Biomedical Science I Exam II

30 Questions | Total Attempts: 123

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Biomedical Science I Exam II - Quiz

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Questions and Answers
  • 1. 
    Which of the following statements is (are) correct(s) about enzymes? Select all that apply.
    • A. 

      As chemical reactions undergo, entropy (disorder) will increase

    • B. 

      Enzymes increase the rate of the reaction by increasing the activation energy (Ea)

    • C. 

      A reaction with a negative ΔG is said to be unfavorable

    • D. 

      Enzymes are specific catalysts that remain unchanged following a reaction

    • E. 

      Polymorphism among individuals can change the activity of enzymes which will effect the metabolism of the drug

  • 2. 
    In a Gs transduction signaling pathway, activation of the effector leads to the activation of?
    • A. 

      G-alpha subunit

    • B. 

      CAMP

    • C. 

      Protein Kinase A (PKA)

    • D. 

      Adenylyl Cyclase

    • E. 

      CREB

  • 3. 
    Which of the following is correct about Gs Signal Transduction Pathway? Select all that apply
    • A. 

      G-protein is monomeric and possesses GTPase activity

    • B. 

      The activation of PKA leads to the amplification of cAMP

    • C. 

      Requires the alpha-subunit to activate Adenylyl Cyclase

    • D. 

      The G-protein requires the binding of GDP for activation

    • E. 

      Can lead to the phosphorylation of CREB

  • 4. 
    Which of the following about enzyme kinetics is false?
    • A. 

      In competitive inhibition, there is an increase in Km and no change in Vmax

    • B. 

      In uncompetitive inhibition, there is a decrease in Km and Vmax

    • C. 

      In non-competitive inhibition, there is a decrease in Km and Vmax

    • D. 

      An increase in Km correlates to a decrease in the affinity of the enzyme to the substrate

  • 5. 
    Which of the following sequence of events is correct for Gs Signal Transduction Pathway?
    • A. 

      Ligand --> Receptor --> G-protein --> PKA --> cAMP --> Adenylyl Cyclase

    • B. 

      Ligand --> Receptor --> G-protein --> Adenylyl Cyclase --> PKA --> cAMP

    • C. 

      Ligand --> G-protein --> Receptor --> PKA --> cAMP --> Adenylyl Cyclase

    • D. 

      Ligand --> Receptor --> G-protein --> Adenylyl Cyclase --> cAMP --> PKA

  • 6. 
    Which of the following statements is correct about enzyme kinetics? Select all that apply
    • A. 

      In competitive inhibition, the inhibitor competes with the substrate for the active site

    • B. 

      Irreversible inhibition includes covalent modifications

    • C. 

      Low Km = Low [S] = High Affinity

    • D. 

      Vmax is the rate of the reaction when the enzyme has low substrate concentration

  • 7. 
    Which of the following statements is correct about types of enzymes? Select all that apply
    • A. 

      Kinases attach phosphate groups to molecules

    • B. 

      Hydrolases cleave water as part of a reaction

    • C. 

      ATPases hydrolyze ADP --> ATP as part of a reaction

    • D. 

      Phosphatases remove phosphate groups off molecules

    • E. 

      Synthases form a large molecule from two small molecules

  • 8. 
    Which of the following statements is false about Receptors and Signal Transduction? 
    • A. 

      Gap junctions, a type of contact-dependent signaling is the fastest form of signaling

    • B. 

      The secretion of the hormone oxytocin from the Posterior Pituitary Gland causes uterine contractions during labor. This signaling occurs quickly and has a short effect.

    • C. 

      Down-regulation of receptors is likely to occur due to high levels of chemical messenger

    • D. 

      Amplification of secondary messengers allows for regulation (e.g. drugs)

    • E. 

      Calcium and cAMP are secondary messengers of Gs Signal Transduction Pathway

  • 9. 
    Which of the following statements are correct about MAPK Signal Transduction? Select all that apply
    • A. 

      Epidermal Growth Factor is the first messenger

    • B. 

      Once the ligand binds to the receptors, the receptors dimerize which allows for phosphorylation to occur

    • C. 

      Ras is heteromeric G protein which activates a kinase that phosphorylates MAPK

    • D. 

