biol1020(–nucleic(acids(– supporngslides · nucleic acids • there are two types of nucleic...
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BIOl1020 – nucleic acids – suppor5ng slides
Bacterial cell Animal cell Plant cell
DNA occurs in all living cells
Bacterial cell Animal cell Plant cell
But – what is it made of, and how can informa5on be stored in this molecule?? Pioneering work: Friedrich Miescher – 1869.
DNA occurs in all living cells
‘Nuclein’ is what we know today as Nucleic Acids
• There are two types of nucleic acids – Deoxyribonucleic acid (DNA) – Ribonucleic acid (RNA)
• DNA – Stores information for the
synthesis of specific proteins – Directs RNA synthesis – Directs protein synthesis
through RNA
• Central Dogma – DNA-> RNA-> Protein
What do nucleic acids look like?
• Nucleic acids exist as polymers called polynucleotides
• Each polynucleotide consists of monomers called nucleotides
• Nucleotides are connected by phosphodiester bonds
• These bonds make the DNA strand directional (5’-3’)
• The sequence of bases along a nucleotide polymer is unique for each gene
Note: The 5’-‐3’ end designa5on of the DNA strand is based on the atoms of the pentose sugar in the backbone
Nucleotides can contain five types of nitrogenous bases
• Nucleotide monomers are made up of nucleosides and phosphate groups
• There are five types of nitrogenous bases
• DNA: A,T,C,G • RNA: A,U,C,G
Inside the DNA double helix, the nitrogenous bases form pairs with each other
• Each pair contains one purine and one pyrimidine base (which is which?)
• Only two types of pairs are formed: A-‐T and G-‐C
• The base pairs are stabilized by either two or three hydrogen bonds
• The two DNA strands are complementary to each other
Inside the DNA double helix, the nitrogenous bases form pairs with each other
• Each pair contains one purine and one pyrimidine base (which is which?)
• Only two types of pairs are formed: A-‐T and G-‐C
• The base pairs are stabilized by hydrogen bonds
• The two DNA strands are complementary to each other
Other DNA proper5es:
• Both DNA and RNA for extensive secondary structures
• Most organisms other than viruses contain double stranded DNA
• Double stranded DNA strands form a helical structure. – Three types: A & B form (right
handed helices) – Z-‐form (le\ handed helix) – B-‐form is most common
B-‐type DNA
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