Unit 3 Movement Through The cell

Plasma Membrane/Cell Membrane Why is the cell membrane important? Selectively Permeable : A membrane that allows some substances to pass through while keeping others out. The cell membrane is like a Fish net…lets water in and out, but keeps the fish in

Plasma Membrane/Cell Membrane Why is the cell membrane important? Cell Membrane : Flexible, selectively permeable boundary that helps control what enters and leaves the cell.

Plasma Membrane/Cell Membrane What are the 2 main parts of the cell membrane? 1. Phospholipid bilayer: 2 layers of lipids (fat)

Plasma Membrane/Cell Membrane What are the 2 main parts of the cell membrane? 2. Protein pump/channel: Proteins that help move large materials across the cell membrane

Homeostasis What is homeostasis? Homeostasis : Regulation of an organism’s internal environment to maintain conditions needed for life. Running increases body temperature Panting decreases body temperature

Homeostasis What is homeostasis? If you sweat, you lose water…. You get dehydrated…. You are not in homeostasis! If you drink water, and replace water levels … You feel good… You ARE in homeostasis!

Homeostasis What is homeostasis? If you have a fever …. You don’t feel good…. You are not in homeostasis! If you don’t have a fever… You feel good… You ARE in homeostasis!

Homeostasis What is homeostasis? If your sugar is too high …. The blood is like syrup…too thick… Blood can’t flow…you don’t feel good…. You are not in homeostasis! If your sugar level is normal… Blood can flow…you feel good… You ARE back in homeostasis! Diabetics can’t regulate sugar levelsInsulin Shots lower sugar levels

Review…. Solute : Any substance (like salt) that is dissolved in water is a solute. Solution : The combination of a solute (salt) and solvent (water). Example: salt in water = saltwater Concentration : Of a solution is the mass of solute in a given volume of solution. Concentration just means how salty the water is

Nature wants to be balanced! One of the most important functions of the cell membrane is to regulate the movement of molecules from one side of the membrane to the other. Remember…

Passive Transport Passive Transport: The movement of molecules from an area of high concentration to an area of low concentration WITHOUT the use of energy. There are 2 Types of Passive Transport a. Diffusion b. Facilitated Transport The next several slides are about the transport of molecules across the cell membrane that does NOT require ENERGY

What are the types of movement through the membrane? Diffusion is a type of movement of molecules through the cell membrane where the molecules move from an area of HIGHER concentration to an area of LESSER concentration. Example: Like moving from the city to the country Higher Concentration Lower Concentration

Diffusion causes many substances to move across a cell membrane but does NOT require the cell to use energy. What is Diffusion? Diffusion tries to get the solute molecules to be equal on each side of the membrane. When both sides of the membrane are equal in terms of solute, the cell is in equilibrium. All cells try to attain equilibrium (BALANCE)!

Osmosis & Diffusion The sound & video does not always match up…you don’t have to point this out!...I know.

What are the types of movement through the membrane? If a substance is able to diffuse across a membrane, the membrane is permeable to that substance. Example: A sponge is permeable. Most cell membranes are selectively permeable which means that some substances can pass across easily and others cannot.

What is osmosis? Osmosis is another type of movement across a membrane. Osmosis is the diffusion of water through a selectively permeable membrane. Lets look at a sugar-water solution. One side of the membrane has a concentrated sugar solution and on the other side is a dilute sugar solution. What type of molecule is sugar? What does “Macro” mean? Can sugar easily move across the membrane? No Macromolecule Large

What is osmosis? Sugar cannot move freely across the membrane because it is too big. The water moves from where there is more water to the area where there is more sugar. So—in this situation, the water moves from an area of Low concentration of Solute to an area of High concentration of Solute. Water “Chases” the sugar!

What are the 3 types of solutions? There are 3 types of solutions. 1. Hypertonic 2. Hypotonic 3. Isotonic Hypotonic Isotonic Hypertonic

Isotonic As you know a cell tries to reach equilibrium. This equal state is also known as an Isotonic solution. Water is still moving in & out equally!

