6632855
Descripción
Test por Med Student , actualizado hace más de 1 año
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Creado por Med Student
hace más de 7 años
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Pregunta 1
Pregunta
Which of the following amino acids have charge at ph 7.0?
Respuesta
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alanine
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arginine
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lysine
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cysteine
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aspartic acid
Pregunta 2
Pregunta
Which of the following statements about noncompetitive inhibitors is TRUE:
Respuesta
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the noncompetitive inhibitor can bind both the enzyme and the ES complex
-
the noncompetitive inhibitor decreases Vmax but does not change Km
-
the noncompetitive inhibitor binds the enzyme at site distinct from the active site
-
the noncompetitive inhibitor is it structural analog of the substrate
Pregunta 3
Pregunta
The consequences of folic acid deficiency is:
Respuesta
-
beri-beri
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scurvy
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pellagra
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megaloblastic anemia
Pregunta 4
Pregunta
Vit. C is involved in:
Respuesta
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the biosynthesis of noradrenaline and adrenaline
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the postsynthetic modification of procollagen to collagen
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the formation of Coenzyme A
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the metabolism one-carbon fragments
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the biosynthesis of bile acids
Pregunta 5
Pregunta
Which of the following amino-acids are sulphur-containing?
Respuesta
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Histidine
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Cysteine
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Threonine
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Methionine
Pregunta 6
Pregunta
Which of the following statements about nuclear DNA are TRUE?
Respuesta
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It contains deoxyribose as pentose
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It contains Uracil instead of Thymine
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It is a double-stranded circular structure
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It is double-stranded helix
Pregunta 7
Pregunta
Denaturation of proteins:
Respuesta
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Can affect primary structure of proteins
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Affect all the structures except the primary structure of proteins
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Can be reversible and irreversible depending on the duration of the denaturating agent
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Breaks down the covalent bonds within the polypeptide chain
Pregunta 8
Pregunta
Which of the following statements about competitive inhibitors are TRUE?
Respuesta
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The competitive inhibitor can bind only with the active site of the enzyme
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The competitive inhibitor can bind only with the ES complex
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The competitive inhibitor can bind both with the active site of the enzyme and the ES complex
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Vmax remains unchanged, Km rises
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Km remains unchanged. Vmax decreases
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The competitive inhibitor is a structural analog of the substrate
Pregunta 9
Pregunta
Which of the following amino acids are hydrophobic and are localized inside the globular protein molecule?
Respuesta
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Lysine and Glutamate
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Leucine and Isoleucine
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Alanine and Valine
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Serine and Cysteine
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Tryptophan and Proline
Pregunta 10
Pregunta
Which of the following are not included in protein structures. but have important biological role?
Respuesta
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Ornithine
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β-alanine
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Histidine
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Homocysteine
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Citrulline
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Citrate
Pregunta 11
Pregunta
Which is the type of covalent bond between a-amino acid residues in polypeptide chain?
Respuesta
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phosphoesteric bond
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glycosidic bond
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sulfur bridge
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peptide bond
-
esteric bond
Pregunta 12
Pregunta
Polypeptide chains are consisted of:
Respuesta
-
α-amino acid residues
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nucleotides
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glycerol
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free fatty acids
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glucose or other monosaccharides
Pregunta 13
Pregunta
The collagen is:
Respuesta
-
fibrilar protein
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globular protein
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rich of Glycine residues
-
rich of Proline residues
-
rich of Glutamate and Glutamine residues
Pregunta 14
Pregunta
Vitamin B1:
Respuesta
-
Its deficiency causes pellagra
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Its deficiency causes “beri-beri"
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Its chemical name is riboflavin
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Its chemical name is thiamine
Pregunta 15
Pregunta
Allosteric effectors:
Respuesta
-
Bind with the active site of the enzyme
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Can change the total amount of the enzymes
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Are Inducers and suppressors
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Are activators and inhibitors
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can cause negative or positive feedback
Pregunta 16
Pregunta
Km
Respuesta
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is equal to (k-1+k2)/k1
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is equal to (k1+k2)/k-1
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Gives information for affinity between the active site of the enzyme and its substrate
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The higher Km is, the greater affinity exists
Pregunta 17
Pregunta
Which of the following belong to the six classes of enzymes according to the enzyme classification:
Respuesta
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hydrolases
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transferases
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esterases
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oxidoreductases
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peptidases
Pregunta 18
Pregunta
The consequences of niacine (Vit. PP) deficiency is
Respuesta
-
beri beri
-
scurvy
-
pellagra
-
rickets
Pregunta 19
Pregunta
Pyridoxal phosphate coenzyme is a:
Respuesta
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derivative of Vit. B2
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derivative of Vit. B3
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derivative of Vit. B6
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participates in oxidation and reduction
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Participates in transfer of amine
Pregunta 20
Pregunta
Which of the following co-factor's participate in reactions catalyzed by oxidoreductases:
Respuesta
-
Biotin
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Pyridoxal phosphate
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NAD+
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CoASH
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FMN
Pregunta 21
Pregunta
In which enzymes participates thiamine diphosphate (TPP)- the active form of vitamin B1.
