Cell Permeability

The video explains passive transport, a process where particles move across cell membranes from high to low concentration without energy. It covers three types: diffusion, osmosis, and facilitated diffusion. Diffusion involves particles moving naturally to achieve equilibrium, exemplified by air freshener spreading in a room. Osmosis is the diffusion of water through a semipermeable membrane, balancing water and solute concentrations. Facilitated diffusion uses protein channels for larger particles to move along the concentration gradient. All these processes occur naturally without energy expenditure.

What is passive transport?

• Movement of particles against the concentration gradient

• Movement of particles using energy

• Movement of particles without using energy

• Movement of particles in a circular motion

Which of the following is NOT a type of passive transport?

• Facilitated diffusion

• Active transport

• Osmosis

• Diffusion

What happens during diffusion?

• Particles move from low to high concentration

• Particles move in a circular pattern

• Particles move from high to low concentration

• Particles remain stationary

Which example illustrates diffusion without a semipermeable membrane?

• Water moving through a cell membrane

• Air freshener spreading in a room

• Saltwater passing through a filter

• Sugar dissolving in water

What is osmosis specifically concerned with?

• Movement of air particles

• Movement of protein molecules

• Movement of water molecules

• Movement of solute particles

In osmosis, what can pass through the membrane freely?

• All particles

• Large solute particles

• Protein molecules

• Water molecules

What role do protein channels play in facilitated diffusion?

• They provide energy for transport

• They dissolve solute particles

• They act as barriers to diffusion

• They allow specific molecules to pass through

Facilitated diffusion is necessary for which type of particles?

• Very small particles

• Particles that can pass through phospholipid layers

• Larger particles that need protein channels

• Particles that require energy to move

What is a common feature of all types of passive transport?

• They move particles against the concentration gradient

• They require energy

• They involve only water molecules

• They occur naturally without energy

Which statement best summarizes passive transport?

• It is a process that moves particles in a circular motion

• It only occurs in plant cells

• It involves the movement of particles along the concentration gradient without energy

• It requires cellular energy to move particles