Unit 3: Cellular Processes. 1. SEPARTION & PROTECTION: the contents of the cell from the. 2. TRANSPORT: the transport of in and out of the cell

Transcription

1 Unit 3: Cellular Processes Name: Aim #14 Cell Membrane: How does the cell membrane function to maintain homeostasis? Date: _ I. The Cell Membrane: What is it? Also known as A thin structure that acts as a barrier to the of the cell from the (outside) environment or Which types of cells have a cell membrane? What is the structure? II. Three Functions of the Cell Membrane 1. SEPARTION & PROTECTION: the contents of the cell from the _ 2. TRANSPORT: the transport of in and out of the cell 3. COMMUNICATION: with other cells through the use of by sending and responding to chemical

2 FUNCTION #1: How does the cell membrane separate the inside of the cell from the outside of the cell? 1. The structure of the cell membrane acts as the between the and the of the cell. 2. Keeps the cell environment in an environment that is (homeostasis) 3. The membrane is : allows certain materials in and out of the cell based on and FUNCTION #2: How does the cell membrane control the transport of molecules in and out of the cell? 1. What types of molecules must ENTER the cell to maintain homeostasis 2. What types of molecules must LEAVE the cell to maintain homeostasis Key Transport Terms: Solvent: a substance that another substance (ex: water) Solute: a substance that is (ex: sugar, salt) Solution: when a substance is dissolved into another substance (ex: ) Concentration: a measure of the amount of a in a solution Which has the greatest concentration of water? Which has the greatest concentration of solute?

3 Types of Cell Transport Type of Transport Definition Which molecules? How do molecules move? Type of Transport Require ATP from the cell? Example 1. Diffusion The movement of molecules (solute) from areas of concentration to Examples of molecules moved: = GLUCOSE (needed by the cell to make energy) areas of concentration of solute Moves from: to concentration The movement of molecules Examples of molecules moved: = SALT Water is usually represented by the white space from concentration 2. Osmosis of water to concentration of water Moves from: to concentration 3. Active Transport The process by which cells use (energy) to transport molecules through the cell membrane from areas of concentration to areas of concentration. Examples of molecules moved: Moves from: to concentration = MINERAL Desert plants use active transport to bring minerals from the soil, which is at very low concentrations, and move it into their root cells where the mineral concentration is higher

4 A cell can be in the following types of solutions: 1. Hypertonic: solution outside of the cell has a high concentration of particles and low concentration of water 2. Hypotonic: solution outside of the cell has a low concentration of particles and a high concentration of water 3. Isotonic: solution outside of the cell has the same concentration of particles and the same concentration of water 1. Name two differences between passive (diffusion) & active transport. 2. Name one similarity between passive (diffusion) and active transport 3. Why is it important that the large organic macromolecules (such as proteins and starches) are digested before passing through the cell membrane? 4. When the macromolecules are broken down into their building blocks, what happens to them upon entering the cell?

5 FUNCTION #3: How does the cell membrane recognize and respond to signals? 1. are in the cell membrane that can receive (hormones, nerve signals) from other cells which is important for and between cells 2. Since receptor molecules are proteins, what can you infer about their interaction with chemical messages? Diagram of cell membrane receptor molecule and a chemical signal = Chemical message Cell A Cell B In the diagram above, which cell will be able to receive the chemical message? Explain why: What would happen if the cell receptor able to receive signals was denatured?

6 Practice Questions A) Read each statement below and WRITE the correct term on each line. You can use the terms more than once! active transport diffusion equilibrium osmosis Energy size passive transport cell membrane semi permeable receptors lipid swell shrink 1. Is used during active transport but not passive transport 2. Particle movement from an area of lower concentration to an area of higher concentration 3. These are located on the cell membrane and recognizes and sends chemical signals 4. If there is more water outside of a cell than inside of the cell, the cell will 5. When a membrane is selective about the materials allowed in and out of the cell 6. The diffusion of water through a cell membrane 7. The movement of substances through the cell membrane without the use of cellular energy 8. If there is more water inside of a cell than outside of the cell, the cell will 9. The semi-permeable structure of a cell that allows molecules to move in and out 10. When energy is required to move materials through a cell membrane 11. When the molecules of one substance are spread evenly throughout another substance to become balanced 12. When molecules move from areas of high concentration to areas of low concentration 13. The main component of a cell membrane 14. This property determines which molecules can enter and leave the cell B) Below each diagram, label the term that defines what is happening in each cell in the box below the image. Use the following terms: diffusion, active transport, osmosis, equilibrium. The arrows show the direction of transport. You may use the terms more than once! High CO2 levels 2 H2O molecules 25 glucose molecules Low CO 2 levels 8 H2O molecules 2 H2O molecules High protein levels 5 glucose molecules 2 H 2O molecules Low protein levels

7 C) Using your knowledge of biology and the images of each cell below, answer the following questions: 1. 5% NaCl 95% H 2O 95% NaCl 5% H 2O a. Draw an arrow to show the passive transport of salt (NaCl) through this cell s membrane b. Draw a dotted arrow to show the direction of osmosis c. Water will flow (into the cell, out of the cell, in both directions). d. The cell will (shrink, burst, stay the same) % Cl 3% Cl e. Is this movement active or passive transport? _ f. Does this movement require energy? g. In what direction will chlorine (Cl) move after the cell dies? Explain why! (Hint: can a dead cell make energy?) 3. 90% NaCl 15% H 2O 10% NaCl 75% H 2O h. Draw an arrow to show the passive transport of salt (NaCl) through this cell s membrane i. Draw a dotted arrow to show the direction of osmosis j. Water will flow (into the cell, out of the cell, in both directions). k. The cell will (shrink, burst, stay the same). 4.

8 a) Does this cell show active or passive transport? Explain WHY b) Name two differences between active transport and diffusion