Biochemistry Exam: MCQ Quiz!

22 Questions | Total Attempts: 730

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Biochemistry Exam: MCQ Quiz!

How do you feel about biochemistry? Biochemistry is the study of biological experiences at the molecular level. The aim is to understand the fundamental chemical principles that govern complex biological systems. Biochemistry is utilized to learn about the biological activities which occur in cells and organisms. Biochemistry may be used to study the properties of biological molecules for several different purposes. Take this brilliant quiz and become an impressive student of biochemistry.


Questions and Answers
  • 1. 
    A weak acid can act as a buffer......
    • A. 

      At pH values=pK±0.1

    • B. 

      At pH values = pK ± 1

    • C. 

      At pH values = pK ± 2

    • D. 

      Only at body temperatures

    • E. 

      None of the above

  • 2. 
    Which of the following is considered to be a fibrous protein?
    • A. 

      Hemoglobin

    • B. 

      Immunoglobulin

    • C. 

      Keratin

    • D. 

      Myoglobin

    • E. 

      None of the above

  • 3. 
    Disulfide bonds most often stabilize the native structure of:
    • A. 

      Dimeric proteins

    • B. 

      Extracellular proteins

    • C. 

      Hydrophobic proteins

    • D. 

      Intracellular proteins

    • E. 

      All of the above

  • 4. 
    In sickle cell anemia, the basis of the malfunction of the hemoglobin molecule is:
    • A. 

      Faulty binding of the heme groups

    • B. 

      Incorrect secondary structure

    • C. 

      Reduced affinity for oxygen

    • D. 

      Substitution of a single amino acid

    • E. 

      None of the above

  • 5. 
    When BPG (2,3-Bisphosphoglycerate) binds to ______ site(s) on hemoglobin ________ its affinity for O2
    • A. 

      Four/decreases

    • B. 

      Four/increases

    • C. 

      One/decreases

    • D. 

      One/increases

    • E. 

      None of the above

  • 6. 
    The complementarity-determining regions (CDRs)
    • A. 

      Are found at the antigen-binding sites

    • B. 

      Reside in the VL and VH regions of the IgG molecule

    • C. 

      Reside in the CL and CH regions of the IgG molecule

    • D. 

      A and B are correct

    • E. 

      A and C are correct

  • 7. 
    Antibodies of the IgG class
    • A. 

      Consist of four subunits

    • B. 

      Are glycoproteins

    • C. 

      Have inter- and intra-chain disulfide crosslinks

    • D. 

      All three choices are correct

    • E. 

      None of the choices are correct

  • 8. 
    The two exonuclease activities of DNA polymerase I
    • A. 

      Are coupled during the formation of "gapped DNA"

    • B. 

      Degrade DNA in a 3' --> 5' direction

    • C. 

      Degrade DNA in a 5' --> 3' direction

    • D. 

      Occur at two different active sites

    • E. 

      None of the above

  • 9. 
    The RNA primers used to initiate replication in E. coli
    • A. 

      Are joined together by DNA ligase

    • B. 

      Are removed by helicase + ATP

    • C. 

      Are removed by Pol I "nick translation

    • D. 

      Result in Okazaki fragments on the leading strand

    • E. 

      None of the above

  • 10. 
    On the ribosome, mRNA binds ____; the peptidyl transferase reaction occurs ____
    • A. 

      Between the subunits; on the large subunit

    • B. 

      Between the subunits; on the small subunit

    • C. 

      To the large subunit; on the small subunit

    • D. 

      To the small subunit; on the large subunit

    • E. 

      None of the above

  • 11. 
    The pKa of an ionizable side chain, such as imidazole in histidine, can be determined with NMR because
    • A. 

      Protonated imidazole has twice the number of protons

    • B. 

      The chemical shift of His differs from that of His+

    • C. 

      The pKa is near neutrality

    • D. 

      Unprotonated imidazole is invisible in the spectrum

    • E. 

