Viruses

Alive or not? Although some scientists disagree, viruses

are classified as NOT ALIVE What do you think?

They CANNOT reproduce without a hostThey are NOT made of cellsThey DO contain DNA or

RNAThey CAN evolve

What is a virus?

- It is a particle of made up of nucleic acid, protein and sometimes lipids that can replicate only by infecting living cells

Virus Structure Draw this and label it!

Lytic Cycle (infection) Animation: http://pgl.ufl.edu/modules/mysterious_invaders/lytic.htm

Lytic Cycle In the lytic cycle, new viruses are

produced in the host cell until it bursts (lyses)

Lysogenic Cycle Animation: http://pgl.ufl.edu/modules/mysterious_invaders/lytic.htm

Lysogenic Cycle In the lysogenic cycle, the viral DNA is

incorporated into the host cell DNA and can stay dormant for years

Vaccines Viruses can only be prevented with

vaccines, they cannot be destroyed with antibiotics

Vaccines are weakened, altered, or blank forms of the virus that cause your immune system to create antibodies

This way if you ever come into contact with the real virus, you already have built up resistance

Diseases Some diseases caused by viruses are:

The Flu (influenza) Common Colds HIV (causes AIDS) West Nile Chicken Pox Herpes Hepatitis HPV (genital warts) Measles Polio Smallpox SARS Mononucleosis Ebola

Bacteria

Classification

Unlike viruses, bacteria ARE alive Bacteria are prokaryotic, and they make

up two domains, Bacteria and Archaea

Characteristics

Bacteria live everywhere on earth! Some bacteria have flagella, which makes

them able to move, some cannot move Some require oxygen to live, some do not Some are heterotrophic (chemoheterotrophs

and photoheterotrophs) and some are autotrophic (chemoautotrophs and photoautotrophs)

Bacteria Shape

Bacteria come in 3 shapes:Rod, Bacilli

Sphere, Cocci

Spiral, Spirilla

Which is which?

Reproduction

Bacteria can reproduce 2 ways:Asexually by binary fission:

Sexually by conjugation:

Pros and Cons

What are the benefits to an organism that reproduces sexually? Asexually?

What are some problems associates with reproducing sexually? Asexually?

Bacterial Diseases Here are some human diseases caused by bacteria:

Tetanus Lyme Disease Tuberculosis Meningitis Flesh-eating Bacteria Strep Throat Whooping Cough Plague Syphillus Leprosy Anthrax Gonorrhea Salmonella

Antibiotics Bacteria diseases can be cured by antibiotics The first antibiotic, penicillin, was discovered

by accident by Alexander Fleming in 1928 Penicillin is actually a mold that forms holes

in the bacteria’s cell walls However, bacteria are quickly evolving to

become antibiotic resistant We can no longer fight all bacteria diseases

with antibiotics

Antibiotic Resistance

Based on what you know about natural selection, how do bacteria evolve to become drug-resistant when we only take half of our prescription?