Download Size and Shape of Viruses

What do you think this is?
Viruses
What do you Think These Objects
are? Are They Living?
Plant Virus Tobacco Mosiac
Bacteria Vs Virus
VIRUSES
Virus: infectious particle that contains DNA or
RNA surrounded by a protein coat that can only
reproduce in a host cell.
Latin for “poison”.
Bacteriophage attacking a bacteria!
Are viruses alive? Scientists are still
arguing!!!
At the boundary of life, between the macromolecules
(which are not alive) and the prokaryotic cells (which
are), lie the viruses and bacteriophages (phages).
These twilight creatures are parasites responsible for
causing many diseases in living things (herpes and
HIV in humans, for example).
Viruses are found everywhere.
In isolation, viruses and
bacteriophages show
none of the expected
signs of life. They do not
respond to stimuli, they
do not grow, they do not
do any of the things we
normally associate with
life.
Characteristics of Living Things
Respond to stimulus: virus respond when a cell is
near and attaches.
Cells: Not cells as we know them
Adapt: The viruses do mutate to become stronger but
only in a host cell.
Reproduces: only in a host cell
Energy: Uses energy of the host
DNA: Yes they do have their own
Grow and develops: Only in host
Viruses are parasites that can only perform certain
characteristics in host cells.
Host: The cell that the virus attaches and uses their
DNA and resources.
How do They Name Viruses
1. After the disease they cause.
2. After the organ or tissue they attack
3. Today, they are given a genus name
ending in the word virus. Code numbers
are given to similar viruses
PARTS OF A VIRUS
Viruses consist of a core of nucleic acid,
either DNA or RNA, and a protective coat of
protein molecules and sometimes
lipids(capsid).
CAPSID: Protein coat
Surrounding the DNA.
Why is Capsid Important?
It is the protein coat around the virus that
protests its DNA or RNA.
IT IS WAY THEY ARE SO HARD TO KILL!!!!!!
How Do Viruses Attack Their
Host
Host - Cell the virus attacks.
Attaches to the host cell and interlocks
with the protein of the host cell.
Viruses are very specific to the cells
they attack. This helps in the spread
of the disease.
The outside envelope matches the cell
that it attacks. Viruses are specific!
Attacking Host
The virus will attach itself to the host cell. It will then shoot
its DNA into the host cell. The virus is a parasite that uses
the host cell for its energy and reproduction. It is a little
different if it is a bacteria cell or eukaryotic cell.
Attacking the host
The size and shape of a virus determines which
cells or host they can attack.
Virus Attached to Host
Size and Shape of Viruses
Viruses come in all shapes sizes. You can only
see them with a microscope.
3 shapes of viruses
1.Enveloped – round with spikes( flu viruses)
2.Helical – Long narrow coiled shape( rabies)
3.Polyhedral- many sides(foot and mouth disease)
The different proteins that make up the
capsid determines the shape of the virus.
Difference between a bacteriophage and a
virus
Bacteriophages attack bacteria (prokaryotes)
viruses attack eukaryotic cells(have a nucleus).
Viruses and bacteriophages invade cells and use the
host cell's machinery to synthesize more of their own
macromolecules.
How Do Vaccines Work
A vaccine contains a killed or weakened part of a
germ that is responsible for infection. Because the
germ has been killed or weakened before it is used
to make the vaccine, it can not make the person
sick. When a person receives a vaccine, the body
reacts by making protective substances called
"antibodies". The antibodies are the body's
defenders because they help to kill off the germs
that enter the body. In other words, vaccines
expose people safely to germs, so that they can
become protected from a disease but not come
down with the disease.
Jenner was operating on the now widely
accepted principle that once a person catches
a certain disease, he or she is immune to it for
the rest of their life. For example, once you've
had the chickenpox, it's extremely unlikely that
you'll ever catch it again. This is because your
body, when exposed again, will recognize the
disease and fight it off. The beauty of vaccines
is that they help the body develop diseasefighting abilities without making you sick.
Vaccines accomplish this amazing feat by
tricking the body into believing it already has
the full-blown disease. Here are the steps in
this process, known as the "immune
Videos
http://virus.stanford.edu/uda/
https://www.youtube.com/watch?v=a34izR
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https://www.youtube.com/watch?v=jJwGN
PRmyTI&list=TLd9hZ4eK7hl9XlSUOM9T
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https://www.youtube.com/watch?v=UEKS
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https://www.youtube.com/watch?v=UhtKo
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Vaccine-preventable Diseases
Anthrax
Cervical Cancer
Diphtheria
Hepatitis A
Hepatitis B
Haemophilus influenzae type b
Human Papillomavirus
Influenza
Japanese encephalitis
Lyme disease
Measles
Meningococcal
Monkey pox
Mumps
Pneumococcal
Polio
Rabies
Rotavirus
Rubella
Shingles
Smallpox
Tetanus
Typhoid
Tuberculosis
Varicella
Yellow Fever
Common Cold
Swine Flu
Bird Flu
Bacteria
1.Organelles
2.Kill with antibiotic
3.Reproduces on own
4.Needs energy
5. Cell
6.Responds
7.Adapts
8.Grows
Virus
DNA
Reproduces
Energy from
host
Mutates
hard to kill
Capsid