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B 1

  1. 1. Cell Structures Unit B1 Analyse the functional interrelationships of cell structures
  2. 2. Students who have fully met the prescribed learning outcomes (PLO’s) are able to: <ul><li>B1. Analyze the functional interrelationships of cell structures. </li></ul><ul><li>Describe the following cell structures and their functions: </li></ul><ul><ul><li>cell membrane </li></ul></ul><ul><ul><li>cell wall </li></ul></ul><ul><ul><li>chloroplast </li></ul></ul><ul><ul><li>cytoskeleton </li></ul></ul><ul><ul><li>cytoplasm </li></ul></ul><ul><ul><li>Golgi bodies </li></ul></ul><ul><ul><li>lysosomes </li></ul></ul><ul><ul><li>mitochondria, cristae and matrix </li></ul></ul><ul><ul><li>nucleus, nuclear pore, nucleolus, chromatin, nuclear envelope, and chromosomes </li></ul></ul><ul><ul><li>smooth and rough endoplasmic reticulum </li></ul></ul><ul><ul><li>ribosomes (polysomes) </li></ul></ul><ul><ul><li>vacuoles </li></ul></ul><ul><ul><li>vesicles </li></ul></ul>
  3. 4. Also….. <ul><li>State the balanced chemical equation for cellular respiration. </li></ul><ul><li>C 6 H 12 O 6 (aq) + 6O 2 (g) -> 6CO 2 (g) + 6H 2 O (l) </li></ul>
  4. 5. And… <ul><li>Describe how the following organelles function to compartmentalize the cell and move materials through it: </li></ul><ul><li>-Rough and smooth endoplasmic reticulum </li></ul><ul><li>-Vesicles </li></ul><ul><li>-Golgi bodies </li></ul><ul><li>-Cell membrane </li></ul>
  5. 6. Lastly…. <ul><li>Identify cell structures depicted in diagrams and electron micrographs . </li></ul>
  6. 7. So lets begin… <ul><li>Cell Membrane </li></ul><ul><ul><li>The “gatekeeper” of the cell; Composed of a flexible phospholipid bilayer with protein molecules partially or entirely embedded; Carbohydrate chains (composed of C 6 H 12 O 6 ) attached to proteins and lipids on the outside of the membrane are called glycoproteins and glycolipids . </li></ul></ul>
  7. 9. Cell Membrane <ul><li>Functions: only 4 for now. </li></ul><ul><ul><li>Separates contents of cell from environment. </li></ul></ul><ul><ul><li>Regulates entrance/exit of molecules via diffusion, osmosis, endocytosis, exocytosis, phagocytosis and/or pinocytosis. </li></ul></ul><ul><ul><li>Cell recognition of foreign cells and microorganisms by glycoproteins or glycolipids. </li></ul></ul><ul><ul><li>Compartmentalizes or divides cell to serve as partitions, or regions for specific reactions within the cell. </li></ul></ul>
  8. 11. Cell Wall <ul><li>Function: provides support and rigidity </li></ul>
  9. 12. Chloroplasts
  10. 13. Chloroplasts <ul><li>Found in plants and algae containing the pigment, chlorophyll </li></ul><ul><li>Contains its own DNA </li></ul><ul><li>Bound by a double phospholipid membrane; consists of flattened membranous sacs and fluid. </li></ul>
  11. 14. Chloroplasts <ul><li>Function: </li></ul><ul><ul><li>Site of photosynthesis </li></ul></ul><ul><ul><li>Converts sun energy into glucose </li></ul></ul>
  12. 16. Cytoskeleton <ul><li>Cyto – Greek for “cell” </li></ul><ul><li>3-D network of protein fibres connected to most organelles </li></ul><ul><ul><li>Microtubules (tubulin) </li></ul></ul><ul><ul><li>Microfilaments (actin) </li></ul></ul>
  13. 17. Microtubules
  14. 18. Actin (red) and Microtubules (green)
  15. 19. Microtubules
  16. 20. So what does the cytoskeleton do? <ul><li>FUNCTIONS: </li></ul><ul><li>Provides framework within cytoplasm for organelle movement </li></ul><ul><li>Provides support for cell shape </li></ul><ul><li>Provides for movement of substances within cells </li></ul><ul><li>Cellular motility </li></ul>
