Agro/Ansc/Bio/Gene/Hort 305

Agro/Ansc/Bio/Gene/Hort 305 Fall, 2017 Review Sheet for Exam #3

TRANSLATION (Chapter 13):

Overview, the genetic code, the Wobble hypothesis; Basic structure of amino acids and the nature of their side chains (R group); peptides, peptide bonds, peptidyl transferase, primary, secondary, tertiary and quaternary structures of proteins; function of proteins. tRNA: structure: anticodon and amino acid acceptor arm; aminoacyl tRNA synthetase, charging tRNA, coding recognition, wobble in anticodon. Ribosomes: small subunit, large subunit, rRNA, ribosomal proteins, the E,P, and A sites on the small subunit. Decoding of mRNA: polyribosomes, (polysomes), initiation codon, initiation of translation, Shine-Dalgarno sequence, initiation factors, charged tRNAs; peptidyl transferase. Translation termination, release factors, stop codons. Translation in eukaryotes: The role of Cap, scanning of 5’UTR, differences in translation initiation between eukaryotes and prokaryotes. Focus on the following concepts: Differences and similarities in translation between eukaryotes and prokaryotes Coupled transcription and translation in prokaryotes The role of aminoacyl tRNA synthetase and peptidyl transferase

REGULATION OF GENE EXPRESSION IN PROKARYOTES (CHAPTER 14):

Overview of the common points of regulation. Transcriptional Regulation: Operons – cis-acting elements, promoters, activator binding sites, operators, terminators, structural genes; regulatory gene, repressor protein.

Polycistronic RNA.

Effector molecules: inducer, co-repressor, inhibitors, allosteric shifts Positive regulation, negative regulation. Induction, repression, activation. Constitutive genes, inducible and repressible operons.

The lactose (lac) operon: Regulation in the presence of lactose and glucose; role cAMP; the effect of mutations on the different elements of the operon and in the regulatory gene. The tryptophan (trp) operon: regulation by repression and Attenuation; the unique features of the leader sequence (Trpl)

Translational control: RNA binding repressor, antisense RNA.

Post-translational regulation: feed-back inhibition/end product inhibition, allosteric enzymes, covalent modification.

Effect of mutations in the different elements in the lac and Trp operons

REGULATION OF GENE EXPRESSION IN EUKARYOTES (Chapters 15, 16):

Overview of the levels of regulation.

Transcriptional regulation:

Core promoter and Regulatory elements - enhancers, silencers. Properties of enhancer and silencer elements.

Transcription factors (TF): General/ basal transcription factors, specialized transcription factors - activators and repressor; TFIID, Mediator Mechanism by which the regulatory transcription factors regulate transcription.

Chromatin structure and gene expression: ATP-dependent chromatin remodeling complex. Histone acetyl transferase and histone deacetylase – their role in chromatin compaction

DNA methylation: its role and mechanism by which it works in gene silencing

Alternate splicing: outcome, sliceosomes, splice sites, splicing factors miRNA mRNA stability: length of poly (A)-tail, destabilizing sequences in the 3’UTR

Translational control: Role of initiation factors, RNA binding proteins, regulation at the level of translation and RNA stability of iron regulated genes (iron response elements, iron response elements – ferritin and transferin receptor.

RECOMBINANT DNA TECHNOLOGY (Chpt 20) Gene Cloning: Cloning vectors : selectable markers, origin of replication, cloning site, LacZ : their function with regards to cloning.

Restriction endonuclease: Restriction sites, cohesive or sticky ends, blunt ends. Ligations, transformation cDNA synthesis: reverse transcriptase.

Polymerase chain reaction (PCR) : Design of primers, the three steps involved in each cycle, Taq polymerase