Respuesta
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aminotransferases
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decarboxylases
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pyruvate dehydrogenase
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α-ketoglutarate dehydrogenase
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transketolase
Pregunta 22
Pregunta
What are the interactions that stabilize the tertiary and the quatemary structure of proteins:
Respuesta
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hydrophobic interactions
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hydrogen bonds
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ion interactions
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peptide bonds
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disulfide bonds in oligomeric proteins
Pregunta 23
Pregunta
The reversible covalent Phosphorylation-dephosphorylation of the enzymes:
Respuesta
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acts on the enzymes active site
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acts on the enzymes allosteric sites
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acts on a single enzyme
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acts on several enzymes
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is under direct neural and hormonal control
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is a mechanism for quick enzyme regulation
Pregunta 24
Pregunta
Which is the vitamin in FMN and FAD:
Respuesta
-
folic acid
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riboflavin
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thiamin
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biotin
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niacin
Pregunta 25
Pregunta
In competitive inhibition:
Respuesta
-
Vmax remains unchanged, Km decreases
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Vmax remains unchanged, Km increases
-
Vmax and Km remain unchanged
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Vmax and Km decrease
Pregunta 26
Pregunta
The feedback inhibition:
Respuesta
-
is a mechanism of regulation of multistep metabolic pathways
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is under direct neural and hormonal control
-
acts on early steps enzymes
-
acts on the enzymes active site
Pregunta 27
Pregunta
Which of the following statements about peptide bond are TRUE:
Respuesta
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the peptide bonds maintain the primary structure of proteins
-
the peptide bonds maintain the secondary structure of proteins
-
the peptide bond is a non-covalent bond
-
the peptide bond has a partial double-bond character
Pregunta 28
Pregunta
The simultaneous increase in AST and ALT is diagnostic marker mostly for:
Respuesta
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Muscle Dieseases
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Cardiac Diseases
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Liver Diseases
-
Brain Diseases
Pregunta 29
Pregunta
Vitamin C
Respuesta
-
It is a water-soluble vitamin
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Its deficiency causes pellagra
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Its deficiency causes scurvy
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It participates as a cofactor in the posttranslational modification of collagen
Pregunta 30
Pregunta
Which of the following is TRUE?
Respuesta
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some of proteins are enzymes
-
all of proteins are enzymes
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some of proteins are hormones
-
all of proteins are hormone
-
some of proteins participate as transporting molecules
Pregunta 31
Pregunta
Nucleotides are derivatives consisted of:
Respuesta
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heterocyclic ring consisted of C- and N- atoms named purine or pyrimidine monosaccaride- ribose or deoxyribose and phosphoric acid
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heterocyclic ring consisted of C- and S- atoms, monosaccaride- an hexose and phosphoric acid
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heterocyclic ring consisted of C- and N- atoms, named purine or pyrimidine- a disaccharide and phosphoric acid
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heterocyclic ring consisted of C- and N- atoms named purine or pyrimidines, monosaccaride- ribose deoxyribose and nitric acid
Pregunta 32
Pregunta
Protein denaturation is a process that:
Respuesta
-
amino acids composition is changed
-
its primary structure is disrupted
-
its biological activity is lost
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chemical and physical feature are changed
-
its conformation is disrupted
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