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I. The Plasma Membrane Quiz:
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1. Controls what comes in and out of the cell. It is selectively permeable. Cell Membrane
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2. Protects and separates the cell from its environment
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3. It is often called a fluid mosaic model
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b. Made of a phospholipid bilayer
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i. Two layers of phospholipids ii. Arranged tail to tail
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ii. Has various proteins, carbohydrates and cholesterol mixed in
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Figure 6-1 Simple Plasma Membrane
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proteins are imbedded in the plasma membrane like raisins in raisin bread
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II. Passive Transport- the movement of particles in and out of the cell without using the cell’s energy.
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A. Diffusion - movement of particle- like gases across the cell membrane.
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B. Makes use of a concentration gradient- the SOLUTE always moves from HIGH concentration to low concentration.
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Will continue until dynamic equilibrium is reached Will continue until dynamic equilibrium is reached
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Can make use of transport proteins- which are selective for certain particles.
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Diffusion of Oxygen
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C. Facilitated Diffusion c. Facilitated diffusion- process of moving particles across the cell membrane using transport proteins.
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– i. Transport proteins-found in the cell membrane 1. Allow some types of ions, sugars and amino acids to pass through the cell membrane
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2. There are different types -each is selective - specific for certain particles – ii. Move particles from areas of HIGH concentration to areas of LOW concentration-moves down the concentration gradient – iii. Form of passive transport ---no energy
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Facilitated diffusion Fig. 6-3
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d. Osmosis-type of passive diffusion -it does not use the cell’s energy 1. It is always the movement of WATER particles 2. It moves WATER molecules across a selectively permeable membrane through which the solute (dissolved particles) cannot pass
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ii. Makes use of a concentration gradient - always moves from HIGH concentration to low concentration Iii. Will continue until dynamic equilibrium of the solute is reached.
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Osmosis the movement of water
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3. Hypotonic solution 2. Hypertonic Solution 1. Isotonic Solution Osmosis can create 3 types of solutions:
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1. Isotonic solution -the solution on the outside of the plasma membrane has the same concentration as the solution on the inside of the membrane. – a. There is no NET movement of WATER molecules – b. Water will move in and out of the cell at the same rate – c. The cell will remain the same size – d. Animal cells do best in isotonic solution
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Isotonic Solution
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2. Hypertonic solutions--the solution outside the cell has less water and more solute than the solution inside the cell. http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm
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a. Water rushes out of the cell b. Cell shrivels up c. Causes plasmolysis in plants, plants wilt
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Ex: slugs
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3. Hyp o tonic solution - the solution on the inside of the cell membrane has less water and more solute than the solution outside of the cell. http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm
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a. Water rushes into the cell b. Cell swells like a big O
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c. Plant cells become turgid due to water pressing outward against cell wall---creates turgor pressure
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d. Plant cells do best in a hypotonic solution. e. Animal cells swell & burst (lyse) if they take in too much water
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III. Active Transport- transport proteins, endocytosis and exocytois A. Moves molecules in and out of the cell – Moves materials AGAINST the concentration gradient – Requires the cell’s energy-- $$$$$$
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iii. Uses transport proteins to help move materials in and out of the cell—3 types include:
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1. Carrier Proteins
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2. GATE Proteins
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3. Channel Proteins-like a straw things can pass through
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b. Endocytosis-the process of taking in large particles i. surrounds the particles with the cell membrane ii. Requires cell energy --$$$$$ iii. “en” - means “ enter”
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2 types of endocytosis 1. Phagocytosis- process of engulfing solid particles to create vesicles 2. Pinocytosis- the process of engulfing liquid particles
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c. Exocytosis - process of removing large particles i. Used to get rid of wastes, undigested food or to release hormones ii. In the cell the material is enclosed in a vesicle, vesicle fuses with the cell membrane and the material is released outside of the cell iii. “ex” - means “exit”
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1. Look at the diagram below. The animal cell has a concentration of 0.7% inside the cell membrane and it is placed in a salt solution with a concentration of 18.5 %. What will happen if the cell remains in the solution? Explain your answer in terms of osmosis. 18. 5% 0.7%
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2.A red blood cell contains a 0.9% concentration of salt inside the cell. If the red blood cell is placed in a solution that is pure water, what will happen to the cell? Is the solution hypertonic, hypotonic, or isotonic?
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3.A plant cell contains a 1% concentration of solute inside the cell. If the plant cell is placed in a solution that is 5% solute, what will happen to the cell? It the solution hypertonic, hypotonic or isotonic?
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Saturated fats Unsaturated fats
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