BY 116 Exam 2 Questions And Correct Answers
Determine if a substance can cross a cell membrane - based on size or lipid solubility
information
Substance can pass across cell membrane if: particle is small, non-polar, in liquid
solution
can't : large molecule and charged atoms/molecules
What must be present for the transport of substances to happen across a membrane?
permeability of membrane and a driving force
What are two major divisions of membrane transport?
Active and passive
Can you list the forms of transport under each type?
Active - vesicular transport ATP
Passive - simple diffusion concentration gradient
What factors will influence the rates of diffusion?
Magnitude, temperature, Permeability, and surface area
How would osmotic pressure vary with altering solute concentration?
Increased solute concentration = Increased osmotic pressure Decreased solute
concentration = Decreased osmotic pressure.
Be able to compare the osmolarities of two solutions
Hypoosmotic - below, and less solute, more water
Isosmotic - same
Hyperosmotic - above (when thinking of osmotic it is ratio to solute)
,Describe how water would move in hypotonic, hypertonic, and isotonic solutions
Isotonic - no net movement of water
Hypotonic - water enters cell
Hypertonic - water leaves cells
Know the forces, i.e., gradient, etc. that cause water and solutes to move across
membranes passively, i.e., without energy.
movement of water w/o energy is caused by conc gradients, osmotic pressure, and
membrane permeability.
Explain the difference between substances that are transported by simple diffusion and
by facilitated diffusion.
Substances transported in simple require no energy, goes down concentration
gradient, which means from high to low
Facilitated substances require no energy, but uses proteins
Describe how the magnitude of a gradient, permeability, temperature, and surface area
influence the rate of diffusion
Temperature - increase temperature = increase diffusion rate
Gradient magnitude - increase gradient = increase in rate of diffusion
Surface area - Increase surface area = increase in rate of diffusion
Permeability - Increased permeability = increase in rate of diffusion
In channel-mediated diffusion, name the types that are continuously open or open upon
stimulus (i.e., name stimulus).
continuously open is leak channels
open on stimuli is gated channel the stimuli is ligands
Know the mechanisms by which substances are moved across membranes against a
concentration gradient (actively, with energy)
, Active transport is against the concentration gradient of the substance and requires
energy (ATP).
-also for primary active, including direct ATP against gradient and secondary active, in
which there is indirect ATP with gradient
Mechanisms of passive and active transport - compare from lecture.
Passive transport depends on proteins and input energy in the forms of ATP to travel
against the concentration gradient. In passive transport, no other input of energy is
required than the potential energy stored.
How do the primary active transport and passive transport differ -i.e., which uses
energy, which is just a diffusion and which uses symport and antiport?
Primary active transport uses the ATP moves against the gradient uses symport,
antiport and uniport
Passive transport does not use energy, moves on the gradient (high to low) uses just the
uniport
What is the difference between uniports, symports and antiport?
Uniport- movement of one thing across membrane
Symports - movement of two things in the same direction
Antiport - movement of two things opposite direction
Does energy get used in secondary active transport, or does it use a gradient created in
primary active transport?
Energy gets used in Secondary by means of the concentration gradient of positively
charged ions that is created by primary
What does it mean when carrier-mediated transport proteins exhibit specificity,
competition, and saturation?
Protein is supposed to bind to a transport (specificity)
There is the competition for binding, (competition)
Determine if a substance can cross a cell membrane - based on size or lipid solubility
information
Substance can pass across cell membrane if: particle is small, non-polar, in liquid
solution
can't : large molecule and charged atoms/molecules
What must be present for the transport of substances to happen across a membrane?
permeability of membrane and a driving force
What are two major divisions of membrane transport?
Active and passive
Can you list the forms of transport under each type?
Active - vesicular transport ATP
Passive - simple diffusion concentration gradient
What factors will influence the rates of diffusion?
Magnitude, temperature, Permeability, and surface area
How would osmotic pressure vary with altering solute concentration?
Increased solute concentration = Increased osmotic pressure Decreased solute
concentration = Decreased osmotic pressure.
Be able to compare the osmolarities of two solutions
Hypoosmotic - below, and less solute, more water
Isosmotic - same
Hyperosmotic - above (when thinking of osmotic it is ratio to solute)
,Describe how water would move in hypotonic, hypertonic, and isotonic solutions
Isotonic - no net movement of water
Hypotonic - water enters cell
Hypertonic - water leaves cells
Know the forces, i.e., gradient, etc. that cause water and solutes to move across
membranes passively, i.e., without energy.
movement of water w/o energy is caused by conc gradients, osmotic pressure, and
membrane permeability.
Explain the difference between substances that are transported by simple diffusion and
by facilitated diffusion.
Substances transported in simple require no energy, goes down concentration
gradient, which means from high to low
Facilitated substances require no energy, but uses proteins
Describe how the magnitude of a gradient, permeability, temperature, and surface area
influence the rate of diffusion
Temperature - increase temperature = increase diffusion rate
Gradient magnitude - increase gradient = increase in rate of diffusion
Surface area - Increase surface area = increase in rate of diffusion
Permeability - Increased permeability = increase in rate of diffusion
In channel-mediated diffusion, name the types that are continuously open or open upon
stimulus (i.e., name stimulus).
continuously open is leak channels
open on stimuli is gated channel the stimuli is ligands
Know the mechanisms by which substances are moved across membranes against a
concentration gradient (actively, with energy)
, Active transport is against the concentration gradient of the substance and requires
energy (ATP).
-also for primary active, including direct ATP against gradient and secondary active, in
which there is indirect ATP with gradient
Mechanisms of passive and active transport - compare from lecture.
Passive transport depends on proteins and input energy in the forms of ATP to travel
against the concentration gradient. In passive transport, no other input of energy is
required than the potential energy stored.
How do the primary active transport and passive transport differ -i.e., which uses
energy, which is just a diffusion and which uses symport and antiport?
Primary active transport uses the ATP moves against the gradient uses symport,
antiport and uniport
Passive transport does not use energy, moves on the gradient (high to low) uses just the
uniport
What is the difference between uniports, symports and antiport?
Uniport- movement of one thing across membrane
Symports - movement of two things in the same direction
Antiport - movement of two things opposite direction
Does energy get used in secondary active transport, or does it use a gradient created in
primary active transport?
Energy gets used in Secondary by means of the concentration gradient of positively
charged ions that is created by primary
What does it mean when carrier-mediated transport proteins exhibit specificity,
competition, and saturation?
Protein is supposed to bind to a transport (specificity)
There is the competition for binding, (competition)
