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NUCLEIC ACIDS. Journey to the tiny world of DNA. Nucleic Acids. Organic molecules, include C, H, O, N and P elements. Have various roles in metabolic activities. Found in all living cells, Even in viruses. Why so important?.
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NUCLEIC ACIDS Journey to the tiny world of DNA
Nucleic Acids • Organic molecules, include C, H, O, N and P elements. • Have various roles in metabolic activities. • Found in all living cells, • Even in viruses
Why so important? • Contain a life code that controls and regulates the activities of a cell. • Cell uses hereditary information to stay alive and to reproduce.
The Structure of a Nucleotide Nitrogenous bases (adenine, guanine, thymine,cytosine, uracil) Phosphate (PO4) 1 3 Phosphodiester bond 2 Glycoside bond 5C Sugar (ribose or deoxyribose) Nucleic acids are polymers of nucleotides.
DNA • Has two strands – double helix • One purine base always pairs with a pyrimidine. • Base pairing system • A – T and G – C • Number of complementary bases are A=T and G=C • Number of Pyrimidine = Purine
3 types of RNA • mRNA, tRNA, rRNA • mRNA (messenger RNA): carry information from the nucleus to the ribosomes in the cytoplasm. It’s synthesized in the nucleus over one strand of DNA and this is called transcription.
tRNA (transfer RNA): • Smaller than other RNAs • Carries free amino acids from cytoplasm to the ribosome where protein synthesis is going to take place. • There are 20 different tRNA molecules. WHY?
rRNA (ribosomal RNA) • Forms the main structure of the ribosomes.