      Ras requires extrinsic GTPase activity; in which Guanine Nucleotide Exchange Factors (GEF) converts GTP --> GDP and GTPase activating Proteins (GAP) converts GDP --> GTP.

    • E. 

      Ras is activated by the binding of GTP

  • 10. 
    Which of the following statements are correct about GPCR's? Select all that apply
    • A. 

      Cholera toxin causes rapid production of Gs signaling which causes diarrhea and dehydration

    • B. 

      Phosphodiesterases (PDEs) are a method of self-regulation which stops signaling by converting cAMP into 5'-AMP, the inactivated form.

    • C. 

      PKA is activated by the binding of 4 cAMP molecules to its regulatory subunit

    • D. 

      Pertussis causes decreased production of a physiological response by inhibiting Gi signaling

    • E. 

      Phosphorylation of GPCR by GRKs prevents arrestin from inhibiting the interaction between the receptor and the G-protein

  • 11. 
    Which of the following statement(s) are correct about SLC proteins? Select all that apply
    • A. 

      SLCs are involved in solute influx

    • B. 

      SLCs do not directly consume ATP in the movement of solute

    • C. 

      Few SLCs are present in tissues that participate in environmental exchange.

    • D. 

      GLUT1 is an example of an SLC protein that transports glucose out of the cell.

    • E. 

      SLC proteins can use facilitated diffusion or secondary active transport

  • 12. 
    Which of the following statements is false about channels? 
    • A. 

      Utilizes passive transport in which the solute flows down the concentration gradient

    • B. 

      Channels bind more specifically to the solute and transport the solute faster than transporters

    • C. 

      Energy is not required for the movement of solutes

    • D. 

      An example of a leak channel are aquaporins

  • 13. 
    Which of the following statement(s) are correct of Aquaporins? Select all that apply
    • A. 

      Conducts the transportation of water via leak channels by simple diffusion

    • B. 

      Aquaporins in the kidney are controlled by Antidiuretic Hormone (ADH); in which high ADH secretion would dilute the urine and concentrate the blood

    • C. 

      Ions are unable to pass through aquaporins due to a narrow pore which hydrated ions are too big to fit in

    • D. 

      A mutation of AQP2 (aquaporins in the kidneys) can result in excess reabsorption of water, thus resulting in dilute urine

    • E. 

      Molecules pass through the channels by moving down their concentration gradient

  • 14. 
    Which of the following statements are correct about Transporters? Select all that apply
    • A. 

      The Na+/K+ Pump is an antiport which pumps 3 Na+ in and 2 K+ out to restore membrane potential by primary active transport

    • B. 

      SGLT2 transports glucose against its concentration gradient by coupling it to the movement of Na+ down its concentration gradient

    • C. 

      ABC transporters utilize primary active transport to transport solutes into cells

    • D. 

      SLCO1B1 transports solutes via a uniporter by facilitated diffusion

    • E. 

      The Na+-Amino Acid transporter utilizes a symporter

  • 15. 
    The receptors of intracellular signaling are located where in the cell? Select all that apply
    • A. 

      Plasma Membrane

    • B. 

      Cytosol

    • C. 

      Nucleus

    • D. 

      Endoplasmic Reticulum

    • E. 

      Mitochondria

  • 16. 
    Which of the following is false about enzymes?
    • A. 

      2nd law of thermodynamics suggests that systems will move towards more disorder

    • B. 

      Substrate alignment is a type of reaction which depends on orientation of enzyme and substrate

    • C. 

      Uncompetitive inhibitors bind to the Enzyme-Substrate Complex which decreases Km and Vmax

    • D. 

      Enzymes are catalysts which lower the activation energy of a reaction

    • E. 

      Isomerases catalyze polymerization reactions

  • 17. 
    Which of the following are correct about SGLT2 Transporters? Select all that apply
    • A. 

      Requires the input of energy eventually

    • B. 

      SGLT2 is a symporter which transports Glucose and Sodium

    • C. 

      Inhibition of SGLT2 would lead to excess blood glucose

    • D. 

      Located in the convoluted proximal tubule of the kidneys

    • E. 

      Inhibition of SGLT2 is used as treatment of Type I Diabetes Mellitus

  • 18. 
    Which of the following are correct of ABC transporters? Select all that apply
    • A. 

      ABC proteins possess an Beta-sheet domain which binds ATP

    • B. 

