molecular genetics
TRANSCRIPT
JJA Obico, InstructorDepartment of BiologyDepartment of BiologyUniversity of the Philippines Manila
fEukaryotic cells store hereditary information in the nucleus
Nucleid acids‐ DNA
Transfer of nucleic acids transfer of h dhereditary traits
P l f l idPolymer of nucleotidenucleotideS h h t Sugar + phophate group + nitrogen containing bases
Nitrogen containing basesPURINE‐G and APYRIMIDINE‐C and U (RNA) or T (DNA)(RNA) or T (DNA)
A= T; G=CEqual proportion of purines and pyrimidines
Double helix structureDouble helix structureAnti parallel
2 chains of nucleotides held by H‐bondbond
During S‐phaseg pSemi‐conservative
Need primers (RNA)Will be replaced later
Synthesis is discontinuous
Most hereditary traits Most hereditary traits reflect the action of enzymesenzymesInfo for the structure of an enzyme DNAan enzyme DNAGENESpecific region in the Specific region in the DNA that codes for an enzymeenzyme
DNA sequence in the gene is transcribed into an RNA sequenceRNA polymerasepromoter
Messenger RNA (mRNA)Transcripts of gene used to direct a.a. assembly into proteins
Ribosomal RNA (rRNA)Combine with proteins to make up the ribosomes
Transfer RNA (tRNA)Transport a.a. to ribosomes
f fDNA encodes for sequence of a.a. in proteinsDNA mRNA transcriptsb d fRibosomes read sequence in increments of 3
nucleotides CODON
GATTACA A A (DNA)CUAAUGU U U (mRNA)CUA‐AUG‐UUU
mRNA transcript is translated into a.a.mRNA transcript is translated into a.a.mRNA binds with rRNA in ribosomesOne codon is exposed at a timeOne codon is exposed at a time
Carries a particular a.a.
dAnticodon
When nonsense codon is exposed
f fchanging the genetics of plants for the benefit of humankindl l l b dClassical plant breeding
Modern plant breedingGenes can be transferred between species through genetic engineeringTRANSGENIC ORGANISM▪ Contains gene from a different organismB (B B ill h i i i )▪ Bt corn (Bt‐ Bacillus thuringiensis)
Restriction enzymes are
used to make bi recombinant
DNA
Bacterial insertionPCR (Polymerase Chain Reaction)Sample DNA, DNA p0lymerase, 4 nucleotides, primers
fReturn to bacteria and allow to infect plant cellsGene gunsElectroporationMicroinjectionLiposomoes
TotipotencyHas the potential to express any of the genes and produce an entire plant
Encourage plant cells to express their i i di i i totipotency in an medium containing
nutrients and hormones