Biochem - LE 5 (2025) Flashcards
- Which enzyme when activated acts on diacylglycerol in the adipose cells?
A. Adipose triacylglycerol lipase
B. Hormone sensitive lipase
C. Monoacyglycerol lipase
D. Colipase
B. Hormone sensitive lipase
- Which is the major pathway of the oxidation of fatty acids?
A. Mitochondrial beta
B. Alpha
C. Omega
D. Peroxisomal
A. Mitochondrial beta
- In which cells does beta oxidation of fatty acids DO NOT occur?
A. Liver cells
B. Muscle cells
C. Red blood cells
D. Cardiac cells
C. Red blood cells
- To which molecule are fatty acids attached when activated?
A. Carnitine
B. CoEnzyme A
C. CoEnzyme Q
D. Acyl Carrier protein
B. CoEnzyme A
- Equivalent to how many moles of ATP are hydrolyzed in the activation of fatty acids?
A. One
B. Two
C. Three
D. Four
B. Two
- Which is source of energy that drives the activation reaction of fatty acids to completion?
A. Acyl adenylate moiety
B. Released AMP
C. PPi
D. CoA
C. PPi
- Which protein transports the palmitoyl carnitine inside the matrix?
A. Tricarboxylate translocase
B. Monocarboxylate translocase
C. Dicarboxylate translocase
D. Carnitine acyl carnitine translocase
D. Carnitine acyl carnitine translocase
- Which reactions, in the order of occurrence, are carried out every time a two carbon moiety is removed from a fatty acid subjected to beta oxidation?
A. Cleavage, hydration, oxidation, oxidation
B. Oxidation cleavage, oxidation, hydration
C. Oxidation, hydration, oxidation, cleavage
D. Hydration, oxidation, cleavage, oxidation
C. Oxidation, hydration, oxidation, cleavage
- To which complex of the ETC accepts are the electrons and protons released from the first oxidation reaction of beta oxidation?
A. NADH-CoQ oxidoreductase
B. ETFP-CoQ oxidoreductase
C. Cytochrome c oxidase
D. Cytochrome oxidase
B. ETFP-CoQ oxidoreductase
- Which enzyme catalyzes the 2nd reaction of beta oxidation?
A. 3-L-hydroxyacylCoA dehydrogenase
B. Acyl CoA dehydrogenase
C. Thiolase
D. Enoly CoA hydratase
D. Enoly CoA hydratase
- How many ATPs does the first reaction of beta oxidation generates after transferring its electrons and protons to the respiratory chain?
A. Two
B. Three
C. Four
D. Five
A. Two
- How many cycles/spirals would a 18
carbon saturated fatty acid undergo in beta oxidation releasing the acetyl CoA moieties?
A. Five
B. Six
C. Seven
D. Eight
D. Eight
- How many ATPs are generated from all the acetyl CoA moieties released from beta-oxidation of stearic acid?
A. 90
B. 102
C. 108
D. 118
C. 108
- What is another product of beta-oxidation of a 19 carbon saturated fatty acid aside from acetyl CoA?
A. Acetyl CoA
B. Isobutyryl CoA
C. Propionyl CoA
D. Valeryl CoA
C. Propionyl CoA
- To which intermediate of the Kreb’s cycle does the product of the last cycle/spiral of beta-oxidation of a 15 carbon fatty acid enter?
A. Fumarate
B. Succinyl CoA
C. Succinate
D. Malate
D. Succinyl CoA
16.Which additional enzyme is used in the beta oxidation of a monounsaturated fatty acid?
A. Δ3Δ2-enoyl CoA isomerase
B. 2,4-dienoyl CoA-reductase
C. Enoyl CoA-reductase
D. Acyl CoA dehydrogenase
A. Δ3Δ2-enoyl CoA isomerase
- How many ATP less would be derived from oxidation of a monounsaturated fatty acid compare with the oxidation of a saturated fatty acid having the same number of carbons?
A. Four
B. Three
C. Two
D. One
C. Two
- Which oxidation process is used to degrade very long chain fatty acids?
A. Mitochondrial beta
B. Alpha
C. Omega
D. Peroxisomal
D. Peroxisomal
- How would the products of oxidation of VLCFA generate energy in the form of ATP?
A. Have to be transported to the mitochondrial matrix
B. Thru the glycolytic pathway
C. Metabolized thru the alpha oxidation
D. Degraded via the omega oxidation
A. Have to be transported to the mitochondrial matrix
- More ATPs are formed per cycle/spiral thru mitochondrial beta oxidation than thru oxidation of VLCFA, by how many?
A. One
B. Two
C. Three
D. Four
B. Two
- Which enzyme catalyzes the rate-
limiting step of beta oxidation of palmitic acid?
A. Carnitine palmitoyl transferase I
B. Carnitine palmitoyl transferase II
C. Acetyl CoA carboxylase
D. Carnitine acyl-carnitine translocase
A. Carnitine palmitoyl transferase I
- To which does the FADH2, generated in the first oxidation step of peroxisomal oxidation, transfers its electrons and protons?
