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    MCQ IN BIOCHEMISTRY

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    تاريخ التسجيل : 22/03/2010
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    MCQ IN BIOCHEMISTRY Empty MCQ IN BIOCHEMISTRY

    مُساهمة من طرف admin الأربعاء نوفمبر 30, 2011 3:01 pm

    MCQs of Bio – 2nd year

    1)A substance that is not an intermediate in the formation of glucuronic acid from glucose is:-
    UDP-galactose
    UPD-glucose
    Glucose-6-phosphate
    UPD-glucuronic acid


    2) Transport of glucose cross the cell membrance is stimulated by insulin in:-
    Brain
    RBCs
    Liver
    Skeletal muscles


    3)The major process responsible for maintaining blood glucose 40hours afterr last meal:-
    Glycolysis
    Glycogenolysis
    The pentose phosphate pathway
    Gluconeogenesis


    4)The major process responsible for maintaining blood glucose 4hours after last meal:-
    Glycolysis
    Glycogenolysis
    The pentose phosphate pathway
    Gluconeogenesis


    Each of the following enzymes is required for the conversion of glycerol to5) glucose EXCEPT:-
    Glucose-6-phosphatase
    Glycerol-3-phosphate dehydrogenase
    Phosphoenol pyruvate carboxykinase
    Fructose 1.6 bisphosphtase


    6)in RBCs how many net molecues of ATP are generated when one molecule of glocuse is oxidized to lactate:-
    0
    1
    2
    12


    All the following about pentose phosphate path way are true EXCEPT:- (7
    There is a net energy production of 8 ATP molecule.
    NADPH+H is produced that is essential for lipids metabolism.
    Deficiency of glucose -6- phosphate dehydrogenase leads to favism
    Its intracellular location is cytosol


    8)Glucokinase:-
    Is found in muscles
    Has low affinity(high KM)to glucose
    Allosterically inhibited by glucose -6- phosphate
    Catalyzes a reversible reaction


    9)IN which compartment does pentose phosphate pathway occur?
    The mitochondria
    The solube cytoplasm (cytosol)
    Both of them
    Non of them


    10)animal fed a high cholesterol diet shows decreased cholesterol synthesis by liver because of th inhibition of which one of the following enzyme:-

    HMG CoA synthetase
    HMGCoA reductase
    Mevalonate kinase
    HMG CoA lyase


    11)Succinyl CoA may undergoes one of the following fateEXCEPT:-

    Heme synthesis
    Activation of ketone bodies
    Glycosaminoglycans synthesis
    Gluconeogenesis


    12)Pancreatic lipase:-

    Is specific for the 1.3 ester linkage of triacylglycerols
    Is specific for the 2 position of triacylglycerols
    Specifically hydrolyzes 2 monoacylglycerols
    Is specific for the phospholipids


    13) which of the following changes would you expect in apatient with decreased activity of lipoprtien lipase?

    Elevation of serum chylomicrons only
    Elevation of both serum chylomicrons and VLDL
    Elevation of HDL only
    Elevation of both serum HDL and LDL


    14)Cholesterol is the precursor of the following compounds EXCEPT

    Bile acids
    Testosterone
    B_Hydroxy butyrate
    Progesterone


    15) the catabolism of hemoglobin involve:

    Oxidative cleavage of porphyrin ring
    Formatin of urobilin
    Liberation of CO
    All of the above


    16) δ-aminolevulonic acid synthetase activity:

    Catalyzing rate limiting step in heme biosynthesis
    Require co enzyme biotin
    Occurs in cytosol
    Stimulated by heavy metals as lead


    17) a normal adult is placed on a diet deficient only in phynyalanine which of the following statement is correct:

    Synthesis of proteins by the liver continues normally
    Signs of myxedema will appear
    Tyrosine is used to compensate missing phynylalanine
    Tyrosine becomes an essential amino acid


    18) which of the following statement is correct:

    The end product of all amino acid catabolism is urea
    All essential amino acids are glycogenic
    Ornithine, citrulline and β-alanine are found in tissue proteins
    In the presense of dietary source of tyrosine , phynyl alanine is not essential


    19) amino transferases:

    Catalyse reaction that result in production of ammonia
    Catalyse irreversible reaction
    Require pyridoxal phosphate as essential co-enzyme for the reaction
    Are not able to catalyse transamination reaction s with essential amino acid


