1. NUCLEIC ACIDS - DNA is a polynucleotide, usually double stranded, made up of nucleotides with bases A,T,C and G. - RNA is a polynucleotide, usually single stranded made up of nucleotides containing the bases A,U,C and G. Objective: describe the structure of RNA and DNA and explain the importance of base pairing and hydrogen bonding

2. C ENTRAL D OGMA OF BIOLOGY DNARNAProtein

3. H OMEWORK : Devise and complete a table of key roles for each specified ion – information coming from bibliographic and web-based research in living organisms: calcium, sodium, potassium, magnesium, chloride, nitrate, phosphate

4. N UCLEIC ACIDS They come in two forms: 1) DNA (deoxyribonucleic acid) 2) RNA (Ribonucleic acid) DNA in eukaryotic cells are found in the nucleus, acting as a information store.

5. C ONTINUED … Nucleic acids are composed of monomers called a nucleotide. A nucleotide is composed of 3 subunits: One phosphate group ; One sugar molecule ; One organic nitrogenous base. These subunits are joined by covalent bonds to form a nucleotide molecule.

7. B ASE TYPES

9. FEATURES OF NUCLEOTIDES DNA(double helix)RNA(single) Same phosphate group 5-carbon sugar normally deoxyribose 5-carbon sugar normally ribose Base pairs Guanine, Cytosine, Adenine and Thymine Base pairs, Guanine, Adenine, Cytosine and Uracil.

10. J OINING N UCLEOTIDES A condensation reaction between the phosphate group of one nucleotide and the sugar of another join the two together. This forms chains called the “Backbone.” Organic bases will project from this, and it is this sequence of bases that forms coded information of nucleic acid.

12. H OW N UCLEOTIDES J OIN T OGETHER

13. DNA STRUCTURE

15. BASE PAIR- ACRONYM G angsters – C an A sk - T ime A-T 2 H bonds G-C 3 H-bonds

16. D RAW AND LABEL THE DIAGRAM EVERY COMPONENT AND BOND

17. D RAW AND LABEL

18. ribosomal RNA (rRNA) Makes up the bulk of the ribosome. Large folded molecule.

19. messenger RNA (mRNA) Carries the genetic message from DNA in the nucleus to the ribosomes where proteins are synthesised (made) accordingly. Long molecule, not folded. Variable in length and base sequence. Readily broken down and remade.

20. Collects amino acids and takes them to the ribosomes for assembly into proteins. Small molecule. Winds back on itself to form a “clover-leaf” shape. One end carries an amino acid. One loop has a special triplet of bases (ANTICODON) which determines the amino acid carried. transfer RNA (tRNA) AMINO ACID ANTICODON

21. RIBONUCLEIC ACID (RNA) Single stranded polynucleotide. Sugar is always ribose. Organic bases are always A, G, C, and U, NEVER T. 3 types :- ribosomal RNA (rRNA) messenger RNA (mRNA) transfer RNA (tRNA) Back