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This educational resource provides an in-depth understanding of the structure and functions of prokaryotic cells, including the nucleus, cell wall, cytoplasmic membrane, and more.
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Výukový materiál MB 04 - 90 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 PROKARYOTIC CELL
PROKARYOTIC CELL • created by only one unseparated part (compartment) • the compartment is enclosed with the plasmatic membrane • the compartment is filled with the cytosol
PROKARYOTIC CELL • the nucleus of the prokaryotic cell : • not enclosed with nuclear membrane • it contains only double helix circular DNA = nucleotid • circular DNA represents only circular chromosome
the cell reproduces by transverse partitioning > into two daughter cells • the cell is covered with cell wall: • the main element of the cell wall is peptidoglycan • in the cytosol there are ribosomes – the synthesis of proteins is proceeded here • one or more flagella > hollow screw-shaped threads PROKARYOTIC CELL
a simple type of the cell • prokaryota are unicellular organisms (bacteria, cyanophyta, mycoplasmata) • size: 1-2 µm • cytoplasm poor in membrane organelles • only photosynthesis doing cyanophyta have biomembranes = thylakoids • they create neither differentiated tissues nor textures PROKARYOTIC CELL
plentiful ribosomes > several thousands in a cell • prokaryotic ribosomes are smaller than eukaryotic ribosomes • cell inclusions are frequent here • they have not got miotic apparatus (partitioning spindles) • they have not got mitochondria ! • material store: • acid beta-hydroxybutyric, glycogen and volutin • they reproduce asexually, by transverse division PROKARYOTIC CELL
PROKARYOTIC CELL • 4 always present structures: • NUCLEOID • ribosomes • cytoplasmic membrane • cell wall • + cytoplasm
core equivalent • not enclosed by any covering • laid loosely in the cytosol • prokaryotic chromosome is 1000 times longer • organized in loops • one chromosome = one DNA >> genes pass in the unchanged form into the daughter cells • haploid prokaryotic cells • circular = cyclic >> it has not got free endings NUCLEOID
PLASMIDS • small circular, double helix DNA molecules = plasmids • they carry additional, not necessary information • they penetrate excellently through the membrane and pass from one cell into another = bearers of new genes into a cell (use in genetic engineering) • they can sometimes bear enormously important genetic information (e.g. gene for resistance against antibiotics) • they bear genes enabling the conjugations of bacteria
function : • it separatesthe only part of the cell • it releases energyfrom organic substances!!!! • it isolates internal environment from the external • it is semipermeable • smooth but it also makes spurs = invagination of the membrane– on those grooves respiratory chain • green bacteria have bacteriochlorophyllhere CYTOPLASMIC MEMBRANE
the only tight structure of the prokaryotic cell • it consists of peptidoglycan • above the wall there can also be a casing from proteins or polysaccharides CELL WALL
very viscous • concentrated solution • cytoplasm is not divided into compartments • it misses organelles typical for eucaryotic cells CYTOPLASM
different from eukaryotic flagellum in both the composition and in the function • a hollow formation • protein flagellin • it is anchored in the cytoplasmic membrane and cell wall – > rotary movement of the flagellum • energy for the movement of the flagellum - without ATP !!!! FLAGELLUM
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. • JELÍNEK, Jan, Vladimír ZICHÁČEK a Miroslav ŠVÁTORA. Biologie pro gymnázia: teoretická a praktická část. 2. dopl. a rozš. vyd. Olomouc: Nakladatelství Olomouc, 1998, 551 s. ISBN 80-718-2050-4 SOURCES