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Life

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Nomenclature semi-systematic. Hepatitis A Virus, HAV. Need host cell for replication ... Standard Linnean nomenclature: Genus species. Bacterial types. Gram ... – PowerPoint PPT presentation

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Title: Life


1
Life
  • Individual survival
  • Reproduction

2
US
Vertebrates
Invertebrates
Plants
Animals
Algae
Fungi
Protozoa
Single-celled
Archaea
Bacteria
UCA
3
Cell Functions
  • Maintenance
  • Recovery of energy from nutrients
  • Storage of energy
  • Synthesis of correct proteins and other cell
    components
  • Perpetuation of self
  • DNA replication
  • Cell division
  • Specialized functions
  • e.g. muscle, blood, nerve cells

4
The molecules of life
  • Nucleic acids (DNA, RNA)
  • Proteins
  • Carbohydrates
  • Lipids
  • Lipoproteins, glycoproteins, vitamins.

5
  • DNA, the blueprint for the cell
  • Four bases, A,C,G,T
  • The order of the bases dictates amino acid
    sequence in proteins - codes for synthesis of
    proteins
  • Double strand, coiled in Double Helix
  • Arranged in chromosomes
  • About 1 yard total in each human cell
  • Inside nucleus
  • RNA takes instructions from nucleus to
    endo-plasmic reticulum where proteins are made

6
Genomics The Genome
Translation protein synthesis
Transcription
DNA RNA Protein
The Proteome Proteomics
DNA DNA
DNA Replication Cell division
7
PROTEINS
  • Chains of amino acids
  • Structural elements - cell walls, membranes
  • Catalysts - enzymes
  • Communication devices - within cells, between
    cells
  • Cytokines
  • Signal transduction factors
  • Receptors
  • Vital in regulation of cell growth, replication

8
Schematic metabolic cycle
Cellular components Nucleic acids, Carbohydrates,
Protein, Fat
Metabolic intermediates
Food Carbohydrates, Fats, Glucose, Proteins
NADPH
NADP
ADP Pi
ATP
Work TransportAssemblyMovementHeat
ATP
NAD
NAD
NADH
NADH
ADP Pi
Wastes CO2, H2O, lactic acid
9
Viruses
  • 0.02-0.3 micrometers diameter
  • Genetic material ss or ds DNA, RNA
  • Protein coat
  • Some enzymes
  • Lipid envelope enveloped/non enveloped viruses
  • Nomenclature semi-systematic
  • Hepatitis A Virus, HAV
  • Need host cell for replication

10
The Flu Virion
11
  • Envelope lipid bilayer membrane
    glycoproteins, typically acquired from host cell
    membranes
  • Capsid (protein coat) multiple copies of 1 or
    more proteins in an array

12
Life-cycle of virus
  • Particle, virion
  • Infects host cell
  • Genetic material uses hosts replication
    apparatus to produce new viral components
    (capsid, core proteins, genetic material)
  • Components assemble into viral particles, exit
    host cell, sometimes lysing host cell

13
  • Each type of virus has its own specific host
  • Viruses that colonize bacteria are bacteriophage
    viruses (bacteriophages).

14
Viruses in the Environmment
  • Must be able to survive outside host cell
  • Non-enveloped viruses are more persistent than
    enveloped viruses
  • lipid envelope more easily damages, protein coat
    confers stability
  • Enteric viruses are almost all non-enveloped
  • Hepatitis A, poliovirus, noroviruses, rotaviruses
  • transmitted by direct and indirect contact,
    fecally contaminated water, food, fomites and
    air.
  • Respiratory viruses adenoviruses, coronaviruses
  • transmitted by direct and indirect contact, air
    and fomites (some also by water and food).

15
Unicellular organisms
  • Bacteria - procaryotes
  • Protozoa
  • Algae - eucaryotes
  • Fungi

16
Procaryotic Cell (left) and Eucaryotic Cell
(right)
17
Procaryotes Bacteria and Others
  • Unicellular organisms
  • Simple internal organization
  • Multiply by binary fission
  • Diameter 0.5-1.0 micrometer
  • Envelope cytoplasmic membrane, cell wall
    capsule (polysaccharide)
  • Some have appendages
  • flagella for locomotion
  • pili attachment to other cells for genetic
    transfer virus receptor site

Standard Linnean nomenclature Genus species
18
Bacterial types
  • Gram positive
  • Gram negative
  • Aerobes
  • Anaerobes
  • Facultative aerobes
  • Rods (bacilli)
  • Spherical (cocci)
  • Comma-shaped (vibrios)
  • Spiral (spirochetes)

