Human-Physiology-Cell-Structure-function-I-lecture-31.July_.2012.ppt
- 1. Human Physiology: Cell Structure and Function Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html BY DR BOOMINATHAN Ph.D. M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGS, Israel), Ph.D (NUS, SINGAPORE) PONDICHERRY UNIVERSITY
- 2. Anatomy, physiology, … • Anatomy is the science of the structure • Physiology is the science of the function • Anatomy and physiology are closely linked, in particular physiology cannot be understood without anatomy • In many respects, both are ‘closed sciences’
- 3. Physiology • Some important moments: • 17th century: William Harvey first describes the closed circulation • 19th century: Claude Bernard formulates the modern version of homeostasis – the constancy of the internal milieu • 19th century: Johannes Muller formulates the ‘law of specific nerve energy’
- 4. Physiology • Some important moments: • 17th century: William Harvey first describes the closed circulation • 19th century: Claude Bernard formulates the modern version of homeostasis – the constancy of the internal milieu • 19th century: Johannes Muller formulates the ‘law of specific nerve energy’ • In general, a slow development of our modern view of the function of the body
- 5. Systems physiology: Missing from the scheme: Structure and motion: • Skeletal system • Muscles Integratory systems: • Nervous system • Hormones
- 6. Cell Structure & Function Source: http://koning.ecsu.ctstateu.edu/cell/cell.html
- 7. Unit-I Outline • Levels of Cellular Organization & function- Organelles, tissues, organs & systems. • Cell theory • Properties common to all cells • Cell size and shape – why are cells so small? • Prokaryotic cells • Eukaryotic cells – Organelles and structure in all eukaryotic cell – Organelles in plant cells but not animal • Cell junctions
- 8. History of Cell Theory • mid 1600s – Anton van Leeuwenhoek – Improved microscope, observed many living cells • mid 1600s – Robert Hooke – Observed many cells • 1850 – Rudolf Virchow – Proposed that all cells come from existing cells
- 9. 9 Cell Theory Cells were discovered in 1665 by Robert Hooke. Early studies of cells were conducted by - Mathias Schleiden (1838) - Theodor Schwann (1839) Schleiden and Schwann proposed the Cell Theory.
- 10. Cell Theory 1. All organisms consist of 1 or more cells. 2. Cell is the smallest unit of life. 3. All cells come from pre-existing cells.
- 11. Cell Theory • All living things are made up of cells. • Cells are the smallest working units of all living things. • All cells come from preexisting cells through cell division.
- 12. 12 Cell Theory Cell Theory 1. All organisms are composed of cells. 2. Cells are the smallest living things. 3. Cells arise only from pre-existing cells. All cells today represent a continuous line of descent from the first living cells.
- 13. 13 Cell Theory Cell size is limited. -As cell size increases, it takes longer for material to diffuse from the cell membrane to the interior of the cell. Surface area-to-volume ratio: as a cell increases in size, the volume increases 10x faster than the surface area
- 14. 14 Cell Theory
- 15. 15 Cell Theory Microscopes are required to visualize cells. Light microscopes can resolve structures that are 200nm apart. Electron microscopes can resolve structures that are 0.2nm apart.
- 16. 16 Cell Theory All cells have certain structures in common. 1. genetic material – in a nucleoid or nucleus 2. cytoplasm – a semifluid matrix 3. plasma membrane – a phospholipid bilayer
- 17. Definition of Cell A cell is the smallest unit that is capable of performing life functions.
- 18. Observing Cells (4.1) • Light microscope – Can observe living cells in true color – Magnification of up to ~1000x – Resolution ~ 0.2 microns – 0.5 microns
- 19. Observing Cells (4.1) • Electron Microscopes – Images are black and white – may be colorized – Magnifcation up to ~100,000 • Transmission electron microscope (TEM) – 2-D image • Scanning electron microscope (SEM) – 3-D image
- 20. SEM TEM
- 21. Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria
- 22. Two Types of Cells •Prokaryotic •Eukaryotic
- 23. Prokaryotic • Do not have structures surrounded by membranes • Few internal structures • One-celled organisms, Bacteria http://library.thinkquest.org/C004535/prokaryotic_cells.html
- 24. 24 Prokaryotic Cells Prokaryotic cells lack a membrane-bound nucleus. -genetic material is present in the nucleoid Two types of prokaryotes: -archaea -bacteria
- 25. 25 Prokaryotic Cells Prokaryotic cells possess -genetic material in the nucleoid -cytoplasm -plasma membrane -cell wall -ribosomes -no membrane-bound organelles
- 27. 27 Prokaryotic Cells Prokaryotic cell walls -protect the cell and maintain cell shape Bacterial cell walls -may be composed of peptidoglycan -may be Gram positive or Gram negative Archaean cell walls lack peptidoglycan.