  17. 21. Cytoplasm <ul><li>Also called: Cytosol </li></ul><ul><li>Remember….”cyto”?.......cell </li></ul><ul><li>Well “plasm” means “fluid substance” </li></ul><ul><li>Jelly Like </li></ul><ul><ul><li>Compartments bounded by cell membrane </li></ul></ul><ul><li>Contains: water, many organelles, dissolved gasses, ions, enzymes, proteins, nucleotides, amino acids, sugars, carbohydrates, organic molecules, etc. </li></ul>
  18. 23. Cytoplasm <ul><li>FUNCTIONS: </li></ul><ul><li>Compartments allow metabolic reactions to occur and suspends organelles </li></ul><ul><li>Assists in the production and distribution of molecules via compartmentalization </li></ul><ul><ul><li>Helps materials move around the cell by moving and churning through cytoplasmic streaming </li></ul></ul><ul><li>The first phase of energy production (glycolysis) takes place here </li></ul>
  19. 24. Golgi bodies/apparatus <ul><li>Consists of 6 or more stacked, flattened membranous sacs called “saccules”. </li></ul><ul><ul><li>One side faces the nucleus and the ER and the other side faces the cell membrane. </li></ul></ul><ul><li>Small membranous sacs occur at edges called vesicles . </li></ul><ul><li>Function: </li></ul><ul><ul><li>Modifies/process , packages , stores and distributes proteins produced by ribosomes on ER into vesicles to be exported or transported to other sites in the cell, e.g. hydrolytic enzymes (proteins) into lysosomes. </li></ul></ul><ul><li>Vesicle video </li></ul>
  20. 25. Golgi bodies
  21. 27. Golgi Bodies
  22. 28. Golgi Bodies Function
  23. 30. Vesicles <ul><li>Small membrane-enclosed sacs that are pinched off portions of membranes moving from the site of one membrane to another </li></ul><ul><li>(Note: the flexibility of the phospholipid bilayer allows for this to occur). </li></ul>
  24. 31. Vesicles <ul><li>Cellular processes which make use of vesicles include the following: </li></ul><ul><ul><li>autolysis, intracellular digestion, pinocytosis and phagocytosis, packaging of neurotransmitters and viruses, storage of Ca 2+ in muscle cells or macromolecules in liver & muscle cells and plant cells, production of cell products in the rER and sER, storage and modification of cell products from Golgi bodies, detoxification of alcohol and drugs into H 2 O-soluble products, and breaking down H 2 O 2 (hydrogen peroxide: a toxic byproduct made by many enzymes) into H 2 O + O 2 via the enzyme catal ase (i.e. in peroxisomes) located in the liver </li></ul></ul>
  25. 32. Two types of vesicles <ul><li>Secretory </li></ul><ul><ul><li>Membrane-bound sacs/vesicles contains products/molecules for secretion, e.g. proteins (enzymes, keratin, collagen, hemoglobin, membrane proteins etc.), enzymes (DNA/RNA polymerase, hydrolytic enzymes, amylase, pepsin, maltase, etc.), hormones (testosterone, estrogen, thyroxin etc.), phospholipids and steroids (sex hormones, aldosterone etc.) produced and released from ribosomes/rER and sER to the Golgi bodies. </li></ul></ul><ul><ul><li>Function </li></ul></ul><ul><ul><li>Modified and repackaged proteins, steroids, hormones etc. from Golgi body are taken in secretory vesicles to the cell membrane for secretion via exocytosis . </li></ul></ul>
  26. 37. <ul><li>Lysosome </li></ul><ul><li>Membrane-bound sacs/vesicles formed by Golgi apparatus, which contain hydrolytic enzymes . </li></ul><ul><ul><li>Hydrolytic enzymes break down polymers into monomers/unit molecules </li></ul></ul><ul><li>Functions </li></ul><ul><li>Destruction of cells by hydrolytic enzymes during development and metamorphosis, i.e. “suicide bags”. </li></ul><ul><li>Used for intracellular digestion of food-filled vesicles/vacuoles by hydrolytic enzymes into simple molecules/monomers, e.g. polypeptides into amino acids. </li></ul><ul><li> 4 H 2 O + ○-○-○-○-○ + hydrolytic enzymes  ○ ○ ○ </li></ul><ul><li>○ ○ </li></ul><ul><li>Auto digestion of damaged/worn cell parts by hydrolytic enzymes for recycling, e.g. mitochondria, red blood cells etc. </li></ul>
