Download Investigating the effectiveness of antibacterial soaps

Investigating the effectiveness
of antibacterial soaps
Hypothesis:
Write it in “ If ….. And then …
form on handout
Change to “If….. And Then
……
The frequency of cricket chirps will change as the temperature
changes.
How can we set up this experiment?
Remember we call all the things that remain the same between
the two set ups:
controls
_____________________
How can we keep track of
data?
 What is the independent variable?
the temperature
What is the dependent viable?
the number of chirps
Preparing to design an
experiment
 Look back in your notes. What is the
hypothesis you wrote to test the effects of
antibacterial soap on bacterial growth?
 Are you still happy with your hypothesis?
If not, you can change
What can you measure to test your
hypothesis?
Bacteria
 Bacteria are
___prokaryotes _______
“first seed” (single cells
that do not contain a
nucleus, or membrane
bound organelles).
 Bacteria are microscopic
and can only be seen
through a microscope
 Bacteria reproduce very
quickly if in contact with a
nutrient source. They are
sensitive to temperature
Bacteria
 A nutrient source that
can be used in the “lab”
is agar
 If an individual bacterial
cell is transferred to the
agar, the bacteria will
multiply into millions in
a short time.
Bacteria Characteristics
 Bacteria are
distinguished from
other living things
because of their
cell structure:
 All bacterial cells
have a cell wall
surrounding a cell
membrane, inside
of which lies the
unbound DNA and
other material.
Bacteria Classification
 There are three types of bacterial cells, based on
shape: spherical (coccus), rod (bacillus), and spiral
(spirillum).
Coccus- diseases caused by this type
of bacteria include: food poisoning,
gonorrhea, strep throat
Bacillus: E. coli
Spirilla- syphilis
Harmful Bacteria
 A number of bacteria
cause disease, these
are called pathogenic
bacteria.
 They can cause
diseases of plants,
animals, fungi,
protists and other
bacteria
 Some bacterial diseases
include: strep throat, scarlet
fever, toxic shock syndrome,
pneumonia, ear infections,
gonorrhea, syphilis,
Tuberculosis
 Bacteria can also be used by
some countries to harm
other countries in an act
called bioterrorism anthrax
Eczema w/ 2o infection
Helpful Bacteria
 live symbiotically in
the guts of animals
 Bacteria put the tang
in yogurt and the
sour in sourdough
bread
 roots of certain
plants, converting
nitrogen into a
usable form.
 break down dead organic matter - decomposers
 of such immense importance because of their
extreme flexibility, capacity for rapid growth and
reproduction, and great age - the oldest fossils
known, nearly 3.5 billion years old
 used in genetic engineering
Bioremediation
A medicine that inhibits the growth of or destroys
microorganisms.
Watch: https://www.youtube.com/watch?v=-iE-JbtxB6w
How they work
 Antibiotics work by being either
by killing the bacteria or
inhibiting their growth
 Penicillin is an antibiotic that
works by preventing the
production of a substance that
form the cell wall.
 This means the cell will continue
to grow without dividing or
developing new cell wall.
Therefore, the wall gets weaker,
and eventually ruptures
 Antibiotic resistance (when an
antibiotic is no longer
effective) is a major problem
 Antibiotic resistance is driven
by overusing antibiotics and
prescribing them
inappropriately.
How does it happen?
A random change in the genetic material of the bacteria, this is
known as a mutation. This can cause the genetic material to make
the bacteria resistant to harm by the drug.
If you are treated with an antibiotic, it can destroy many
of the harmless strains of bacteria that live in and on the
body. This allows resistant bacteria to quickly multiply
and take their place
Viruses
Are they living things?
Viral structure
 Viruses are not cells.
 They need a living cell to
survive
 Basic structure:
 Protein coat (not a cell wall)
 Nucleic acid core (RNA or
DNA)
Are viruses alive?
 Only 1 characteristic of life: reproduction
 Can only reproduce inside a host cell!
 Process or reproduction = lytic cycle
Lytic Cycle
 Virus attaches to host cell’s membrane and injects its
nucleic acid into the host cell.
 The viral nucleic acid takes over protein synthesis,
creating new viruses.
 The host cell bursts, lyses, releasing the newly formed
viruses.
Before attachment
Attachment
Penetration and uncoating
Release
Assembly
Replication
Examples of common human diseases
caused by viruses include:
the common cold, influenza, chickenpox, and
cold sores. Many serious diseases such as
Ebola virus disease, AIDS, avian influenza, and
SARS are caused by viruses
How do we fight viruses?
Vaccines work by stimulating our
immune system to produce antibodies
(substances produced by the body to
fight disease) without actually infecting
us with the disease