Figure 17.1a The Flow of Genetic Information TENTH EDITION Pearson Education, Inc.

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1 Figure. MPBLL BIOLOY Figure.a he Flow of enetic Information NH DIION Reece rry ain Wasserman Minorsky Jackson! he information content of genes is in the specific sequences of nucleotides! he inherited by an organism leads to specific traits by dictating the synthesis of proteins ene xpression: From ene to! s are the links between genotype and phenotype! ene expression, the process by which directs protein synthesis, includes two stages: ion and translation Lecture Presentation by Nicole unbridge and Kathleen Fitzpatrick n albino racoon 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. oncept.: enes specify proteins via ion and translation vidence from the Study of abolic Defects Nutritional Mutants in Neurospora: Scientific Inquiry 0 Pearson ducation, Inc. Figure. Results able! In 90, British physician rchibald arrod first suggested that genes dictate phenotypes through enzymes that catalyze specific chemical reactions! eorge Beadle and dward atum exposed bread mold to X-rays, creating mutants that were unable to survive on minimal media! He thought symptoms of an inherited disease reflect an inability to synthesize a certain enzyme! sing crosses, they and their coworkers identified three classes of arginine-deficient mutants, each lacking a different enzyme necessary for synthesizing arginine! ells synthesize and degrade molecules in a series of steps, a metabolic pathway 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. rowth: Wild-type cells growing and dividing Figure.a Figure.b Summary of results ene (codes for enzyme) ene ene B ene ondition ontrol: Minimal medium lass I mutants ene (codes for enzyme) lass I mutants gene ) ene citrulline ene B 0 Pearson ducation, Inc. he Products of ene xpression: Developing Story Basic Principles of ranscription and ranslation 8 ene an grow on ornithine, citrulline, or arginine an grow only on citrulline or arginine an grow with or without any supplements lass II mutants lass III mutants gene B) gene ) Require arginine to grow 0 0 Pearson ducation, Inc. lass II mutants lass III mutants ornithine Summary of results 9 Figure.d arginine (control) No growth: Mutant cells cannot grow and divide lass III mutants gene ) lasses of Neurospora crassa rowth: Wild-type cells growing and dividing Require arginine to grow lass II mutants gene B) Minimal medium (MM) (control) an grow only on citrulline or arginine lass I mutants gene ) 0 Pearson ducation, Inc. Results able an grow with or without any supplements Figure.c an grow on ornithine, citrulline, or arginine arginine (control) No growth: Mutant cells cannot grow and divide lass III mutants citrulline ontrol: Minimal medium 0 Pearson ducation, Inc. lass II mutants ornithine! hey developed a one geneone enzyme hypothesis, which states that each gene dictates production of a specific enzyme lass I mutants ondition! How was the fundamental relationship between genes and proteins discovered? lasses of Neurospora crassa Minimal medium (MM) (control) 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.! Some proteins aren t enzymes, so researchers later revised the hypothesis: one geneone protein! RN is the bridge between genes and the proteins for which they code! In prokaryotes, translation of can begin before ion has finished! Many proteins are composed of several s, each of which has its own gene! ranscription is the synthesis of RN using information in! In a eukaryotic cell, the nuclear envelope separates ion from translation Nuclear envelope! herefore, Beadle and atum s hypothesis is now restated as the one geneone hypothesis! It is common to refer to gene products as proteins rather than s! ranscription produces messenger RN ()! ranslation is the synthesis of a, using information in the (a) Bacterial cell 0 Pearson ducation, Inc. Pre-! s are the sites of translation 0 Pearson ducation, Inc.! ukaryotic RN s are modified through RN processing to yield the finished 0 Pearson ducation, Inc. (b) ukaryotic cell 0 Pearson ducation, Inc.