  27. 38. Lysosome Function
  28. 40. Lysosome
  29. 42. Vacoule <ul><li>Vacuole </li></ul><ul><li>A larger membrane-enclosed sac. </li></ul><ul><li>Function </li></ul><ul><li>Storage of macromolecules such as a food vacuole formed by phagocytosis. </li></ul><ul><li>Storage of water and/or waste products. </li></ul>
  30. 44. Mitochondria <ul><li>The “ powerhouse ” of the cell </li></ul><ul><ul><li>Membrane-bound organelle with its own DNA (deoxyribonucleic acid, i.e. mDNA (mitochondrial DNA) </li></ul></ul><ul><ul><li>Contains 2 membranes: an inner folded/convoluted membrane called cristae and a smooth outer membrane. </li></ul></ul><ul><ul><li>The matrix is the inner fluid-filled space containing DNA, RNA, ribosomes, proteins, enzymes, H+/protons etc. (Note: membranes are also composed of phospholipids and proteins) </li></ul></ul>
  31. 45. Mitochondria <ul><li>Function </li></ul><ul><ul><li>Undergoes process of aerobic cellular respiration . See balanced chemical equation below. (Mitochondria are very active and numerous in muscle cells, cardiac cells, neuron cells, sperm cells and proximal and distal convoluted tubule cells of the nephron/kidney). </li></ul></ul><ul><ul><li>enzymes </li></ul></ul><ul><ul><li>C 6 H 12 O 6 + 6O 2  6H 2 O + ATP + 6CO 2 </li></ul></ul>
  32. 46. Aerobic cellular respiration <ul><li>C 6 H 12 O 6 + 6O 2  6H 2 O + ATP + 6CO 2 </li></ul><ul><ul><li>C 6 H 12 O 6 = glucose/carbohydrate </li></ul></ul><ul><ul><li>ATP = A denosine t ri p hosphate </li></ul></ul><ul><ul><ul><li>The cells energy source for cellular activities such as: cellular respiration, DNA replication, protein synthesis, hydrolysis & dehydration syntheses, enzymatic reactions, active transport, endo/exocytosis, pino/phagocytosis, nerve transmission, Na+/K+ pumps, cellular detoxification, sperm motility, organelle movement, muscle contraction etc. </li></ul></ul></ul>
  33. 47. Mitochondria <ul><li>Cristae – the folds </li></ul><ul><ul><li>increases surface area for cellular respiration and the production of ATP with the aid of several proteins and complexes (e.g. ATP complexes, transport proteins/electron transport chains). </li></ul></ul>
  34. 48. Mitochondria <ul><li>Matrix – the space between the folds </li></ul><ul><ul><li>Assists in the chemical production of ATP/the metabolic/oxidative breakdown of C 6 H 12 O 6 via several enzymes. </li></ul></ul><ul><ul><li>Contains mitochondrial DNA, RNA, ribosomes, proteins, enzymes etc. necessary for their own protein synthesis. </li></ul></ul><ul><ul><li>Enzymes = proteins that are required to catalyze/speed up the rate of reaction. </li></ul></ul>
  35. 49. Nucleus <ul><li>Large membrane-bound organelle consisting of two layers of phospholipids similar to the cell membrane; contains the chromatin/ chromosomes of the cell. </li></ul><ul><li>Functions: </li></ul><ul><li>Stores genetic information as DNA (deoxyribonucleic acid). </li></ul><ul><li>Contains genetic information for making proteins. </li></ul><ul><li>Controls all cellular activities and protein synthesis </li></ul>
  36. 52. Nuclear envelope/membrane and nuclear pores <ul><li>Double membrane consisting of phospholipids and many protein pores / nuclear pores surrounding the nucleus. </li></ul><ul><li>Functions: </li></ul><ul><ul><li>Forms a boundary separating contents of nucleus from cytoplasm. </li></ul></ul><ul><ul><li>Allows transfer of molecules between nucleolus and cytoplasm through the nuclear pores , e.g. nucleotides, mRNA, rRNA and proteins/enzymes. </li></ul></ul>
