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Do Now What are cells? Why do we need them? List different types of cells that you know of… Cellular Structure and Function Chapter 7 Objectives Describe how cells were discovered and named. Compare and contrast light microscopes vs. electron microscopes. Explain what is found in a basic cell. Where do living things come from?? Spontaneous Generation: ◦ The idea that life arises from non-life Ex: mud gives rise to worms?? We can make mice out of hay?? Fransisco Redi: ◦ An Italian scientist ◦ Tested the idea of spontaneous generation. What happens when you leave meat out for a long time? Redi’s Experiment- 1668 He placed meat in both an open container, and a closed container to see what happened… Redi’s Conclusions Maggots come from FLIES, not meat. Life must come from life, not spontaneous generation right? ◦ Not completely rejected until later on… Now what? Louis Pasteur experimented with the “Theory of biogenesis”. Theory of Biogenesis: ◦ Only living organisms can produce other living organisms. Pasteur’s Experiment Tested the idea of spontaneous generation again Nutrient rich broth was exposed to air but not dust and spores Pasteur’s Conclusion Living organisms must be able to enter the broth in order to grow Living things do NOT spontaneously generate What are cells? Basic structural and functional unit of all living organisms! They come in all shapes and sizes Lets take a look… http://www.cellsalive.com/howbig.htm Cells! Egg cell How did we figure out cells even existed, what they looked like, what they do?... Nerve cell Bacteria cell Robert Hooke 1665- saw dead plant cells from cork, tree stems, roots and ferns using a light microscope Called them “cellulae” (small rooms) - reminded him of the cubicles or cells where monks live Anton van Leeuwenhoek First person to observe living cells Made microscope with a magnification 10X that of Hooke’s- “Father of microscopes” Observed spirogyra and protists Matthias Schleiden Studied plant tissues and concluded that plants were composed of cells too! Theodor Schwann Reported animal tissues also were made up of cells! Rudolph Virchow All cells are produced from the division of existing cells! The “Cell Theory” Scientists expressed 3 main observations about cells: All living organisms are composed of one or more cells Cells are the basic units of structure and organization of all living organisms Cells come only from the reproduction of existing cells Cell Theory https://www.youtube.com/watch?v=4OpBylwH9DU What do we use to look at cells? Cells were discovered using MICROSCOPES! Compound Light Microscopes Uses visible light to produce magnified image. Maximum = 1,000x magnification Electron Microscopes Specimen must be dead Use magnets and electrons Allows much greater magnification Ex: Transmission Electron = up to 500,000x Electron Microscopes Transmission Electron Microscope Electrons are sent through a specimen Allows us to see organelles inside! Image appear 2D Scanning Electron Microscope Electrons are sent over the surface of a specimen. Images appear 3D http://www.udel.edu/biology/ketcham/microscope/scope.html Do Now Label this microscope! Basic Parts of any Cell DNA/RNA Needs some type of genetic information! Plasma membrane Cell’s outer boundary that acts as a barrier Cytoplasm Region of cell that includes fluid, cytoskeleton and all organelles except the nucleus Cytosol- part of cytoplasm that included molecules and small particles but not organelles Control Center Contains a cell’s DNA Nucleus- membrane- bound structure in eukaryotes Nucleoid- region of DNA in prokaryotes Prokaryotic vs. Eukaryotic Organisms can be made up of either prokaryotic or eukaryotic cells. Prokaryotic Cells… Do not have a distinct nucleus Have circular DNA No membrane-bound organelles Ex: bacteria (many scientists think that prokaryotes are similar to the first EVER organisms on Earth) Eukaryotic Cells… Contain a nucleus Have linear DNA Contain membrane-bound organelles Makes up most multicellular organisms Ex: US, plants, animals, etc. (also some unicellular organisms like algae and yeast) Lets Review! Who discovered cells? Why was Leeuwenhoek so special if someone had already observed cells before? What are the different types of microscopes we talked about. Which would be best to look at tiny projections on the surface of a bug? How are eukaryotes different from prokaryotes? Do Now Get with ONE other person. Come up with a team name Go to m.socrative.com Enter Bio607 as the room name. Wait quietly for me to explain the next steps. Do Now What are the differences between prokaryotic and eukaryotic cells? Why do we need so many more organelles than bacteria? Explain. Objectives List the different organelles of a cell. Explain the function of each organelle. Identify each organelle in a diagram of a cell. Organelle Song https://www.youtube.com/watch?v=dngsFl2X3nc Organelle Jigsaw Activity Plasma Membrane The wall!