gene control

• RNA polymerase builds RNA from the template DNA.
• RNA polymerase binds to a promoter sequence before the gene.
• In prokaryotes, the protein sigma binds to the RNA polymerase.
• Sigma and RNA polymerase bind and are called the holoenzyme.
• Within the prokaryote, the promoter has specific sequences called -35 box and -10 box.
• These sequences specify the orientation of sigma.
• In eukaryotes, instead of sigma they have transcription factors.
• Prokaryotes immediately start translating RNA, but eukaryotes have to transport the mRNA.
• In RNA processing, two things are added to the RNA: a poly-A tail and a 5' cap.
• A poly-A tail is a string of adenines added to mRNA to protect it from degrading enzymes.
• A 5' cap is a modified guanine added to the end of RNA to protect from enzymes.
• During processing, non-coding DNA is removed through splicing.
• Introns are parts of DNA that are removed.
• Exons are parts of DNA that remain and are put together after processing.
• Alternative splicing is the ability to create many different strands of RNA based on what exons are kept.
• tRNA is transfer RNA and is utilized in translation.
• tRNA can attach to amino acids, and is called aminoacyl tRNA.
• Aminoacyl-tRNA synthetase is an enzyme that adds amino acids to tRNA.
• Wobble pairing occurs when nucleotides on the outside of the codon do not follow base-pairing rules.
• Eukaryotes have great ability to control gene expression as transcription and translation occur in different places.
• Transcriptional control will be negative or positive.
• Negative control is the use of a repressor to bind to DNA and stop transcription.
• Positive control is use of activator to bind to DNA and trigger transcription.
• Operons are a group of genes encoded into one strand of RNA.
• Operons have a section of DNA called an operator, where regulatory proteins bind.
• Regulatory proteins include repressors and activators.
• The lac operon normally has a repressor protein; the presence of lactose binds to this so transcription occurs.
• DNA wrapped around histone proteins is called chromatin.
• A group of eight histone proteins wrapped by DNA is a nucleosome.
• Chromatin is not accessible for transcription because it's packed tightly.
• Epigenetics are how other factors affect gene expression.
• Epigenetics don't necessarily pass down, but if they cause a mutation, that could be passed down.
• In eukaryotes, most promoters have a TATA box in place of -10/-35 box.
• RNA interference controls of expression of genes by target specific mRNA.
• RNA interference uses RNA molecules like miRNA and a protein complex.
• The miRNA guides to mRNA, then binds to it, and the protein complex comes and cleaves the RNA so it can't make proteins.
• Master regulators are the boss of the cell and begin a series of events to specialize cells.
• Apoptosis is programmed cell death.