  37. 55. Nucleolus <ul><li>Found within the nucleus; consists of 2 or more darker, spherical bodies in non-dividing cells. </li></ul><ul><li>Contains rRNA (ribosomal ribonucleic acid), proteins and ribosomal DNA. </li></ul><ul><li>Function: </li></ul><ul><ul><li>Ribosome synthesis (produces rRNA which is a necessary subunit for the formation of ribosomes). </li></ul></ul>
  38. 57. Chromatin <ul><li>Chromatin are masses of fine fibres (long, double-stranded molecule of DNA and proteins) in the nucleus of a non-dividing cell. </li></ul><ul><li>Function: </li></ul><ul><ul><li>Contains all the genetic information that condenses during cell division to make chromosomes. </li></ul></ul>
  39. 60. Chromosome <ul><li>Chromosomes are rod-like, coiled structures composed of chromatin fibres found within the nucleus . </li></ul><ul><li>Chromosomes remain condensed and visible in the nucleus just prior to cell division. </li></ul><ul><li>Humans have 46 chromosomes except in gamete cells. </li></ul><ul><li>Function: </li></ul><ul><ul><li>Contains all the genetic information in triplet codes, </li></ul></ul><ul><li> e.g. CAT GAG TCA. </li></ul>
  40. 63. Ribosomes <ul><li>Made of 2 sub-units, rRNA (ribosomal RNA) and proteins and therefore are not membrane-bound. </li></ul><ul><li>rRNA sub-unit is produced by the nucleolus. </li></ul><ul><li>They may be free, i.e. suspended in the cytoplasm or attached to the rough endoplasmic reticulum. </li></ul><ul><li>Function </li></ul><ul><ul><li>Site of protein synthesis . Produces secretory proteins or polypeptides, such as enzymes (as they are required for all chemical reactions), Hb, glycoproteins etc (See Unit B4). </li></ul></ul>
  41. 64. 1 = large sub-unit 2 = small sub-unit
  42. 69. Polysomes <ul><li>A linear collection of several ribosomes attached to one mRNA. </li></ul><ul><li>Function: </li></ul><ul><ul><li>Produces many copies of polypeptides (via protein synthesis) when attached to the mRNA, e.g. the protein pigment Hb (hemoglobin) is formed by polysomes. </li></ul></ul>
  43. 71. Endoplasmic reticulum <ul><li>Consists of tubular canals that attaches to the nuclear envelope and branch out throughout the cytoplasm thus increasing surface area. Most eukaryotic cells contain ER. </li></ul><ul><li>There are 2 types: smooth and rough </li></ul>
  44. 72. Smooth Endoplasmic Reticulum <ul><li>Appears smooth because it lacks ribosomes. </li></ul><ul><li>Abundant in testes (interstitial cells), ovaries, adrenal glands and liver. </li></ul><ul><li>Functions: </li></ul><ul><ul><li>Synthesizes sex hormones (e.g. testosterone, estrogen)/steroids, aldosterone, membrane lipids (phospholipids, i.e. assembly of glycerol and fatty acids) and packages them into vesicles. </li></ul></ul><ul><ul><li>Detoxifies alcohol, drugs and poisons in the liver with the help of enzymes into H 2 O-soluble products. </li></ul></ul>
  45. 74. Rough Endoplasmic Reticulum <ul><li>Have ribosomes (produced by nucleolus) attached to an extensive membranous network of tubules and sacs. </li></ul><ul><li>Abundant in villi (small intestines) for the production of digestive enzymes, red bone marrow for RBC and WBC production etc. </li></ul><ul><li>Funtion: </li></ul><ul><ul><li>Attached ribosomes produce proteins, which are then transported throughout the cell in tubules/canals to be exported out. </li></ul></ul>
  46. 77. For some extra fun…. <ul><li>There are a few additional structures to know. </li></ul>
