Passive Cell Transport Lesson 5 Flashcards
What is the name of a cell membrane with proteins embedded within it that allow for the transfer of materials across the membrane?
phospholipid bilayer
What kind of cell membrane is it where some materials may cross, but others cannot?
semi-permeable
A solution contains two main things. What are they?
solute and solvent
What is a substance that is being dissolved called? Give an example.
solute - example is salt
What is a solvent? Give an example.
A substance that is being dissolved into - example = water
How can a concentration of a solution can be increased? Two ways…
- dissolving more solute
2. removing some of the solvent
What is it called when solutions of two different concentrations exist beside each other, possibly separated by a membrane?
concentration gradient
Which direction does a solute naturally want to move?
down a concentration gradient from areas of high concentration to low areas of concentration
What is the process called when a solute moves down a concentration gradient from an area of high to low concentration?
diffusion
When will diffusion stop?
once a state of equilibrium is reached - where both solutions have the same concentration, removing the concentration gradient
What is it called when a concentration gradient has a solution with the higher concentration of solute?
hypertonic
What is it called when a concentration gradient has a solution with the lower concentration of solute?
hypotonic
When solutions have the same concentration, what are they called?
Isotonic solution
What is the natural movement of material across a cell membrane NOT requiring energy from the cell?
Passive Transport
When does passive transport always occur?
It always occurs DOWN a concentration gradient from areas of HIGH concentration to areas of LOW concentration.
What are the three types of passive transport?
- diffusion
- osmosis
- facilitated diffusion
What is Diffusion?
A type of passive transport; very small particles can pass DIRECTLY ACROSS the cell membrane from areas of HIGH concentration to areas of LOW concentration
What two gases can diffuse directly across the cell membrane WITHOUT requiring the cell to expend energy to intake or remove them?
Oxygen and Carbon Dioxide
What is Osmosis?
A type of passive transport; Osmosis is the diffusion of water molecules across a cell membrane.
Water CANNOT cross the phospholipid bilayer of the cell membrane directly, but the cell membrane contains a large number of PORES to allow water in or out of the cell.
Typically, if a solute can diffuse across a semi-permeable membrane, why does it do it?
To equalize the concentration gradient
If the solute CANNOT cross the membrane (too large, electrically charged, etc) what will the solvent do?
The solvent will cross instead of the solute. This changes the amount of water inside and outside of the cell.
When a cell is placed in an extremely hypotonic solution what will the water do?
Water will rush into the cell to try to equalize the concentration of solute. In extreme cases, this intake of water may cause the cell to BURST - cytolysis
What is cytolysis?
When the water rushes into the cell to try and equalize the concentration of solute and causes the cell to BURST.
What is facilitated diffusion?
a type of passive transport using transport proteins to help substances that are large (like glucose) to diffuse through cell membranes directly; these transport proteins help materials enter and leave the cell
What are two types of transport proteins used in facilitated diffusion?
Carrier Proteins
Channel Proteins
What is a carrier protein?
Used in facilitated diffusion - a type of passive transport. These proteins allow one particular type of molecule to enter or leave the cell by RECOGNIZING ITS SHAPE.
What is a channel protein?
Used in facilitated diffusion - a type of passive transport.
These proteins are PORES in the membrane filled with WATER that can open to allow CHARGED IONS to cross the membrane.