19
Bacteria in the Environment
  • Some bacteria form spores
  • highly resistant to physical and chemical agents
    and
  • very persistent in the environment

20
Pathogenic Bacteria
  • Pathogenic bacteria possess structures or
    chemical constituents that contribute to
    virulence properties
  • Outer cell membrane of Gram negative bacteria
    endotoxin (fever producer)
  • Exotoxins
  • Pili for attachment to cells and tissues
  • Invasins to invade cells

21
Unicellular Eucaryotes
  • More complex internal organization
  • organelles discrete nucleus, mitochondria
  • Wide range of sizes 2 micrometers and larger

22
Protozoa
  • Unicellular non-photosynthetic flexible cell
    membrane no cell wall some are parasites, have
    complex life-cycles
  • Wide range of sizes and shapes 2 micrometers to
    2 mm
  • Disease-causing
  • Amoebae Entamoeba histolytica
  • Flagellates Giardia lamblia
  • Ciliates Balantidum coli
  • Sporozoans Plasmodium vivax
  • Coccidians Cryptosporidium parvum
  • Microsporidia
  • Cyclosopora cayetanensis

23
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24
Cryptosporidium parvum oocysts 5 ?m diameter
Wet mount by differential interference contrast
microscopy
Acid fast stain of fecal preparation
25
Giardia lamblia cyst 10 x 8 micrometers
26
More Protozoans Fungi
  • Fungi (yeasts and molds)
  • non-photosynthetic
  • immotile
  • rigid cell wall
  • Molds
  • grow as branched, interlacing chains or filaments
    (hyphae) called mycelia
  • Yeasts
  • do not form mycelia
  • grow as single cells that bud
  • sexual reproduction possible

Mitospores (conidia) of Penicillium, one of the
asexual Ascomycota
Yeasts
27
Algae
  • Photosynthetic
  • Rigid cell wall
  • Simple plants, protists, protozoa, plancton,
    derived from cyanobacteria ?
  • Wide range of sizes and shapes
  • 2 micrometers and larger
  • Some algae are harmful
  • Algal booms
  • Toxins
  • Anabaena, anatoxins

Nostoc
28
Helminths (Worms)
  • Multicellular animals
  • Some are human and/or animal parasites
  • Eggs pass via human and animal excreta to water,
    food, soil.
  • Several major groups
  • Roundworms, Nematodes eg. Ascaris, Trichinella
    spiralis, hookworms
  • Flatworms Platyhelminthes Cestodes (tapeworms)
    pork, beef tapeworms, and Trematodes (flukes) eg
    Schistosomes
  • Annelids (leeches)

Necator (hookworm) eggs
adult
29
  • Eggs hatch in soil
  • Infective stage larvae
  • Penetrate skin, migrate to blood, lungs, trachea
  • or are ingested
  • Adults mature in intestine
  • Attach to intestinal walls
  • anemia
  • Necator americanus , Ancylostoma duodenale
    (hookworm)

30
Trematodes
  • Schistosomes (blood flukes)
  • Liver fluke

31
Cestodes
  • Head (scolex) attaches to tissue
  • beef tapeworm, Taenia saginata
  • pork tapeworm (T. solium)
  • Grows in intestine

http//www.marvistavet.com/html/body_tapeworm.html
32
Multicellular organisms
  • Plants
  • Animals
  • Invertebrates
  • Vertebrates

33
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34
The plasma membraneLipid bilayer
Glycolipid
Glycoprotein
Av. Width 7.5 nm (75 Å)
Sugar
Polar
Non-polar (Lipid)
Protein
35
The cell cycle
Mitosis (Cell division)
36
Different cell types
  • Connective tissue, fibroblasts
  • Endothelial cells, lining of blood vessels
  • Epithelial cells, outside of several tissues
  • Hepatocytes, liver cells
  • Some cell populations are continually being
    renewed (turnover), others are permanent

37
Rat fibroblasts
38
Cell renewal
  • Renewal by differentiation of stem cells
  • eg skin, intestinal wall, blood cells
  • Renewal by duplication - proliferation
  • eg endothelial cells
  • pancreas
  • hepatocytes ?

39
Cell reproduction, cell development
Generic Specialized Stem cells
Differentiated cells Pluripotent stem
cells Different types of
differentiated cells Totipotent (embryonic) stem
cells Organs, organisms ?
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