Biochemistry MCQ Exam 1- PMU 2nd Year

Descripción

Prof Stakonova's MCQs specifically for Biochemistry
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Resumen del Recurso

Pregunta 1

Pregunta
Which of the following amino acids have charge at ph 7.0?
Respuesta
  • alanine
  • arginine
  • lysine
  • cysteine
  • aspartic acid

Pregunta 2

Pregunta
Which of the following statements about noncompetitive inhibitors is TRUE:
Respuesta
  • 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
  • scurvy
  • pellagra
  • megaloblastic anemia

Pregunta 4

Pregunta
Vit. C is involved in:
Respuesta
  • the biosynthesis of noradrenaline and adrenaline
  • the postsynthetic modification of procollagen to collagen
  • the formation of Coenzyme A
  • the metabolism one-carbon fragments
  • the biosynthesis of bile acids

Pregunta 5

Pregunta
Which of the following amino-acids are sulphur-containing?
Respuesta
  • Histidine
  • Cysteine
  • Threonine
  • Methionine

Pregunta 6

Pregunta
Which of the following statements about nuclear DNA are TRUE?
Respuesta
  • It contains deoxyribose as pentose
  • It contains Uracil instead of Thymine
  • It is a double-stranded circular structure
  • It is double-stranded helix

Pregunta 7

Pregunta
Denaturation of proteins:
Respuesta
  • Can affect primary structure of proteins
  • Affect all the structures except the primary structure of proteins
  • Can be reversible and irreversible depending on the duration of the denaturating agent
  • Breaks down the covalent bonds within the polypeptide chain

Pregunta 8

Pregunta
Which of the following statements about competitive inhibitors are TRUE?
Respuesta
  • The competitive inhibitor can bind only with the active site of the enzyme
  • The competitive inhibitor can bind only with the ES complex
  • The competitive inhibitor can bind both with the active site of the enzyme and the ES complex
  • Vmax remains unchanged, Km rises
  • Km remains unchanged. Vmax decreases
  • 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
  • Lysine and Glutamate
  • Leucine and Isoleucine
  • Alanine and Valine
  • Serine and Cysteine
  • Tryptophan and Proline

Pregunta 10

Pregunta
Which of the following are not included in protein structures. but have important biological role?
Respuesta
  • Ornithine
  • β-alanine
  • Histidine
  • Homocysteine
  • Citrulline
  • Citrate

Pregunta 11

Pregunta
Which is the type of covalent bond between a-amino acid residues in polypeptide chain?
Respuesta
  • phosphoesteric bond
  • glycosidic bond
  • sulfur bridge
  • peptide bond
  • esteric bond

Pregunta 12

Pregunta
Polypeptide chains are consisted of:
Respuesta
  • α-amino acid residues
  • nucleotides
  • glycerol
  • free fatty acids
  • glucose or other monosaccharides

Pregunta 13

Pregunta
The collagen is:
Respuesta
  • fibrilar protein
  • globular protein
  • rich of Glycine residues
  • rich of Proline residues
  • rich of Glutamate and Glutamine residues

Pregunta 14

Pregunta
Vitamin B1:
Respuesta
  • Its deficiency causes pellagra
  • Its deficiency causes “beri-beri"
  • Its chemical name is riboflavin
  • Its chemical name is thiamine

Pregunta 15

Pregunta
Allosteric effectors:
Respuesta
  • Bind with the active site of the enzyme
  • Can change the total amount of the enzymes
  • Are Inducers and suppressors
  • Are activators and inhibitors
  • can cause negative or positive feedback

Pregunta 16

Pregunta
Km
Respuesta
  • is equal to (k-1+k2)/k1
  • is equal to (k1+k2)/k-1
  • Gives information for affinity between the active site of the enzyme and its substrate
  • 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
  • hydrolases
  • transferases
  • esterases
  • oxidoreductases
  • 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
  • derivative of Vit. B2
  • derivative of Vit. B3
  • derivative of Vit. B6
  • participates in oxidation and reduction
  • Participates in transfer of amine

Pregunta 20

Pregunta
Which of the following co-factor's participate in reactions catalyzed by oxidoreductases:
Respuesta
  • Biotin
  • Pyridoxal phosphate
  • NAD+
  • CoASH
  • FMN

Pregunta 21

Pregunta
In which enzymes participates thiamine diphosphate (TPP)- the active form of vitamin B1.
Respuesta
  • aminotransferases
  • decarboxylases
  • pyruvate dehydrogenase
  • α-ketoglutarate dehydrogenase
  • transketolase

Pregunta 22

Pregunta
What are the interactions that stabilize the tertiary and the quatemary structure of proteins:
Respuesta
  • hydrophobic interactions
  • hydrogen bonds
  • ion interactions
  • peptide bonds
  • disulfide bonds in oligomeric proteins

Pregunta 23

Pregunta
The reversible covalent Phosphorylation-dephosphorylation of the enzymes:
Respuesta
  • acts on the enzymes active site
  • acts on the enzymes allosteric sites
  • acts on a single enzyme
  • acts on several enzymes
  • is under direct neural and hormonal control
  • is a mechanism for quick enzyme regulation

Pregunta 24

Pregunta
Which is the vitamin in FMN and FAD:
Respuesta
  • folic acid
  • riboflavin
  • thiamin
  • biotin
  • niacin

Pregunta 25

Pregunta
In competitive inhibition:
Respuesta
  • Vmax remains unchanged, Km decreases
  • Vmax remains unchanged, Km increases
  • Vmax and Km remain unchanged
  • Vmax and Km decrease

Pregunta 26

Pregunta
The feedback inhibition:
Respuesta
  • is a mechanism of regulation of multistep metabolic pathways
  • 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
  • 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
  • Muscle Dieseases
  • Cardiac Diseases
  • Liver Diseases
  • Brain Diseases

Pregunta 29

Pregunta
Vitamin C
Respuesta
  • It is a water-soluble vitamin
  • Its deficiency causes pellagra
  • Its deficiency causes scurvy
  • It participates as a cofactor in the posttranslational modification of collagen

Pregunta 30

Pregunta
Which of the following is TRUE?
Respuesta
  • some of proteins are enzymes
  • all of proteins are enzymes
  • 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
  • heterocyclic ring consisted of C- and N- atoms named purine or pyrimidine monosaccaride- ribose or deoxyribose and phosphoric acid
  • heterocyclic ring consisted of C- and S- atoms, monosaccaride- an hexose and phosphoric acid
  • heterocyclic ring consisted of C- and N- atoms, named purine or pyrimidine- a disaccharide and phosphoric acid
  • 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
  • chemical and physical feature are changed
  • its conformation is disrupted
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