Announcements Exam I: Returned at recitation take-home 58% + in-class 80% = 72.7% DRAFT2: Returned in lab this week Class Average: 162/205 = 79% [trajectory] Tomorrow in recitation: Reading sheet Update resumé: PCR, CF, primer design, gel, genome isolation, w/ Luckie CF lab & Nadal… VF: Start at my office W-29 Holmes
Stand up: If did reading for today…
Philosophy: The remaining topics of the lecture are review…
mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS CYTOPLASM 1
mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS mRNA CYTOPLASM Movement of mRNA into cytoplasm via nuclear pore 1 2
mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS mRNA CYTOPLASM Movement of mRNA into cytoplasm via nuclear pore Ribosome Amino acids Polypeptide Synthesis of protein 1 2 3
TRANSCRIPTION RNA PROCESSING DNA RNA transcript 3 5 RNA polymerase Poly-A RNA transcript (pre-mRNA) Intron Exon NUCLEUS Aminoacyl-tRNA synthetase AMINO ACID ACTIVATION Amino acid tRNA CYTOPLASM Poly-A Growing polypeptide 3 Activated amino acid mRNA TRANSLATION Cap Ribosomal subunits Cap 5 E P A A Anticodon Ribosome Codon E
History
5 end Nucleoside Nitrogenous base Phosphate group Sugar (pentose) (b) Nucleotide (a) Polynucleotide, or nucleic acid 3 end 3C3C 3C3C 5C5C 5C5C Nitrogenous bases Pyrimidines Cytosine (C) Thymine (T, in DNA)Uracil (U, in RNA) Purines Adenine (A)Guanine (G) Sugars Deoxyribose (in DNA) Ribose (in RNA) (c) Nucleoside components: sugars Structure
Vocab deoxy Central Dogma 5’ vs 3’ base vs nucleotide purine vs. pyrimidine
Who is a purine? a. b. c.d.
5' end 5'C 3'C 5'C 3'C 3' end (a) Polynucleotide, or nucleic acid (b) Nucleotide Nucleoside Nitrogenous base 3'C 5'C Phosphate group Sugar (pentose) Is this DNA or RNA?
a.DNA b.RNA c.Neither d.Not determinable
Nucleoside components: nitrogenous bases Purines Guanine (G) Adenine (A) Cytosine (C) Thymine (T, in DNA)Uracil (U, in RNA) Nitrogenous bases Pyrimidines
Ribose (in RNA)Deoxyribose (in DNA) Sugars Nucleoside components: sugars
Is this DNA or RNA? a.DNA b.RNA c.Neither d.Not determinable
Sugar-phosphate backbones 3' end 5' end Base pair (joined by hydrogen bonding) Old strands New strands Nucleotide about to be added to a new strand What process is this? a.Transcription b.Translation c.PCR d.DNA Replication e.Restriction
What nucleotide is next? a.A b.T c.G d.C e.U
What is missing?
Who is missing?
(a) Rosalind Franklin (b) Franklin’s X-ray diffraction photograph of DNA
Biology Theatre?
Living S cells (control) Living R cells (control) Heat-killed S cells (control) Mixture of heat- killed S cells and living R cells Mouse dies Mouse healthy Living S cells RESULTS EXPERIMENT
Fig Genomic DNA TECHNIQUE Cycle 1 yields 2 molecules Denaturation Annealing Extension Cycle 2 yields 4 molecules Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence Target sequence Primers New nucleo- tides
Fig. 20-8a 5 Genomic DNA TECHNIQUE Target sequence 3 3 5
Fig. 20-8b Cycle 1 yields 2 molecules Denaturation Annealing Extension Primers New nucleo- tides
Fig. 20-8c Cycle 2 yields 4 molecules
Fig. 20-8d Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence
Fig Mixture of DNA mol- ecules of different sizes Power source Longer molecules Shorter molecules Gel Anode Cathode TECHNIQUE RESULTS – –
Fig Normal allele Sickle-cell allele Large fragment (b) Electrophoresis of restriction fragments from normal and sickle-cell alleles 201 bp 175 bp 376 bp (a) DdeI restriction sites in normal and sickle-cell alleles of -globin gene Normal -globin allele Sickle-cell mutant -globin allele DdeI Large fragment 376 bp 201 bp 175 bp DdeI
Fig TECHNIQUE RESULTS Gel electrophoresis cDNAs -globin gene PCR amplification Embryonic stages Primers mRNAs cDNA synthesis 1 2 3