Download non-cellular organisms

Výukový materiál MB 04 - 101
Tvůrce: Mgr. Šárka Vopěnková
Tvůrce anglické verze: ThMgr. Ing. Jiří Foller
Projekt: S anglickým jazykem do dalších předmětů
Registrační číslo: CZ.1.07/1.1.36/03.0005
Tento projekt je spolufinancován ESF a SR ČR
NON-CELLULAR ORGANISMS
2014
NON-CELLULAR ORGANISMS
simple structure and different way of life
> different from general features of
organisms
 it occurs on the border between biotic
and abiotic nature
 microbiologists firstly observed them only
in 1940´s
 electron microscope
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VIRUSES
viruses are not capable of:
 independent growth and division
 they have not got own proteosynthetic
apparatus (ribosomes, tRNA)
 they have not got metabolic apparatus
 they have not got excitability
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NON-CELLULAR ORGANISMS
intracellular parasites:
 they can reproduce only in the host cell
 host cell:
 bacteria, algae, animals, fungi, plants
 the size of viruses: 20 – 300 nm
 > a thousand times smaller than bacteria
 > smaller than ribosomes in the eukaryotic
cell
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THE STRUCTURE OF VIRUSES
viruses made up from:
 nucleic acid closed in a protein coat
 viruses have got either:
 DNA or RNA > never both of them
simultaneously!!!
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VIRION
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virus-like particle = virion consists of:
1) nucleic acid (genetic program of the virus)
2) capsides (from capsomeres, protein molecules)
viral nucleic acid DNA or RNA is:
single helix / double helix
linear / circular
inside the capsides there are enzymes ( => for the
reproduction inside the host cell)
in some cases outer membrane covering from
glycolipids around the capsid
THE REPRODUCTION OF VIRUSES
two alternative cell infection cycles:
 1) lytic cycle :
 it ends with a lysis (falling apart) of a cell and
release of reproduced viruses
 2) lysogenic cycle:
 viral genome becomes a part of chromosome
of the host cell
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LYSOGENIC CYCLE
virogenic cycle
 placement of the viral genome into the
chromosome of the cell
 viral DNA , which became a part of DNA of
host cell is called provirus
 there occurs hidden or latent infection
 e.g. virus of herpes > from the latent state
the virus is woken up by the fever, with the
influence of UV, hormones, stress

ONCOVIRUSES
provirus able to cause tumourous
change of the cell
 provirus can stay in cells for many
generations
 tumourous change of the cell > influence
of carcinogenic substances

RETROVIRUSES
a group of viruses
 RNA viruses able for virogenic
 reproduction starts with so called reversible
transcription
 reverse direction of genetic information
stream >
 special enzyme reverse transcriptase
overwrites genetic information from RNA into
DNA

RETROVIRUSES
among retroviruses belongs also the virus
HIV
 it causes disease AIDS = >
 acquired immunodeficiency syndrome
 virus HIV attacks T–lymphocytes
 (T – lymphocytes produce antibodies)
 > it comes to a collapse of immunity system

RETROVIRUSES
transfer of HIV:
 by sexual intercourse (HIV included in
the sperm and vaginal secretion)
 blood way (infected injection needles>
abuse of drugs, tattoo, piercing of skin)
 from the pregnant woman into the foetus
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BACTERIOPHAGES
viruses attacking bacteria
 specific form
 1) head (in the shape of polyhedron) >
DNA placed here
 2) contractive flagellum with flagellar
fibres
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VIROIDS
small RNA molecules without capsides
 more Simple and smaller than viruses
 they cause viral diseases of plants
 they disrupt metabolism of plants
 they stop the growth of plants
 e.g. destroying of more than a million
coconut palms on Philippines
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STRUCTURE OF VIRUSES
DESCRIBE BOTH THE PICTURES
SOURCES
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JELÍNEK, Jan a Vladimír ZICHÁČEK. Biologie pro gymnázia:
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KUBIŠTA, Václav. Obecná biologie. Praha: Fortuna, 2000, ISBN
80-7168-714-6.
CHALUPOVÁ - KARLOVÁ, Vlastimila. Obecná biologie. Olomouc:
Nakladatelství Olomouc, 2010, ISBN 978-80-7182-282-0.
ZÁVODSKÁ, Radka. Biologie buněk. Praha: Scientia, 2006, ISBN
80-86960-15-3.
ROSYPAL, Stanislav. Nový přehled biologie. 1. vyd. Praha:
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