Answer the following questions:
 Do
bacteria have a nucleus??
 Do bacteria have different shapes?
 Do bacteria have a cell membrane?
A cell wall?
 How fast and how do bacteria divide?
 Are bacteria prokaryotes or
eukaryotes?
 WHAT are viruses- are they cells?
Are they alive? What are they made
of?
The Good,
Bad, and Ugly
The GOOD and the BAD!
 Bacteria
are both GOOD for us
and our environment and BAD for
our health.
 Can anyone name a GOOD
purpose for bacteria?
 Can anyone name a Disease
caused by bacteria?
Microbiology
The
study of single cell
organisms too small to see
with the unaided eye.
Includes BACTERIA,
Archaea, Fungi, Protists,
and VIRUSES.
Kingdom Monera
Characteristics of bacteria:
No membrane bound nucleus Have cell
membrane, but NOT membrane bound
organelles (like mitochondria)
Most are unicellular & very small
Ribosomes are different from ones in our
cells
 Bacteria & most monerans have a cell wall!

How Big are Bacteria?
A
BACTERIUM is the size of a
PITCHER’S MOUND,
 And,
ONE CELL from your BODY
is the size of the BALLPARK!!!
BACTERIA
 Free
living
organisms.
 Multiple
shapes:
rod, sphere,
or spiral
BACTERIA, cont.




They can be found at extreme temperatures
(boiling to freezing).
They “eat” everything from sugar to chemicals.
Classified as PROKARYOTES because they do
NOT have a nucleus.
DNA is the genetic material
How do bacteria reproduce?
Primarily by Binary fission- Simple & FAST!
 The
DNA is copied
 The cell & cell wall divide in the middle to form 2
identical ‘daughter’ cells.
Under optimal conditions, bacteria divide every 20
to 30 minutes.
 Occasionally, bacteria have sex (called
conjugation) to increase genetic diversity and
improve survival
 Process
involves exchange of DNA between cells
Diseases caused by Bacteria:
 Lyme
Disease (Borellia)
 Necrotizing Fasciitis (“Flesh eating”
bacteria; Streptococcus pyogenes)
 Strep Throat (Streptococcus)
 Food poisoning (Salmonella sp.,
Staphylococcus aureus)
 Meningitis (Neisseria)
How do we treat (kill) bad bacteria?

ANTIBIOTICS!!
 The
first antibiotic was discovered by
Alexander Fleming in 1928. He
noticed a mold (penicillium) stopped
bacteria from growing.
 He isolated the chemical from the
mold and named it Penicillin.
Q. If antibiotics are so effective
at killing living bacterial cells,
why don’t they hurt our cells?
A. Bacteria do not have the same
organization as our cells.
Also, antibiotics are SPECIFIC for the
bacteria they can kill- they are only
effective at killing certain types of
bacteria
Problems with antibiotics:

The main difficulties with antibiotics
are:
1. Allergies
2. Killing off the “good” bacteria in
our bodies
“GOOD” Bacteria
 Bacteria
turns MILK into YOGURT
(Lactobacillus acidophilus) and
CHEESE.
 Bacteria help us digest our FOOD and
produce Vitamin K (Escherichia coli).
 Clean wastes from sewage water at
water treatment plants (Pseudomonas
putida).
Good Bacteria, cont.
A
natural pest killer in gardens and on
crops (Bacillus thuringiensis).
 Clean up chemicals at hazardous
waste dumps and landfills
(Methanotrophs).
 Make medicines, like ANTIBIOTICS
or using biotechnology, Human
Insulin.
VIRUSES

Tiny parasites
composed:
 Genetic
material
(DNA or RNA)
 Protein
 Membranous
Envelope
(sometimes)
VIRUSES, cont.



Straddle between living and not living.
No energy to do anything when outside of cells.
Thousands of different viruses in a variety of
shapes.



Viruses exist to reproduce!
If contacts a cell it CAN infect, the virus takes
over the cell and makes lots of copies of itself!
Viruses infect every form of life (plants, animals,
fungi, bacteria)
VIRAL DISEASES
AIDS (Human Immunodeficiency Virus)
 Flu (Influenza virus)
 Chicken Pox
 “Kissing Disease” or Mononucleosis (EBV)
 Hepatitis (Hepatitis A, B, C, etc)
 Colds (rhinovirus, coronavirus)
 Measles (rhabdovirus)

Q. How do we treat viruses?

A. With
an antiviral.
1. This is a drug that will stop a virus
from reproducing in our cells.
2. There are VERY few antivirals.
3. Antivirals are more toxic to our
normal cells.