- 28. 28 Prokaryotic Cells Flagella -present in some prokaryotic cells -used for locomotion -rotary motion propels the cell
- 29. Prokaryotic Cell Structure • Prokaryotic Cells are smaller and simpler in structure than eukaryotic cells. –Typical prokaryotic cell is __________ –Prokaryotic cells do NOT have: • Nucleus • Membrane bound organelles
- 30. Prokaryotic Cell
- 33. Eukaryotic • Contain organelles surrounded by membranes • Most living organisms Plant Animal http://library.thinkquest.org/C004535/eukaryotic_cells.html
- 36. 36 Eukaryotic Cells Eukaryotic cells -possess a membrane-bound nucleus -are more complex than prokaryotic cells -compartmentalize many cellular functions within organelles and the endomembrane system -possess a cytoskeleton for support and to maintain cellular structure
- 39. 39 Eukaryotic Cells Nucleus -stores the genetic material of the cell in the form of multiple, linear chromosomes -surrounded by a nuclear envelope composed of 2 phospholipid bilayers -in chromosomes – DNA is organized with proteins to form chromatin
- 41. 41 Eukaryotic Cells Ribosomes -the site of protein synthesis in the cell -composed of ribosomal RNA and proteins -found within the cytosol of the cytoplasm and attached to internal membranes
- 42. Cell Structure • All Cells have: –an outermost plasma membrane –genetic material in the form of DNA –cytoplasm with ribosomes
- 45. Cell Membrane • Outer membrane of cell that controls movement in and out of the cell • Double layer http://library.thinkquest.org/12413/structures.html
- 46. Cell Wall • Most commonly found in plant cells & bacteria • Supports & protects cells http://library.thinkquest.org/12413/structures.html
- 47. Inside the Cell
- 48. Nucleus • Directs cell activities • Separated from cytoplasm by nuclear membrane • Contains genetic material - DNA
- 49. Nuclear Membrane • Surrounds nucleus • Made of two layers • Openings allow material to enter and leave nucleus http://library.thinkquest.org/12413/structures.html
- 50. Chromosomes • In nucleus • Made of DNA • Contain instructions for traits & characteristics http://library.thinkquest.org/12413/structures.html
- 51. Nucleolus • Inside nucleus • Contains RNA to build proteins http://library.thinkquest.org/12413/structures.html
- 52. Cytoplasm • Gel-like mixture • Surrounded by cell membrane • Contains hereditary material
- 53. Endoplasmic Reticulum • Moves materials around in cell • Smooth type: lacks ribosomes • Rough type (pictured): ribosomes embedded in surface http://library.thinkquest.org/12413/structures.html
- 54. Ribosomes • Each cell contains thousands • Make proteins • Found on ribosomes & floating throughout the cell http://library.thinkquest.org/12413/structures.html
- 55. Mitochondria • Produces energy through chemical reactions – breaking down fats & carbohydrates • Controls level of water and other materials in cell • Recycles and decomposes proteins, fats, and carbohydrates http://library.thinkquest.org/12413/structures.html
- 56. Golgi Bodies • Protein 'packaging plant' • Move materials within the cell • Move materials out of the cell http://library.thinkquest.org/12413/structures.html
- 57. Lysosome • Digestive 'plant' for proteins, fats, and carbohydrates • Transports undigested material to cell membrane for removal • Cell breaks down if lysosome structure is disrupted. http://library.thinkquest.org/12413/structures.html
- 58. Vacuoles • Membrane-bound sacs for storage, digestion, and waste removal • Contains water solution • Help plants maintain shape http://library.thinkquest.org/12413/structures.html
- 59. Chloroplast • Usually found in plant cells • Contains green chlorophyll • Where photosynthesis takes place http://library.thinkquest.org/12413/structures.html
- 60. 1. Plasma Membrane • All membranes are phospholipid bilayers with embedded proteins • The outer plasma membrane –isolates cell contents –controls what gets in and out of the cell –receives signals
- 61. 2. Genetic material in the form of DNA –Prokaryotes – no membrane around the DNA (no nucleus) –Eukaryotes – DNA is within a membrane (there is nucleus)
- 62. 3. Cytoplasm with ribosomes –Cytoplasm – fluid area inside outer plasma membrane and outside DNA region –Ribosomes – make proteins
- 63. Cell Structure • All Cells have: –an outermost plasma membrane –genetic material in the form of DNA –cytoplasm with ribosomes
- 64. Why Are Cells So Small? (4.2) • Cells need sufficient surface area to allow adequate transport of nutrients in and wastes out. • As cell volume increases, so does the need for the transporting of nutrients and wastes.