      ABCB1 can efflux substrates such as hydrophilic drugs

    • C. 

      A mutation resulting of gain of function of P-gp can lead to reduced drug levels in tissue

    • D. 

      Requires secondary active transport

    • E. 

      Efflux solutes from kidney cells into the blood

  • 19. 
    Which of the following are correct of Enzyme-Linked Receptor Signaling? Select all that apply
    • A. 

      Receptor dimerization provides access for kinases to autophosphorylate

    • B. 

      Ras is a monomeric G protein which require extrinsic enzymes to activate it

    • C. 

      Guanine Nucleotide Exchange Factors (GEF) converts GTP --> GDP

    • D. 

      Most enzyme-linked receptors are tyrosine kinase receptors

    • E. 

      Epidermal Growth Factor binds to eventually activate MAPK

  • 20. 
    A patient has been prescribed Diltiazem, a Calcium Channel Blocker. Diltiazem is metabolized by CYP3A4. After collecting the patients medication history, you realize he has been treated for a respiratory tract infection with erythromycin. Erythromycin is an inhibitor of CYP3A4. Which of the following statements depicts the effect and plan of action?
    • A. 

      More drug would be metabolized; increase dose

    • B. 

      No effect on Diltiazem

    • C. 

      Less drug would be metabolized; increase dose

    • D. 

      Less drug would be metabolized; reduce dose

    • E. 

      More drug would be metabolized; reduce dose

  • 21. 
    Which of the following statements are correct about drug metabolism? Select all that apply
    • A. 

      CYP2E1 metabolizes 25-30% of all used medications

    • B. 

      N-acetyltransferases are responsible for phase I of biotransformation in which the transfer of acetyl groups aids in the metabolism of drugs

    • C. 

      CYP3A4 is found in the liver and small intestine and metabolizes about 50% of drugs, endogenous and exogenous compounds

    • D. 

      Polymorphism of NAT-2 can results in increased cancer

    • E. 

      NAT-1 and NAT-2 are found in almost all tissues

  • 22. 
    Which of the following statements are correct of the K+ Leak Channel? Select all that apply
    • A. 

      The presence of negatively-charge amino acids on the entrance of the pore restricts the entrance of anions but not cations

    • B. 

      Na+ can enter the pore but can't move through the selectivity filter due to the presence of carbonyl oxygens in the selectivity filter in which can't fully bind to

    • C. 

      The dehydration of K+ ions allows for entry into the selectivity filter

    • D. 

      The vestibule is located in the hydrophobic pore where it shortens the distance travelled by the ion

    • E. 

      The inner and outer helices provide stabilization to the channel by interacting with lipids in the membrane

  • 23. 
    Which of the following statements of NAT-2 is false?
    • A. 

      Cytosolic enzyme mainly found in the liver, small intestine, and colon

    • B. 

      A slow acetylator is more likely to cause drug toxicity

    • C. 

      A rapid acetylator is more likely to cause drug toxicity

    • D. 

      Functions in the activation and deactivation of drugs

    • E. 

      Involved in Phase II of biotransformation

  • 24. 
    Which of the following statements are correct of Signal Transduction Pathways? Select all that apply
    • A. 

      A partial agonist competes with the agonist for the binding site

    • B. 

      An effector for the Gs Signal Transduction Pathway is G-alpha subunit

    • C. 

      Calcium and IP3 are the only secondary messengers for the Gq Signal Transduction Pathway

    • D. 

      Densensitization can occur via receptor sequesteration, down-regulation, and inactivation when a receptor is constantly exposed to ligands

    • E. 

      Glucocorticoid and Thyroid Hormone receptors are located in the nucleus

  • 25. 
    Which of the following statements are correct of enzyme and enzyme kinetics? Select all that apply
    • A. 

      Negative ΔG reactions are unfavorable, thus coupling them to favorable positive ΔG reactions is can allow the reaction to proceed

    • B. 

      Bond distortion is a strategic method used by enzymes in which the substrate's electrons are rearranged, creating opposite charges to favor the reaction

    • C. 

      An enzymes functional ability is dependent on temperature and pH

    • D. 

      CYP450 enzymes are located in the liver in which they catalyze oxidative reactions as part of phase I of biotransformation

    • E. 

      Vmax is dependent on the rate at which the product dissociates from the enzyme

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