Outline the functions of membranes. [2] Define phospholipid. [1] Check In Outline the functions of membranes. [2] Define phospholipid. [1] Homework Study for your test on Friday Oct. 5

Check In Homework Define diffusion. [1] Outline how your test preparation is going using supportive language. Possible sentence frames: It is my opinion that __ because __. I believe __ because __. Homework Study for your test on Friday Oct. 5

Define osmosis. [1] Outline an example of osmosis. Check In Define osmosis. [1] Outline an example of osmosis. Homework Cut out your cell membrane

Outline the process shown below. [2] Check In Outline the process shown below. [2] Before: After:

Outline the process shown below. [2] Check In Outline the process shown below. [2] Markscheme: Osmosis Water leaves the cell Hypertonic solution outside of the cell Plasmolysis

Copyright Pearson Prentice Hall 2–4 The elements or compounds produced by a chemical reaction are known as reactants. enzymes. products. waste. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 2–4 Chemical reactions always involve changes in energy. enzymes. catalysts. changes in the atomic number of the reactants. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 2–4 The factor that prevents many energy-releasing reactions from occurring at relatively low temperatures is called catalytic energy. chemical bond energy. enzyme energy. activation energy. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 2–4 Which of the following statements is true? All proteins are enzymes. All catalysts are enzymes. All enzymes are catalysts. All catalysts are proteins. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 2–4 What happens to an enzyme after the reaction it catalyzes has taken place? The enzyme is destroyed, and the cell must make another. The enzyme holds on to the product until another enzyme removes it. The enzyme is unchanged and ready to accept substrate molecules. The enzyme changes shape so it can accept a different kind of substrate. Copyright Pearson Prentice Hall

Notes – Membrane Transport

Passive transport Movement of molecules across a membrane without using energy Types: Diffusion Osmosis Facilitated diffusion

Diffusion Movement of molecules from high concentration to low concentration Equilibrium = the concentration is the same on both sides of the membrane

Review #1 If a substance is more highly concentrated outside the cell than inside the cell and the substance can move through the cell membrane, the substance will move by diffusion from inside the cell to outside. remain in high concentration outside the cell. move by diffusion from outside to inside the cell. cause water to enter the cell by osmosis. 3

Review #3 Describe what is happening…

Review #3 Describe what is happening…

Review #4 Describe what is happening…

Review #4 Describe what is happening…

Osmosis Movement of water molecules across a membrane from high water concentration to low water concentration Fingersurvey: Where is there a high water concentration? To which number will water move? 1 2

Osmosis Movement of water molecules across a membrane from high water concentration to low water concentration

Osmosis Movement of water molecules across a membrane from high water concentration to low water concentration Hypertonic = higher solute concentration Hypotonic = lower solute concentration Isotonic = equal solute concentration

Review… 1 2

Facilitated Diffusion Glucose molecules Facilitated Diffusion Diffusion of molecules across a membrane through protein channels During facilitated diffusion, molecules, such as glucose, that cannot diffuse across the cell membrane’s lipid bilayer on their own move through protein channels instead. Protein channel

Review Describe what is happening…

Review Describe what is happening…

Concentration Gradient A difference in concentration on either side of a membrane

Active transport Movement of molecules across a membrane using energy Movement of molecules from low concentration to high concentration Active transport is done by protein pumps Molecule to be carried

Copyright Pearson Prentice Hall Last Review The process by which molecules diffuse across a membrane through protein channels is called active transport. endocytosis. facilitated diffusion. osmosis. Copyright Pearson Prentice Hall

Check Out Define osmosis (use the word concentration in your definition). [1] Outline an example of osmosis. [1] Homework Study for your test on Friday Oct. 5

Define active transport. [1] Warm up Define active transport. [1] Outline the relationship between active transport and concentration gradients. [2] Homework none

Warm Up What is an analogy for surface area in a cell? What is the relationship between cell size and the surface area to volume ratio? Why is it important?

Warm Up What was the smallest object from the homework last night? What is the definition? What was the shortest inverse location? What was the longest inverse location?