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Introduction – What is a Cell

Introduction – What is a Cell

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Introduction – What is a Cell

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  1. Introduction – What is a Cell • Smallest unit of structure making up every living thing. • What does this mean? • Can’t be considered “living” unless you have the properties of at least one cell • Lowest common denominator of all living things – the cell • Development of Cell Theory

  2. The Cell Theory (?’s 2-7) • Question #7 What are the three components of cell theory? • All living things are composed of cells • Cells are the basic unit of structure and function in living things • New cells are produced from existing cells

  3. The Cell Theory • Historically, how did it develop? • #2 Anton van Leeuwenhoek (1600) • developed the microscope and saw tiny living organisms in a drop of water • learned to grind lenses and put them to together in combinations to magnify things • was a businessman who originally developed microscope to examine threads • 1st to see blood cells, bacteria, sperm cells

  4. The Cell Theory • #3 – Robert Hooke (1665) • looked at cork under microscope and thought they looked like tiny chambers • first to coin the term “cells” – in reference to monastery rooms called cells

  5. The Cell Theory • # 4 Mathias Schleiden (1838) • Concluded that all plants are made of cells

  6. The Cell Theory • #5 Theodor Schwann (1839) • Concluded that all animals made of cells

  7. The Cell Theory • #6 Rudolph Virchow (1855) • Observed cells dividing and replicating • concluded that all cells come from pre-existing cells

  8. Basic Cell Structures(? 8) • Despite a variety of sizes, shapes, and specific cell roles, certain structures are common to almost all cells: • Cell membrane (all cells) • Cytoplasm (all cells) • Cell wall (many cells, notable exception are animals) • Nucleus (most cells, notable exception prokaryotes – bacteria)

  9. Basic Cell Structures • Cell Membrane – thin flexible barrier around cells. • Cell Wall – a strong layer around the cell membrane • Nucleus – contains the cells genetic material and controls cell activities • Cytoplasm – material inside the cell, NOT including nucleus

  10. Prokaryotes and Eukaryotes • A way of classifying cells

  11. Cell membrane Cytoplasm Cell membrane Cytoplasm Prokaryotic and Eukaryotic Cells Section 7-1 Prokaryotic Cell Nucleus Eukaryotic Cell Organelles Go to Section:

  12. Prokaryotes and Eukaryotes • 10. True about prokaryotes • they grow and reproduces • they have cell membrane and cytoplasm • 11. Organelle – specialized structure in eukaryotes that perform specific task • 12. Not all eukaryotes are large and multicellular like us. Many are single celled organisms.

  13. 7-1 Concept Map Cell theory States all living things made of Contain basic Categorized as Categorized as prokaryotes include include include Include all example example Cells Cell structures eukaryotes Cell membrane nucleus bacteria Cell wall cytoplasm animals plants

  14. Section Outline Section 7-1 • 7–1 Life Is Cellular A. The Cell Theory B. Basic Cell Structures C. Prokaryotes and Eukaryotes 1. Prokaryotes 2. Eukaryotes Go to Section:

  15. Interest Grabber Section 7-2 Division of Labor • A cell is made up of many parts with different functions that work together. Similarly, the parts of a factory work together to carry out different functions. • Answer the following question. • What would you see if you walked into a factory? What are the functions of these things? Go to Section:


  17. CELL WALL • Found in plants, fungi, most prokaryotes, and algae • Very outermost part of the cell • Provides support and protection • 4. Made up of cellulose (starch/carbohydrate)


  19. Nucleus • It controls most cell processes. CONTAINS THE HEREDITARY material. • The material is called DNA or deoxyribonucleic acid. • In one human cell = 3 meters of DNA • Number of cells in body = 50 to 70 trillion • Multiply = approximately 66 trips around the sun!!! • 10. Chromosomes – DNA wrapped up protein (protein acts as a spool) • Nucleolus – Produces ribosomes (factory workers) • Nuclear envelope – membrane around nucleus. Contains nuclear pores

  20. Nucleus (organization) nucleolus protein DNA chromosome Nuclear envelope

  21. Cytoskeleton • 14. Network of proteins that helps to maintain its shape (microtubules and microfilaments)

  22. Assignment • Work independently • Guided Reading 16-37

  23. Section Outline Section 7-2 E. Organelle DNA F. The Cell as a Factory G. Comparing Cells • 7–2 Cell Structures • A. Cell Wall • B. Nucleus 1. Chromatin and Chromosomes 2. Nucleolus 3. Nuclear Envelope • C. Cytoskeleton • D. Organelles in the Cytoplasm 1. Ribosomes 2. Endoplasmic Reticulum 3. Golgi Apparatus 4. Lysosomes 5. Vacuoles 6. Chloroplasts 7. Mitochondria Go to Section:

  24. Organelles in the Cytoplasm • Ribosomes • F. Produces protein following instructions from nucleus Factory workers producing final product. • Endoplasmic Reticulum • 19. D. Internal membrane system. Proteins are constructed here. • Assembly line or conveyor system. Ribosomes work along • this assembly line putting together proteins.

