BIO 230W week 3

• Genome: the entire set of genetic information within an organism, carrying the information for the synthesis of protein and molecules.
• Genome size: different organisms have different amounts of base pairs when it comes to the number of genomes (genetic material).
• Only about 3% of the human genome is protein coding (controls functions of the body).
• Genome regulatory and structural components include genes (instructions for synthesizing proteins and RNA molecules), exons (coding regions, regions that are turned into proteins), introns (non-coding regions that are transcribed (turned into mRNA) but never translated (turned into protein)), promoters (control the initiation(start) of transcription by RNA polymerase), RNA polymerase (role is to synthesize RNA molecules from template DNA (transcription)), Enhancers (controls and enhance the level of transcription (speed, amount, rate)), centromeres (determines where to divide the cell during
• There is a trend that genome size increases with multicellularity.
• Differential Gene Expression: different genes in the body all have the same genetic makeup only that some of them are expressed at different levels.
• Basal transcription Factors assist RNA polymerase with promoter element.
• Examples of basal transcription factors include TFIID, and TATA binding protein (TBP) which bind to the core promoter region(TATA box) and transcription start site.
• Co-Activators increase transcription time by binding to transcription factors and the transcription machinery.
• Examples of co-activators include p300, CBP, and SRC-1 which bind to transcription factors (not DNA) or TIC.
• Activators stimulate the transcription of specific genes to contribute to differential gene expression.
• Examples of activators include NF-Y, NF-X, and NF-E1 which bind to enhancer sequences sections distant from the promoter.
• Repressors blocking the transcription of certain genes to permit expression and contribute to differential gene expression.
• Examples of repressors include NF-Y, NF-X, and NF-E1 which bind to silencer sequence.
• Silencer sequence- regions that control(regulate) gene expression.
• Basal transcription factors are foundational to the function of transcription and contribute to the evens while the others (co-activators, activators, repressors) contribute to transcription regulation.
• Basal transcription factors such as TBP, and TFIID recognize and bind to the TATA box.
• TATA box: DNA sequence in the core promoter of genes, its function is to indicate what portion of the DNA should be read for transcription, and determines the direction transcription will occur in the DNA.
• Transcription Initiation Complex signifies the RNA polymerase to start mRNA synthesis.
• Alternative splicing allows for a single gene to code for multiple different gene expressions (phenotypes).
• Promoter recognition-BTFs recognize TATA box.
• Single nucleotide mutations include substitution, insertion, and deletion.
• RNA interference involves miRNA interfering with transcribed mRNAs and preventing translation to protein.
• SnRNPs complete the function of splicing.
• Transcription initiation involves TFIIH helicase activity unwinding the DNA, RNA making mRNA.
• Formation of mature mRNA involves capping, splicing, and polyadenylation.
• Transcription occurs in the nucleus, pre-mRNA processing occurs in the nucleus, translation occurs in the cytoplasm, and protein synthesis occurs in the endoplasmic reticulum.
• Coding strand is identical to mRNA, while template strand is the opposite of coding strand and serves as a template for RNA synthesis, transcribed to mRNA.
• Pre-initiation complex assembly involves TFIID and TBP binding to form a preinitiation complex, which positions RNA polymerase II and denatures DNA, preparing the active site for transcription.
• Genetic regulation changes in gene expression not sequence, changes in chromatin structure, it is reversible.
• The rate of formation of the transcription initiation complex (TIC) determines the rate of transcription.
• Histone modification involves using histone midifiers to control gene expression.
• RNA polymerase II binds to the promoter region of the DNA sequence, separating the DNA for transcription.
• miRNA are non-coding RNA molecules that prevent the translation of mRNA to protein, they bind to 3’ noncoded regions.
• DNA is transcribed from 5’ to 3’.
• DNA methylation involves adding a methyl group to the cytosine sequence of a DNA molecule, while histone modification involves adding or removing chemical groups to the histone group, making it harder for DNA to interact with transcription factors and RNA polymerase for transcription.
• Epigenetics is an additional control/regulation as to how the genetic sequences of our cell are expressed.
• RNA polymerase binding involves the pre initiation complex binding RNA polymerase II to the promoter region.
• DNA methylation involves the addition of a methyl group to a DNA molecule, repressing gene transcription.