MOLECULAR GENETICS 2014 Výukový materiál GE 02 – 45 Tvůrce: Mgr. Šárka Vopěnková Tvůrce anglické verze: ThMgr. 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

NUCLEIC ACIDS 2 types of nucleic acids: DNA a RNA DNA: key importance for keeping and transfer of genetic information structure of DNA discovered in 1957 J.D. Watson, Crick, R. Franklin, Wilkins

NUCLEIC ACIDS nucleic acids are polymers > consist of connected nucleotides nucleic acids = polynucleotides the elementary structure unit of polynucleotide chain are nucleotides

STRUCTURE OF DNA

DNA DNA nucleotides contain: 1) deoxyribose pentose (it contains 5 carbon atoms) on the 2nd position the oxygen is absent 2) on the positions 3 and 5 phosphate groups are bound by a covalent bond 3) on the position 1 nitrogen base is bound purine bases: adenine and guanine pyrimidine bases: thymine and cytosine

nucleotid

DNA

NUCLEOTIDE

DNA nucleotides organised behind each other in a particular order= sequence a gene in DNA = characteristic sequence of nucleotides sequence is written with the abbreviations of bases, e.g.: 5´ A A C T G C G A A T G C C C 3´ numbers 5´a 3´mean free endings of carbons on deoxyribose => orientation of the chain

DNA the DNA molecule is formed by two anti-parallel polynucleotide chains wind up in a double helix polynucleotide chains are connected by hydrogen bridges between bases complementarity of bases: A connected with T by two hydrogen bonds (bridges) C connected with G by three hydrogen bonds so called Chargaff rules

DNA very stable formation destruction of hydrogen bonds possible by: high temperature 90 – 100°C enzymes action = denaturation of DNA renaturation of DNA -> chilling down, complementary again

DNA DNA molecules in nuclei of eukaryotic cells: linear DNA molecules in mitochondria, chloroplasts and in prokaryotic cells: circular in prokaryotic cells there are also small DNA molecules = plasmids

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SOURCES KOČÁREK, Eduard. Genetika: obecná genetika a cytogenetika, molekulární biologie, biotechnologie, genomika. 2. vyd. Praha: Scientia, 2008, 211 s. ISBN 978-80-86960-36-4.