- protects the internal structures of the cell. Determines what comes in and out of the cell. Selective Permeability Found in: Plant, Animal, and Prokaryotic Cytoplasm/Cytoskeleton Cytoplasm- clear FLUID that contains the organelles Cytoskeleton- Provides the FRAMEWORK for the cell, holds organelles in place. Found in: Plant, Animal, and Prokaryotic Nucleus Nucleus- CONTROLS the cell. Nucleolus- produces ribosomes. Nuclear Pores- allow things in and out of nucleus. Nuclear Envelope- Membrane around the nucleus Found in : Plant and Animal Ribosomes Makes polypeptide chains of amino acids, Producing Proteins! Found in: Plant, Animal, and Prokaryotic Endoplasmic Reticulum Rough- contains ribosomes and synthesizes PROTEINS. Smooth- No ribosomes, synthesizes LIPIDS (fats). Found in: Plant and Animal Golgi Apparatus Modifies proteins and fats and gets them ready for export! Found in: Plant and Animal Central Vacuoles Large WATER “bubble” in a plant cell. Maintains the SHAPE of the cell, without it, the plant cell would shrink and the plant would wilt. Found in: Plant Cells Lysosomes Contain ENZYMES, break down cellular waste product and debris. Found in: Animal Centrioles Groups of Microtubules involved in cell division (we will talk about this more later when we do mitosis!) Found in: Animal Mitochondria Convert oxygen into ENERGY (we will talk about this more when we do cellular respiration!) Powerhouse!! Found in: Plant and Animal Cilia and Flagella Flagella- Used in cells for movement (longer and less numerous than cilia Cilia- Used in stationary cells for moving substances around the outside of the cell. (hairs) Found in: Animal and Prokaryote Chloroplasts Capture light ENERGY and convert it to chemical energy (sugar). Contain Thylakoids (where photosynthesis takes place) Found in: Plant Cell Wall Rigid structure (made of carbohydrate cellulose) Provides strength for the cell. Works with vacuole to maintain “turgor pressure” Found in: Plant coLAR Mix!! Please download the coLAR mix free app! Then color code the animal cell Use the app to watch some magic happen! (the dots) What are the differences between plants and animals? http://www.youtube.com/watch?v=-zafJKbMPA8 Compare and contrast plant and animal cells. Plants Animals Quiz Study Guide Organelles- what each of them do Diagrams- label both plant and animal cell. Scientists- who were they and what did they do? Cell Theory- what is it? Prokaryotes vs. Eukaryotes- what’s the difference? Do Now What is the plasma membrane? What does it do? What would happen if it didn’t exist? Objectives Understand the role of the plasma membrane. Identify the components of the plasma membrane and their functions. Define diffusion. What does the membrane do? Maintains an internal environment that is different from the external environment. Determines what molecules enter and exit the cell Made of a phospholipid bilayer Selective Permeability Controls the movement of substances in and out of the cell Controls AMOUNT of substances entering and leaving the cell Fish net analogy Phospholipid Gylcerol, 2 fatty acid chains, and a phosphate group “Phospho”-Hydrophillic (water loving) Polar (heads) “lipid”-Hydrophobic (water hating) Non-polar (tails) Bilayer Water or other hydrophilic substances Fats (hydrophobic) Water or other hydrophilic substances The bilayer makes up the plasma membrane that surrounds the cell! Which of the 4 organic molecules do you see in the plasma membrane? –P.C.F.NA. Structure of the plasma membrane Proteins: Receptors, structure, transport. Cholesterol: Prevents tails from sticking Proteins and other components are embedded like a mosaic: Fluid Mosaic Model http://www.youtube.com/watch?v=Qqsf_UJcfBc Cholesterol Prevents fatty acid tails from sticking together Carbohydrates Attached to proteins Help cell identify chemical signals Ex. Help disease-fighting cells recognize harmful cells Proteins Provide channels for transport Act as cell receptors (transmit signals) Provide structure Conclusion activity Do Now- Label the different parts Define diffusion. Objectives Identify the conditions that effect the rate of diffusion. Explain facilitated diffusion. Compare