Exam 2 Flashcards
Which one of the following is NOT true regarding glycogen storage?
a) Glycogen to maintain blood glucose is stored in the liver
b) Glycogen stored in skeletal muscle is reserved for anaerobic metabolism IN THE MUSCLE only
c) Glycogen stored in liver is depleted within 12-24 hours
d) Glycogen stored in the muscle is depleted within 8 hours of vigorous exercise
d) Glycogen stored in the muscle is depleted within 8 hours of vigorous exercise…false….within 1 hour
Glycogen breakdown (glycogenolysis) is catalyzed by 3 enzymes. Which one is NOT of of those 3?
a) transketolase
b) glycogen phosphorylase
c) debranching enzyme
d) phosphoglucomutase
a) transketolase (a mutation in this enzyme and severe deficiency in thiamine (vitamin B1) causes Wernicke-Korsakoff syndrome)
b) glycogen phosphorylase (cleaves glucose from non-reducing end, releasing glucose-1-phosphate)
c) debranching enzyme (bifunctional enzyme which 1st cleaves and transfers 3 glucose from branchpoint to NR end then cleaves off single remaining glucose from branchpoint as free glucose)
d) phoshoglucomutase (converts glucose-1-phosphate to glucose-6-phosphate)
Debranching enzyme is bifunctional. What are the 2 functions of this enzyme?
1) transferase (cleaves and transfers 3 glucose from branchpoint to non-reducing end)
2) a1–6 glucosidase (cleaves single remaining glucose from branchpoint as free glucose)
Which one of the following is NOT true regarding glycogen synthesis?
a) reducing end is attached to the core protein
b) glycogen synthase adds glucose from UPD-glucose carrier to non-reducing end of growing glycogen chain
c) gylcogen-branching enzyme is used
d) glycogen synthase does not require a “primer”
d) glycogen synthase does not require a “primer”…false…its does and glycogenin provides that primer.
* The glycogenin dimer uses manganese as a cofactor
Which one of the following is NOT true?
a) Both skeletal muscles and the liver respond to both epinephrine and glucagon
b) glycogenesis is energy storage, while glycolysis is energy production
c) insulin promotes glycogen synthesis (fed state), while glucagon promotes glycogen breakdown (fasting state)
d) The pentose phosphate pathway has an oxidative and a non-oxidative phase
a) Both skeletal muscles and the liver respond to both epinephrine and glucagon…false….the liver has receptors for both, however, muscles only have receptors for epinephrine, not glucagon
Which of the following is NOT true?
a) Most free radicals are produced by cellular respiration
b) It is important to keep high levels of NADPH to protect RBC’s from oxidative stress
b) Deficiency in G6PDH is an X-linked disorder and protects AGAINST Malaria
c) A pt with a G6PDH deficiency should be on a low-dose aspirin regimen
c) A pt with a G6PDH deficiency should be on a low-dose aspirin regimen….false…exposure to aspirin can cause acute hemolysis (breakdown of RBC’s)
- *Pt’s with 6DPDH deficiency can experience acute hemolysis if exposed to these 5 chemicals (remember “FSNAP”)
1) Fava beans (divicine)
2) Sulfonamides (antibiotic type)
3) Napthalene (moth balls)
4) Aspirin (NSAIDS)
5) Primaquine (anti-malarial)
Which of the following is NOT true?
a) The non-oxidative phase of the pentose phosphate pathway recycles ribulose-5-phosphate to make glucose-6-phosphate in order to generate NADPH in abundance
b) The end product of the oxidative phase of the PPP is ribose-5-phosphate and 2 NADPH
c) The enzyme associated with the oxidative phase of the PPP is ribose-5-phosphate dehydrogenase
d) The enzymes associated with the non-oxidative phase of PPP is transketolase and transaldolase
c) The enzyme associated with the oxidative phase of the PPP is ribose-5-phosphate dehydrogenase…false…its glucose-6-phosphate dehydrogenase
Which one of the following is NOT true?
a) ribulose is the “ketose” form of ribose, while ribose is the “aldose” form of ribulose
b) transaldolase requires a cofactor
c) transketolase transfers 2 carbons, while transaldolase transfers 3 crabons
d) G6PDH deficiency is found in the same geographical region as HbS (sickle cell anemia)
b) transalsolase requires a cofactor…false…because the ketose group attaches directly to lysine residue of transaldolase
What are the 5 cofactors for PDH (pyruvate dehydrogenase)?
