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Herpes

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Herpes - PowerPoint PPT Presentation


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VIRUSES. Herpes. Viruses –. are particles that are NOT ALIVE. Viruses reproduce ONLY inside a living CELL. The Structure Of a Virus. Inner core of nucleic acid (This is the Viruses genetic material) Some contain DNA or RNA but never both.

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PowerPoint Slideshow about 'Herpes' - scarlet-christensen


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Presentation Transcript
slide1

VIRUSES

Herpes

viruses
Viruses –

are particles that are NOT ALIVE.

the structure of a virus
The Structure Of a Virus
  • Inner core of nucleic acid (This is the Viruses genetic material)
  • Some contain DNA or RNA but never both.
  • Surrounded by one or two protein coats called a capsid.
examples of the many different shapes of viruses
EXAMPLES OF THE MANY DIFFERENT SHAPES OF VIRUSES
  • Tobacco Mosaic Virus
  • Polio Virus
  • Human Immunodeficiency Virus (HIV)
  • Bacteriophage T4
e coli and the bacteriophage

E. Coli and the Bacteriophage

What it looks like in real life

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Every virus has a specially shaped device called an attachment protein that can only attach to a few kinds of cells.
slide9
Example of what bacteriophage (a type of virus) does to a cell:

Step 1: ATTACHMENT

Step 2: ENTRY: Bacteriophage injects nucelic acid into the bacterial cell

Step 3: REPLICATION: Host’s metabolic machinery makes viral nucleic acid and proteins

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Step 4: ASSEMBLY: New Virus particles are assembled

Step 5: LYSIS AND RELEASE: Host cell breaks open and releases new virus particles

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Receptor proteins are proteinsembedded in the cell membrane that bind to a signal molecule enabling it to respond to the signal molecule.
  • Viruses are segments of nucleic acids contained in a protein coat. They are pathogens and reproduce by infecting cells and using the cell to make more viruses.
  • Are viruses living? NO
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Viruses have a protein coat and nucleic acid which are characteristics of living cells.
  • Viruses also have characteristics of nonliving cells which are: viruses do not respire, do not grow and CANNOT reproduce outside a living cell.
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BECAUSE THEY DO NOT HAVE ALL THE PROPERTIES OF LIVING THINGS BIOLOGISTS DO NOT CONSIDER THEM LIVING.
viruses reproduce using 2 different cycles
Viruses reproduce using 2 different cycles:
  • Lytic cycle : Virus injects the cell with its genetic information, the information is integrated with the host’s DNA , the host is now replicating viral genes assembles the new viruses, and host cell is broken to release the new viruses. EX: cold & flu
  • Lysogenic cycle_: Virus infects the cell, integrates its genetic information with the host’s DNA, the host divides normally, and then provirus may enter the lytic cycle. EX: herpes & HIV
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attaches

Bacterial

Lytic cycle

DNA

normally

viruses

Viruses

DNA

hiv is a virus that causes aids
HIVis a virus that causes AIDS.
  • It has spikes on its surface that matches a receptor protein on macrophages, which is an immune system cell that engulfs pathogens, and infections fighting cells called lymphocytes.
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AIDS is: a disease in which an individual is unable to defend the body against infections that do not normally occur in healthy individuals.
  • HIV infected people fell healthy for years and can spread it to others without knowing they are infected. HIV is NOT spread through casual contact but is transmitted in body fluids. This includes: sexual contact, blood, and breast milk
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Structure of HIV: envelope composed of lipid bilayer from host cell, capsid and genetic material in the form of RNA.
  • HIV attached to the cell at the receptors called CD4 which activates a co-receptor that in turn starts endocytosis.
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This process occurs for years after infection an eventually mutates to a point it now recognizes a new cell surface receptor on T-Cells. HIV reproduces in the T cells and destroys them. This increases the amount of viral particles in the blood. The destruction of T cells blocks the body’s immune response and signals the onset of AIDS.
smallpox
Smallpox

30% Fatal

vaccines
Vaccines
  • Are used to PREVENT viral infections- What vaccines have you received in your lifetime?
  • Viruses grown on chicken embryos are attenuated vaccines
  • Another type of vaccine is made by heat killing the virus
bacteria monerans
BACTERIA (MONERANS)
  • Are the simplest of all living things and are prokaryotes (unicellular, Do NOT have a nucleus, and NO membrane bound organelles) Most are heterotrophs (Feed on other organisms).
characteristics of bacteria
Characteristics of Bacteria:
  • Small
  • Unicellular
  • Circular DNA called a plasmid
  • Can form endospores under harsh conditions
2 types of reproduction
2 types of reproduction:
  • Binary fission (Asexual) – Chromosomes replicate and the cell divides
  • Conjugation (Sexual) – Exchange of genetic material through cell to cell contact
2 groups of bacteria
2 Groups of Bacteria:
  • Archaebacteria (Ancient)
    • Methanogens – produce methane
    • Thermophiles – live in hot water
    • Halophiles – live in salty conditions (in the Dead Sea)
  • Eubacteria
archaebacteria
Archaebacteria

Methanogens- Produce methane

**Found in peat in marshes or hot springs

**Responsible for flatulence

archaebacteria1
Archaebacteria

Thermophiles- live in HOT water

Thermophiles produce some of the bright colors of Grand Prismatic Spring, Yellowstone National Park

Pompei worms survive with symbiotic relationship with thermophilic archaebacteria

archaebacteria2
Archaebacteria

Halophiles- Live in salty conditions (Dead Sea)

structure of bacteria
STRUCTURE OF BACTERIA
  • Capsule: prevents bacteria from being easily engulfed by white blood cells
  • Flagella: Long thread-like (whip-like) tail that enables the bacteria to move
  • Cell wall: gives the cell shape and prevents osmosis from bursting the cell (Scientist use Gram-Staining to reveal the cell wall structure)
structure of bacteria1
STRUCTURE OF BACTERIA
  • Chromosomes (nuclear material): not enclosed in a nucleus; a single DNA molecule; arranged as a CIRCULAR chromosome
  • Plasma Membrane: regulates what enters and leaves the cell
shapes of bacteria
SHAPES OF BACTERIA

Bacilli,or rod-shaped

Spirilli, or spiral

shaped

Cocci, or round

antibiotics
ANTIBIOTICS
  • Are used to kill bacterial infections
  • DO NOT WORK AGAINST VIRUSES
mutualism
Mutualism
  • Symbiosis in which two of the species live together in such a way that both benefit from the relationship
  • Eg. E-coli