YIJC [H2] CI2.4_Gene Expression and Regulation I (N)(S) vetted (wo checkpoint answers)

2024 JC1 BIOLOGY LECTURE NOTES CORE IDEA 2: GENETICS AND INHERITANCE TOPIC 2.4: GENE EXPRESSION AND REGULATION (PART 1) Learning Outcomes: (c) Describe how the information on DNA is used to synthesize polypeptides in prokaryotes and eukaryotes (description of the processes of transcription, formation of mRNA from pre-mRNA and translation is required) (d) [modified] Describe the structure and organisation of eukaryotic genomes (including DNA / RNA, single- / double-stranded, number of nucleotides, packing of DNA, linearity/circularity and presence of introns). (i) 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) (j) explain how differential (i.e. spatial and temporal) gene expression in eukaryotes can be regulated at different levels: (i) chromatin level (histone modification and DNA methylation) (ii) transcriptional level (control elements, such as promoters, silencers and enhancers, and proteins, such as transcription factors, including activators and repressors) (iii) post-transcriptional level (processing of pre-mRNA in terms of splicing, polyadenylation and 5’ capping) Use the knowledge gained in this section in new situations or to solve related problems. References: Reece, J. B. et al. (2018). Campbell Biology (11th Ed). Chapter 18: Regulation of Gene Expression, pp. 368 – 385. Note: This textbook is available in our library. You may wish to borrow the book to supplement your reading when necessary. H2

2 Contents 1. Glossary of Terms ....................................................................................................................... 3 1.1 Organisation of DNA ................................................................................................................ 5 1.2 Definition of a Gene ................................................................................................................. 7 1.3 Structure and Organisation of Eukaryotic Genomes .......................................................... 8 1.4 Non-coding DNA ..................................................................................................................... 12 1.4.1 Introns ............................................................................................................... 12 1.4.2 Centromere ....................................................................................................... 13 1.4.3 Telomere ........................................................................................................... 14 1.4.4 Promoter ........................................................................................................... 19 1.4.5 Enhancer ....................