1 / 98

Biology

lottie
Download Presentation

Biology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Chapter 5 Biology

    2. Cells Make Up Living Things

    4. Cell Theory 1. All organisms are made up of cells. 2. Cells are the smallest units of life 3. Cells are the primary structural and functional units of all organisms. 4. Cells are capable of self-reproduction.

    5. Louis Pasteur Ch. 26

    6. Cells Are Small How big is a FOOT? Cells range in size from a frog's egg (one millimeter) down to one micrometer or less.

    9. Why are Cells small? 1. Cells need surface area of plasma membrane large enough to adequately exchange materials.  2. Surface-area-to-volume ratio requires that cells be small.

    11. How do we see Cells? 1. Light microscope uses light rays focused by glass lenses.  2. Electron microscope uses electrons focused by magnets.

    13. Revolution in Optics New glass-making techniques were introduced by Italians in the 1590s Antony van Leeuwenhoek (1632-1723) Robert Hooke (1635-1703) Galileo Galilei (1564-1642)

    14. Microscopy of Today  Magnification is the increase in apparent size of an object  Resolution is minimum distance between two objects before they are seen as one larger object.

    25. Prokaryotic Cells

    27. Prokaryotic Cells are relatively simple 1. Bacteria are prokaryotic cells 2. 1-10 um in diameter, just visible with light microscopes. 3. Metabolically diverse. 4. No True Nucleus

    31. Procaryotic Structure - Plasma membrane is the outermost membrane; regulates the entrance and exit of molecules. - Cell wall is for structural support. - Bacteria may be surrounded by a capsule and/or gelatinous sheath called a slime layer. - Motile bacteria usually have flagella, which rotate like propellers to move through fluid medium. - Fimbriae are short appendages that help them attach to an appropriate surface.

    33. Procaryotic Structure  Cytoplasm consists of cytosol, a semifluid medium.  Ribosomes are granular inclusions that coordinate synthesis of proteins.  Nucleoid contains most genes in a circular DNA molecule.  Plasmids are small accessory rings of DNA aside from the nucleoid.  Thylakoids are flattened discs with light-sensitive pigment molecules

    36. Eukaryotic cells

    38. Cellular Components

    40. Compartmentalization Why are there organelles? Optimization of process. Protection of processes. Specificity of processes.

    42. Eukaryotic Cells Components Cell Wall contains cellulose support and protection Cell membrane / Plasma membrane Phospholipid bilayer with embedded proteins boundary layer and transport Nucleus nuclear envelope, nucleoplasm, chromatin, nucleoli storage and synthesis of genetic material. Nucleolus chromatin, RNA and proteins Ribosome formation

    43.   d. Nucleoplasm is semifluid medium of nucleus; has a different pH from cytosol.  e. Nucleoli are dark-staining spherical bodies in nucleus; sites where rRNA joins proteins to form ribosomes.  f. Nuclear envelope is a double membrane that separates nucleoplasm from cytoplasm.  g. Nuclear pores (100 nm) permit passage of proteins into nucleus and ribosomal subunits.

    48. Eukaryotic Cells Components Ribosomes protein and RNA in 2 subunits protein synthesis Endoplasmic Reticulum (ER) membranous flattened channels and tubular canals site of protein synthesis and other substances transport products in vessicles

    50. The Endomembrane System   a. Endoplasmic Reticulum (ER) is system of membranous channels continuous with outer membrane of the nuclear envelope.   b. Rough ER is studded with ribosomes; is site where proteins are synthesized and enter the ER interior for processing and modification.  c. Smooth ER is continuous with rough ER, but lacks ribosomes; site of various synthetic processes, detoxification, and storage; smooth ER forms transport vesicles.

    51. Ribosomes Are Sites of Protein Synthesis 1. Ribosomes of eukaryotic cells are 20 nm by 30 nm; those of prokaryotic cells are slightly smaller.  2. Ribosomes are composed of a large and a small subunits 3. Each subunit has its own mix of proteins and rRNA.  4. Ribosomes coordinate assembly of amino acids into polypeptide chains (i.e., protein synthesis).  5. Polyribosomes are several ribosomes synthesizing same protein; may be attached to ER or may lie free.

