Viruses, Bacteria

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Viruses, Bacteria Protists

• Quarter 4 Week 2

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Viruses Structure and Reproduction

• Structure
• --biological particles composed of DNA or RNA and
  a protein coat
• --Protein coat can be all different types of
  shapes
• --Some contain a membrane-like envelope to help
  it reproduce (chicken pox, influenza, HIV)

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Reproduction

• cannot reproduce on their own
• ?inserts virual DNA into a cell, which then takes
  over the cells reproduction and quickly produces
  
• new viruses until the cell dies and breaks open
  (called the lytic cycle).
• ?some virus DNA will incorporate into the cells
  DNA and will wait to make more viruses until
  there is some external stimuli (fever, stress,
  etc.). All of the cells offspring will include
  this viral DNA (called the lysogenic cycle)

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Reproduction
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Viruses

• ?viruses gain new genetic material through
  mutations
• ?This ability to inject DNA into a cell is used
  now as a treatment method. Ex A person cannot
  make insulin and has diabetes. Put the gene
  within a disabled virus and it injects it into
  the DNA of the sick person.
• Because they do not meet all of the
  characteristics of life?they are considered
  non-living and do not have their own kingdom!!

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Bacteria Structure Reproduction

• Archaebacteria
• --prokaryotic, so basically DNA and ribosomes
  within a membrane
• --oldest type of bacteria
• --live in extreme habitats (early Earth was a
  toxic place!)
• --Reproduction through binary fission (grow and
  then divide into two cells) this is asexual
  reproduction.

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Bacteria

• -Methanogens make methane gases (intestines of
  humans and cows and bottom of swamps)
• -Extreme halophiles live in high salt
  environments (Great Salt Lake)
• -Thermoacidophiles live in extremely hot and
  acidic places (hot springs)

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Eubacteria

• --prokaryotic
• --have one of three basic shapes
• -bacilli or rod-shaped
• -spirrilla or spiral
• -cocci or spherical (in chains or
• clusters)
• --uses cell membrane to produce ATP and go
  through photosynthesis

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Bacteria structure
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Bacteria

• --DNA is a closed loop that floats in cytoplasm
  with ribosomes
• --capsules or endospores form for protection if
  conditions become to harsh for survival
• --pili are found in some bacteria that help it
  attach to things and transfer some genetic
  material
• --Reproduction is mostly asexual (binary
  fission) new DNA can be gained through
  mutations, pili, viral attacks, and taking in DNA
  from environment

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Protists

• --eukaryotic, so contain nucleus and other
  membrane-bound organelles
• --can be divided into three groups
• -Animal-like (Protozoas)heterotrophic, move
  independently unicellular
• -Plant-like (Algae)make food through
  photosynthesis some can be multicellular
• -Fungus-like (slime molds)

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Protist

• --protists that are motile use many structures to
  move
• -flagella (one or two long hairs that have a
  whip motion)
• -cilia (many small hairs that beat back and
  forth rhythmically)
• -pseudopodia (extensions of cell moves like the
  Blob)
• --Reproduction is mostly binary fission (asexual)
• ?some can go through can get new DNA through
  conjugation
• ?plant-like protists have sexual and asexual
  reproductive stages

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Protists
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Fungi

• --most are microscopic molds or yeasts
• --molds and mushrooms produce filaments to absorb
  their food
• -hyphae-filaments
• -mycelliummat of hyphae you can see
• -cells of hyphae can be divided or undivided

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Fungi

• Remember that fungi are DECOMPOSERS. As the
  hyphae digest the materials around them, the
  chemicals that they do not absorb are returned to
  the soil. They work at every trohpic level and
  are the most important part of the nitrogen cycle
  (working at every stage).

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Fungi

• --Reproduction--both sexual and asexual
• ?asexually they produce genetically identical
  spores, bud, or produce new hyphae
• ?sexual reproduction through fusion of hyphae
  which creates a genetically unique individual.

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Fungi