Biochem Tb Chapter 1

34 Questions | Total Attempts: 261

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  • 1. 
    All are distinctive properties of living systems except:
    • A. 

      Living organisms are relatively simple

    • B. 

      Biological structures play a role in the organism´s existence

    • C. 

      The living state is characterized by the flow of energy trough the organism

    • D. 

      Living organism are highly organized

    • E. 

      Living organism are actively engaged in energy transformation

  • 2. 
    Even though the building blocks have fairly simple structures, macromolecules are exquisitely organized in their intricate three-dimensional architecture known as: 
    • A. 

      Configuration.

    • B. 

       conformation.

    • C. 

      Sequence.

    • D. 

      Lewis structure.

    • E. 

      Structural maturation.

  • 3. 
    All of the following activities require the presence of ATP or NADPH EXCEPT: 
    • A. 

      Osmoregulation.

    • B. 

       biosynthesis.

    • C. 

      Movement of muscles.

    • D. 

      Light emission.

    • E. 

      None, they are all energy-requiring activities.

  • 4. 
    Which are the four most common elements in the human body? 
    • A. 

      Hydrogen, calcium, oxygen and sodium

    • B. 

       hydrogen, oxygen, iron and carbon

    • C. 

      Hydrogen, oxygen, carbon and nitrogen

    • D. 

      Oxygen, carbon, iron and nitrogen

    • E. 

      Oxygen, silicon, calcium and nitrogen

  • 5. 
    What makes carbon such an abundant element in biomolecules? 
    • A. 

      It can form up to five bonds by sharing its electrons.

    • B. 

       It forms only single bonds.

    • C. 

      It provides low bond energy.

    • D. 

       It forms stable covalent bonds by electron pair sharing.

    • E. 

      It does not usually bond to other carbons, allowing a more diverse combination of elements.

  • 6. 
    The major precursors for the formation of biomolecules include all EXCEPT:
    • A. 

      Nitrate and dinitrogen.

    • B. 

      Water.

    • C. 

      Carbon dioxide.

    • D. 

      Ammonium ion.

    • E. 

      None, all are major precursors.

  • 7. 
     From the major precursors, the complex biomolecules are made in which sequence?
    • A. 

       metabolites, building blocks, macromolecules, supramolecular complexes

    • B. 

      Macromolecules, building blocks, metabolites, supramolecular complexes

    • C. 

       building blocks, macromolecules, supramolecular complexes, metabolites

    • D. 

      Metabolites, macromolecules, building blocks, supramolecular complexes

    • E. 

      Metabolites, building blocks, supramolecular complexes, macromolecules

  • 8. 
    The structural integrity of supramolecular complexes (assemblies) of multiple components are bonded to each other by all of the following forces EXCEPT: 
    • A. 

       covalent bonds

    • B. 

      Van der Waals forces

    • C. 

      Hydrogen bonds

    • D. 

      Hydrophobic interactions

    • E. 

      Ionic interactions

  • 9. 
    Organelles have what three attributes? 
    • A. 

      Only in prokaryotic cells, membrane bound, have a dedicated set of tasks.

    • B. 

      Only in eukaryotic cells, membrane bound, have a dedicated set of tasks.

    • C. 

      Only in eukaryotic cells, seldom membrane bound, have a dedicated set of tasks.

    • D. 

      Only in prokaryotic cells, membrane bound, multi-functional.

    • E. 

      In both prokaryotic cells and eukaryotic cells, membrane bound, have a dedicated set of tasks.

  • 10. 
    Membrane structures are maintained primarily by: 
    • A. 

      Hydrophobic interactions.

    • B. 

      Covalent bonds.

    • C. 

      Hydrogen bonds.

    • D. 

      Non-spontaneous assembly

    • E. 

      Ionic interactions.

  • 11. 
     All of the following are properties of membranes EXCEPT: 
    • A. 

      Supramolecular assemblies.

    • B. 

      Define boundaries of cellular components.

    • C. 

      Spontaneous assemblies resulting from hydrophobic interactions.


    • D. 

      Identical protein and lipid composition in the major organelles.

    • E. 

      None, all are true.

  • 12. 
    Which of the following properly ranks the non-covalent interactions in order of increasing strength?
    • A. 

      Ionic, hydrogen bond, van der Waals

    • B. 

       van der Waals, hydrogen bond, ionic

    • C. 

      Van der Waals, ionic, hydrogen bond

    • D. 

      Hydrogen bond, van der Waals, ionic

    • E. 

      Cannot be determined since ionic interactions and hydrogen bonds often vary in strength

  • 13. 
     Weak forces that create constantly forming and breaking interactions at physiological temperatures, but cumulatively impart stability to biological structures generated by their collective activity include all EXCEPT: 
    • A. 

       hydrogen bonds

    • B. 

      Van der Waals forces

    • C. 

      Covalent bonds

    • D. 

      Ionic interactions

    • E. 

      Hydrophobic interactions

  • 14. 
    Which of the following is a true statement about non-covalent bonds? 
    • A. 

      They are all the result of electron sharing.

