bio exam 3

which of the following substances would have to most trouble crossing a biological membrane? a)CO2 b)O2 c)Na+ d)a small, non polar molecule such as butane (C4H10)

Na+

a plant cell in a hypotonic solution: a)bursts because of an inflow of water b)wilts because of an outflow of water c)becomes turgid because of an inflow of water d)shrivels because of an outflow of water

becomes turgid because of an inflow of water

which of the following statements regarding diffusion is false? a)diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated b)diffusion requires no input of energy into the system c)diffusion occurs even after equilibrium is reached and no net change is apparent d)diffusion is a result of the thermal energy of atoms and molecules

diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated

Small, nonpolar, hydrophobic molecules such as fatty acids: a)very slowly diffuse through a membrane's lipid bilayer b)easily pass through a membrane's lipid bilayer c)are actively transported across cell membranes d)require transport proteins to pass through a membrane's lipid bilayer

easily pass through a membrane's lipid bilayer

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will: a)exhibit an equal movement in both directions across the membrane b)exhibit a net movement to the side with lower solute concentration c)exhibit a net movement to the side with lower free water concentration d)exhibit a net movement to the side with higher free water concentration

exhibit a net movement to the side with lower free water concentration

paramecium has special organelles called contractile vacuoles that continually eliminate excess water from the cell. the presence of these organelles tell you that the environment: a)is hypotonic to the paramecium b)is hypertonic to paramecium c)contains a higher concentration of solutes than paramecium d)is isotonic to paramecium

is hypotonic to the paramecium

a cell that neither gains nor loses water when it is immersed in a solution must be: a)isotonic to its environment b)hypotonic to its environment c)hypertonic to its environment d)metabolically inactive

isotonic to its environment

in a hypotonic solution, an animal cell will: a)shrivel b)lyse c)neither gain nor lose water d)experience tutor

lyse

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of: a)active transport b)endocytosis c)passive transport d)exocytosis

passive transport

Oxygen crosses a plasma membrane by a) osmosis. b) active transport. c) pinocytosis. d) passive transport.

passive transport

the molecules responsible for membrane transport are: a)steroids b)proteins c)carbs d)phospholipids

proteins

which of the following statements is true among all types of passive transport: a)only small polar molecules are able to cross the plasma membrane b)proteins are needed to transport molecules across the membrane c)the concentration gradients is the driving force d)ions never cross the plasma membrane by passive transport

the concentration gradients is the driving force

Osmosis can be defined as: a)active transport b)diffusion of a solute c)the diffusion of water d)the diffusion of non polar molecules

the diffusion of water

If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference? a)the fact that plant cells are isotonic to tap water b)the expulsion of water by the plant cell's central vacuole c)the relative inelasticity and strength of the plant cell wall d)the relative impermeability of the plant cell to water

the relative inelasticity and strength of the plant cell wall