CELL MEMBRANE AND CELL TRANSPORT NOTES Standard Cell
CELL MEMBRANE AND CELL TRANSPORT NOTES
Standard Cell Biology l 1. a. Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings. l https: //www. youtube. com/watch? v=ow. Egq rq 51 z. Y
What is the cell membrane? The cell membrane regulates what enters and leaves the cell and also provides protection and support.
The structure of the cell membrane l The cell membrane consists of a lipid bilayer (lipid = fat; bi=2) plus proteins that straddle the bilayer. Attached to the proteins are carbohydrates. l Many of these proteins are channels and pumps that allow substances through or not!
Draw the cell membrane
Cell Membrane Video l https: //www. youtube. com/watch? v=S 7 CJ 7 x. ZOjm 0
You should be able to answer these questions: 1. 2. 3. 4. 5. Describe the structure of the cell membrane. How do molecules get into and out of the cell? What is selective permeability? What is diffusion and how does it work? What is facilitated diffusion and how does it work? 6. What is active transport and how does it work? 7. What is osmosis and how does it work? 8. What is the function of transport proteins?
Transport through the Cell Membrane
Cell membranes are selectively permeable (semipermeable). l Permeable- ability to pass through a membrane l Impermeable- can’t pass through l Selectively Permeable (semipermeable)some things can pass through and some can’t
Copy the chart into your notes Type of Transport Simple Diffusion Facilitated Diffusion Active Transport Protein Used? Direction of movement Requires Energy input from cell? Classification of transport? Types of Substances
Transport Through the Membrane Passive Transport: 1. Simple Diffusion 2. Facilitated Diffusion Active Transport
Simple Diffusion l No transport protein used l Movement WITH the concentration gradient (high to low) l No additional cell energy required l PASSIVE l Examples: water, carbon dioxide and oxygen
Type of Transport Protein Used? Direction of movement Requires Energy input from cell? Classification of transport? Types of Substances Simple Diffusion NO With concentration gradient (high to low) NO PASSIVE WATER, CO 2, O 2 Facilitated Diffusion Active Transport
l Solution- a liquid with one or more substances dissolved in it l Solvent- the liquid that the solute is dissolved in l Solute- the substance dissolved in a solution l Concentration- how strong it is the solute/volume (percentage)
Think of living cells like little bags of solutions surrounded by a semipermeable membrane! For the cell to survive, the concentration of solutes must stay within a safe range to maintain homeostasis.
Concentration Gradient- when there is a difference in concentrations l High concentration: more particles l Low concentration: fewer particles l In diffusion, particles move from high to low concentration to reach an equal concentration (equilibrium) on each side.
Facilitated Diffusion l Transport protein used: carrier protein or channel protein l Movement WITH the concentration gradient (high to low) l No additional cell energy required l PASSIVE l Example: Glucose molecules
Type of Transport Protein Used? Direction of movement Simple Diffusion NO With concent. gradient Facilitated Yes: With Diffusion Channel concent. Proteins or gradient Carrier Proteins Active Transport Classification of transport? Types of Substances NO PASSIVE WATER, CO 2, O 2 NO PASSIVE GLUCOSE Requires Energy input from cell?
Carrier Proteins
Channel Proteins
Passive Transport: Facilitated Diffusion l https: //www. youtube. com/watch? v=v. KGN_ Zhz 8 AY
Active Transport l Transport protein used: carrier protein l Movement AGAINST the concentration gradient (low to high) l Additional cell energy required l ACTIVE l Example: Sodium-Potassium Pump: pumps Na+ ions out of cell and K+ ions into cell
Classification of transport? Type of Substance NO PASSIVE WATER, CO 2, O 2 With concent. gradient NO PASSIVE GLUCOSE Against concent. gradient YES ACTIVE Na+ and K+ ions Type of Transport Protein Used? Direction of movement Simple Diffusion NO With concent. gradient Facilitated Diffusion Yes: Channel Proteins or Carrier Proteins Active Yes: Carrier Proteins Transport Requires Energy input from cell?
Active Transport
Active Transport l https: //www. youtube. com/watch? v=yz 7 EH JFDEJs
Other Types of Active Transport l Endocytosis – the process of taking material into the cell by folding in pockets of the cell membrane into pouches called vesicles ¡Phagocytosis – endocytosis involving large solid particles ¡Pinocytosis – endocytosis involving liquid l Exocytosis – the process of removing material out of the cell where vesicles merge with the cell membrane to release contents
Endocytosis and Exocytosis l https: //www. youtube. com/watch? v=qpw 2 p 1 x 9 Cic
Osmosis- the diffusion of water l No transport protein used l With the concentration gradient (high to low) l No additional cell energy required l Passive
Concentration Strength l Isotonic – the solution and the cell have the same concentration strength l Hypotonic – the solution has a lower concentration than the cell l Hypertonic – the solution has a higher concentration strength than the cell
Osmotic Pressure l Osmotic Pressure is the pressure that water exerts on the hypertonic side of a selectively permeable membrane. l It can be problematic for living cells because they can burst from over-inflation with water or shrivel up from loss of water.
Red Blood Cells in a Hypertonic Solution l https: //www. youtube. com/watch? v=OYoa. L zob. Qmk
Plants and Osmosis
Applications of Osmosis l Water overdose/intoxication l High concentration of fertilizer kills plants l Water enters the roots of plants l Why drinking salt water can kill you l Why putting salt on a slug or snail kills it l How dialysis machines work l The preservation of foods in salt brines (olives, fish vegetables) kills bacteria l Refresh wilted salad greens by putting in water
Cell Quiz 1. 2. What are two differences between prokaryotes and eukaryotes? An animal cell is a prokaryotic/eukaryotic cell. (circle the correct answer) 3. When preparing a wet mount, the cover slip should be put on at an angle to avoid ______. 4. The ______ contains the DNA and controls the cell. 5. Diffusion is the movement of molecules from a ______ to a _______ concentration. 6. If a cell has 95% water and it is placed in a hypertonic solution, water will move out of/into the cell. (circle the correct answer) 7. _____ are where photosynthesis occurs in plant cells. 8. A bacteria is a prokaryotic/eukaryotic cell. (circle the correct answer) 9. On high power, more/less of the cell can be seen. circle the correct answer) 10. What two things happen to an image when viewed under a microscope? 11. Choose and explain one of the following: endocytosis, phagocytosis, pinocytosis, or exocytosis.
- Slides: 39