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FA Biochemistry


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What are the four irreversible enzymes in glycolysis?
1. hexokinase/glucokinase
2. phosphofructokinase-1
3. pyruvate kinase
4. pyruvate dehydrogenase
What is the rate-limiting step in glycolysis?
Conversion of Fructose-6-phosphate into Fructose-1,6 BP via phosphofructokinase 1
What factor negatively inhibits hexokinase in glycolysis?
What factors (2) negatively inhibit PFK-1 in glycolysis?
1. ATP
2. citrate
What factors (2) positivcely affect PFK-1 in glycolysis?
1. AMP
2. fructose-2,6-BP
What factors (2) NEGATIVELY inhibit pyruvate kinase in glycolysis?
1. ATP
2. alanine
What factor positively affects pyruvate kinase in glycolysis?
fructose-1,6 BP
What factors (3) negatively inhibit pyruvate dehydrogenase in glycolysis?
1. ATP
3. acetyl-Coa
What enzymes (2) CONVERT D-glucose into Glucose-6-phosphate in glycolysis?
1. hexokinase
2. gLucokinase (liver only)
What enzyme CONVERTS PEP into pyruvate?
pyruvate kinase
What enzyme CONVERTS pyruvate into Acetyl-CoA
pyruvate dehydrogenase
What enzyme converts Fructose-6-P into Fructose-1,6-BP?
Phosphofructokinase (rate-limiting step)
What glycolytic enzyme deficiencies result in hemolytic anemia? (7)
1. hexokinase
2. glucose phosphate isomerase
3. aldolase
4. triosephosphate isomerase
5. phosphate glycerate kinase
6. enolase
7. pyruvate kinase
Do RBCs possess mitochondria?
no: metabolize glucose anaerobically and thus depend solely on glycolysis
Order of enzymes in a phagolysosome that destroy bacteria in oxygen-dependent respiratory burst?
2. SOD
What enzyme converts O2 into its free radical?
What enzyme converts an O2 free radical into H2O2?
What enzyme converts H2O2 into HOCl free radical
myeloperoxidase, using a chloride anion
What enzyme converts GSH into GSSG?
catalase, via oxidation using H2O2
What enzyme converts NADPH into NADP+ using GSSG?
glutathione reductase, resulting in GSH and NADP+
What enzyme restores NADPH by converting G6P into 6-phosphogluconolactone?
Glucose-6-phosphate dehydrogenase
A deficiency in what enzyme can cause chronic granulomatous disease?
How many enzymes does the Pyruvate Dehydrogenase Complex contain?
3 enzymes
What are the 5 co-factors for the Pyruvate Dehydrogenase Complex?
1. Pyrophosphate
2. FAD
3. NAD
4. CoA
5. Lipoic acid