    • B. 

      Hydrogen bonds, ionic bond and hydrophobic interactions all carry a degree of specificity while van der Waals interactions are induced.

    • C. 

      All noncovalent bonds are formed between oppositely charged polar functions.

    • D. 

      Van der Waals interactions are not affected by structural complementarity, while hydrogen bonds, ionic bonds and hydrophobic interaction are affected by structural complementarity.

    • E. 

      Hydrogen, van der Waals, and hydrophobic interactions do not form linear bonds.

  • 15. 
    Which of the statements about the nature of the hydrogen bond is true? 
    • A. 

      The donor is a hydrogen atom bonded to a carbon.

    • B. 

      The more linear the bond, the stronger the interaction.

    • C. 

      The acceptor must be similar in electronegativity to hydrogen.

    • D. 

      It is a type of covalent bond.

    • E. 

       A hydrogen bond is weaker than van der Waals forces.

  • 16. 
     Electrostatic forces 
    • A. 

      Include ionic interactions between negatively charged carboxyl groups and positively charged amino groups.

    • B. 

      Average about 2 kJ/mol in aqueous solutions.

    • C. 

      Typically are directional like hydrogen bonds.

    • D. 

      Require a precise fit like van der Waals interactions.

    • E. 

      Include ionic, induced dipole and permanent dipole interactions.

  • 17. 
    All are true about hydrophobic interactions EXCEPT: 
    • A. 

      Hydrophobic interactions result from the strong tendency of water to exclude nonpolar groups or molecules.

    • B. 

      Hydrophobic interactions result because water molecules prefer the stronger interactions that they share with one another, compared to their interactions with nonpolar molecules.

    • C. 

      Hydrophobic interactions result from hydrogen bonds between water and the hydrophobic molecules.

    • D. 

      The preferential interactions between water molecules "exclude" hydrophobic substances from aqueous solution and drive the tendency of nonpolar molecules to cluster together.

    • E. 

      Hydrophobic interactions result in nonpolar regions of biological molecules being buried in the molecule's interior to exclude them from the aqueous milieu.

  • 18. 
    Which of the following molecular recognition mechanisms is based upon structural complementarity?
    • A. 

      Interaction of a protein with a metabolite.

    • B. 

      The association of a strand of DNA with its complementary strand.

    • C. 

       the ability for a sperm cell to bind to an egg.

    • D. 

      The binding of a hormone to its receptor.

    • E. 

      All of the above

  • 19. 
    All of the statements about structural complementarity are true EXCEPT:
    • A. 

      Weak chemical forces mediate it.

    • B. 

      . It produces strong irreversible interactions.

    • C. 

       It is the interaction of a biological macromolecule and its ligand.

    • D. 

      It is the basis of many biological functions.

    • E. 

      It is the means of recognition in bimolecular interactions.

  • 20. 
    Which of the following statements regarding molecular recognition is correct? 
    • A. 

       Covalent bonds are a common interaction used in molecular recognition.

    • B. 

       Molecular recognition takes place only between protein molecules.

    • C. 

      For molecular recognition to occur, complementarity of the molecules is required.

    • D. 

      Hydrogen bonds are not effective mediators of molecular recognition due to their low strength.

    • E. 

      None of the above are correct.

  • 21. 
    Biological molecules are functionally active only within a narrow range of environmental conditions with denaturation occurring in all EXCEPT: 
    • A. 

      Dramatic increase in temperature.

    • B. 

      Change in ionic strength.

    • C. 

      Efrigeration.

    • D. 

      Addition of strong acid or base.

    • E. 

      None, all will denature biological macromolecules.

  • 22. 
    Which of the following statements about metabolism is true? 
    • A. 

      Metabolism only occurs inside of organelles.

    • B. 

      Metabolism is rarely organized into pathways.

    • C. 

      Metabolism always results in a production of ATP.


    • D. 

      Metabolism has two components: anabolism and catabolism.

  • 23. 
    All of the following functions of an enzyme are true EXCEPT: 
    • A. 

      Enzymes help to catalyze virtually every metabolic reaction.

    • B. 

      Enzymes mediate the rates of cellular reaction in proportion to cellular requirements.

    • C. 

      Enzymes are sensitive to temperature, pH, and concentration changes.

    • D. 

      An increased activity of an enzyme increases the amount of energy produced.

    • E. 

      Enzymes are used as a catalyst to increase reaction rates many orders of magnitude.

  • 24. 
    All are true for prokaryotic cells EXCEPT: 
    • A. 

      Some have flagella.

    • B. 

      They have a simple plasma or cell membrane.

    • C. 

      They posses a distinct nuclear area, but no nucleus.

    • D. 

      They have ribosomes, but no mitochondria.

    • E. 

      All are true.

  • 25. 
     Composed of peptidoglycan, a rigid framework of polysaccharide cross-linked by short peptide chains, describes what structural feature of a prokaryotic cell? 
    • A. 

      Cytosol

    • B. 

      Ribosome

    • C. 

      Nuclear area

    • D. 

      Cell membrane

    • E. 

      Cell wall

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