathione Peroxidase (GSH) GSS
question

glutathione is a _________ containing enzyme and since it is ___________, it is responsible for the ________ environment of the cytoplasm of cells
answer

selenium reducing
question

inside of the cell, _____ bonds are common and outside of the cell (also in the ER), ____ bonds are common
answer

SH SS
question

NADPH produced by _____________ maintains the supply of glutathione needed to destroy peroxides
answer

glucose-6P-dehydrogenasee
question

a deficiency in _________ is extremely common with a similar distribution as malaria and sickle cell anemia since they all affect red blood cells
answer

glucose-6-phosphate
question

when you have a G6PDH deficiency, __________ form in RBC’s when the cells are exposed to an oxidizing chemical in vitro. These form (like a precipitation of hemoglobin) due to the ________ bonds between hemoglobin molecules since there is not enough reducing activity to keep the hemoglobins in a ______ state
answer

heinz bodies disulfide SH
question

these are immature RBC’s often seen as a side effect in someone with a G6P DH deficiency
answer

Reticulocytes
question

if you put _______ stress on a person who has a glucose-6-phosphate Dehydrogenase activity, there will be displayed symptoms. Situations that put this type of stress are…
answer

oxidative, sulfonamides, aspirin, NSAIDs, Quinine, Quinadine, Napthylene, Fava Beans
question

in glucose-6-phosphate dehydrogenase deficiency, what change in the normal red blood cell leads to hemolytic anemia?
answer

decreased concentration of NADPH, defect in GSSG
question

why are RBC’s so sensitive to NADPH?
answer

they only have one way to make NADPH!
question

why dont RBC’s do the TCA cycle?
answer

they don’t have a mitochondira
question

glycogen is the main source of energy until about ____ hours of starvation in which ________ becomes the main source of glucose
answer

16 gluconeogenesis
question

In Claude Bernard’s Experiment, he concluded that dogs do not eat carbohydrates from looking at the portal vein which _______ the liver and has a _____ glucose conc and the hepatic vein which _______ the liver and has a _______ glucose conc
answer

enters low leaves high
question

approximately 90 % of gluconeogenesis occurs in the ______, 10% in the ________ and the fraction of glycolysis increases in the _________ during starvation
answer

liver kidney kidney
question

what are the precursors for gluconeogenesis?
answer

pyruvate, lactate, amino acids, glycerol
question

this GNG precursor comes from pyruvate
answer

lactate
question

this GNG precursor comes from pyruvate and TCA intermediates
answer

amino acids
question

this GNG precursor comes from dihydroxyacetone phosphate
answer

glycerol
question

the reaction of GNG that involves pyruvate carboxylase takes place in what sub-cellular location?
answer

mitochondria
question

the reaction of GNG that involves glucose-6-phosphatase occurs in what sub-cellular location?
answer

ER
question

what are the reactants of gluconeogenesis?
answer

2 Pyruvate, 4 ATP, 2 GTP, 2 NADH, 2 H
question

what are the products of gluconeogenesis?
answer

glucose, 2 ADP, 2 GDP, 2 NAD+, 6 Pi
question

oxaloacetate is converted to ______ or ______ to be transported out of mitochondria
answer

malate, aspartate
question

in order to transport oxaloacetate out of the mitochondira, it has to be ________ to malate in the mitochondria and then ________ back to oxaloacetate in the cytoplasm
answer

reduced oxidized
question

the mitochondria has a _______ environment and the cytoplasm has a ___________ environment
answer

oxidizing reducing
question

oxaloacetate is converted to aspartate in the mitochondria via __________ from glutamate and then converted back to oxaloacetate in the cytoplasm by ____________
answer

transamination cytoplasmic transaminase
question

the cofactors necessary for pyruvate carboxylase activity are _______, _______, and _______ ions and the activator necessary is ________
answer

biotin, magnesium, manganous, acetyl CoA
question

Biotin is covalently attached to __________. When it is attached, it functions as a carrier of _________
answer

carboxylase protein activated CO2 (HCO3-)
question

this binds biotin with a high affinity and therefor can prevent pyruvate carboxylase from converting pyruvate to oxaloacetate
answer

avidin
question

what proteins are involved in Glucose-6-Phosphatase’s complex function?
answer

phosphatase, translocase 1, translocase 2
question

this subunit of G6Pase is on the side of the membrane that is not in direct contact with the cytoplasm. It catalyzes hydrolysis of G6P to glucose
answer

phosphatase
question

this subunit of G6Pase mediates transport of glucose-6-phosphate from the cytoplasm to the opposite side of the ER membrane, where the phosphatase enzyme is located
answer

T1 (translocase 1)
question

this subunit of G6Pase mediates transport of the phosphate back to the cytosol
answer

T2 (translocase 2)
question

these are the only cells able to convert G6P back to Glucose aka the only cells with glucose-6-phosphatase activity. They are responsible for returning glucose back to circulation after its absorption from portal blood, intestinal lumen, or glomerular filtrate.
answer

liver, intestine, kidney .
question

how is glucose-6-phosphatase in the liver different from others?
answer

maintains blood glucose levels, maintains supply of glucose to other tissues, rate of catalysis depends on substrate supply, not regulated by feedback inhibition
question

pyruvate dehydrogenase converts pyruvate to _______ and is inhibited by ________ and _________
answer

Acetyl CoA NADH ATP
question

pyruvate carboxylase is stimulated by high levels of __________ and ________
answer

pyruvate, Acetyl CoA
question

pyruvate dehydrogenase is ___________ by insulin and _________ by phosphorylation of serine at its E1a subunit
answer

activated inhibited
question

Fructose-1,6-bisphosphatase is inhibited by _________ and ________ and activated by _________
answer

AMP F-2,6-Bisphosphate Citrate
question

conversion of PEP to Glucose is ______ by Glucagon and ________ by Insulin
answer

activated inhibited
question

Pyruvate Carboxykinase is . activated by _______ and ________ and inhibited by _______
answer

glucagon steroids insulin
question

Insulin targets ______ but Glucagon does NOT
answer

muscle
question

Insulin targets ______ metabolism but Glucagon does NOT
answer

protein
question

in gluconeogenesis, PFK2 is _______ when it is phosphorylated
answer

activated
question

glucocorticoids increase the synthesis of __________ and __________
answer

PEP carboxykinase, glucose-6-phosphatase
question

this is the process of transporting lactate from muscle and erythrocytes to the liver for re-synthesis of glucose. This process means that erythrocytes and muscles can . use glycolysis efficiently since they don’t have to supply the energy for glucose!
answer

Cori Cycle
question

this is when pyruvate in the muscle is transaminated into Alanine, brought to the liver, and transformed back into pyruvate, giving off its amino group for another transamination reaction
answer

Cahill Cycle
question

what are the major metabolic problems of individuals with deficiencies . in gluconeogenic enzymes?
answer

hypoglycemia, acidosis (from build up of substrates such as lactate, pyruvate, and alanine)
question

what are the symptoms associated with hypoglycemia or acidosis from metabolic problems with individuals in gluconeogenesis?
answer

adrenergic effect responses (anxiety, sweating, heart palpation) or neuroglycopenia (confusion, coma, seizures, death)

Get instant access to
all materials

Become a Member