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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. 2014. NON-CELLULAR ORGANISMS.
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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 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 NON-CELLULAR ORGANISMS
viruses are not capable of: • independent growth and division • they have not got own proteosynthetic apparatus (ribosomes, tRNA) • they have not gotmetabolic apparatus • they have not got excitability VIRUSES
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 NON-CELLULAR ORGANISMS
viruses made up from: • nucleic acid closed in a protein coat • viruses have got either: • DNA or RNA > never both of them simultaneously!!! THE STRUCTURE OF VIRUSES
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 VIRION
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 THE REPRODUCTION OF VIRUSES
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 LYSOGENIC CYCLE
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 ONCOVIRUSES
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 transcriptaseoverwrites 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
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
viruses attacking bacteria • specific form • 1) head (in the shape of polyhedron) > DNA placed here • 2) contractive flagellum with flagellar fibres BACTERIOPHAGES
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 VIROIDS
JELÍNEK, Jan a Vladimír ZICHÁČEK. Biologie pro gymnázia: teoretická a praktická část. 2. dopl. a rozš. vyd. Olomouc: Nakladatelství Olomouc, 1998. ISBN 80-718-2050-4 • 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: Scientia, 2003, 797 s. ISBN 80-718-3268-5 SOURCES