Download Prokaryote vs. Eukaryote

Prokaryote vs. Eukaryote
• 1st division
Prokaryotes
• Found in bacteria and archaea
kingdoms
• Characteristics include
 1-10μm(micrometer-one
millionth of a meter)
 lack a true nucleus so keep
DNA in nucleoids
 no membrane bound nucleus
or organelles
 many are anaerobic so they do
not require O2
 Unicellular
 Have a cell wall(peptidoglycan)
Eukaryotes
• Found in protists, plants, fungi,
and animal kingdoms
• Characteristics include

100-1000 μm
 Presence of a nucleus
 Presence of membrane bound
organelles
Ex: mitochondria is an organelle
that gives energy
 most are aerobic so they
require O2 for cellular
respiration
 most are multicellular
Summary chart
• Prokaryotes
– 1-10 μm
– Lack a true nucleus
– No membrane bound
organelles or nucleus
– Many are anaerobic
– Unicellular
– Have a cell wall
• Eukaryotes
– 100-1000 μm
– Presence of a nucleus
– Has membrane bound
organelles
– Most are aerobic
– Mostly multicellular
(pluricellular)
Viruses
•
Debate over whether viruses are “alive”
 Arguments that they are not-living
• Cannot live independently (require a host or
remain dormant) (parasites of living cells!!)
• Not Cellular
 Arguments that they are living
• Contain genetic material (RNA and DNA)
• Reproduce
Classifying viruses
1) Classification based on capsid
• protein coat that surrounds
the genetic material of a virus
 Spherical
 Cylindrical
 Crystalline
2) Classification based on diseases they cause
• Viruses that affect humans are divided into 21
groups based on the differences in their
genome and replication methods
How viruses replicate (no cellular
division)
1) The Lytic Cycle
• kills host cell
• 5-step process:
– Virus binds itself to host cell (attachment)
– Injects the viral genetic material into the host cell
(entry)
– The host replicates the viral genetic material
(replication)
– New viral particles are assembled (assembly)
– The host cell breaks (lysis) and releases new viral
particles (release) which can go infect other cells.
The Lytic Cycle
•
•
•
•
•
1. Attachment
2. Entry
3. Replication
4. Assembly
5.a) Lysis
b) Release
How viruses replicate (cont’d)
2) The Lysogenic Cycle
• Viral RNA becomes part of the cells
chromosomes. It does not take over the cell but
the RNA gets copied with the cell. The onset of
disease can be postponed until the virus goes
into its lytic cycle
b)Process
– Attachment
– Entry
– Viral DNA becomes part of the host cell’s
chromosomes (provirus formation)
The Lysogenic Cycle
1.
2.
3.
Attachment
Entry
Provirus
Formation
Viral disease
• Cyclical symptoms can be explained by
the replication method of a virus
ex. cold sores
• appear during the lytic cycle
• disappear during the lysogenic replication
cycle
(Virus is always in a person, never goes away so
always susceptible to cold sores)
Virus working for us
Virus use in biotechnology:
1) Gene therapy
i) addition of a specific gene into the
virus
ii) virus can deliver and force
organism to replicate that gene
iii) “typos” corrected ex. Parkinsons
2) Bacteriophages
 viruses attack bacteria
(45 min = 200 new viruses)
3) Reovirus (Respiratory Enteric Orphan Virus)
 kills cancer cells
-head, neck, lung, liver cancers
- few side effects
Prions
• Protein
1) Do not contain RNA or DNA (not a virus)
•
Becomes harmful when it changes its
molecular shape
-because they can cause several deadly brain
diseases such as:
Creutzfeld-Jakob disease
Mad-cow disease in bovine