  25. Organelles in the Cytoplasm • Golgi apparatus or Golgi body • 20. B. Stack of membranes in which enzymes attach carbohydrates and lipids to proteins. Golgi packages final product and sends it to its final destination. • Customization shop where finishing touches are put on the product.

  26. Organelles in the Cytoplasm • Lysosome • G. Filled with enzymes used to break down food into particles that can be used • Also help to break down old cell parts • Custodial staff

  27. Organelles in the Cytoplasm • Vacuole • E. Saclike structure that stores material. • most notably it stores water in plants • warehouse

  28. Organelles in Cytoplasm • Chloroplast • 23. A. Uses energy from the sunlight to make energy rich food. Photosynthesis. • Makes energy that the cell can use. • Solar power plants

  29. Organelles in the Cytoplasm • Mitochondrion • 24. C. Converts energy (from food produced by chloroplast) to energy the cell can use. • Coal Burning facility (release the energy from the coal) • Fire place (releasing energy from wood)

  30. Cell Wall Chloroplasts Venn Diagrams Section 7-2 Prokaryotes Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Lysosomes Go to Section:

  31. Smooth endoplasmic reticulum Vacuole Ribosome (free) Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparatus Nucleus Mitochondrian Rough endoplasmic reticulum Figure 7-5 Plant and Animal Cells Section 7-2 Plant Cell Go to Section:

  32. Ribosome (attached) Ribosome (free) Nucleolus Nucleus Cell Membrane Nuclear envelope Mitochondrian Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus Figure 7-5 Plant and Animal Cells Section 7-2 Animal Cell Go to Section:

  33. Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Michondrion Figure 7-7 Cytoskeleton Section 7-2 Go to Section:

  34. Interest Grabber Section 7-3 In or Out? • How is a window screen similar to a cell membrane? Read on to find out. • 1. What are some things that can pass through a window screen? • 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? • 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell? Go to Section:

  35. Section Outline Section 7-3 • 7–3 Movement Through the Membrane A. Cell Membrane B. Diffusion C. Osmosis 1. How Osmosis Works 2. Osmotic Pressure D. Facilitated Diffusion E. Active Transport Go to Section:

  36. Introduction to Movement Through the Membrane • What types of things need to enter and leave the cell? • Are they all the same size? oxygen Carbon dioxide water proteins food

  37. Cell Membrane • Regulates what enters and leaves the cell, and also provides protection and support

  38. Carbohydrate chains Proteins Cell membrane Protein channel Lipid bilayer Figure 7-15 The Structure of the Cell Membrane Section 7-3 • Core is lipid bi-layer • Proteins form channels and pumps that help to • move material into and out of cell • Carbohydrates act as identification cards • (immune system). Outside of cell Inside of cell (cytoplasm) Go to Section:

  39. Diffusion – the way things move across the cell membrane • What is diffusion? It is the process by which molecules tend to move from an area of high concentration to an area of less concentration. • What is concentration? It is the mass of solute (solid) in a given volume of solution or mass/volume. • Example: Sugar water solution • 20 grams of sugar in 1 liter of water = 20 grams/Liter (more concentrated) • 10 grams of sugar in 1 liter of water = 10 grams/Liter (less concentrated) • The cytoplasm in the cell is a solution of water and other dissolved solutes (sugars, salts, etc.) How Diffusion Works

  40. Diffusion sugar High concentration of sugar 20 gram/Liter Cell membrane Low concentration of sugar 10 grams/Liter

  41. Osmosis – Diffusion of water • 8. Selectively Permeable – Some things can pass through and others cannot • Osmosis – Diffusion of water across a selectively permeable membrane. Example (oatmeal, raisin) • 10. False – water moves from high to low concentrations

  42. Figure 7-17 Osmosis Section 7-3 Water molecules Higher Concentration of Water Cell membrane Lower Concentration of Water Sugar molecules Go to Section:

  43. Today’s Outline • Transport across membrane without energy (Passive – High to Low) • Diffusion – particles from high to low • Osmosis – water from high to low • Facilitated Transport or Facilitated Diffusion • Transport across membrane with energy (Active – Low to High) • Active Transport • Pump • Endocytosis • Exocytosis

  44. What happened in your lab? • add the salt • B. Isotonic – the solution outside the cell is equal to the solution of the cytoplasm. Iso means the same. • Water will move equally in both directions. • No net movement across cell membrane. Isotonic solution

  45. What happened in your lab today? • A. Hypertonic – the solution outside the bag is “hyper” meaning it is above strength. Hyper means high so the solution is high in solute, low in water. • Water will move in both directions but more will move to an area of low concentration. This will cause the cell to lose water. • Just like your potato in salt water. Hypertonic solution More solute = less water

  46. What happened in lab today? • C. Hypotonic – the solution outside the bag is “hypo” meaning below strength. Hypo means below so the solution is low in solute and high in water. • Water will move in both directions but more will move inside the cell. Hypotonic solution

  47. High in solute Low in water. Same as inside the cell. Low in solute High in water Cell will swell Cell will not change Cell will shrink

  48. Diffusion and Osmosis through the cell membrane (small molecules such as H2O, O2, CO2) Cell membrane