A. Complex II
B. ETFP-CoQ oxidoreductase
C. Oxygen
D. Complex I
D. Complex I
- Which is the product of peroxisomal oxidation of VLCFA?
A. Acetyl CoA
B. Propionyl CoA
C. Fatty dicarboxylyl CoA
D. Octanoyl CoA
D. Octanoyl CoA
- Which coenzyme is used in the oxidation steps of omega oxidation of fatty acids?
A. NAD+
B. NADH + H+
C. NADP+
D. NADPH + H+
A. NAD+
- Which enzyme is activated by cortisol in times of energy need?
A. Colipase
B. Desnutrin
C. Hormone sensitive lipase
D. Monoacylglycerol lipase
B. Desnutrin
- The chemical formula for AA is:
A. C20H32O2, 20:4(ω3)
B. C20H32O2, 20:4(ω6)
C. C20H32O2, 20:4(ω9)
D. C18H28O2, 20:4(ω3)
B. C20H32O2, 20:4(ω6)
- Significant precursors of eicosanoids include the following, except?
A. 5-8-11,14 - eicosatetraenoic acid
B. 8,11,14 - eicosatetraenoic acid
C. 5,8,1,14,17 - eicosapentaenoic acid
D. 6,9,11,14,17 - eicosapentaenoic acid
D. 6,9,11,14,17 - eicosapentaenoic acid
- Endogenous sources of arachidonic acid?
A. Linoleic acid
B. Dihomo-g-Linolenic acid
C. Oleic acid
D. N-Arachidonoyl
D. N-Arachidonoyl
- Arachidonic acid is most abundant in?
A. Liver
B. Lymphocytes
C. Platelets
D. Bone marrow
A. Liver
- Yields arachidonic acid from phospholipids by hydrolysis of the sn-2 position in one single step?
A. Phospholipase A1
B. Phospholipase A2
C. Phospholipase C
D. Phospholipase D
B. Phospholipase A2
- Requirement for activation and expression of phospholipases, as a response from cellular activation signals?
A. G coupled transducing protein
B. Toll-like receptor 4
C. Purinergic receptors
D. Tumor promoting agents
A. G coupled transducing protein
- Non-enzymatic reactions of arachidonic acid include which of the following?
A. Production of PGH2 by prostaglandin synthase.
B. Production of nitroeicosatetranoic acid by CCL4.
C. Production of LTA4 by 5-lipoxygenase.
D. Production of epoxyeicosatrienoic acid by epoxygenase.
B. Production of nitroeicosatetranoic acid by CCL4.
- Which following statement is false regarding cell to cell interactions in eicosanoid biosynthesis?
A. AA metabolism are usually similar from cell to cell and from tissue to another.
B. There is variability in enzyme expression depending on the state of the cell.
C. Unstable intermediates are transferred to another cell to trigger biosynthesis.
D. In an injured tissue, at least two cells must contain the complete enzyme cassette.
A. AA metabolism are usually similar from cell to cell and from tissue to another.
- Contributes to eicosanoids production and acts in a paracrine manner, propagates and amplifies inflammatory response to neighboring cells?
A. Cytosolic calcium dependent phospholipase A2
B. Secretory phospholipase A2
C. Cytosolic calcium independent phospholipase A2
D. Specialized phospholipase A2
B. Secretory phospholipase A2
- The principal mediator of inflammation, mitogenesis and angiogenesis?
A. Cyclooxygenase-1
B. Cyclooxygenase-2
C. Cyclooxygenase-3
D. Lipoxygenase
B. Cyclooxygenase-2
- Responsible for cell to cell signaling, tissue homeostasis and cytoprotection?
A. Cyclooxygenase-1
B. Cyclooxygenase-2
C. Cyclooxygenase-3
D. Lipoxygenase
A. Cyclooxygenase-1
- The 1st product of COX which is an unstable compound that quickly converts to PGH2?
A. Cyclic 8,10 endoperoxide, 15 hydroperoxide compound
B. Cyclic 6, 8 endoperoxide, 15 hydroperoxide compound
C. Cyclic 9, 11 endoperoxide, 15 hydroperoxide compound
D. Cyclic 6, 11 endoperoxide, 15 hydroperoxide compound
C. Cyclic 9, 11 endoperoxide, 15 hydroperoxide compound
- Effector function by PGI2?
A. Recruit basophils and eosinophils
B. Bronchoconstriction
C. Vasoconstriction
D. Uterine contraction
D. Uterine contraction
- TXA2 is converted from PGH2 by?
A. Thromboxane synthase
B. PGI2 synthase
C. Endoperoxide-D isomerase
D. Reductase
A. Thromboxane synthase
- The structural characteristics of PGI2 is similar to other prostaglandins, except?
A. Presence of a 5-member ring.
B. Presence of hydroxyl group
C. Presence of double bonds
D. Arrangement of carbonyl group
D. Arrangement of carbonyl group