(First 4 B vitamins plus lipoic acid)
From what is PyroPhosphate derived in the PDH complex?
1. Vitamin B1 (thiamine)
2. TPP
From what is FAD derived in the PDH complex?
Vitamin B2 (riboflavin)
From what is NAD derived in the PDH complex?
Vitamin B3 (niacin)
From what is CoA derived in the PDH complex?
Vitamin B5 (pantothenate)
What is the overall reaction in the PDH complex?
pyruvate + NAD+ + CoA --> acetyl-CoA + CO2 + NADH
What three factors activate PDH during exercise?
1. increase in NAD+/NADH ratio
2. increase in ADP ratio
3. increase in Ca2+
PDH complex is similar to what other complex by having the same cofactors, similar substrate, and similar action?
PDH is similar to alpha-KG DH complex
What enzyme deficiency cause cause lactic acidosis?
PDH complex deficiency from a backup of pyruvate and alanine
Alcoholism with a Vitamin B1 deficiency can also cause what (besides Wernicke-Korsakoffe)?
PDH deficiency (B1 is a co-factor)
What are the findings in PDH complex deficiency?
neurologic deficits
What is the treatment for PDH complex deficiency?
1. increase intake of KETOGENIC nutrients (high fat content)
2. increase intake of LEUCINE and LYSINE
What four items can pyruvate be converted into?
1. alanine
2. oxaloacetate
3. acetyl-Coa
4. lactate
How can OAA be used after it is converted from pyruvate?
1. replenish TCA cycle
2. gluconeogenesis
What enzyme converts pyruvate into alanine?
What enzyme converts pyruvate into OAA?
pyruvate carboxylase (using CO2 + ATP)
What enzyme converts pyruvate into Acetyl-CoA?
PDH (using NAD+ and releasing CO2)
What enzyme converts pyruvate into lactate in the cytosol?
LDH (using NADH)
What is the purpose of the Cori cycle?
Cori cycle transfers excess reducing equivalents from RBCs and muscle --> liver, allowing muscle to function anaerobically.
In the TCA cycle, what are the products per one acetyl CoA?
1. 3 NADH
2. 1 FADH2
3. 2 CO2
4. 1 GTP
How many ATP are produced from a single acetyl-Coa in the TCA cycle?
12 ATP/acetyl-Coa in the TCA cycle
How many ATP are produced from a single glucose molecule in the TCA cycle?
24 ATP
In the TCA cycle, what are the products per one glucose molecule?
1. 6 NADH
2. 2 FADH2
3. 4 CO2
4. 2 GTP
What three factors inhibit PDH?
1. ATP
2. Acetyl-Coa
What factor inhibits Citrate synthase?
wWhat enzyme converts Acetyl-CoA + OAA --> citrate?
citrate synthase in the TCA cycle
What enzyme converts Isocitrate into alpha-KG?
Isocitrate dehydrogenase
What 2 factors negatively inhibit Isocitrate DH?
1. ATP
What factor positively affects Isocitrate DH?
What two molecules are released in the conversion of Isocitrate into alpha-KG?
1. CO2
what enzyme converts alpha-KG into Succinyl-CoA
alpha-KG DH
What two molecules are released in the conversion of alpha-KG into Succinyl CoA?
1. CO2
What 3 factors negatively inhibit alpha-KG?
1. Succinyl-CoA
3. ATP
What 2 molecules are released in the conversion of Succinyl-CoA --> Succinate?
1. GTP
2. CoA
What molecule is released in the conversion of Succinate --> Fumarate?
What molecule is released in the conversion of malate into OAA?
1 NADH yields how many ATP?
3 ATP per 1 NADH
1 FADH2 yields how many ATP?
2 ATP per 1 FADH2
Name 4 electron transport inhibitors:
1. rotenone
2. antimycin A
3. CN-
4. CO
What is the end result of electron transport inhibition?
1. decrease in proton gradient
2. block of ATP synthesis
What is an example of a mitochondrial ATPase inhibitor?
The enzymes for gluconeogenesis are located in what organs only?
1. liver
2. kidney
3. intestinal epithelium
Can muscle participate in gluconeogenesis?
The pentose phosphate pathway (HMP Shunt) produces [...] from G6P for nucleotide synthesis
The Pentose Phosphate Pathway (HMP Shunt) produces [...] from [...] for FA and steroid biosynthesis and for maintaining reduced glutathione inside RBCs.
All rxns in the HMP Shunt ocur in the [...].
[...] ATP is used or produced in the HMP Shunt.
What are the organs involved in the HMP Shunt (Pentose Phosphate Pathway)?
1. lactating mammary glands
2. liver
3. adrenal cortex
4. all sites of FA or steroid synthesis
[...] is the rate-limiting enzyme in the HMP shunt
Hemolytic anemia is caused by a decrease in [...] in RBCs due to poor RBC defense against oxidizing agents.
What are the oxidizing agents involved in hemolytic anemia due to a G6PD deficiency?
1. fava beans
2. sulfonamide
3. primaquine
4. Anti-TB drugs
What are Heinz bodies?
altered H.emoglobin precipitates within RBCs
What is the inheritance pattern of G6PDH deficiency?
X-linked recessive
Glucose-6-Phosphate DH converts G6P and NADP+ into what?
1. 6-PG
Glutathion reductase converts NADPH and oxidized GS-SG into what?
1. NADP+
2. 2 GSH (reduced)
Hydrogen peroxide reacts with what to produc GS-SG (oxidized) + 2 H2O?
2 GSH (reduced)
What enzyme is associated with Essential fructosuria?
What enzyme is associated with Fructose intolerance?
Aldolase B
What is the end result of Fructose intolerance?
1. Fructose-1-phosphate accumulates
2. DECREASE in available phosphate
What are the symptoms of hereditary aldolase B deficiency (Fructose intolerance)?
1. hypoglycemia
2. jaundice
3. cirrhosis
4. vomiting
What is the treatment for Fructose intolerance?
1. DECREASE intake of fructose
2. DECREASE intake of sucrose (glucose + FRUCTOSE)
Aldolase B converts Fructose-1-P into what 2 products?
2. glyceraldehyde
What enzyme converts Glyceraldehyde into Glyceraldehyde-3-P?
Triose kinase
What enzyme converts Galactose-1-P to Glucose-1-P?
Galactose-1-phosphate uridyltransferase
Galactosemia is caused by the absence of what enzyme?
Galactose-1-phosphate uridyl transferase
What are the symptoms of galactosemia?
1. cataracts
2. hepatosplenomegaly
3. mental retardation
What is the treatment of galactolsemia?
1. EXCLUDE galactose
2. EXCLUDE LACTOSE (galactose + glucose) from diet
What causes the symptoms of galactosemia?
accumulation of toxic substances (galactitol)
What enzyme converts UDP-galactose back into UDP-glucose?
What is the mnemonic for all essential amino acids?
P.riV.aT.e T.I.M. H.A.L.L.
What are the glucogenic/ketogenic essential amino acids?
1. P.henylalanine
2. I.le
3. T.ryptophan

