OCPEG_Organisation

1 EJC H2 Biology T1W3 Organisation of Prok and Euk Genomes I Organisation of Prokaryotic and Eukaryotic Genomes I 1. Introduction An organism’s genome holds the blueprint of all the information necessary for it to survive and reproduce. You have learnt previously in the topic of DNA and Genomics how genes are made of DNA, where a specific DNA sequence determines the function of a gene. You have also understood the central dogma of life involving the processes of transcription of DNA into RNA, and translation of mRNA into proteins. Each of these steps within the central dogma is controlled by specif ic sequence elements within the gene, making them functional and regulated in their expression. Much of the gene structure of eukaryotes and prokaryotes is broadly similar. However, there are k ey differences in the genome organisation between eukaryotes and prokaryotes which reflect their divergent transcription and translation machinery. It is important to understand the structure/ organisation of both the prokaryotic and eukaryotic genomes a s a foundation to understanding gene expression, regulation and function, as well as appreciate the difference between prokaryotic and eukaryotic genomes. This lecture series encompass 3 parts. In Part 1, you will first learn the difference s in the organisation of both prokary otic and eukaryotic genomes. Part 2 explains how both genomes are controlled/ regulated, and Part 3 covers the topic of cancer. 2. Learning Outcomes 2 (d) Describe the structure and organisation of viral, prokaryotic and eukaryotic genomes (including DNA/RNA, single -/double-stranded, number of nucleotides, packing of DNA, linearity/circularity and presence/absence of introns) (Some parts covered in JC1 Biology). 2 (h) Describe the structure and function of non -coding DNA in eukaryotes (i.e. portions that do not encode protein or RNA, including introns, centromeres, telomeres, promoters, enhancers and silencers) (knowledge of transposons, satellite DNA, pseudo-genes and duplication of segments is not required) 3. References Campbell, N.A. and Reece, J.B. (2008). Biology, 8th edition. Pearson.

2 EJC H2 Biology T1W3 Organisation of Prok and Euk Genomes I 4. Organisation of Lecture Content 1. Introduction 1 2. Learning Outcomes 1 3. References 1 4. Organisation of Lecture Content 2 5. Comparison of the structure and organisation of Prokaryotic and Eukaryotic genomes Table 1: Comparing structure of Prokaryotic and Eukaryotic Genomes 3 Table 2: Comparing organisation of Prokaryotic and Eukaryotic Genomes 6 6. Organisation of the Eukaryotic Genome A. Non-coding DNA sequences 7 B. Typical Features of the Eukaryotic Gene 8 C. Non-coding DNA sequences with Important Functions i. Promoters 9 ii. Introns 10 iii. Terminators iv. Enhancers and Silencers