Download - Viruses and Diseases in the Civil War
Be able to summarize both the lytic and lysogenic cycle.
Be able to compare the structure and characteristics of viruses and bacteria.
Be able to properly perform a swab technique.
Objectives
Earliest form of life (3 billion years ago) Prokaryotic cells (no organelles, no nucleus) Single celled have a cell wall
Bacteria
Give off chemicals called toxins that can make us sick
Our body fights off bacterial infections using antibodies
How Bacteria Infect
Single-celled Not considered living
Cannot reproduce on their own
They are not made up of cells
They cannot respond to the external environment
Cannot move on their own Called “particles” or
“agents” About 4,000 different types
of viruses
Viruses
Have genetic material (DNA or RNA) enclosed in a capsid Some viruses have a
viral envelope covering their capsid (taken from host cell)
sneaky
Viruses
Lytic cycle 1. entry into cell 2. replicate DNA 3. make viral proteins 4. assemble new generation 5. exit from infected cell—host cell bursts open
(lyses) and virus is released into the environment, host cell dies
http://www.youtube.com/watch?v=3DP-MAhr0YY
How Viruses Infect
Lysogenic cycle (sneaky!) 1. entry into cell 2. DNA incorporated into host cell’s DNA 3. host cell copies chromosomes 4. host cell divides and replicates—all new cells
have virus’ DNA incorporated into their own 5. steps 3-5 from lytic cycle
http://wrate.me.vccs.edu/courses/env108/lesson2_4.htm
How Viruses Infect
Swab Demo:http://www.youtube.com/watch?v=2U6usyE80io Note: we will not be wetting our swabs in
distilled de-ionized water as the video says
Microbiology Lab—Microbes Around Us