      None of the above

  • 12. 
    During the synthesis of a 100 residue protein, the number of GTP molecules used during initiation, elongation, and termination are, respectively:
    • A. 

      1, 100, 1

    • B. 

      1, 198, 1

    • C. 

      1, 200, 1

    • D. 

      2, 198, 2

    • E. 

      None of the above

  • 13. 
    Peripheral membrane proteins
    • A. 

      Are not accommodated by the fluid mosaic model

    • B. 

      Are only of peripheral interest to membrane biologists

    • C. 

      Can be dissociated from membranes relatively easily, e.g., high salt treatment

    • D. 

      Can undergo transverse membrane motion, i.e. "flip-flop"

    • E. 

      None of the above

  • 14. 
    During glycolysis the following reaction requires NAD+:
    • A. 

      Alcohol dehydrogenase

    • B. 

      Glyceraldehyde-3-phosphate dehydrogenase

    • C. 

      Lactate dehydrogenase

    • D. 

      Pyruvate dehydrogenase

    • E. 

      All of the above

  • 15. 
    Since the energy released by all the reactions of glycolysis is 185 kJ/mol glucose, and ____ mol ATP is/are produced per mol glucose, the overall efficiency of glycolysis is about ____
    • A. 

      1/ 16%

    • B. 

      1 /33%

    • C. 

      2 /33%

    • D. 

      2 /50%

    • E. 

      None of the above

  • 16. 
    Glycogen digestion in the gut begins with a ________ reaction; intracellular glycogen breakdown begins with a ________ reaction.
    • A. 

      Hydrolysis; hydrolysis

    • B. 

      Hydrolysis; phosphorolysis

    • C. 

      Hydrolysis; phosphorylation

    • D. 

      Phosphorolysis; hydrolysis

    • E. 

      None of the above

  • 17. 
    The correct order, from fastest-acting to slowest, for the time scale of these regulatory mechanisms is:
    • A. 

      Allosteric - covalent - genetic

    • B. 

      Allosteric - genetic - covalent

    • C. 

      Covalent - genetic - allosteric

    • D. 

      Genetic - allosteric - covalent

    • E. 

      None of the above

  • 18. 
    Mitochondrial ATP synthesis requires:
    • A. 

      A [H+] gradient

    • B. 

      A membrane potential

    • C. 

      An intact inner mitochondrial membrane

    • D. 

      All of the above

    • E. 

      None of the above

  • 19. 
    Which of the following enzymes does not catalyze a physiologically irreversible step in glycolysis?
    • A. 

      Hexokinase

    • B. 

      Phosphofructokinase

    • C. 

      Phosphoglycerate kinase

    • D. 

      Pyruvate kinase

    • E. 

      None of the above

  • 20. 
    Following the addition of a mitochondrial respiratory inhibitor, components of the electron transport chain.
    • A. 

      All components will be oxidized

    • B. 

      Downstream of the blockage will be reduced

    • C. 

      Upstream of the blockage will be oxidized

    • D. 

      Upstream of the blockage will be reduced

    • E. 

      None of the above

  • 21. 
    For the following reaction: [FAD] + 2 Cyt c (Fe2+) + 2H+ -> [FADH2] + 2 Cyt c (Fe3+) the electron donor is _______; the reduced product is ________
    • A. 

      2 Cyt c (Fe2+); [FADH2]

    • B. 

      [FAD]; [FADH2]

    • C. 

      2 Cyt c (Fe2+); 2 Cyt c (Fe3+)

    • D. 

      [FAD]; 2 Cyt c (Fe3+)

    • E. 

      None of the above

  • 22. 
    Acetyl groups (e.g. for lipid biosynthesis) are transported out of the mitochondria indirectly using:
    • A. 

      Acetyl carnitine

    • B. 

      Acetyl phosphate

    • C. 

      Citrate

    • D. 

      Malate

    • E. 

      All of the above

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