- 65. Why Are Cells So Small? • However, as cell volume increases the surface area of the cell does not expand as quickly. – If the cell’s volume gets too large it cannot transport enough wastes out or nutrients in. • Thus, surface area limits cell volume/size.
- 66. Why Are Cells So Small? • Strategies for increasing surface area, so cell can be larger: –“Frilly” edged……. –Long and narrow….. • Round cells will always be small.
- 67. Eukaryotic Cells • Structures in all eukaryotic cells – Nucleus – Ribosomes – Endomembrane System • Endoplasmic reticulum – smooth and rough • Golgi apparatus • Vesicles – Mitochondria – Cytoskeleton
- 68. CYTOSKELETON MITOCHONDRION CENTRIOLES LYSOSOME GOLGI BODY SMOOTH ER ROUGH ER RIBOSOMES NUCLEUS PLASMA MEMBRANE Fig. 4-15b, p.59 VESICLE CYTOPLASM
- 69. Nucleus (4.5) • Function – isolates the cell’s genetic material, DNA – DNA directs/controls the activities of the cell • DNA determines which types of RNA are made • The RNA leaves the nucleus and directs the synthesis of proteins in the cytoplasm at a ______________
- 70. Nucleus • Structure –Nuclear envelope • Two Phospholipid bilayers with protein lined pores –Each pore is a ring of 8 proteins with an opening in the center of the ring –Nucleoplasm – fluid of the nucleus
- 71. Nuclear pore bilayer facing cytoplasm Nuclear envelope bilayer facing nucleoplasm Fig. 4-17, p.61
- 72. Nucleus • DNA is arranged in chromosomes –Chromosome – fiber of DNA with proteins attached –Chromatin – all of the cell’s DNA and the associated proteins
- 73. Nucleus • Structure, continued –Nucleolus • Area of condensed DNA • Where ribosomal subunits are made – Subunits exit the nucleus via nuclear pores
- 74. ADD THE LABELS
- 75. Endomembrane System (4.6 – 4.9) • Series of organelles responsible for: –Modifying protein chains into their final form –Synthesizing of lipids –Packaging of fully modified proteins and lipids into vesicles for export or use in the cell –And more that we will not cover!
- 76. Structures of the Endomembrane System • Endoplasmic Reticulum (ER) –Continuous with the outer membrane of the nuclear envelope –Two forms - smooth and rough • Transport vesicles • Golgi apparatus
- 78. Endoplasmic Reticulum (ER) –The ER is continuous with the outer membrane of the nuclear envelope –There are 2 types of ER: • Rough ER – has ribosomes attached • Smooth ER – no ribosomes attached
- 79. Endoplasmic Reticulum • Rough Endoplasmic Reticulum (RER) • Network of flattened membrane sacs create a “maze” – RER contains enzymes that recognize and modify proteins • Ribosomes are attached to the outside of the RER and make it appear rough
- 80. Endoplasmic Reticulum • Function RER • Proteins are modified as they move through the RER • Once modified, the proteins are packaged in transport vesicles for transport to the Golgi body
- 81. Endomembrane System • Smooth ER (SER) – Tubular membrane structure – Continuous with RER – No ribosomes attached • Function SER – Lipids are made inside the SER • fatty acids, phospholipids, sterols.. – Lipids are packaged in transport vesicles and sent to the Golgi
- 82. 82 Endomembrane System Vacuoles -membrane-bound structures with various functions depending on the cell type There are different types of vacuoles: -central vacuole in plant cells -contractile vacuole of some protists -vacuoles for storage
- 83. 83 Endomembrane System Endomembrane system -a series of membranes throughout the cytoplasm -divides cell into compartments where different cellular functions occur 1. endoplasmic reticulum 2. Golgi apparatus 3. lysosomes
- 84. 84 Endomembrane System Rough endoplasmic reticulum (RER) -membranes that create a network of channels throughout the cytoplasm -attachment of ribosomes to the membrane gives a rough appearance -synthesis of proteins to be secreted, sent to lysosomes or plasma membrane
- 85. 85 Endomembrane System Smooth endoplasmic reticulum (SER) -relatively few ribosomes attached -functions: -synthesis of membrane lipids -calcium storage -detoxification of foreign substances
- 87. 87 Endomembrane System Golgi apparatus -flattened stacks of interconnected membranes -packaging and distribution of materials to different parts of the cell -synthesis of cell wall components
