FA-Mol and Cell Biochem

fewirage's version from 2015-07-26 03:37


Question Answer
Only histone not in nucleosome coreH1(ties nucleosome beads together)
Heterochromatin vs. EuchromatinHeterochormatin (dense, transcriptionally inactive)
DNA Acetylation vs. MethylationMethylation - mute, Acetylation - active
Methylation occurs on ?cytosine and adenine
Methylation in DNA replication allows?mismatch repair enzymes to distinguish old from new
Inc. G-C PairingHigher Tm
(Lac Operon) Lactose does what?Lactose inhibits the repressor
(Lac Operon) Glucose does what?Glucose inhibits activator
(Lac Operon) Promoter free in what state?when lactose present, repressor isn't bound to promoter
AA needed for purine synthesisGlycine, Aspartate, Glutamine (GAG)

DNA Mutations

Question Answer
Silentcodes for same AA, often base change in 3rd position in codon (tRNA wobble)
Missensechanged AA
Nonsensechange resulting in early stop codon (stop the nonsense!)
Frame Shiftchange resulting in misreading of all downstream nucleotides (usually results in truncated, nonfn. protein)
Severity of mutationsnonsense > missense > silent

DNA Replication

Question Answer
DNA Topoisomerasescreate nicks in helix to relieve supercoils
Primasemakes RNA primer where DNA Polymerase III can begin replication
DNA Polymerase III(Prokaryotes only) elongates leading strand by adding deoxynucleotides to 3' end. Elongates laggin strand until reaches primer of preceding fragment
DNA Polymerase III synthesis5'->3' synthesis
DNA Polymerase III proofreadingexonuclease proofreads in 3'->5' direction
DNA Polymerase I(Prokaryotes only) degrades RNA primer and fills in gap with DNA (5'->3' exonuclease)
Exonucleasework by cleaving nucleotides one at a time from end (eco) of polynucleotide chain
Endonucleasecleaves phosphodiester bonds in middle (endo) of polynucleotide chain


Question Answer
DNA synthesis direction5'->3'
RNA synthesis direction5'->3'
mRNA reading direction5'->3'
DNA 5' end has ?triphosphate
DNA 3' end has ?-OH
Most abundant RNArRNA
Longest RNAmRNA
smallest RNAtRNA
r,m,t RNA mnemonicRampant (most abundant), Massive (longest), Tiny (smallest)
Start codonAUG (codes for Met)
Stop codonsUGA, UAG, UAA (U go away, U are gone, U are away)
RNA Polymerase IrRNA
RNA Polymerase IImRNA (blocked by a-amanitin causes liver failure, death cap mushroom)
RNA Polymerase IIItRNA

Gene organization

Question Answer
Promoter (5' or 3' end of DNA?)found further down 3' end (b/c mRNA synth in 5'-3' direction
Promoter fn.TATA rich, site where transcription factors and RNA polymerase bind
Enhancer(3' end of DNA) alters gene expression by binding TF (can be located far away from gene)
Silencer(3' end of DNA) alters gene expression by binding repressors (can be far away)
mRNA ProgressionhnRNA -> pre-mRNA
pre-mRNA (all in nucleus) 3 steps to become mRNA5' cap (G) PolyA tail (3' end) splicing out introns
RNA that helps splice out intronssnRNP


Question Answer
2/2 structure?cloverleaf formation
All have ___ at 3' endCCA with AA bound to 3' end
3' endCCA (reading 5' to 3')
where does AA bind?3' end to CCA residue
Anticodonmatches mRNA coding for specific AA (reading 5' to 3')
Aminoacyl-tRNA synthetase"charges" tRNA by using ATP to attach AA

Protein Synthesis

Question Answer
Eukaryote rRNA40S + 60S = 80S
Prokaryote rRNA30S + 50S = 70S
ATPcharges tRNA
GTPbegin protein synth (tRNA Gripping and Going places)
Sites of Protein formation on ribosomeA, P, E (Going APE)
A Siteincoming AA-tRNA
P Siteholds Prolonging Peptide
E Siteholds Empty tRNA

Cell biology

Question Answer
Rough ERsynthesis of secretory (exported) proteins
Free ribosomessynthesis of cytosolic and organellar proteins
Smooth ERsynthesis of steroids and detox drugs/poison
mannose-6-Phosphateadded to proteins in Golgi to signal trafficking to lysosome
Perioxisomemetabolize very long chain fatty acids and AA
Proteasomedegrades damaged/unnecessary proteins tagged with ubiquitin
Dyneinretrograde (+ to -) mvmt on MT
Kinesinanterograde (- to +) mvmt on MT
9+2 arrangementseen in MT
inc. cholesterol in bilayerinc. Tm and dec. fluidity
Neuroglia stain with?GFAP
Collagen IbONE, skin, tendONE
Collagen IIcarTWOlage
Collagen III defective in Ehlers-Danlos (threED)
Collagen IVBM (4 under the floor) (Alport syndrome)
Elastin rich in which AAs?proline and glycine