1) Thiamine-TPP (vit B1)
2) Riboflavin-FAD (vit B2)
3) Niacin-NAD+ (vit B3)
4) Panthothenate-Coenzyme A (vit B5)
5) lipoate
Which one of the following is not 1 of the 3 enzymes that make up the PDH (pyruvate dehydrogenase) complex?
a) E1: pyruvate dehydrogenase (TPP is a cofactor)
b) E2: Dihydrolipoyl transacetylase (coenzyme A and lipoate are components)
c) E3 Dihydrolipoyl dehydrogenase (FAD is a component and NAD+ is a cofactor)
d) all of the above are correct
d) all of the above are correct
Which one of the following is NOT true?
a) The starting components of pyruvate dehydrogenase are pyruvate and NAD+
b) The end products of pyruvate dehydrogenase are Acetyl-CoA and NADH
c) The products of the TCA cycle are: 1 CO2, 3 NADH, 1 FADH2, 1 GTP
d) all of the above are true
d) all of the above are true
Which one of the following is NOT one of the 3 enzymes that produce NADH in the TCA cycle?
a) isocitrate dehygrogenase
b) alpha ketoglutarate dehydrogenase complex
c) malate dehydrogenase
d) all of the above are all 3
d) all of the above are all 3
Match the enzymecomplex with its prosthetic group:
1) NADH dehydrogenase
2) Succinate dehydrogenase
3) ubiquinone/cytochrome c oxidoreductase
4) cytochrome c
5) cytochrome oxidase
a) Fe-S
b) Heme,Fe-S
c) Heme
1) NADH dehydrogenase–a) Fe-S
2) Succinate dehydrogenase–a) Fe-S
3) ubiquinone/cytochrome c oxidoreductase–b) Heme,Fe-S
4) cytochrome c–c) Heme
5) cytochrome oxidase–c) Heme
Which one of the following is NOT true?
a) Amphibolic refers to both catabolic and anabolic nature of TCA cycle intermediates
b) A Niacin deficiency is characterized by the 3 D’s: dermatitis, diarrhea, and dementia
c) Wilson’s disease is a copper overload and treated with chelation therapy
d) there are 2 iodine deficiency disorders, called goiter and cretinism caused by a deficient synthesis of thyroxine (T4) and triiodothyrinine (T3)
e) deficiency in vitamin A is related to spina bifida
e) deficiency in vitamin A is related to spina bifida…false…vitamin A is a major teratogen and spina bifida is caused by a folate (vit B9) deficiency
Which one of the following is NOT true?
a) The polyol pathway increases NADPH levels needed to neutralize reactive oxygen species (ROS’s)
b) The hydroxyl radical (HO*) is the most reactive free radical
c) Retinal is a component of rhodopsin
d) Lipid (fat) soluable vitamins are: A,D,E, and K
a) The polyol pathway increases NADPH levels needed to neutralize reactive oxygen species (ROS’s)…false…it contributes to ROS’s by depleting NADPH
Which one of the following is NOT true?
a) a deficiency in vitamin A can lead to night blindness
b) antioxidant vitamins are A,C, and E
c) Vitamin K is an anti-clotting vitamin
d) Rickets and osteomalacia are vitamin D deficiencies
c) Vitamin K is an anti-clotting vitamin…false…its function is to help with blood clotting
Which one of the following is NOT true?
a) Beriberi is a deficiency in thiamine (B1)
b) Pellagra is a deficiency in Niacin (B3)
c) spina bifida is caused from too much folate (B9) in pregnancy
d) Pernicious anemia is a deficiency in cobalamin (B12)
c) spina bifida is caused from too much folate (B9) in pregnancy…false…spina bifida is caused from folate deficiency during pregnancy
Which one of the following is NOT true?