Hypotonic Example of a Hypotonic solution: Freshwater (no solute) The cell will have more salt in it and less outside of it. In a Hypotonic solution, water rushes into the cell causing the cell to expand and eventually burst. Water “Chases” the solute into the cell Low Concentration HIGH Concentration

How to Remember!!!! Hypo = EXPLODE

Hypertonic Example of a Hypertonic solution: Saltwater The cell will have less salt in it and MORE outside of it. In a Hypertonic solution, water rushes out of the cell causing the cell to shrivel and shrink. Water “Chases” the solute out of the cell

How to Remember!!!! Hyper = shrink

Cells in Solutions 15% Salt.1% 15% Salt.1% 5% Salt 5% Hypo = Below Hypo = ExplodeHyper = Shrink Hyper = Above Iso = Same

What is facilitated diffusion? Facilitated Diffusion is a process in which the cell membrane uses the protein channels to allow/help bigger molecules such as ions, sugars, and salts to cross in either direction. This is still diffusion! No energy is used to move these molecules. The protein channels just “help” the molecules across. Cell Membrane Protein Channel Solute

Active Transport NEEDS ENERGY! From Low To High

What type of cellular movement requires energy? Sometimes, molecules move against the concentration gradient. This means that they are going from a lower area of solute to a higher area of solute. They are crazy! For this, they need energy to move against the gradient/difference. Example: Like walking up a hill. You’ll need ENERGY ! ATP = Energy

What type of cellular movement requires energy? Active Transport uses the protein channels to move these molecules against the gradient with the input of energy. This is the only movement that requires energy ! This type of transport is often referred to as a pump.

Active transport…needs ENERGY! Low concentration of solute HIGH concentration of solute

What are 2 types of Active Transport? There are 2 types of Active Transport 1. Endocytosis is the process of taking material into the cell by means of in-foldings, or pockets, of the cell membrane. This pocket, breaks loose from the cell membrane and forms a type of vacuole within the cytoplasm. Large molecules, like food and other cells can be taken up by endocytosis.

Endocytosis

2. Phagocytosis is the process of large particles being taken into the cell by means of extensions of cytoplasm that go out and engulf the large particles. This is a leukocyte (white blood cell) in your blood that is shooting out extensions to get the large particles that you see.

2 Types of Active Transport 2. Exocytosis is the cell’s ability to remove large amounts of materials out of the cell. During exocytosis, the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.

Clicker Question #1 A cell membrane is like a window screen because: a. it provides support b. it prevents water from entering c. it controls what enters & leaves the cell d. it prevents everything from leaving

Clicker Question #2 These allow larger substances to move into and out of the cell membrane: a. Lipids b. Phospholipid bilayer c. Carbohydrate pumps d. Protein pumps

Clicker Question #3 This is another name for the cell membrane: a. Nucleus b. Phospholipid bilayer c. Homeostasis d. Protein pump

Clicker Question #4 What is a word that can be associated with “homeostasis”? a. Balance b. Unbalance c. Fluctuate d. Unstable

Clicker Question #5 Salt is an example of a(n): ____ a. Solvent b. Solute c. Solution d. All of the above

Clicker Question #6 Type of movement of molecules through the cell membrane where the molecules move from an area of HIGHER concentration to an area of LESSER concentration. a. Diffusion b. Homeostasis c. Photosynthesis d. Active transport

Clicker Question #7 Diffusion requires energy. a. True b. False

Clicker Question #8 Means that some substances can pass across easily and others cannot. a. Diffusion b. Homeostasis c. Selectively permeable d. Active transport

Clicker Question #9 Is the diffusion of water through a selectively permeable membrane. a. Diffusion b. Osmosis c. Selectively permeable d. Homeostasis

Clicker Question #10 What does water “chase”? a. Sugar or Salt b. Water c. Oxygen d. All of the above

Clicker Question #11 Which of the following is an example of a hypotonic solution? a. Sugar water b. Salt water c. Both (a) & (b) d. Fresh water

Clicker Question #12 What type of solution is this cell in? a. Hypertonic solution b. Hypotonic solution c. Isotonic solution d. None of above.5% Salt 5% Salt

Clicker Question #13 Process in which the cell membrane uses the protein channels to allow/help bigger molecules such as sugars & salts to cross in either direction: a. Osmosis b. Hypertonic solution c. Facilitated diffusion d. Equilibrium

Clicker Question #14 Molecules move against the concentration gradient. This means: a. that it does not require energy b. that Solutes are equal on both sides c. moving from a higher area of solute to a lower area of solute d. moving from a lower area of solute to a higher area of solute

Clicker Question #15 Active Transport uses the ____ to move these molecules against the gradient with the input of energy. a. Protein channels b. Lipid chains c. Nucleic acid double helix d. Carbohydrate channels

Clicker Question #16 The process of taking material into the cell by means of in-foldings, or pockets, of the cell membrane. a. Osmosis b. Passive transport c. Exocytosis d. Endocytosis

The End

1.C11. D 2.D12. B 3.B13. C 4.A14. D 5.B15. A 6.A16. D 7.B 8.C 9.B 10.A Clicker Question Answers