Chapter 2 Section 3 Life Science

THE Cell Membrane  Cells survive by allowing some items to pass through the cell membrane.  Selectively Permeable- “selects” certain materials to go in and out of the cell membrane.

2 types of Movement through the Cell Membrane: 1. Passive Transport- does not require energy to pass through cell membrane 2. Active Transport- requires energy

Miss Rogers’ Hill

Passive Transport  The movement of substances through the cell membrane without the input of energy is called Passive Transport.  There are three types of Passive Transport that can occur.

1 st Type of Passive Transport  Diffusion- movement of “materials” from an area of high concentration to low concentration.  Examples- Febreeze  Oxygen and Carbon Dioxide molecules moving across membrane

EQUILIBRIUM  Ending Result- Equilibrium  This is when it’s EQUAL on both sides –BALANCED!!! Balance the smiley faces

2 nd Type of Passive Transport  Osmosis- movement of water from an area of high concentration to low concentration  Examples- Wilting Plant (needs H 2 O)

EQUILIBRIUM  Ending Result... Equilibrium  This is when it’s EQUAL on both sides –BALANCE!!! Balance the water molecules

3 rd Type of Passive Transport  Facilitated Diffusion- Diffusion that is helped by transport proteins with NO energy needed.  Like a “revolving door” –When large items are too big to pass through the cell membrane they enter with “help” from transport proteins !!! (squeezing through)

Ending Result???  Ending Result... Equilibrium  This is when there is the same amount of items on both sides. –BALANCE!!!  Examples- Sugar molecules entering cells; Minerals entering plant roots.

Think of student at bottom of hill… What type of Transport requires Energy? Active Transport!

 Active Transport involves… Transport Proteins and Energy are used to move materials through cell membrane

 Examples- A Soccer/Football Game; Overtime requires a lot of extra energy.  Balance the sugar molecules

Active Transport  What if items are too big to pass through the Transport Proteins?  When items are too big, the cell membrane folds in on itself and encloses the item in a sphere called a vesicle (or vacuole).  Example of Plastic Bag…

How do items enter then??? 1. En docytosis- when items are surrounded by the cell membrane and create a vesicle/vacuole (“a pod”)

2. Ex ocytosis- when large items are passed out of the cell by having the vesicle/vacuole attach to the cell membrane and open up to the outside.