If antivirals aren’t the answer, how do we
protect ourselves from viral infections?
To Do:
Make
2 columns on your
page, and list 4 ways
Bacteria and Viruses differ!!
HOW DO BACTERIA AND
VIRUSES DIFFER?
SIZE: Bacteria are much larger.
 STRUCTURE: Bacteria are much more
complex. Bacteria have a thick cell wall, a
chromosome, & ribosomes. A virus has a
small amount of nucleic acid and a protein
coat.
 Antibiotics kill bacteria. Antibiotics do
NOT kill viruses. Only antivirals kill
viruses.

HOW DO BACTERIA AND
VIRUSES DIFFER, cont…
Bacteria are free living- they contain ALL
they need to grow and reproduce
themselves. One cell divides into 2
‘daughter’ cells.
 Viruses are moochers- they only contain
limited genetic information. They invade a
cell and hijack its machinery to turn it into
a VIRUS FACTORY!

How do we protect
ourselves from viral or
bacterial infections?
 With
VACCINES!!
Vaccines, cont…
 1.
What are they?
Part of a bacteria OR virus (or a
weakened version of the organism)
that is injected into a person.
To be most protective, a person is
usually injected multiple times
months apart.
Vaccines must be given weeks or
months BEFORE you are infected
Vaccines, cont…
 2.
How do they work?
The
vaccine does NOT give the person
the disease.
BUT the immune system of the person
“SEES” the bacteria or virus as an
invader and REACTS to it by preparing
the weapons to fight it off.
Vaccination, cont
Normally, it takes our immune system
several days to a week to “see” a foreign
invader (bacteria or virus) and mount a
response against it. (that’s why we feel
sick!)
 If you’ve been vaccinated, your body will
immediately “see” the bacteria or virus as
an invader and it has the weapons to
immediately fight it off. You may NEVER
know you were infected.

How does the immune response
react?


One way the immune
response reacts is to
make specific
ANTIBODIES against a
virus or bacteria.
Later, if you are infected
with that microorganism,
the antibodies in your
body will bind to it and
stop it from infecting you.
What do antibiotics & vaccines
have in common?
Both fight & kill infectious
agents
How are Antibiotics &
Vaccines different?
 Antibiotics
kill ONLY bacteria.
 Vaccines can result in protection
against a specific bacteria OR
virus.
How they work is
different!
 Antibiotics
start to kill the bacteria
immediately after you take them
 Vaccines PREVENT diseaserequire several weeks (and possibly
several shots) before they protect
against the disease; don’t work if
you are already sick!
What happens when we
sneeze:
How else do we prevent disease?
Excellent Sanitation Practices!
Wash hands frequently!
 Wash foods before eating
 Avoid crowds & coughers/ sneezers
 Careful food storage and preparation
 Treat human excrement to kill germs
 Clean water supplies for drinking
 Clean cuts & wounds immediately
 Sterile practices in hospitals

Challenger Questions:
1.
2.
3.
4.
Name 2 differences between Bacteria
and our cells
Name 2 difference between Bacteria
and Viruses.
Do antibiotics work when you have a
cold (VIRUS infection)?
Name a disease caused by a
bacteria.
5.
6.
7.
8.
Name a disease caused by a
virus.
Name 2 good purposes for
Bacteria.
What is one way the body fights
off bacteria and viruses?
What is the most effective way to
PREVENT infection with bacteria
OR viruses?
INFLUENZA VIRUS

Why do we need to be vaccinated EVERY year
against Influenza?
Build an Influenza Virus:
Working at your table, you will build an
influenza virus using the dirctions & the
package of supplies. Do NOT throw any of
the parts away!!!
 Read the directions
 Build the virus, then answer the questions
on the sheet.

Why do people get a vaccine for
Flu EVERY year?
Many different strains of Flu!
 DIFFERENT types infect people each year.
 Influenza is one of the MOST changeable
viruses! It makes mistakes when it copies
the RNA genome.

These
result in changes (mutations)
in the HA & NA protein.
What happens when HA & NA
change?
Our immune response “sees” & makes
antibodies to HA & NA (it’s on the outside
of the virus!). These antibodies bind to
HA & NA to stop the virus from infecting
our cells.
 IF HA or NA have changed, antibodies
may not bind well enough to stop the
virus from infecting our cells

What do we call it when the HA &
NA change from year to year?

ANTIGENIC DRIFT: Small changes
changes in HA or NA over time.
 Parts of the HA or NA are similar, but
enough of it is different that antibodies
to “old” version no longer protect from
infection
What happens when HA & NA
are VERY different?
 Antigenic
 An
Shift:
abrupt, major change in influenza
viruses infecting humans
 People have little or no immunity to the
“new” virus- their immune response has
never “seen” it
 Happens ONLY occasionally
 Like when an animal influenza virus (like
SWINE FLU or avian influenza) infects
PEOPLE!