2. Describing the
characteristics, the
replication, and the roles
of virus in life
Identify the characteristics
of virus
Distinguish the structure of
virus
Explain the virus life style
Explain the replication of
virus
Explain the roles of the
harmful and the harmless
viruses
BASIC COMPETENCY INDICATOR
2
3. HISTORY OF THE SEARCH FOR VIRUS
1883, Adolf Mayer (Germany) do research to tobacco plant have
mosaic disease can cause tobacco plant become dwarf and leaves
have spotted. Conclusion : new kind of bacteria
1892, Dmitri Iwanowski (Russian) do filter extract tobacco leave with
filter so bacteria or other micro organism can’t infection plant tobacco
in fact extract tobacco have been filtered but tobacco plant infection
mosaic disease. Conclusion : pathogen bacteria
1893, Martinus W. Beijerink (Dutch) he assumed that there are agent
can infection tobacco plant, he called that agent is filterable virus
because can out from bacteria filter and can’t to have seen with light
microscope
3
4. CHARACTERISTICS OF VIRUSES
Viruses are not cell
Viruses extremely small (0,05-0,2 µm or 50x smaller than
bacteria size. To observe viruses need electron microscope
Contain some materials found in cells, made of a core of
nucleic acid surrounded by a protein DNA or RNA
Can’t do reproduction it self
Can’t do metabolisms it self
Can be crystalloid
4
5. DIFFERENCE OF VIRUS WITH CELL
Only have one type nucleic
acid (RNA or DNA)
Can’t do reproduction it self
Don’t have metabolisms it
self
Body cell have two type
nucleic acid DNA and RNA
Can do reproduction
Have metabolism system
VIRUS CELL
5
6. STRUCTURE BODY OF VIRUS
1
2 3 3
4
5
1. Protein coat
2. Nucleic acid
3. Head
4. Wrapper tail
5. Tail fiber
Model of a virus Information Picture
6
8. REPRODUCTION OF VIRUSES
Absorption
(virus attaches to cell)
Penetration
(virus DNA enters cytoplasm
cell)
Replication and synthesis
(virus directs cell to make new
viruses)
Shape of new virus
(arrange nucleic acid and
protein virus)
Released
(cell burst releasing new virus)
Process lyshogenic cycle
similar with lytic cycle step
but in in step replication
there are step addition or
insertion genetic material
virus in bacteria material
which called profage
LYTIC CYCLE LYSHOGENIC CYCLE
8
10. CLASSIFICATION OF VIRUS
Based on hospes cell (sel inang) virus divided into
three, they are :
1. Bacteria Virus (virus which infection bacteria cell)
2. Animal Virus (virus which infection animal cell)
3. Plant Virus (virus which infection plant cell)
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11. DISEASE IN ANIMAL CAUSED BY VIRUS
Kind of Virus Kinds of Disease
New castle disease Tetelo in aves
Rhabdovirus Rabies in dog, monkey
Rous sarcoma virus Cancer in chicken
Herpesvirus simiae Herpes in monkey
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17. USES OF VIRUS
Insect Control
Some viruses cause disease in insects. Scientists are trying to
use these viruses to kill insects that damage crops. In time,
such viruses may replace insecticides.
Cell Research
Scientist study viruses to understands DNA, RNA, and other
cell compounds. Such research may add to our knowledge of
cell activities.
Control of Viral Diseases
Scientists use some virus to produce vaccines. Vaccines are
substances that help your body defend against diseases.
Several vaccines are made from chemical treated viruses.
These vaccines are injected into the body. The body then
produces substances that protect against these viruses 17
18. Thank You for your Attention
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orang yang mau memahami, mengerti , dan
terus belajar
GANBATTE
18
