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?
- Glucose-6-Phosphate
- 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
2. NADH
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?
-
1. NADPH OXIDASE
2. SOD
3. MYELOPEROXIDASE - What enzyme converts O2 into its free radical?
- NADPH OXIDASE, using NADPH
- What enzyme converts an O2 free radical into H2O2?
- SOD
- 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?
- NADPH OXIDASE DEFICIENCY --> CGD
- 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?
- ALT
- 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
3. NADH - What factor inhibits Citrate synthase?
- ATP
- 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
2. NADH - What factor positively affects Isocitrate DH?
- ADP
- What two molecules are released in the conversion of Isocitrate into alpha-KG?
-
1. CO2
2. NADH - 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
2. NADH - What 3 factors negatively inhibit alpha-KG?
-
1. Succinyl-CoA
2. NADH
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?
- FADH2
- What molecule is released in the conversion of malate into OAA?
- NADH
- 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?
- Oligomycin
- The enzymes for gluconeogenesis are located in what organs only?
-
1. liver
2. kidney
3. intestinal epithelium - Can muscle participate in gluconeogenesis?
- NO
- The pentose phosphate pathway (HMP Shunt) produces [...] from G6P for nucleotide synthesis
- ribose-5-P
- The Pentose Phosphate Pathway (HMP Shunt) produces [...] from [...] for FA and steroid biosynthesis and for maintaining reduced glutathione inside RBCs.
- NADPH from NADP+
- All rxns in the HMP Shunt ocur in the [...].
- cytoplasm
- [...] ATP is used or produced in the HMP Shunt.
- NO
- 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
- G6PD
- Hemolytic anemia is caused by a decrease in [...] in RBCs due to poor RBC defense against oxidizing agents.
- NADPH
- 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
2. NADPH - 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?
- Fructokinase
- 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
3. INHIBITION of GLYCOGENOLYSIS and GLUCONEOGENSIS - 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?
-
1. DHAP
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?
- 4-epimerase
- 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?
- Histidine
- What is the most basic AA?
- Arginine
- 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?
- NADPH
- 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?
- liver
- In what organelle does carbamoyl phosphate incorporation occur?
- mitochondria
- Where do the remaining steps of the Urea Cycle occur, besides the mitochondria?
- cytosol
- What is released in the conversion of Arginine --> Ornithine?
- Urea
- 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?
-
1. DECREASE Phe
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?
- 1/10,000
- 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
- Albinism
- Full-term neonate of uneventful delivery becomes mentally retarded and hyperactive and has a musty odor. What is the D(x)?
- PKU
- 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)?
- Kwashiorkor
- 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)?
- Akaptonuria
- 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?
- viruses
- 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.
- Primase
- [...] 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?
- LEADING-strand DNA
- What is the function of Eukaryotic DNA polymerase gamma?
- LAGGING-strand DNA
- What is the function of Eukaryotic DNA polymerase delta?
- MITOCHONDRIAL DNA
- What is the function of Eukaryotic DNA polymerase epsilon?
- DNA repair
- X-rays can damage DNA, and a repair defect can cause what?
- ataxia-telangiectasia
- 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?
-
1. RNA POLYMERASE I
2. RNA POLYMERASE II
3. RNA POLYMERASE III - Do RNA polymerases have proofreading function?
- NO
- 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?
- yes
- What binds to a PROMOTOR site?
-
1. RNA polymerase
2. transcription factors
(UPSTREAM FROM THE GENE) - 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
- processed
- The [...] the Km, the higher the affinity.
- lower
- 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
- mitosis
- Most cells are in what phase?
- Go
- 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 [...]
- phagocytosis
- 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?
- collagen
- What are the components of Type I collagen?
-
1. B.one
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
8. CAN'T make COLLAGEN FIBRILS from TROPOCOLLAGEN! - What are the 9 major points concerning OSTEOGENESIS IMPERFECTA?
-
1. AUTOSOMAL DOMINANT (UNIQUE)
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
9. CAN'T make PROCOLLAGEN from PREPROCOLLAGEN - 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?
- Galactokinase
- 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-phosphatase
- Glucose-6-phosphate --> 6-phosphogluconolactone by what enzyme?
- Glucose-6-phosphate dehydrogenase (G6PD)
- Hemolytic anemia is caused by a deficiency of what enzyme?
- G6PD
- Ribulose-5-phosphate --> fructose-6-phosphate by what enzyme?
- transketolase
- A deficiency of what enzyme causes ESSENTIAL fructosuria?
- fructokinase
- 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?
- biotin
- What is an activated 1-carbon unit carrier?
- tetrahydrofolate
- What is an activated carrier of aldehydes?
- TPP
- What is an activated carrier of choline?
- CDP-choline
- ATP + methionine --> SAM. using what cofactor?
- B12
- 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