and contrast active and passive transport. What is diffusion? Diffusion-Movement of molecules from High concentration to Low Concentration by random motion (no energy required) High Concentration Low Concentration Diffusion continued… Mixing continues until concentrations are the same in all ares Dynamic Equilibrium-continues movement but NO NET overall change. Balanced Concentration Explain what’s happening… Diffusion Video http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/a nimation__how_diffusion_works.html Diffusion across the plasma membrane *Cells also need ions and small molecules to perform cellular functions (Ex. Ions and Sugars) (Ex.H2O, O2, CO2) T.P Large and/or ChargedTransport Protein Small and/or non-polar molecules Diffusion of Water- OSMOSIS Water can move right through the phospholipids from high to low concentration Facilitated Diffusion Most substance cannot readily pass through the membrane. Facilitated diffusion: Movement of materials across the plasma membrane using proteins Channel Proteins Carrier Proteins Types of Transport Proteins Channel Proteins Pores that allow charged ions to pass through the membrane Carrier Proteins Change shape to help molecules pass through the membrane Do Now What does “passive” transport mean? What are the different types of passive transport? What is the difference between passive and active transport? Objectives To explain passive and active transport. To understand what happens during osmosis. To compare and contrast hypertonic, hypotonic, and isotonic solutions. Passive Transport Movement of particles across the cell membrane without using energy Diffusion of Water Things that Affect the speed of Passive Transport 1. Heat- Hotter faster 2. Size – Bigger slower 3. State of Matter Solid- Slow Liquid – Fast Gas- Fastest Active Transport Specific protein can pump molecules across the membrane Usually in opposite direction of diffusion (Low concentration to high concentration) Requires ENERGY (ATP) Sodium Potassium Pump Type of Active Transport Moves three Na+ ions out of the cell and two K+ ions into the cell Sodium Potassium Pump: Video http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/ani mation__how_the_sodium_potassium_pump_works.ht ml Transport of Large Molecules Usually Transported byVesicles Endocytosis-Into the cell Exocytosis-Exiting the cell What kind of molecules do you think are usually found in the Vesicle? Osmosis -Water always flows via osmosis from HIGH water concentration to LOW water concentration through a semi permeable membrane. Osmosis Which container has more water in it? http://www.stolaf.edu/people/giannini/flashanimat/transport/osmosis.swf Osmosis- diffusion of water across a membrane Remember: Water always flows via osmosis from HIGH water concentration to LOW water concentration This cell would shrink! 22% Salt 5% Salt H2O H2 O Osmosis- diffusion of water across a membrane Water always flows vis osmosis from HIGH water concentration to LOW water concentration This cell Bursts! 22% Salt 45% Salt H2O H2O Cellular Structure and Function Isotonic Solution Water and dissolved substances diffuse into and out of the cell at the same rate. Plant Cell Blood Cell 11,397x HypOtonic Solution Solute concentration is higher inside the cell. Water diffuses into the cell, cell swells/bursts Plant Cell Blood Cell 13,000x Hypertonic Solution Solute concentration is higher outside the cell. Water diffuses out of the cell, cell shrivels Plant Cell Blood Cell 13,000x 3 Types of Solutions Cell in ________ Solution H2 O H2 O Cell in ________ Solution H2 O H2 O Cell in ________ Solution H2 O H2 O For each solution, determine if the solute concentration of the solution is high, the same, or low as compared the cell. Real life osmosis examples Your garden is infested with slugs so you go around pouring salt on them What type of solution is this salt? What is going to happen to the cells of the slug? (Don’t do this to the poor slugs ) Real life osmosis examples A salt water fish is put into a freshwater aquarium. What type of solution is the freshwater? What is going to happen to the cells of the fish? Important Vocab… Plasmolysis: State where plant cells shrink in hypertonic environment (animal cells= “crenation”) Plant Animal Important Vocab… Flaccid: State where a plant cell is placed in isotonic solution Plant Animal Important Vocab… Cytolysis: State where cells Burst in hypotonic environment Turgid: State where plant cells swell in hypotonic solutions Creates Turger Pressure in plants (animal cells= Lyse) Plant Animal
