Chapter 5 Section 1: Passive Transport

Use Modern Biology Textbook pgs. 97-102

  1. Cell membranes help organisms maintain homeostasis (balance) by: ______. Some substances can cross the cell membrane without any input of energy by the cell in a process known as ______.
  2. Define diffusion:
  1. The different in concentrations of a substance across an area is called the ______.
  2. Molecules are constantly in ______.
  3. Define equilibrium:
  1. If a molecule can pass through a cell membrane, it will diffuse from an area of ______concentration on one side of the membrane to an area of ______concentration on the other side.
  2. Define osmosis:
  1. List one way osmosis is different from diffusion.
  1. List one way osmosis is the same as diffusion.
  1. List an example of a solute.
  2. List an example of a solvent.
  1. Does passive transport require energy from the cell?
  1. When the concentration of solute molecules outside the cell is lower than the concentration in the cytosol, the solution outside is ______to the cytosol. In this situation, water diffuses ______the cell until equilibrium is established.
  1. When the concentration of solute molecules outside the cell is higher than the concentration in the cytosol, the solution outside if ______to the cytosol. Water diffuses ______of the cell until equilibrium is established.
  1. When the concentration of solutes outside and inside the cell are equal, the outside solution is said to be ______.
  1. Look at Figure 5.2 on page 99 of the paramecia. They have ______- ______that collect excess water that moves by osmosis into the cytosol.
  1. When water diffuses into a plant cell and builds up firm pressure, that is called ______. (pg. 100)
  1. When water diffuses out of a plant cell and causes the cell membrane to shrink, that is called ______.
  1. Define facilitated diffusion:
  1. In facilitated diffusion, the movement of molecules across the membrane is assisted by specific proteins called ______.
  1. List the four steps of facilitated diffusion (Figure 5.5 on page 101).

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  1. A good example of facilitated diffusion is the transport of ______.
  2. What are ion channels?
  1. Ion channels transport ions such as ______(Na+), ______(K+), ______(Ca+), and ______(Cl).
  1. Each type of ion channel is usually ______for one type of ion. For example, ______channels only allow ______ions to go through, but will not allow ______ions of ______to enter the cell.
  1. Some ion channels are always ______. Others have “______” that open to allow ions to pass or close to stop their passage.
  1. List 3 kinds of stimuli that may open or close the gates of ion channels.

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  1. List the four types of passive transport (as mentioned in the textbook).

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