    20) in the formation of urea from ammonia by urea cycle, all of the following are correct except:

    The site of urea formatin is the kidney
    Fumarate is produced
    Aspartate supplys one of the nitrogen found in urea
    Genetic deficiency of any one of enzymes can lead to hyper ammoemia


    21) removal of amino group from amino acids in man is performed mainly by:

    Transaminatin only
    Oxidative deamination only
    Transamination followed by oxidative deamination
    Non oxidative deamination


    22) all of the following about serine is correct except:

    it is essential for phosphoproteins synthesis
    precursor of carnitine
    reacts with palmityl Co-A to form sphingosine base
    it gives choline by decarboxylation and transmethylation


    23) which of the following amino acids can be metabolized to fatty acids in mammals:

    histidine
    methionine
    arginine
    leucine


    24) which amino acid undergoes transamination to form glyoxlic acid:

    alanine
    aspartate
    glycine
    lysine


    25) all of thefollowing are correct about ornithine except:

    is a precursor about spermin and spermidine
    it is non protein amino acid
    is a source of N1 in purine bases
    plays amajor role in urea cycle


    26) all of the following about glutamate dehydrogenase are true except:

    it catalses a reversible reaction
    synthesis of non essential amino acxid
    it is an enzyme that present in most tissues
    its co-enzyme is FAD


    27) alkptonuria is due to absence of :

    homogintisic acid oxidase
    phenyl alanine oxidase
    tyrosine oxidase
    dopa decarboxylase


    28) the precursor of adrenaline is:

    alanine
    tryptophan
    tyrosine
    cysteine


    29) phenylketonuria is:

    associated with mental retardation
    due to hereditary deficiency of phenylalanine hydroxylase
    associated with excecretion of phenyl lactate and phenyl pyruvate
    all of the above


    30) the metabolism of tryptophan results in the production of a substance that:

    forms heme
    prevents albinism
    causes vasoconstriction
    causes phenylketonuria


    31) albinism is due to abscense of:

    tyrosnase
    Dopa oxidase
    Tryptophan pyrrolase
    homogintisic acid oxidase


    32) in the gluconeogenesis each of the following is needed for the convertion of pyruvate to phosphoenolpyruvate except:

    CO2
    GTP
    Pyruvate carboxylase
    Pyruvate kinase


    33) glycosuria may be caused by the following except:

    Glycosuria in pregnancy
    Diabetes mellitus
    Diabetes insipidus
    Low renal threshold for tubular reabsorption of glugose


    34) all the following about glycogenolysis are true except:

    It is the breakdown of glycogen to glucose
    Glucose is the end product in liver and muscle
    It is stimulated by adrenaline and nor adrenaline
    Von-jierk's disease deficiency of glucose-6- phosphatase
    35) diabetes mellitus is due to deficiency of the action of:



    Glucagons
    Insulin
    Thyroxin
    Adrenaline


    36) fructose and galactose enter the liver and are phosphorylated at carbon :

    1
    3
    6
    5


    37) oxidative decarboxylation of pyruvate requires :

    biotin
    cytochrome P 450
    thiamin pyrophosphate
    NADP+


    38) the activity of phosphofructokinase-1 can be decreased by all the following except:

    ATP
    Citrate
    Glucagon
    AMP


    39) pyruvate dehydrogenase is inhibited by the following except :

    Acetyl Co-A
    ATP
    NADH+H
    Insulin


    40) all of the following are intermediates of tricarboxylic acid cycle except :

    Citrate
    Malate
    Propionyl Co- A
    Oxaloacetate


    41) cAMP directly activates:

    Hexokinase
    Glycogen synthase
    Phosphofructokinase -1
    Protein kinase


    42) NADPH + H is produced by:

    Pentose phosphate pathway
    Glycolysis
    Citric acid cycle
    Uronic acid pathway


    43) which of the following enzymes of glycolysis is utilized in gluconeogenesis:

    Glukokinase
    Aldolase
    Phosphpfructokinase
    Pyruvate kinase


    44) gluconeogenesis occurs in

    Mitochondria
    Cytosol
    Both of them
    Non of them


    45) apolipoproteinC-ΙΙ activates :

    LCAT
    ACAT
    Lipoprotein lipase
    HMG-CO Areductase


    with best wishes
    Dof3tna Team


      الوقت/التاريخ الآن هو الأحد سبتمبر 22, 2024 2:36 am