STUDY GUIDE FOR BACTERIA AND VIRUSES
Answers too, important words underlined.
1. Identify structures A – F.
A. Cell Wall, made of Peptidoglycan in Eubacteria, Archeabacteria uses a
different substance.
B. Cell Membrane, note that all cells have a cell membrane
C. Plasmid, small circle or loop of DNA. This is the genetic material that
bacteria exchange in Conjugation (a form of sexual reproduction where
bacteria exchange plasmids but DO NOT go thru meiosis.)
D. Pili, these help the bacteria stick to surfaces.
E. DNA
F. Flagellum (plural – flagella)
2. Identify the structures that are different between eubacteria and
archaebacteria.
The cell wall is made of different material (peptidoglycan) some of the lipids are
different. Other chemical and genetic differences lead us to believe that
archaebacteria are the true ancestors of Eukaryote cells and that organelles
found in Eukaryote cells like the mitochondria and chloroplasts are the
remnants of symbiotic bacteria that infected cells soon after life began.
3. Name and describe the 3 shapes of bacteria.
Bacillus – rod shaped.
Coccus – sphere shaped
Spirilla - spiral
4. Name several ways to kill bacteria.
Disrupt the chemical processes of the bacteria, destroy the cell walls, or destroy
the cell membranes. Antibiotics do these when you are sick. See number 10.
Often times antibiotics kill the good as well as the bad viruses and give you
diarrhea.
5. What are antibiotics work and not work on?
Bacteria but not on viruses.
6. The structure pictured is a __T-4 Bacteriophage (latin for “bacteria eater”) .
7. Name the labeled structures.
a. Capsid
b. Tail sheath
c. DNA
d. Tail fibers
8. Know the stages of the lytic and lysogenic cycles and what gets destroyed.
Read the above chart. Not all viruses are lysogenic but all lysogenic viruses need to
be lytic at some point. The lysogenic viruses will need to go over to the lytic cycle if
they are to spread beyond just the infected daughter cells in the lysogenic cycle.
When the virus is hidden in the host DNA it is called a Prophage (not to be confused
with the Prophase cycle in meiosis.)
9. Describe how an immunization works.
By exposing the body to a pathogen (thing that causes disease, like a bacteria or
virus) the body will develop antibodies to combat the pathogen. It is a race to see
who wins the battle, the pathogen to create more copies or your immune system to
fight the pathogen. If the pathogen wins, you die. Once you have the antibodies to a
pathogen your immune system will remember and react much faster the next time
you are exposed, so you will win the next race. You are now IMMUNE to the
disease. See VACCINE, #12.
10. What is the easiest way to control bacteria reproduction?
Thru sterilization by heat, disinfectants, and PROPER food storage and handling.
Disinfectants like bleach will kill bacteria on surfaces. High heat will sterilize food
(kill the bacteria in it). Proper food storage and processing will SLOW BUT NOT
STOP the reproduction of bacteria. Warm foods left out should be kept above 140
degrees and refrigerate leftovers within 2 hours because bacteria can reproduce
rapidly in the 50-100 degree temperature range. Note that bacteria can form tough
endospores to survive when times are tough and no method is 100% effective.
11. Describe how the virus that causes AIDS does harm and what kind of cells
most often gets destroyed.
HIV (the virus that causes AIDS), attacks the helper T-cells (part of your immune
system) and infects them. See picture page 1040 and page 1045. By destroying your
immune system you are now open to diseases that your body would normally fight
off easily. Most people with AIDS die of these OTHER infections by bacteria,
fungus, ameaba’s, and viruses.
12. What is a vaccine and how does it work?
A vaccine is a weakened or dead pathogen that is injected into you and will cause an
immune response but it is not strong enough to kill you. Now you cannot get the
disease. You only need to be immunized once for some things (DNA viruses and
some bacteria) but you need to be immunized again for diseases that mutate quickly
(such as RNA viruses like influenza – the flu). If enough of the population is
vaccinated then the disease does not have enough new hosts to spread.
13. Scientists disagree about whether viruses are living or non-living. What
characteristics can be used to say that it is living? What characteristics does
it lack that living things usually have?
See the chart page 483 in text. Like a living thing: it has genetic information (DNA
or RNA) and it can mutate and reproduce (once inside a host cell). It cannot do the
things a living cell can such as: obtain and use energy or respond to the
environment. Cell theory says that all living things are made of cells, Virus is just
genetic information with a protein coat around it.
14. Study the charts on page 486 and 489 in your book. Know which are caused
by bacteria and which are caused by viruses. Know how they are spread.
Bacterial: Lyme disease, Tetanus (commonly called Lock Jaw), Tuberculosis,
Diptheria, Bacterial Meningitis, Strep Throat, Tooth Decay.
Viral: Cold, Flu, Smallpox, Warts, AIDS, Chickenpox, Measles, Hepatitis, Poli,
West Nile.
15. The mouth and intestines both have a lot of bacteria. What is it about these
two places that make them such a great place for bacteria?
They are warm, dark, moist and contain many nutrients for bacteria.
16. Speaking of bacteria and intestines, what kind do we have in our intestines
and what do they do for us?
Escherichia coli (abbreviated E. coli) helps us digest food and make vitamin K
for us to use.
17. Describe symptoms that can be associated with bacterial infections.
Bacteria symptoms are usually confined to one area of the body because they are
one-celled organisms. The area affected by a bacterial infection produces such
symptoms as redness, rashes, lesions (sores), swollen glands, swelling and pain. For
example, a person who has a throat or ear infection will only feel pain in the infected
area. Virus infections attack more than one area of the body. Therefore, people
may experience multiple symptoms, such as sneezing, headache, fatigue, rash, a
runny nose, sinus congestion, cough, sore throat and body aches. Both will produce
fever or chills and inflammation as the body responds to them.
18. What are endospores and how do they help bacteria?
See #10.
Eukaryote cells
Relatively large.
DNA in a nucleus.
Cell membrane, may have
cell wall too.
Complex organelles like
mitochondria and
chloroplasts that were once
bacteria.
Ribosomes to make cell
products.
Bacteria Cells
Viruses
Small.
Very very very small.
DNA, no nucleus, plus extra DNA DNA or RNA.
in plasmid loops.
Protein coat around genetic
Cell membrane and cell wall.
material.
Ribosomes to make cell products Hijacks the cells machinery
No mitochondria (it makes ATP in to make copies of itself.
a different way).
Exists only as parasites,
Can be pathogenic or good for
always bad.
you..