Cool Cats Dont Run Cool Cats Dont Run
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Cool Cats Don’t Run
Cool Cats Don’t Run y t o p l a s m el l m e m b r a n e N A i b o s o m e s
DNA 1/27/16 • Take out quiz photo and corrected responses for acct check. • Write analogies (like in yesterday’s activity) for the following organelles. Continue on the same sheet of paper from yesterday, so they are all in one place: 1. Ribosome 2. Mitochondria 3. Cell Wall
Nucleus Nucleolus (made up of DNA)
Endoplasmic Reticulum Vacuole Ribosomes
Cell Membrane Cell Wall
Share with Your Partner 1. What are some things that you bring into your home because you need them? 2. What are some things that are not wanted in your home so you keep them out? 3. What are some things that are sent out of your house?
The Cell Membrane: The Gatekeeper of the Cell
What does Alice have to do with Cell Membranes?
Class Brainstorm What properties could the cell membrane use to distinguish between molecules? Physical Properties Chemical Properties
What is the cell membrane? • Every cell is surrounded and protected by a plasma membrane (aka cell membrane) • The cell membrane is made mostly of lipids, carbohydrates, and some protein channels
What does the cell membrane do? The cell membrane has two main jobs: 1. It separates the inside of the cell (the intracellular space) from the outside of the cell (the extracellular space) 2. It acts as a gatekeeper by only allowing certain molecules in or out
Components of the Cell Membrane • The cell membrane is made of special lipids called phospholipids • Phospholipids have two parts: –Hydrophilic (waterloving), or polar heads –Hydrophobic (waterfearing) or nonpolar tails
Drawing out phospholipids
DNA 1/28/16 Draw a phospholipid. Label the two parts of phospholipids that make up the phospholipid bilayer. • Which part of the phospholipid is hydrophobic? Which part is hydrophilic?
Announcements • Tomorrow = last day of plant data collection • Case study paragraphs due tonight at 11: 59 PM. • Plant data section due Tues at beginning of class. (hard copy in class for peer review. No turnitin submission)
Today! • There is a hiring symposium that I am sneaking away to watch. Here is what to do: • 1. Collect and record plant data. • 2. Work on case study paragraphs (peer revise all paragraphs in your group to make sure that the reasoning makes sense for all 4!! Use the rubric!) • 3. Make revisions to intro and methods section of plant lab. (If I have not written your feedback yet, look at someone’s feedback within your group. There were a lot of common errors)
Other parts of the cell membrane • Several types of proteins are embedded in the cell membrane. • Two major ones are: • Protein channels: proteins that allow a passage way into and out of the cell • Protein receptors: Binds to a signaling molecule outside of the cell that causes a reaction inside of the cell
Other parts of the cell membrane • The cell membrane also has carbohydrates on the outer surface that play a role in cell recognition and cholesterol around the lipid tails to regulate membrane fluidity
Activity: Modeling the Cell Membrane • Work together with your shoulder partner to make a model of the cell membrane • Make sure you READ each step carefully and WORK together! Q-tip = Phospholipid String = carbohydrate Straw = Protein channel Cholesterol Cotton ball = nucleus Candle = protein receptor
Step 1: Identifying the phospholipid • First identify which parts of the q-tip are the polar phosphate head and the nonpolar lipid tail • Which part does not want to come into contact with water? Q-tip = Phospholipid
Step 2: Building the cell membrane • Imagine that the surface of your desk is made up of water. Arrange your q-tips in a way so that the minimum number of hydrophobic (nonpolar regions) are exposed to water.
Step 3: Building the cell membrane • Arrange your q-tips in a way that results in an inner compartment that can also have water. Water inside
Step 4: Building the cell membrane • Add your protein receptor and channels to the membrane to allow things to communicate and enter/exit the cell. Straw = Protein channel Candle = protein receptor
Step 5: Adding cholesterol and carbohydrates • Snugly pack the cholesterol strands between the lipid tails. • These cholesterol molecules help maintain membrane fluidity • Add carbohydrates to the outer layer of phospholipids. Cholesterol • These carbohydrates allow the cells to be recognized by other cells and String = carbohydrate molecules (and viruses yikes!)
Step 6: Nucleus • Add your nucleus to the cell. • Is this cell a eukaryotic or prokaryotic cell? How do you know? • What does the nucleus hold in these cells? Cotton ball = nucleus
Drawing out our cell membrane
What does the cell membrane do? • The cell membrane helps cells maintain homeostasis by allowing SOME things to enter/exit the cell and not others – it is SEMIPERMEABLE
Questions: • If ANYTHING could freely move in and out of the membrane, would it still be called semi-permeable? • If NOTHING could move in and out of the membrane, would it still be called semi-permeable?
Semi-permeable • Semi = Partially • Permeable = Allowing things to pass through • Semi-permeable means that some things can enter and leave while other things cannot