    52. How do we know all this?

    55. Eukaryotic Cells Components Golgi apparatus membranous sacs process, package and distribute proteins and lipids Vacuoles and vesicles membranous sacs storage Lysosomes membranous vesicles digestive enzymes for intracellular digestion Peroxisomes membranous vesicles specific enzymes for metabolic tasks

    57. Vacuoles a. A vacuole is a large membranous sac; vesicles are smaller than vacuoles.  b. More prominent plant cell vacuoles (usually one or two) are water filled and give support to cell.  c. Plant vacuoles store water, sugars, salts, pigments and toxic substances to protect plant from herbivores.  d. Vacuoles in protozoa include digestive vacuoles and water-regulating contractile vacuoles.

    59. Eukaryotic Cells Components Mitochondria membranous cristae, bound by outer membrane cellular respiration Chloroplast membranous grana, bound by two membranes photosynthesis Cytoskeleton microtubules, intermediate and actin filaments cell shape and movement Cilia and Flagella 9+2 arrangement of microtubules, movement of cell Centriole 9+0 arrangement of microtubules, formation of basal bodies

    60. Energy-Related Organelles Chloroplasts and Mitochondria

    63. 6CO2 + 6H2O ?? C6H12O6 + O2 glucose

    66. Chloroplasts  Chloroplast is bounded by a double membrane organized into flattened sacs (thylakoids) piled into stacks called grana with a fluid-filled space around thylakoids called the stroma.  Chlorophyll is located within the thylakoid membranes.  The stroma contains enzymes that catalyze reactions involved in synthesis of carbohydrates.  There are no chloroplasts in cyanobacteria; chlorophyll is bound to cytoplasmic thylakoids.

    67. Chloroplast structure

    70. Mitochondria are sites of cellular respiration 0.5-1.0 µm in diameter and 7 µm in length. double membrane; inner membrane has folds (cristae) that project into inner space (matrix) with enzymes that break down carbohydrate-derived products; ATP production occurs at cristae.  e. Mitochondria contain ribosomes and their own DNA that specifies some proteins; other proteins are coded by nucleus DNA.

    72. Mitochondrial structure

    74. Cytoskeleton Contains Filaments and Microtubules Maintain cell shape Allows organelles to move. Elements can disassemble and reassemble

    80. Cytoskeleton Centrosome and Centrioles Cilia and Flagella Actin filaments (7 nm) Intermediate Filaments (8-11 nm) Microtubules (25 nm)

    81. Actin Filaments for Structure and Movement a. Long, thin fibers (7 nm) that occur in bundles or meshlike networks. b. Actin filaments in microvilli of intestinal cells likely shorten or extend cell into intestine. c. In plant cells, they form tracts along which chloroplasts circulate. d. Similar action accounts for pinching off cells during cell division and for amoeboid movement

    83. Intermediate Filaments   a. 8-11 nm in diameter   b. They are rope-like assemblies of fibrous polypeptides.   c. Some support nuclear envelope, others support plasma membrane, form cell-to-cell junctions.  

    85. Microtubules a. Small hollow cylinders (25 nm & 200 nm-25 µm in length). b. Microtubules are composed of a globular protein - tubulin. c. Regulation of microtubule assembly is under control of a microtubule organizing center MTOC: a centrosome.

    87. Centrioles a. Centrosome contains two centrioles lying at right angles to each other.  b. Centrioles are short cylinders with a 9 + 0 pattern of microtubule triplets.  c. Centrioles serve as basal bodies for cilia and flagella. d. Plant and fungal cells have equivalent of a centrosome but it does not contain centrioles.

    90. Cilia and Flagella a. Cilia are short, usually numerous hairlike projections that can move in an undulating fashion (e.g., Paramecium, lining of human upper respiratory tract).   b. Flagella are longer, usually fewer, whip-like projections that move in whip-like fashion (e.g., sperm cells).  c. Both have similar construction, but differ from prokaryotic flagella.

    94. Cilia and Flagella  1) Cylinder of nine pairs of microtubules encircling two singe microtubules (9 + 2 pattern of microtubules).  2) Cilia and flagella move when the microtubules slide past one another.  3) Cilia and flagella have basal body at base with same arrangement of microtubule triples as centrioles.  4) Cilia and flagella grow by the addition of tubulin dimers to their tips.

    98. The End.

More Related