7.2: Transcription and gene expression
Teaching time: 3 hours Practical time: 0 hours
key vocabulary
prior learning & retrieval practice
Review 7.1 DNA structure
Review 2.7 replication transcription, translation
Essential idea: Information stored as a code in DNA is copied onto mRNA.
Exercise 1: Watch this video up to the end of the process of transcription (7min30secs) and connect-extend-challenge.
Regulation of gene expression
U2: Nucleosomes help to regulate transcription in eukaryotes.
Exercise 2: Outline how methyl groups and Acetyl groups can attach to histones and regulate transcription.
U5: Gene expression is regulated by proteins that bind to specific base sequences in DNA.
Exercise 3: Explain, with examples, the roles of protein in regulating gene expression. What does it mean for a gene to be "expressed"?
U6: The environment of a cell and of an organism has an impact on gene expression.
Exercise 4: List some of the ways in which the environment may influence gene expression
S1: Analysis of changes in the DNA methylation patterns.
Exercise 5: What is methylation of DNA? How does it differ from methylation of histones? Complete the data analysis questions on page 358 of the Allott & Mindorff textbook.
NoS: Looking for patterns, trends and discrepancies—there is mounting evidence that the environment can trigger heritable changes in epigenetic factors. (3.1)
Exercise 6: Read the webpage linked to here on epigenetics. What evidence shows that environment can trigger heritable changes in epigenetic factors?
Transcription direction
A1: The promoter as an example of non-coding DNA with a function.
Exercise 7: What is a transcription promoter? How does it work?
U1: Transcription occurs in a 5’ to 3’ direction.
Guidance from the syllabus: RNA polymerase adds the 5´ end of the free RNA nucleotide to the 3´ end of the growing mRNA molecule.
Exercise 8: Explain transcription using the terms, sense strand (coding strand), antisense strand (template strand), 5' and 3'. Why can only the 5' end be added to the 3' end of the strand?
Post-Transcriptional modification
U3: Eukaryotic cells modify mRNA after transcription.
Exercise 8: Outline how eukaryotic cells modify mRNA after transcription? What is an intron? What is an exon?
U4: Splicing of mRNA increases the number of different proteins an organism can produce.
Exercise 9: Outline the process of RNA splicing.
