8.3 - 8.4 Membrane Transport and Homeostasis

What is the mechanism driving diffusion?

• the constant, random movement of particles in a solution

• the stationary nature of particles in a solution

• tendency for particles to move from areas where they are less highly concentrated to areas where they are more highly concentrated

• tendency for particles to move from areas where they are more highly concentrated to areas where they are less highly concentrated

• membrane proteins pumping molecules against their concentration gradient

How is facilitated diffusion different from diffusion?

• it take significantly longer time to happen

• it allows uncharged particles to diffuse across the membrane

• it requires the presence of protein channels in the cell membrane

• it allows smaller particles to diffuse across the membrane

• it requires energy to happen

Facilitated diffusion...

• does not require cellular energy

• requires cellular energy

• is a type of active transport

• allows small and uncharged molecules to diffuse across the membrane

• allows large and charged molecules to diffuse across the membrane

What is the difference between active and passive transport?

• active transport requires cellular energy, whereas passive transport does not

• passive transport requires cellular energy, whereas active transport does not

• active transport moves substances against their concentration gradient

• active transport moves substances down their concentration gradient

• active transport moves larger, charged molecules across the membrane

A substance moving against its concentration gradient is moving from

• an area of high concentration to an area of low concentration

• an area of low concentration to an area of high concentration

A solute moves across a membrane from an area of low concentration of the solute to an area of high concentration. This is an example of...

• passive transport

• active transport

• molecular transport

• facilitated diffusion

• osmosis

Osmosis...

• is when water moves towards the solution with lower concentration of solute

• requires cellular energy

• only occurs when the membrane is impermeable to the solute in solution

• is a type of facilitated diffusion

• is diffusion of water from high to low concentration

In osmosis, water flows towards an area of (a)   concentration of water.

In osmosis, water moves towards an area of (a)   concentration of solute.

An isotonic solution has....

• an equal concentration of solute as another solution

• a higher concentrations of solute as another solution

• a lower concentration of solute as another solution