"Gluco/ketogenic is the P.I.T.s"
What are the Glucogenic essential amino acids?
1. M.ethionine
2. T.hreonine
3. V.aline

4. A.rginine
5. H.istidine

"MTV? AH!"
What essential amino acids are required during growth?
1. Arginine
2. Histidine

both increase GH
What basic amino acid has no net charge at body pH?
What is the most basic AA?
What 2 amino acids are found in histones?
1. Arginine
2. Lysine

(both have an extra NH3 group)
What is formed in the conversion of glutamate --> alpha-KG?
The Urea Cycle degrades [...] into amino groups.
amino acids
What accounts for 90% of nitrogen in the urine?
Urea Cycle
In what organ does the Urea Cycle occur?
In what organelle does carbamoyl phosphate incorporation occur?
Where do the remaining steps of the Urea Cycle occur, besides the mitochondria?
What is released in the conversion of Arginine --> Ornithine?
Tryptophan is used to form what 3 things?
1. Niacin
2. Serotonin
3. Melatonin
Glycine is used to form what?
glycine --> porphyrin --> heme
Arginine is used to form what?
1. Creatine
2. Urea
3. Nitric oxide
In PKU, what constituents(2) are deficient?
1. phenylalanine hydroxylase
2. tetrahydrobiopterin cofactor
What are the findings (5) in PKU?
1. MR
2. growth retardation
3. fair skin
4. eczema
5. musty body odor
What is the R(x) for PKU?
2. INCREASE Tyr in diet
What are the 3 phenyllactones that accumulate in PKU?
1. phenylacetate
2. phenyllactate
3. phenylpyruvate
What is the incidence of PKU?
What enzyme converts Phe --> Tyr?
Phenylalanine hydroxylase
What enzyme converts DHB --> THB and restores NADP+?
dihydropterin reductase
What are the 2 possible causes of albinism?
1. deficiency of TYROSINASE (inability to synthesize malanin from tyrosine)
2. Defective tyrosine transporters (DECREASE amounts of tyrosine and thus melanin)
[...] can result from a lack of migration of neural crest cells
Full-term neonate of uneventful delivery becomes mentally retarded and hyperactive and has a musty odor. What is the D(x)?
Stressed executive comes home from work, consumes 7 or 8 martinis in rapid succession before dinner, and becomes hypoglycemic. What is the mechanism?
NADH increase prevents gluconeogenesis by shunting pyruvate and OAA to lactate and malate.
2-year-old girl has an increase in abdominal girth, failure to thrive, and skin and hair depigmentation. What is the D(x)?
Alcoholic develops a rash, diarrhea, and altered mental status. What is the vitamin deficiency?
Vitamin B3 (pellagra)
51-year-old man has black spots in his sclera and has noted that his urine turns black uon standing. What is the D(x)?
25-year-old male complains of severe chest pain and has xanthomas of his Achilles tendon. What is the disease, and where is the defect?
Familial hypercholesterolemia; LDL receptor.
What is the definition of UNAMBIGUOUS when describing the genetic code?
each codon specifies only 1 AA
What is the definition of Degenerate when describing the genetic code?
more than 1 codon may code for the same AA
Why organism does NOT have a commaless, nonoverlapping genetic code?
What are the EXCEPTIONS to a universal genetic code?
1. mitochondria
2. archaeobacteria
3. Mycoplasma
4. yeasts (some)
[...] makes an RNA primer on which DNA polymerase III can initiate replication in PROKARYOTIC DNA replication.
[...] degrades the RNA primer in PROKARYOTIC DNA replication.
DNA polymerase I
DNA polymerase III has [...] synthesis and proofreads with [...] exonuclease
5'--> 3' synthesis; 3' --> 5' exonuclease (DNA polymerase III for PROKARYOTES)
In PROKARYOTIC DNA replication, DNA polymerase I excises the RNA primer with a [...] exonuclease
5' --> 3'
Where does replication begin for Eurkaryotic DNA polymerases?
consensus sequences of AT base pairs.
What is the function of Eukaryotic DNA polymerase alpha?
synthesize RNA PRIMERS
What is the function of Eukaryotic DNA polymerase beta?
What is the function of Eukaryotic DNA polymerase gamma?
What is the function of Eukaryotic DNA polymerase delta?
What is the function of Eukaryotic DNA polymerase epsilon?
DNA repair
X-rays can damage DNA, and a repair defect can cause what?
Radiation can damage DNA, and a repair defect can cause what?
Bloom's syndrome
Cross-linking agents can damage DNA, and a repair defect can cause what?
Fanconi's anemia
DNA, RNA, and protein are all synthesized in what direction?
5' --> 3'
AA's are linked [...] to [...]
N --> C
What are the types of RNA polymerases for EUKARYOTES?
Do RNA polymerases have proofreading function?
Alpha-amantin inhibits which RNA polymerase?
RNA polymerase II
Where does RNA polymerase II bind?
promotor site of DNA
In Prokaryotes, does RNA polymerase make all 3 kinds of RNA?
What binds to a PROMOTOR site?
1. RNA polymerase
2. transcription factors

