Biology 1005 Test 3 Review Chapters 11 12 13 Chapter 11 11 1 11 2 11 3 11 4 11 5 Be familiar with the experiment by Griffith showing that genes are made of DNA If you can describe the experiment without notes you are probably in good shape here o S strain has pneumonia R strain doesn t o Injected heat killed S strain into mouse didn t get pneumonia o Injected R strain into mouse didn t get pneumonia o Injected both at the same time and the mouse got pneumonia b c S strain DNA got into R strain cells and made pnemonia o Conclusion you can kill cells but not the DNA DNA will mix with other cells You should know the structure of DNA VERY WELL o Double helix o Backbone sugar phosphate sugar phosphate etc o Bases A G C T Hydrogen bonds b t bases o DNA is made up of nucleotides one sugar deoxyribose phosphate group base Review figures 11 3 and 11 4 Know the complementary base pairing of DNA o A T and G C pair together o Hydrogen bonds between the base pairs o Adenine Guanine larger b c they consist of two fused rings DNA encodes information not because of the number of nucleotides but the sequence of nucleotides Know the basics behind DNA Replication o DNA helicases enzymes pull apart two DNA strain s at the hydrogen bond o DNA polymerase enzymes matches complementary nucleotides onto base strands o Two new DNA strands parental pairs w daughter and winds together You should be able to explain figure 11 6 but it wouldn t hurt to understand figure E11 7 The take home message is that DNA replication is semiconservative because the newly formed strands have one parental strand and one new strand You should know all the different types of mutation that can occur during DNA replication o Point mutation one nucleotide is changed o Insertion one or more pairs of nucleotides inserted o Deletion one or more pairs of nucleotides deleted o Inversion piece of DNA is cut out turned around and reinserted o Translocation large chunk of DNA is removed inserted in another chromosome Be able to explain figure 11 8 12 1 One gene codes for one protein Know the difference between DNA and RNA table 12 1 Chapter 12 o RNA 1 strand ribose Uracil matches w Adenine o DNA 2 strands deoxyribose sugar Thynine matches Adenine contains genes There are three types of RNA know their functions figure 12 1 mRNA carries code for protein gene from DNA to ribosome rRNA combines w proteins to form ribosomes tRNA carries amino acids to ribosomes Transcription DNA codes for RNA table 12 2 Translation RNA codes for a protein Genetic code is in Codons three bases of mRNA Codons code for amino acids o Codons of mRNA pair w Anti codons of tRNA Don t need to know all the amino acids but should recognize that multiple codons code for some amino acids and start and stop codons begin and end translation process o Start AUG o Stop UAA UGA UAG 12 2 Need to know the basics behind Transcription DNA transcribed in RNA 1 Initiation 2 Elongation a RNA polymerase finds beginning of the DNA promoter b RNA polymerase binds to promoter regions c Begins separating DNA at the promoter region a RNA polymerase travels down template DNA strand synthesizes single complementary RNA A pairs with U b Ribose nucleotides are added to RNA strand c RNA drifts away but DNA stays attached to RNA polymerase 3 Termination a RNA continues down template strand until it reaches termination signal b RNA polymerase releases DNA c RNA polymerase is free to bind w other promoters Know figure 12 3 VERY WELL If you know this then you know transcription 12 3 Transcription and translation are different between prokaryotes and eukaryotes o prokaryotes both take place in the same place and time What are introns and exons What importance do they serve o Exons segments of DNA expressed in a protein o Introns segments of DNA not expressed in a protein hidden within a gene o After DNA is transcribed RNA is organized so introns are cut out and different proteins are made from different varieties of exons Know the basics behind Translation RNA codes for Protein 1 Initiation a Pre initiation complex tRNA proteins small ribosomal subunits bind to mRNA scan for start codon tRNA anticodon binds w mRNA start codon AUG b c Large ribosomal subunit binds w small subunit traps mRNA and hold tRNA in first tRNA binding site 2 Elongation a Second codon of mRNA binds to second anticodon of tRNA b Catalytic site on large subunit breaks first bond of codon anti codon c First empty tRNA stain is released d Ribosome moves down mRNA and second amino acid forms peptide bond w first amino acid 3 Termination a Process is repeated until stop codon is reached b mRNA and completed peptide are released c Subunits separate d Ribosomes can translate another mRNA Know figure 12 7 VERY WELL If you know this then you probably understand translation Understand complementary base pairing You may have to derive RNA5 sequences from given DNA sequences or vice versa o A goes back to T no U s in final RNA 12 4 Know the different types of mutations and which ones are the most problematic o Point o Deletion o Insertion o Insertion o Translocations What could be the possible results of substitutions o Protein unchanged o New protein has same function as old one o New protein new function o Protein function is destroyed by amateur stop codon 12 5 well How are genes regulated in prokaryotes operons Understand figure 12 9 relatively o DNA organized into packages called operons o Operons are genes that have similar functions and lie close to each other so that functionally similar proteins are synthesized at the same time o Four parts of operon Regulatory gene controls timing of rate of transcription of other genes Promoter Where RNA polymerase begins transcribing Operator governs the access of RNA to the promoter Structural genes encode related enzymes or other proteins There are 5 methods of gene regulation in eukaryotes and they occur at certain times in the process of DNA to Protein Can you describe them and where they take place figure 12 10 1 Cells can control frequency at which an individual gene is transcribed Transcription in Nucleous certain genes are needed at different times 2 Same gene can be used to produce different mRNA and proteins mRNA processing in Nucleous different mRNA s can be produced from a single gene 3 Cells can control stability and rate of translation of mRNA s Translation in Cytoplasm 4 Proteins may require moderation before they can carry out functions Modification in Cytoplasm Cells can