1. Learning Outcomes: Describe how DNA and RNA encode for the amino acid sequence in a polypeptide chain. Describe the structure of DNA and RNA in terms of a sugar–phosphate backbone and attached bases. Storyline EP2 (p 144 to 149) Activities EP2.7 and EP2.8. Explain the role of hydrogen bonding in the pairing of bases in DNA, and the replication of genetic information by RNA. Illustrate and explain the role of hydrogen bonds as intermolecular forces, which help determine the sequence of amino acids in a polypeptide chain. Chemical Ideas: Chapter 5.4 (p 102 to 108)

2. Cell structure Rough endoplasmic reticulum ~ protein synthesis Nucleus DNA ~ genetic material Ribosomes ~ protein synthesis cytoplasm ~ gel of molecules

3. DNA ~ genetic information and the blue print for protein synthesis Bases in DNA:  Thymine T  Cytosine C  AdenineA  Guanine G Hydrogen bonds between base pairs

4. Part of a DNA strand- a gene – unzips and transcription of the base pairs produces a strand of mRNA.

5. Nucleus (DNA) Transcription DNA used as a blue print to make mRNA 1 gene 1 polypeptide chain mRNA carries the code for protein synthesis and goes to ribosomes. tRNA collect amino acids in the cell’s cytoplasm and carry them to the ribosomes where they will be built into a polypeptide chain ~ translation RNA ~ Ribonucleric acid in a cell

6. Bases in DNA:  Thymine T  Cytosine C  AdenineA  Guanine G Bases carried on the DNA strands code for an amino acid sequence that will form a protein. Bases in RNA:  UracilU  Cytosine C  AdenineA  Guanine G How bases pair to form mRNA: AdenineA UracilU Cytosine C Guanine G Thymine T AdenineA Guanine G Cytosine C

7. Three bases ~ tripet base codes, or codons, are used for each amino acid. mRNA from the nucleus Anti-codon for binding to a codon on mRNA: in this example it would bind to GCC, the codon for alanine

8. Bases that make up the triplet base codons are attached to sugar phosphate molecules, which together are called RNA sugar phosphate molecule base

9. Chemical composition of Ribonucleric Acid Ribose sugar molecules ~ C 5 H 10 O 5 Phosphate groups H 2 PO 4 One of 4 bases: A,U,G or C

10. A unit of RNA HOHO O O BASE phosphate H2OH2O H2OH2O OH

11. Representations of the structure of RNA

12. one t RNA - C -H2NH2NCOOH CH 3 H - C -H2NH2NC = O CH 3 H How an ester bond is formed between the t RNA and an alanine molecule: alanine molecule an ester link + H 2 O

13. When a tRNA collects an amino acid it takes it to the mRNA strand that has become attached to a ribosome.

14. Protein synthesis: ribosome read codons on mRNA. Ribosome moles along the mRNA chain

15. tRNA molecules bring amino acids to the mRNA in the ribosome tRNA leave the ribosome when it has delivered its amino acid Amino acids bond into the polypeptide chain H2NH2N COOH

16. The bases in RNA are planar and the bases fit together so that groups are in just the right positions for hydrogen bonds to form ~ molecular recognition. 2 hydrogen bonds between uracil and adenine

17. 3 hydrogen bonds between cytocine and guanine

18. Make your own summary notes/annotated diagrams about how amino acids are converted into polypeptide chains inside cells EP2 Protein building pages 140 to 149 Read in Chemical Storylines: