Midterm #1 (tox 300) Questions With Correct
Answers
toxicokinetics
mathematical |determination |of |the |time |course |of |disposition |(ADME) |of |a |xenobiotic |in |the |
body. |What |the |body |does |to |the |xenobiotic.
Xenobiotic
A |chemical |substance |foreign |to |the |biological |system
Toxicodynamics
what |the |chemical |does |to |the |body. |mechanisms |by |which |xenobiotics |cause |toxic |effects.
what |determines |the |concentration |of |a |xeno |at |its |site |of |action?
toxicokinetics |(ADME)
3 |routes |of |absorption
dermal, |ingestion, |inhalation. |ingestion |is |most |major.
what |is |the |common |route |of |an |ingested |xenobiotic |destined |for |bile |excretion?
,ingested, |travels |through |GI |tract, |absorbed |into |blood, |travels |through |hepatic |portal |vein |to |
liver, |enters |bile, |travels |through |gallbladder, |travels |back |to |GI |tract, |excreted |in |the |feces
what |is |the |most |important |factor |a |xeno's |ability |to |diffuse |across |membranes?
lipophilicity. |molecular |size |is |also |important!
4 |ways |xenobiotics |can |cross |cell |membranes?
passive |transport: |diffusion, |facilitated |diffusion, |paracellular |transport. |active |transport: |ABC |
transporters.
what |is |the |most |common |absorption |pathway?
passive |diffusion. |xeno |follows |concentration |gradient |across |the |membrane.
What |is |Kow?
octanol:water |partition |coefficient. |measures |lipophilicity |of |a |chemical. |high |log |Kow |(>5) |
indicates |significant |potential |for |accumulation |and |toxicity.
what |determines |the |% |ionization |of |a |weak |acid |of |base?
pKa |of |the |xeno |and |pH |of |the |solution |it |is |in
what |is |the |log |of |100,000?
, 5
which |form |of |a |weak |acid |or |base |can |penetrate |cell |membranes?
only |the |non-ionized |form |can |penetrate |cell |membranes |easily.
What |is |the |pKa |of |a |drug?
The |pH |at |which |the |molecule |is |50% |ionized |and |50% |unionized
What |is |the |Henderson-Hasselbalch |equation?
pKa |- |pH |= |Log |([HA] |/ |[A-])
what |is |the |pH |of |the |kidney |filtrate?
slightly |acidic
What |is |filtration?
xeno |moves |with |water |through |gap |junctions |between |cells |due |to |pressure |gradient |(i.e. |
blood |pressure). |size |of |xenobiotic |is |most |important |here.
gap |sizes |in |different |cells?
most |cells |= |4nm
Answers
toxicokinetics
mathematical |determination |of |the |time |course |of |disposition |(ADME) |of |a |xenobiotic |in |the |
body. |What |the |body |does |to |the |xenobiotic.
Xenobiotic
A |chemical |substance |foreign |to |the |biological |system
Toxicodynamics
what |the |chemical |does |to |the |body. |mechanisms |by |which |xenobiotics |cause |toxic |effects.
what |determines |the |concentration |of |a |xeno |at |its |site |of |action?
toxicokinetics |(ADME)
3 |routes |of |absorption
dermal, |ingestion, |inhalation. |ingestion |is |most |major.
what |is |the |common |route |of |an |ingested |xenobiotic |destined |for |bile |excretion?
,ingested, |travels |through |GI |tract, |absorbed |into |blood, |travels |through |hepatic |portal |vein |to |
liver, |enters |bile, |travels |through |gallbladder, |travels |back |to |GI |tract, |excreted |in |the |feces
what |is |the |most |important |factor |a |xeno's |ability |to |diffuse |across |membranes?
lipophilicity. |molecular |size |is |also |important!
4 |ways |xenobiotics |can |cross |cell |membranes?
passive |transport: |diffusion, |facilitated |diffusion, |paracellular |transport. |active |transport: |ABC |
transporters.
what |is |the |most |common |absorption |pathway?
passive |diffusion. |xeno |follows |concentration |gradient |across |the |membrane.
What |is |Kow?
octanol:water |partition |coefficient. |measures |lipophilicity |of |a |chemical. |high |log |Kow |(>5) |
indicates |significant |potential |for |accumulation |and |toxicity.
what |determines |the |% |ionization |of |a |weak |acid |of |base?
pKa |of |the |xeno |and |pH |of |the |solution |it |is |in
what |is |the |log |of |100,000?
, 5
which |form |of |a |weak |acid |or |base |can |penetrate |cell |membranes?
only |the |non-ionized |form |can |penetrate |cell |membranes |easily.
What |is |the |pKa |of |a |drug?
The |pH |at |which |the |molecule |is |50% |ionized |and |50% |unionized
What |is |the |Henderson-Hasselbalch |equation?
pKa |- |pH |= |Log |([HA] |/ |[A-])
what |is |the |pH |of |the |kidney |filtrate?
slightly |acidic
What |is |filtration?
xeno |moves |with |water |through |gap |junctions |between |cells |due |to |pressure |gradient |(i.e. |
blood |pressure). |size |of |xenobiotic |is |most |important |here.
gap |sizes |in |different |cells?
most |cells |= |4nm
