-
8/14/2019 Microorganisms and Disease
1/21
1
VIRUS & BACTERIAK. GOPI
-
8/14/2019 Microorganisms and Disease
2/21
2
MICROORGANISMS ANDDISEASES
Infectious diseases are caused by:pathogens &
uncontrollable
natural flora Damages tissue directly or by toxin
Pathogens: viruses, ba
cteria, fungi,protoctista and metazoa (worms)
-
8/14/2019 Microorganisms and Disease
3/21
3
VIRUS
Smallest: 50x smaller than bacteria
Not cells
Arrangements of genetic material & protein
invades living cells to reproduce (obligate
intracellular parasites) Evolve in adaptive way: withstand
drying,
long storage period & resistant towardsmost drugs (acyclovir
prevents herpes- coldsore and genital herpes)
-
8/14/2019 Microorganisms and Disease
4/21
4
STRUCTURE OF VIRUS Geometric shape
Variation in genetic material, protein coat(capsid) &
presence of envelope
Capsid- capsomeres,repeated unit tominimise usage of genetic
material &
simple assembly Protein coat covered by lipid envelope
(host cell)- easier to pass from cell to cell,but vulnerable to
ether
Viral DNA or RNA maybe double stranded
or sometimes single stranded
-
8/14/2019 Microorganisms and Disease
5/21
5
STRUCTURE OF VIRUS
Viral DNA template
mRNA to induce viral proteinsynthesis
DNA virus- small pox,adenovirus & bacteriophage
RNA virus- directs synthesis ofreverse transcriptase
ex: tobacco mosaic virus & HIV
-
8/14/2019 Microorganisms and Disease
6/21
6
ATTACHMENTS OFVIRUSES
Attach by specific protein(VAPS)
Target: protein in host cellmembrane
-
8/14/2019 Microorganisms and Disease
7/21
7
LIFE CYCLE OF VIRUS
Bacteriophages inject only their DNAinto the bacteria cell
forming plasmid
Endocytosis; capsid digested and viral
genetic material released Fusing of virus envelope to the
host
cell surface
Vector (plant virus)>Aphid to pierce
the cellulose wall
-
8/14/2019 Microorganisms and Disease
8/21
8
ROUTES OFINFECTION
Lysogenic pathway
Lytic pathway
-
8/14/2019 Microorganisms and Disease
9/21
9
LYSOGENIC PATHWAY
Non virulent ; DNA replicated via division ofhost cell,
provirus
mRNA is not produced from viral DNAbecause of repressor protein
production
Lysogeny period: virus is a part ofreproducing host cell and
dormant
Activated when host cells are damaged,repressor protein
decreases and virulent
-
8/14/2019 Microorganisms and Disease
10/21
10
LYTIC PATHWAY
Viral genetic materialsreplicate independently in thehost
Mature viruses were made &host cells burst
Releasing new viruses
Virulent and lytic pathway:process of replicating andkilling
cells
-
8/14/2019 Microorganisms and Disease
11/21
11
-
8/14/2019 Microorganisms and Disease
12/21
-
8/14/2019 Microorganisms and Disease
13/21
13
-
8/14/2019 Microorganisms and Disease
14/21
14
BACTERIA
Structure; refer toprokaryote notes
Gram positive and Gramnegative
-
8/14/2019 Microorganisms and Disease
15/21
15
GRAM NEGATIVE
Thinner layer ofpeptidoglycan &
withoutpresence oftechoic acid
-
8/14/2019 Microorganisms and Disease
16/21
-
8/14/2019 Microorganisms and Disease
17/21
17
CLASSIFYINGBACTERIA Gram staining
Shape- spherical (cocci), Rod shaped(bacilli), twisted
(spirilla) and commashaped (vibrios)
Respiratory requirements-obligateaerobes (O2), facultative
anaerobes ( use O2 but can manage
without it) and obligate anaerobes(absence of O2)
-
8/14/2019 Microorganisms and Disease
18/21
18
REPRODUCTION OFBACTERIA
Asexual andsexualreproduction
Asexual- binaryfission (every 20mins)
Sexual-transformation,transduction &conjugation
-
8/14/2019 Microorganisms and Disease
19/21
19
BINARY FISSION
Lorem ipsum dolor sit amet,consectetuer adipiscing elit.Vivamus
et magna. Fusce sed
sem sed magna suscipit egestas. Lorem ipsum dolor sit amet,
consectetuer adipiscing elit.Vivamus et magna. Fusce sedsem sed
magna suscipit egestas.
-
8/14/2019 Microorganisms and Disease
20/21
20
Title
Lorem ipsum dolor sit amet,consectetuer adipiscing elit.Vivamus
et magna. Fusce sed
sem sed magna suscipit egestas. Lorem ipsum dolor sit amet,
consectetuer adipiscing elit.Vivamus et magna. Fusce sedsem sed
magna suscipit egestas.
-
8/14/2019 Microorganisms and Disease
21/21
21
THANK YOU