- 88. 88
- 89. 89 Endomembrane System Lysosomes -membrane bound vesicles containing digestive enzymes to break down macromolecules -destroy cells or foreign matter that the cell has engulfed by phagocytosis
- 90. 90
- 91. 91 Endomembrane System Microbodies -membrane bound vesicles -contain enzymes -not part of the endomembrane system -glyoxysomes in plants contain enzymes for converting fats to carbohydrates -peroxisomes contain oxidative enzymes and catalase
- 92. Golgi Apparatus • Golgi Apparatus – Stack of flattened membrane sacs • Function Golgi apparatus – Completes the processing substances received from the ER – Sorts, tags and packages fully processed proteins and lipids in vesicles
- 94. Golgi Apparatus • Golgi apparatus receives transport vesicles from the ER on one side of the organelle – Vesicle binds to the first layer of the Golgi and its contents enter the Golgi
- 95. Golgi Apparatus – The proteins and lipids are modified as they pass through layers of the Golgi – Molecular tags are added to the fully modified substances • These tags allow the substances to be sorted and packaged appropriately. • Tags also indicate where the substance is to be shipped.
- 96. Golgi Apparatus
- 97. Transport Vesicles • Transport Vesicles – Vesicle = small membrane bound sac – Transport modified proteins and lipids from the ER to the Golgi apparatus (and from Golgi to final destination)
- 98. Endomembrane System • Putting it all together –DNA directs RNA synthesis RNA exits nucleus through a nuclear pore ribosome protein is made proteins with proper code enter RER proteins are modified in RER and lipids are made in SER vesicles containing the proteins and lipids bud off from the ER
- 99. Endomembrane System • Putting it all together ER vesicles merge with Golgi body proteins and lipids enter Golgi each is fully modified as it passes through layers of Golgi modified products are tagged, sorted and bud off in Golgi vesicles …
- 100. Endomembrane System • Putting it all together Golgi vesicles either merge with the plasma membrane and release their contents OR remain in the cell and serve a purpose
- 101. Vesicles • Vesicles - small membrane bound sacs – Examples • Golgi and ER transport vesicles • Peroxisome – Where fatty acids are metabolized – Where hydrogen peroxide is detoxified • Lysosome – contains digestive enzymes – Digests unwanted cell parts and other wastes
- 102. Lysosomes (4.10) • The lysosome is an example of an organelle made at the Golgi apparatus. – Golgi packages digestive enzymes in a vesicle. The vesicle remains in the cell and: • Digests unwanted or damaged cell parts • Merges with food vacuoles and digest the contents • Figure 4.10A
- 103. Lysosomes (4.11) • Tay-Sachs disease occurs when the lysosome is missing the enzyme needed to digest a lipid found in nerve cells. – As a result the lipid accumulates and nerve cells are damaged as the lysosome swells with undigested lipid.
- 104. Mitochondria (4.15) • Function – synthesis of ATP – 3 major pathways involved in ATP production 1. Glycolysis 2. Krebs Cycle 3. Electron transport system (ETS)
- 105. Mitochondria • Structure: – ~1-5 microns – Two membranes • Outer membrane • Inner membrane - Highly folded – Folds called cristae – Intermembrane space (or outer compartment) – Matrix • DNA and ribosomes in matrix
- 106. Mitochondria
- 107. Mitochondria (4.15) • Function – synthesis of ATP – 3 major pathways involved in ATP production 1. Glycolysis - cytoplasm 2. Krebs Cycle - matrix 3. Electron transport system (ETS) - intermembrane space
- 108. Mitochondria TEM
- 110. 110 Mitochondria Mitochondria -organelles present in all types of eukaryotic cells -contain oxidative metabolism enzymes for transferring the energy within macromolecules to ATP -found in all types of eukaryotic cells
- 111. 111 Mitochondria -surrounded by 2 membranes -smooth outer membrane -folded inner membrane with layers called cristae -matrix is within the inner membrane -intermembrane space is located between the two membranes -contain their own DNA
- 112. 112 Mitochondria