Absorption, Distribution, and Storage of Chemicals

The water soluble phosphate group of the lipid bilayer _____

• a.faces inside the cell.
• b.faces outside the cell.
• c.faces both inside and outside the cell.
• d.lies inside the lipid bilayer.

Chemicals moving via passive diffusion

• a.move from higher to lower concentration.
• b.move from lower to higher concentration.
• c.require ATP for energy.
• d.move easier if polar in nature.

The ability of molecules to diffuse across membranes is dependent upon the chemical's

• a.oil-water partition coefficient.
• b.state of ionization.
• c.molecular weight.
• d.all of the choices

The extent of ionization of a chemical depends on its

• a.molecular weight.
• b.lipid solubility.
• c.pKa and the pH of the solution it is in.
• d.water solubility.

The blood brain barrier means that

• a.only small amounts of chemicals are in brain vessels.
• b.only a small volume of blood reaches the brain.
• c.special cells form a tight covering on the brain's capillaries.
• d.the pH of brain tissue prevents chemicals from entering.

The placenta prevents some chemicals from reaching the fetus by

• a.metabolizing the chemical.
• b.separating the maternal and fetal blood supplies.
• c.having a molecular weight of around 1000 daltons.
• d.all of the choices

Long term storage sites for chemicals in the body include

• a.liver and brain.
• b.fat and bone.
• c.liver and fat.
• d.muscle and stomach.

Facilitated diffusion means that

• a.energy is required.
• b.a carrier protein helps transport the chemical through the membrane.
• c.a large molecule pushes a small molecule through the membrane.
• d.two molecules go through at the same time.

Chemicals stored in bone may be harmful

• a.to the bone itself.
• b.when released from bone during pregnancy.
• c.when released from bone during exercise.
• d.both bone and when released from bone during pregnancy.

The surrounding and transport of molecules by the cell membrane is called

• a.entrapment.
• b.endocytosis.
• c.engulfment.
• d.capture and movement.