What binds to an ENHANCER site?
transcription factors
What binds to an OPERATOR?
repressors (a repressive operator)
Only [...] RNA is transported out of the nucleus
The [...] the Km, the higher the affinity.
The S phase of the cell cycle involves what?
Synthesis of DNA
The G0 phase in the cell cycle is a quiescent [...] phase
G1 phase
In the cell cycle, [...] is the shortest phase
Most cells are in what phase?
RER does what 2 things?f
1. synthesis of secretory (exported) proteins
2. N-linked oligosaccharide addition to many proteins
What are the major functions of the Golgi?
1. MODIFIES N-oligosaccharides on asparagiNe
2. ADDS O-oligosaccharides to serine and threOnine
3. sulfation of sugars on proteoglycans
4. sulfation of Tyrosine
5. ADDITION of mannose-6-phosphate to lysosomal proteins, which targets the protein to the lysosome.
What are the symptoms of I-cell disease?
1. coarse facial features
2. restricted joint movement
What are the 3 key features of microtubules?
1. helical
2. alpha + beta tubulin dimers (2 GTP bound each)
3. forms flagella, cilia, and mitotic spindles
What are 5 drugs that act on microtubules?
1. Mebendazole/thiabendazole
2. Taxol
3. Griseofulvin
4. Vincristine/vinblastine
5. Colchicine
Chediak-Higashi syndrome is due to a microtubule polymerization defect, resulting in a DECREASE in [...]
What are the 2 key features of Cilia?
1. 9 + 2 arrangment of microtubules (9 doublets)
2. doublets linked by Dynein, an ATPase
Kartagener's syndrome is due to a dynein arm defect, resulting in [...] cilia.
immotile cilia
What 2 components in the plasma cell membrane can INCREASE the melting temperature?
1. cholestrol
2. long saturated fatty acids
Name 5 functions of Phosphatidylcholine:
1. RBCs
2. myelin
3. bile
4. surfactant (DiPalmitoyl Phosphatidyl Choline)
5. esterification of cholesterol (LCAT)
Ouabain INHIBITS the Na+/K+ pump by binding to what?
K+ site
What is the most abundant protein in the human body?
What are the components of Type I collagen?
2. tendon
3. skin
4. dentin
5. fascia
6. cornea
7. late-wound repair
What are the components of Type II collagen?
1. C.artilage ("Type II: carTWOlage"); hyaline too
2. vitreous body
3. nucleus pulposus
What are the components of Type III collagen?
1. R.eticulin
2. skin
3. blood vessels
4. uterus
5. fetal tissue
6. granulation tissue
What are the components of Type IV collagen?
1. B.asement membrane
2. basal lamina "Type IV: under the FLOOR (basement membrane)"
What is the component of Type X collagen
epiphyseal plate
What is the mnemonic for the first four collagen types (I-IV)?
"B.e C.ool, R.ead B.ooks"
What is the 1st step in collagen synthesis INSIDE fibroblasts?
collagen alpha chains (PREPROCOLLAGEN) translated on RER--usually Gly-X-Y polypeptide (X and Y are proline, hydroxyproline, or hydroxylysine)
What is the 2nd step in collagen synthesis INSIDE fibroblasts?
ER--> hydroxylation of specific proline and lysine residues (requires vitamin C)
What is the 3rd step in collagen synthesis INSIDE fibroblasts?
Golgi --> glycosylation of pro-alpha-chain lysine residues and formation of PROCOLLAGEN(triple helix of 3 collagen alpha chains)
What is the 4th step in collagen synthesis INSIDE fibroblasts?
PROCOLLAGEN molecules are exocytosed into the extracellular space
What is the 5th step in collagen synthesis OUTSIDE fibroblasts?
PROCOLLAGEN peptidases cleave terminal regionals of PROCOLLAGEN, transforming PROCOLLAGEN into insoluble TROPOCOLLAGEN
What is the 6th and last step in colagen synthesis OUTSIDE fibroblasts?
staggered TROPOCOLLAGEN molecules are reinforced by covalent lysine-hydroxylysine cross-linkage (by lysyl oxidase) to make COLLAGEN FIBRILS
What are the 8 major points concerning Ehlers-Danlos syndrome?
1. faulty collagen synthesis
2. hyper-extensible skin
3. easy bleeding/brusing
4. hypermobile joints
5. berry aneurysms
6. type III collagen (reticulin: blood vessels, skin)
7. mitral valve prolapse
What are the 9 major points concerning OSTEOGENESIS IMPERFECTA?
2. faulty collagen synthesis
3. brittle bone disease
4. translucency of CT over choroid (blue sclerae)
5. hearing loss: abnormal middle ear bones
6. lack of dentition
7. Type II OI: fatal
8. Indicence of OI: 1/10,000
What three metabolic processes occur in the mitochondria?
1. B.eta-oxidation
2. A.cetyl-CoA production
3. K.rebs cycle
What five metabolic processes occur in the cytoplasm?
1. glycolysis
2. FA synthesis
3. protein synthesis
4. steroid synthesis
5. HMP shunt
What 2 metabolic processes occur in BOTH the mitochondria and cytoplasm?
1. H.eme synthesis
2. U.rea cycle
3. G.luconeogenesis

