Physiology the central dogma of biology is... the belief that DNA is transcriped to mRNA by RNA Polymerase II, which is then translated into amino acid chains by ribosomes that make the finished protein. Define "one gene - one protein" hypothesis... the theory that each single gene synthesizes a single polypeptide How does DNA code for genes? by using the four bases ATCG to create sequences that can be turned into proteins How are genes transcribed into mRNA? RNA Polymerase II starts transcription at AUG and copied the single strand of DNA. transcription How are mRNA turned into proteins? By ribosomes going down the mRNA and translating it into amino acid sequences. What elements and properties make up the genetic code? A adenine, guanine, cytosine, and thymine. Also a sugar phosphate backbone. Double helix structure. What is a codon... a codon is a 3 nucleotide sequence of DNA/RNA that codes a specific amino acid Write the template strand of DNA from 5' ATG GAG TTG CGG TGA 3'... 3' TAC CTC AAC GCC ACT 5' What is the mRNA sequence from template strand 3' TAC CTC AAC GCC ACT 5' 5' AUG GAG UUG CGG UGA 3' A mutation is... any permanent change in an organisms DNA genotype makes new alleles Different types of mutations are... Point mutations: result from single base change Chromosome level mutations: addition or deletion of chromosomes Missense mutation... changes sequence of encoded protein Nonsense mutation... converts amino acid codon into stop codon. Silent mutations... do not change sequence of gene product Mutations fall into 3 categories of effects... Beneficial, neutral, and deliterious. Most mutations neutral or slightly deliterious. aneuploidy is... the addition or deletion of a chromosome polyploidy is... an increase in the number of each type of chromosome how many codons are there in total... 64 total, 61 amino acids, 3 stop codons. Different cells express different genes because... they have different histone mods and regulatory proteins two types of proteins bind to regulatory sequences... regulatory transcription factors (bind to enhancers, silencers, responsible for expression of genes ) AND basal transcription factors (don't regulate gene expression just interact w/ promotor have to be there for transcription) genes are turned on when... regulatory proteins bind to enhancers and promoter proximal elements genes are turned off when... regulatory proteins bind to silencers or chromatin is condensed mediator complex known for... starting transcription. doesn't bind DNA, makes loop between promotors, enhancers, silencers, etc transcription initiation steps... STEP 1: regulatory transcription factors bind to DNA to undo chromatin STEP 2: expose promotor by loosening chromatin STEP 3: more regulatory proteins bind to appropriate sequences STEP 4: basal transcription factors make the basal complex then gets RNA to begin transcription Once mRNA is made, a series of events happen before the final product... Splicing of mRNA, altering the start rate of translation, modifying life span of mRNA/proteins Alternative splicing is... splicing the same mRNA multiple ways. introns spliced out in nucleus, leads to distinct mRNA. some exons may be removed changing expression hypertrichosis is... abnormal hairiness not resulting from androgen stimulation. can be aquired hirsutism is... excess hairiness due to androgen surplus. androgen replaced vellus hair with terminal hair stability of mRNA is ___ variablee... some degraded raplidly, some stable RNA interference... controls life span of mRNA by binding microRNA to mRNA if there is no microRNA mechanisms... controlling timing, controlling bindings to mRNA and ribosomes enzymes modify proteins by... carbohyrate addition and cleaving certain amino acids proteins can be activated/deactivated using... phosphorlation proteins can be destroyed by... being tagged with ubiquitin. tags are added to cyclin proteins and recognized by proteasome which cuts protein into short segments abnormal gene regulation leads too... abnormalities and cancers cancers are... uncontrolled cell growth and results from defects in protein cell cycle cancers are most dangerous when... they become metastatic and perform angiogenesis tumor suppressor genes... code for tumor supressing genes that stop/slow cell cycle proto oncogenes are... genes that trigger cell growth/division by initiating cell cycle phases p53 gene is... tumor supressor that guards genome. arrests process of divison until repair or death is decided. most human cancers relate to... defects in p53 gene leading to damaged DNA, increased cancer mutation rate. free energy is defined as... the amount of energy available to do work why is ATP so high energy? the negative O -'s repel each other atp works by... phosphorylating target molecules Removing a phosphate from ATP makes... ADP, adenosine di phosphate what phosphate leaves to make ADP? the lefternmost, via hydrolysis (adding water) atp coupling... a protein being phosphorylated is exergonic, this is paired with an endergonic rxn hexokinase is important b/c... it makes ATP donate P to glucose making glucose 6 phosphate steps of enzyme catalysis initiation (substrates oriented to fit active site), transitition state facilitation (enzyme binds), termination (enzyme/products is released). what determines enzyme reaction rate... substrate/enzyme availability why do all enzymes show saturation kinetics... the amount of enzyme present does not change the rate enzymes can be processed what groups help enzymes... cofactors ( inorganic ions) coenzymes ( organic molecules) prosthetic groups (non-amino acids/molecules) competitive inhibition... a similar molecule prevents substrate from joining the active site allosteric activation/inhibition... when a regulatory molecule changes the shape of the active site function of enzyme is altered by... a chemical change in its structure enzymes are commonly modified by... adding phosphate groups phosphorylation is reversible... T/F TRUE what are metabolic pathways and what do they do... a series of rxns catalyzed by different enzymes that build biological molecules feedback inhibition is... when an enzyme pathway is shut down by the prodoct of pathway