  47. 78. Cilia and Flagella <ul><li>Cilia are short organelles and more numerous than flagella. </li></ul><ul><ul><li>E.g. they line the nasal passageway and respiratory tract, sweeping the mucus & trapped foreign materials. In the fallopian tube, cilia help to sweep the egg along. (See C8 &15) </li></ul></ul><ul><li>Flagella are long, hair like organelles which permit movement for sperm cells. </li></ul>
  48. 79. Cilia line the upper respiratory tract (400x)
  49. 80. Flagella
  50. 81. Microvilli <ul><li>Microscopic finger-like extensions of the cell membrane composed of cytoskeleton filaments. </li></ul><ul><li>Function: </li></ul><ul><ul><li>To increase surface area for absorption and secretion of molecules and enzymatic activity. E.g. abundant in epithelial cells of intestinal villi, and proximal convoluted tubule cells of the nephron/kidney. (See C1 & 13) </li></ul></ul><ul><li>Note: all the above structures require the use of ATP. </li></ul>
  51. 83. Time to get creative!!
  52. 84. Cell Compartmentalization <ul><li>Movement video </li></ul>
  53. 86. How it works…. <ul><li>The cell is divided into several compartments containing organelles & enzymes. This increases the surface area for each compartment to perform specific functions and thus become specialized. </li></ul><ul><li>*-The following membrane-bound structures, nucleus / nuclear envelope , ER (rough and smooth), Golgi bodies , vesicles , vacuoles and lysosomes , have a functional interrelationship. They function together in the synthesis and transport of molecules within the cell or for export out of the cell. For example, the production, distribution and secretion of a protein such as enzymes, hemoglobin, keratin, collagen etc. See the following description and diagram: </li></ul>
  54. 87. <ul><li>1.) Nucleus contains genetic code for a protein. </li></ul><ul><li>2.) Ribosomes produce proteins (protein synthesis). </li></ul><ul><li>3.) Rough ER temporarily stores proteins or enzymes (made by ribosomes) in the tubules, travels through the ER, and pinches off to form vesicles . </li></ul>
  55. 88. <ul><li>4.) Vesicles migrate (assisted by microtubules/cytoskeleton ) to the Golgi bodies from the ER and the Golgi modifies and repackages proteins into another vesicle . Depending on the substances within the vesicle, it can be……. </li></ul><ul><li>5a.) Secretory vesicles containing secretory proteins are moved by microtubules/cytoskeleton to the cell membrane . Vesicles fuse with cell membrane and release the proteins through exocytosis OR, </li></ul>
  56. 89. <ul><li>b.) Lysosome vesicles containing hydrolytic enzymes (proteins) are retained in the cell to fuse with a food vacuole/vesicle (cell membrane folds in and around food/molecules producing a vacuole/vesicle through endocytosis ) and breaks down the macromolecules into smaller molecules, i.e. intracellular digestion . </li></ul><ul><li>http://highered.mcgraw-hill.com/olc/dl/120067/bio01.swf </li></ul>
  57. 90. For more review <ul><li>Links: </li></ul><ul><li>http://www.coolschool.ca/lor/BI12/unit3/U03L01.htm (Work through the Biocoach/Cell Structure & Ftn/Concept 3: Features of Eukaryotic Cell; Practice, Review & Self-Quiz) </li></ul><ul><li>http://www.cellsalive.com/cells/3dcell.htm (Interactive Animal & Plant Cell Animations) </li></ul><ul><li>http://www.ibiblio.org/virtualcell/textbook/chapter3/chapter3.htm (A terrific Virtual Cell web page) </li></ul><ul><li>http:// www.sirinet.net/~jgjohnso/biologyI.html (Great links, reviews, diagrams, etc.) </li></ul>
  58. 91. Yeeehaaaaa <ul><li>You are done with Unit B1!! </li></ul><ul><li>Review and study hard!! </li></ul>