Recommandé
Contenu connexe
Similaire à Nucleic Acids: DNA, RNA and Their Functions
Similaire à Nucleic Acids: DNA, RNA and Their Functions (20)
Dernier
Dernier (20)
Nucleic Acids: DNA, RNA and Their Functions
- 1. NUCLEIC ACIDS BIOCHEMISTRY – ENV 103 Lyimo, C. M.
- 2. Nucleic Acids • These are biomolecules which consist of one or two ring of nitrogenous base, either purine or pyrimidine derivatives, a five carbon sugar (pentose sugar) and one or more phosphate groups
- 8. Myths of DNA Fibonacci sequences – 0,1,1,2,3,5,8,13.21,34,55,89…. Golden Ratio Φ = 1.61803 Leonardo Bonacci aka Fibonacci
- 12. • Nucleic acids are polymers of nucleotides that occurring in all living systems • Nucleic acids are the chemical carriers of an organism’s genetic information which play a great role functions in a living system • Store and transmit genetic information • Translation of genetic information • Nucleotide participates in almost all biochemical processes and is the one of the most important metabolites of the cell Nucleic Acids
- 13. Understanding Nucleic Acids •Nucleic acids are the chemical carriers of an organism’s genetic information (DNA & RNA) •Nucleic acids are polymers of nucleotides •They store, transmit and translation of genetic information •Composed with Sugar, base and Phosphate group
- 14. 14 Nucleotides and Nucleoside • Building blocks of nucleic acids - Sugar + Base = Nucleoside - Nucleoside + Phosphate = Nucleotide ▲ Nucleotides are monophosphate esters of nucleosides
- 15. 15 Structure of nucleic acid Nucleic Acid has 3 components: (i) Pentose sugar (ii) Nitrogenous base & (iii) Phosphate group (i) Pentose sugar
- 16. 16 (ii) Nitrogenous base Either from purine or pyrimidine derivatives - Purine: Adenine (A) and Guanine (G) - Pyrimidine : Thymine (T), Cytosine (C) & Urasil (U) Purine Pyrimidine
- 17. 17 • Purine derivatives bases
- 18. 18 • Pyrimidine derivative bases
- 19. 19 (iii) Phosphate group • The most common site of phosphorylation of nucleotides found in cells is the hydroxyl group attached to the 5'- carbon of the ribose.
- 20. 20 Polynucleotides • There two types of polynucleotides: DNA and RNA • Deoxyribose-containing nucleotide, deoxyribonucleotides, are the monomers of DNA and • Ribose-containing nucleotides, ribonucleotides, are the monomers of RNA
- 21. 21 • Common representation of the primary structure of DNA or RNA molecules is to write the nucleotide sequences from left to right synonymous with the 5' -----> 3' direction • Known as Sugar-phosphate backbone Condensation commonly occurs between 5'-phosphate of one nucleotide and 3'-hydroxyl of a second (Phosphodiester bond)
- 22. 22 (i) Deoxyribose Nucleic Acid (DNA) • DNA contains two polynucleotide strands wound around each other and form helical structure • The backbone of each consists of alternating deoxyribose and phosphate groups bonded to the 5' carbon atom of one deoxyribose is covalently bonded to the 3' carbon of the next • The backbone of sugar phoshate of each strand is on the outside of the double helix, whereas the purine and pyrimidine bases are inside
- 23. 23
- 24. 24 • The two strands are "antiparallel"; that is, one strand runs 5′ to 3′ while the other runs 3′ to 5′. • Purine or Pyrimidine attached to each deoxyribose projects in toward the axis of the helix
- 25. 25 • The most important aspect of the DNA double helix is the specificity of the pairing of bases.
- 26. 26 DNA replication or duplication • DNA replication is the process by which a replica or identical copy of DNA are made in the cells • Cells do not live forever, they must pass their genetic information on to new cells • It is also required that fragments of DNA (genes) have to be copied to code for particular bodily function • It is essential that the replication of it is EXACT
- 27. 27 • In order for replication to occur, the following must be available: ｷ The actual DNA to act as an exact template ｷ A pool of relevant and freely available nucleotides ｷ Supply of the relevant enzymes to stimulate reaction ｷ ATP to provide energy for these reactions
- 28. 28 • During replication of DNA, the two strands of a double helix unwind and separate. • Each parent strand act as a template for the formation of a new complementary strand.
- 30. 30 (ii) Ribonucleic acid (RNA) • RNA is a long unbranched macromolecule consisting of nucleotides joined by 3' - 5' phosphoester bonds. • RNA are responsible for putting the genetic information to use in protein synthesis. • Unlike DNA, RNA molecules have single strands; it does not have complementary base ratios and the sugar unit in RNA is a ribose rather than dioxyribose. • One of the four bases in RNA is Uracil (U) instead of thymine (T). • Uracil like thymine form a base pair with Adenine (A).
- 31. 31 There three types of RNA (a) Messenger RNA – (mRNA) (b) Ribosomal RNA (rRNA) and (c)Transfer RNA (tRNA)
- 32. 32 (a) Messenger RNA (mRNA) • Account for 5 – 10% of the cell RNA. This is a single- stranded molecule formed on a single strand of DNA by the process known as transcription. • In the formation of mRNA only one strand of the DNA molecule is copied i.e. the base sequence is complementary to that of its DNA template. • mRNA act as the template for protein synthesis and it carries genetic information from DNA for the AAs sequences of the protein to be synthesized.
- 33. 33 (b) Ribosomal RNA (rRNA) • These are found in cell ribosomes and accounts for 75 – 80% of cell RNA. • It is synthesized by genes present on the DNA. • The base sequence of rRNA is similar in all organisms from bacteria to higher plants and animals. • Ribosomes are the sites of protein synthesis. Here the mRNA code is translated into a sequence of amino acids in a polypeptide chain.
- 34. 34 (c)Transfer RNA (tRNA) • These account for 10 – 15% of the cell RNA. • tRNA transfer amino acids present in cytoplasm to the ribosome. • Acts as an intermediate molecule between the triplet code of mRNA and the amino acid sequence of the polypeptide chain. • They are carriers of activated amino acids during protein synthesis.