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:
Pregunta 13
Pregunta
The collagen is:
Pregunta 14
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
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:
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.
Pregunta 22
Pregunta
What are the interactions that stabilize the tertiary and the quatemary structure of 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
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