Bacteria

  • Most numerous on Earth
  • Prokaryotes
  • Some can survive where no other organisms can.
  • Most bacteria are beneficial (helpful)
  • Grouped based on:
  • Structure & physiology.
  1. Archaebacteria: found in extreme conditions.

Chemosynthetic bacteria use sulfur to make ATP (Energy)

  1. Eubacteria: Larger group

3 basic shapes:

  • Bacilli – rod-shaped
  • Spirilla – spiral-shaped
  • Cocci – sphere-shaped

Staphylococci-grape like clusters

Streptococci – in chains

Structure / Function
Cell Wall / Protects and gives shape
Outer Membrane / Protects against antibodies
Cell Membrane / Regulates movement of materials
Cytoplasm / Contains DNA, ribosomes, essential compounds
Chromo-some / Carries genetic information
Plasmid / Contains some genes
Flagellum / Moves the cell

Bacteria reproduces by Fission (Asexual Reproduction) resulting in two identical cells.

Most bacteria are helpful:

  • Medical: production of antibiotics, hormone and vaccines.
  • Food Production: cheese, yogurt, vinegar.
  • Pollution Control: sewage treatment, bioremediation of polluted environments.

Bacteria that cause diseases are called pathogenic. Human Diseases: tuberculosis, pneumonia, strep throat.

Toxins: poison produced by bacteria.

Pasteurization is a process of heating and killing most bacteria

Antibiotics: Medicine used to treat bacterial infections like strep throat

Vaccines: substance made up of dead or weakened bacteria cells and viruses that prevent diseases.

Endospore: Protective coating when conditions are not suitable for the bacteria growth.

Saprophyte: and organism that use dead material as food as an energy source, thus recycling nutrients.

Antibiotic Resistance:When a population of bacteria is exposed to an Antibiotic, the most susceptible DIE. A Few bacteria that are resistant to the Antibiotic continue to grow. A Resistant Population then grows through reproduction.These new Population are Antibiotic-Resistant. This has resulted from the Over Use of Antibiotics. Many diseases that were easy to treat are now difficult to treat because these bacteria are resistant (unaffected) by the antibiotic.

Nitrogen fixing bacteria: bacteria that makes nitrogen available to organisms. It saves farmers money in fertilizers.

Virus:

  • Nonliving particle.
  • Cause many diseases

Classification of Viruses:

Shape, kind of hereditary material, kind of organism that infects, method of Reproduction

All viruses have two main parts:

  • DNA or RNA – genetic info (hereditary material)
  • Protein coat

VIRAL SHAPE

  • Many-sided – looks like a crystal. Ex: herpes, chickenpox, polio
  • Helix – Coiled spring. Ex: Rabies, measles, tobacco mosaic

Char. Of Life / Virus / Cell
Growth / No / Yes
Homeostasis / No / Yes
Metabolism / No / Yes
Nucleic acid / DNA or RNA / DNA
Reproduction / Only within host cell / Independently by cell division
Structure / Nucleic acid, protein covering, some have envelope / Cytoplasm, cell membrane, etc..

Virus Reproduction:

Host cell: Cell in which the virus reproduce

1.Active virus: Immediate use of host cell. This cell makes new viruses that destroy the host cell.

  • Attach
  • Invade
  • Copy
  • Release
  1. Latent Virus:
  • Nucleic acid of virus becomes part of the host cell’s chromosome
  • Virus hides in the host cell without destroying it.
  • HIV follows this pattern: Infects WBC and remains latent
  • As immune system fails, opportunistic infections occur = AIDS

AIDS:

Disease that allows the body to be attacked by many organisms that cause disease

Control and Prevention of spread.

  • Vaccination & Antiviral drugs. Ex: chickenpox vaccine, AZT, tamiflu.
  • No Treatment: Let it run its course
  • Interferon, protein that can protect non-infected cells.

Gene Therapy:

Enclosing helpful DNA in a virus and allowing it to move into defective cells to help in the treatment of disorders such as cancer or sickle cell anemia.