Bio 151, Exam 2 Big Concepts, Yahn&Blair, UW Madison, 2025

Gene Expression - ANS controlling what proteins to make or skip Prokaryotic gene expression - ANS should we make mRNA or not(simple) Eukaryotic gene expression - ANS many steps to control; transcribe rna; exit nucleus; transport mRNA to ribosome; etc. Promoter - ANS specific nucleotides that are recognized and bound by proteins transcription factors - ANS Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription. Lac operon and CRP LacL repressor protein - ANS transcription factor that blocks transcription from bacterial Lac Operon; binds to operator DNA near promoter Lac Operon - ANS the operon that controls the metabolism of lactose Lac Y - ANS lactose permease; helps import lactose Lac Z - ANS B galactosidase; helps break down Lactose Repression of Repressor - ANS in presence of lactose; allows lac operon transcription activator transcription factor (CRP) - ANS controlled by atp levels; once activated it increases lac operon to get more ATP When ATP is low, cyclic AMP is - ANS high cAMP binds to - ANS CRP, increasing lac operon and increasing ATp levels Enhancer DNA - ANS stimulates transcription in euk's Silencer DNA - ANS repress transcription in euk's Chromatin remodeling - ANS wrap DNA in histones; tighter the wrap harder it is to transcribe Acetylated histones - ANS increase transcription by loosening DNA wrap DNA methylation - ANS adding methyl group to base; reduces nearby transcription of bases; temporary Epigenetic changes - ANS pass from one cell generation to the next but do not alter nucleotide sequence. Gentice change - ANS changing nucleotide sequence DNA mutations influence - ANS how and wether epigenetic changes alter where to bind transcription factors Transcription factors can act like - ANS master switches for many genes linked together; selector for targeting one gene Trafficking of proteins in eukaryotes is - ANS more complex due to membrane bound organelles chromatin - ANS strands of chormosome nucleolus - ANS site of rRNA synthesis, assembly of large and small ribosomal subunits nuclear envelopes - ANS two lipid bilayers Inner and outer nuclear membranes - ANS perforated by nuclear pores signal sequence - ANS The sequence within a protein that directs the protein to a particular organelle. Importin - ANS shuttles back and forth in nuclear pore, imports proteins bound to it Nuclear localization signal sequence - ANS sequence of aminos that bind importin protein mRNA export from nucleus - ANS binds export adaptor proteins that contain nuclear export signal sequences Endomembrane system - ANS ER; Golgi; Vesicles Rough ER - ANS ribosomes; secretion signal sequence allows insertion of growing proteins through sequence receptor Smooth ER - ANS Lumen on inside has proteins for synthesizing molecules; stores Ca2+ secretory vesicles - ANS secrete proteins Golgi - ANS packages proteins made in rough ER transport veiscle - ANS ER to golgi secretory vesicle - ANS golgi to outside protein processing in golgi - ANS cleave proteins to smaller polypeptides, link proteins, link to other molecules(carbs+GLYCOSYLATION) Lysosome - ANS An organelle containing digestive enzymes Movement of vesicles are not - ANS simply diffusion Cytoskeleton - ANS intracellular rods and fibers that support cell; drives cell division; moves chromosomes motor proteins - ANS move cytoskeleton microtubule - ANS helical; tubulin microtubles can - ANS push and pull by altering length; attatch to motor proteins to walk vesicles; slide past each other with motor proteins Kinesin or Dynein - ANS motor proteins used Cilia and Flagella - ANS sliding microtubules Microfilament - ANS double helix of actin proteins; change length by altering amount of actin Myosin - ANS motor protein Pseudopodia - ANS blobby actin feet Filopodia - ANS fine actin feet Lamellipodia - ANS flat actin feet Cytoplasmic streaming - ANS done by actin intermediate filaments - ANS structural meshwork Progeria ( premature aging) - ANS mutant in nuclear intermediate filament Lamin