1) Wilson’s disease presents with Kayser-fleisher rings
2) Lathyrism is a pyroxidine (B6) deficiency
3) Linolenic acid is the least important fatty acid
4) Barth sydrome is an x-linked disorder caused by a defect in cardolipin processing protein
3) Linolenic acid is the least important fatty acid…false…its the most important. It is an Omega 3 that is anti-arrhythmic, anti-infammatory, and anti- thrombotic
Which one of the following is NOT true?
a) the ETC (electron transport chain) occurs in the inner membrane of the mitochondria
b) The goal of the ETC is to produce a proton gradient that drives ATP synthase
c) The 2 mobile carriers in the ETC are ubiquinone and cytochrome C
d) cytochrome C carries electrons between complex II and complex III
d) cytochrome C carries electrons between complex II and complex III….false, its between complex III and IV
Which one of the following is NOT true?
a) cyanide blocks ETC, therefore blocking ATP production
b) 2 disorders caused by mitochondrial genome mutations are LHON and MERFF (Lebers hereditary optic neuropathy and Myoclonic epilepsy and regged-red fiber)
c) cytochrome C acts as a trigger for apoptosis by stimulating the activation of a family of proteases called capsases
d) all of the above are true
d) all of the above are true
Which of the following is NOT true?
a) sphingolipids are derived from fat
b) Tay-Sachs disease is a lysosomal storage disorder
c) Pt’s with Tay-sachs disease present with cherry red maculae
d) bile salts are the most abundant product of cholesterol
a) sphingolipids are derived from fat….false…they are derived from serine
Which one of the following is NOT true?
a) Eicosinoids are derived from arachodonic acid
b) During apoptosis of a cell, phosphatidylserine flips to the outside to signal macrophages
c) Botox promotes exocytosis
d) Lipid rafts are stable microdomains of cholesterol and sphingolipids that serve as sites for lipid-linked protein attachment to the lipid bilayer
c) Botox promotes exocytosis…false…Botox blocks the signal for exocytosis
Describe the 6 integral membrane proteins
1 and 2: single transmembrane helix
- *1: amino terminal outside the cell
- *2: amino terminal inside the cell
3: single protein, multiple transmembrane helices
4: multiple proteins, single transmembrane proteins
5: lipid-linked proteins
6: both transmembrane and lipid-linked domains
(T/F) People who inherit 2 defective (mutant) genes for the LDL receptor have receptors that function poorly or not at all creating excessively high levels of LDL in their blood and predisposes them to atherosclerosis and heart attacks. This disorder is called Familial hypercholesteremia
true
Which one of the following is NOT true?
a) Voltage-gated channels respond to changes in membrane potential
b) ligand-gated channels respond to extracelleular neurotransmitters like ACH
c) signal-gated channels respond to intracellular signal transduction events like cAMP and Ca++
d) resting ion channels are always closed
d) resting ion channels are always closed….false, they are always open
Which one of the following is NOT true?
a) Most fatty acid synthesis occurs in the cytoplasm of liver cells
b) Fatty acid synthesis requires 4 ingredients: ATP, NADPH, Acetyl-coA carboxylate (rate limiting), and fatty acid synthase
c) During the elongation phase of FA synthesis, NADPH is used to reduce aldehyde to alcohol and to reduce double bonds
d) Threonine is the backbone of sphingolipids
d) Threonine is the backbone of sphingolipids…false, serine is
Which one of the following is NOT true?
a) cholesterol synthesis is inhibited by statins
b) COX 1 inhibitor drugs are suspected of causing clots
c) Leukotriene antagonists are used to help treat asthma
d) HDL is good cholesterol and LDL is bad cholesterol
b) COX 1 inhibitor drugs are suspected of causing clots….false, COX 2 inhibitors are suspected of causing clots. Many of them have been taken off the market because of this. There is only one on the market (celecoxib) and it has a black box warning
Which one of the following is NOT true?