"H.U.G. both the mitochondria and cytoplasm for their metabolism."
A deficiency of what enzyme causes MILD galactosemia?
A deficiency of what enzyme causes SEVERE galactosemia?
Galactose-1-phosphate uridyltransferase
Galactose-1-phosphate --> Glucose-1-phosphate by what enzyme?
Galactose-1-phosphate uridyltransferase
A deficiency of what enzyme causes Von Gierke's disease?
Glucose-6-phosphate --> 6-phosphogluconolactone by what enzyme?
Glucose-6-phosphate dehydrogenase (G6PD)
Hemolytic anemia is caused by a deficiency of what enzyme?
Ribulose-5-phosphate --> fructose-6-phosphate by what enzyme?
A deficiency of what enzyme causes ESSENTIAL fructosuria?
A deficiency of what enzyme causes fructose INTOLERANCE?
Aldolase B
F1P --> DHAP + Glyceraldehyde. What enzyme?
aldolase B
PEP --> pyruvate. What enzyme?
pyruvate kinase
Pyruvate --> Acetyl-CoA. What enzyme?
pyruvate dehydrogenase
Acetyl-CoA --> Malonyl-CoA. What cofactor?
biotin to tranfer CO2
HMG CoA --> mevalonate. What enzyme?
HMG-CoA reductase
pyruvate --> OAA. What enzyme?
pyruvate carboxylase
OAA --> PEP. What enzyme?
PEP carboxykinase
Acetyl-CoA + OAA --> citrate. What enzyme?
citrate synthase
alpha-KG --> Succinyl-CoA. What enzyme?
alpha-ketoglutarate dehydrogenase
Ornithine + Carbamoyl phosphate --> citrulline. What enzyme?
ornithine transcarbamylase
Aerobic metabolism of glucose --> 38 ATP via [...]
malate shuttle
Aerobic metabolism of glucose --> 36 ATP via [...]
G3P shuttle
What are 2 activated ACYL carriers?
1. coenzyme A
2. lipoamide
What is an activated CO2 carrier?
What is an activated 1-carbon unit carrier?
What is an activated carrier of aldehydes?
What is an activated carrier of choline?
ATP + methionine --> SAM. using what cofactor?
NADPH used in 3 processes:
1. anabolic processes
2. respiratory burst
3. p-450
What enzymes involve NADPH in respiratory burst?
1. NADPH oxidase
2. glutathione reductase
3. Glucose-6-Phosphate dehydrogenase

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