a) carnitine is an electron carrier
b) The digestion and absorption of dietary lipids occurs in the small intestines
c) The final step of fat metabolism is: fatty acids are oxidized as fuel or re-esterfied for storage
d) fatty acid oxidation (opposite of synthesis) occurs in mitochondrial matrix
a) carnitine is an electron carrier…false, it is lipid carrier and is found in energy drinks like Monster
Which one of the following is NOT true?
a) Arginine is an essential AA in maintaining a positive nitrogen balance
b) transaminases are responsible for “swapping” amino groups of AA’s for carbonyls of alpha-keto acids
c) Low urea in blood indicates a kidney problem
d) high ammonia concentration is a liver issue
c) Low urea in blood indicates a kidney problem…false, high levels do
**keep it straight: high urea=kidney problem, high ammonia=liver problem
Which one of the following is NOT true?
a) The urea cycle takes place in the mitochondrial matrix of kidney cells
b) nitrogen excretion products include urea, ammonia, and uric acid and urea makes up 86% of all nitrogen excretion products
c) The 3 BCAA’s (branched chain amino acids) are Val, Ile, and Leu
d) Maple syrup urine disease is a deficiency of branched chain alpha-keto acid dehydrogenase complex
a) The urea cycle takes place in the mitochondrial matrix of kidney cells….false, it takes place in the mitochondrial matrix of LIVER cells
Which one of the following NOT true regarding phenyketonuria (PKU)?
a) it is an autosomal recessive disease
b) lack of treatment results in severe mental retardation
c) Tyrosine is an essential AA for these pt’s
d) These pt’s end up with an excess of phenylalanine hydroxylase
c) These pt’s end up with an excess of phenylalanine hydroxylase….false, they have a deficiency of phenylalanine hydroxylase. This enzyme converts phenyalanine to tyrosine. They end up with an exess of phenylalanine
Which one of the following is NOT true?
a) Alkaptonuria is caused by a defect in homogentisate oxidase and causes purple lesions called “ochronosis”
b) Leu and Lys are the only 2 AA that are strictly ketogenic
c) newborns are screened for 86 different disorders
d) Arginine is the only essential AA that can be recycled
d) Arginine is the only essential AA that can be recycled….false, methionine is the only one that can be recycled and is considered psuedoessential (arginine is considered psuedoessential also because it is insufficient in infants)
know the essential AA’s: Phe, Trp, Ile, Leu, Val, Lys, His, Arg, Thr, Met
Which one of the following is NOT true?
a) elevated serum homocysteine levels is a risk for CVD (cardiovascular disease)
b) Tyrosine is a precursor to thyroid hormones and melanin
c) kidney damage results in Jaundice
d) Heme synthesis occurs primarily in Liver and bone marrow and starts with Gly+succinylCoA
c) kidney damage results in Jaundice…false, LIVER damage results in jaundice
Which one of the following is NOT true?
a) Radioimmunoassay detects hormones in the bloodstream, widely used in endocrinology
b) Repeated cell signaling leads to desensitization
c) Cholera toxin and pertussin toxin interfere with G protiens (Gs and Gi)
d) all of the above are true
d) all of the above are true
Cholera toxin ADP-ribosylates Gs, rendering it permanently active, increasing cAMP in intestinal epithelium. Pertussis toxin ADP ribosylates Gi so adenylate cyclase is not inhibited, increasing cAMP in lung epithelium.
Match the major classes of G-proteins with their functions:
1) Gs
2) Gi
3) Gq
a) inhibits adenylate cyclase
b) stimulates phosphlipase C
c) stimulates adenylate cyclase
1) Gs–c) stimulates adenylate cyclase
2) Gi–a) inhibits adenylate cyclase
3) Gq–b) stimulates phosphlipase C