2 0 Pearson ducation, Inc. Figure.a- Figure.a- Figure.b- Figure.b- Nuclear envelope Nuclear envelope Pre- Pre- (a) Bacterial cell (a) Bacterial cell 8 (b) ukaryotic cell 9 (b) ukaryotic cell 0 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.b- Nuclear envelope Figure.N0 he enetic ode! primary is the initial RN from any gene prior to processing! How are the instructions for assembling amino s into proteins encoded into? Pre-! he central dogma is the concept that cells are governed by a cellular chain of command: RN protein RN! here are 0 amino s, but there are only four nucleotide bases in! How many nucleotides correspond to an amino? (b) ukaryotic cell 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. odons: riplets of Nucleotides! he flow of information from gene to protein is based on a triplet code: a series of nonoverlapping, three-nucleotide words! he words of a gene are transcribed into complementary nonoverlapping three-nucleotide words of Figure. template strand! During ion, one of the two strands, called the template strand, provides a template for ordering the sequence of complementary nucleotides in an RN! he template strand is always the same strand for a given gene! During translation, the base triplets, called codons, are read in the direction! ach codon specifies the amino (one of 0) to be placed at the corresponding position along a! hese words are then translated into a chain of amino s, forming a odon rp Phe ly Ser 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. mino 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 8 racking the ode! ll codons were deciphered by the mid-90s! Of the triplets, code for amino s; triplets are stop signals to end translation! he genetic code is redundant (more than one codon may specify a particular amino ) but not ambiguous; no codon specifies more than one amino! odons must be read in the correct reading frame (correct groupings) in order for the specified to be produced 9 Figure. First base ( end of codon) Second base Phe Leu Leu Ile or start Val Ser Pro hr la yr His ln sn Lys sp lu ys rp rg Ser rg ly hird base ( end of codon) 0 volution of the enetic ode! he genetic code is nearly universal, shared by the simplest bacteria to the most complex animals! enes can be transcribed and translated after being transplanted from one species to another Figure. (a) obacco plant expressing a firefly gene (b) Pig expressing a jellyfish gene 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.

3 0 Pearson ducation, Inc. Figure.a Figure.b oncept.: ranscription is the -directed synthesis of RN: closer look! ranscription is the first stage of gene expression Molecular omponents of ranscription! RN synthesis is catalyzed by RN, which pries the strands apart and joins together the RN nucleotides! he RN is complementary to the template strand! RN does not need any primer (a) obacco plant expressing a firefly gene (b) Pig expressing a jellyfish gene! RN synthesis follows the same base-pairing rules as, except that uracil substitutes for thymine 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.- Initiation Promoter ranscription unit Start point RN Figure.- Initiation Promoter ranscription unit Start point RN Figure.- Initiation Promoter ranscription unit Start point RN nimation: ranscription nwound RN emplate strand of longation nwound RN emplate strand of Rewound RN Direction of ion ( downstream ) longation ermination nwound RN emplate strand of Rewound RN Direction of ion ( downstream ) 8 ompleted RN Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.! he sequence where RN attaches is called the promoter; in bacteria, the sequence signaling the end of ion is called the terminator! he stretch of that is transcribed is called a ion unit Synthesis of an RN ranscript! he three stages of ion! Initiation! longation! ermination RN Polymerase Binding and Initiation of ranscription! Promoters signal the ional start point and usually extend several dozen nucleotide pairs upstream of the start point! ranscription factors mediate the binding of RN and the initiation of ion! he completed assembly of ion factors and RN II bound to a promoter is called a ion initiation complex! promoter called a box is crucial in forming the initiation complex in eukaryotes Figure.8 box ranscription factors RN II! Promoter Start point Nontemplate strand ranscription initiation complex! emplate strand ranscription factors! RN! Several ion factors bind to. eukaryotic promoter ranscription initiation complex forms. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. longation of the RN Strand! s RN moves along the, it untwists the double helix, 0 to 0 bases at a time! ranscription progresses at a rate of 0 nucleotides per second in eukaryotes! gene can be transcribed simultaneously by several RN s! Nucleotides are added to the end of the growing RN molecule Figure.9 RN Newly made RN Nontemplate strand of RN nucleotides end Direction of ion emplate strand of ermination of ranscription! he mechanisms of termination are different in bacteria and eukaryotes! In bacteria, the stops ion at the end of the terminator and the can be translated without further modification! In eukaryotes, RN II transcribes the polyadenylation signal sequence; the RN is released 0 nucleotides past this polyadenylation sequence oncept.: ukaryotic cells modify RN after ion! nzymes in the eukaryotic nucleus modify pre (RN processing) before the genetic messages are dispatched to the cytoplasm! During RN processing, both ends of the primary are usually altered! lso, usually certain interior sections of the molecule are cut out, and the remaining parts spliced together 8 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.

4 0 Pearson ducation, Inc. lteration of nds Figure.0 Split enes and RN Splicing Figure.! ach end of a pre- molecule is modified in a particular way! he end receives a modified nucleotide cap! he end gets a poly- tail! hese modifications share several functions! hey seem to facilitate the export of to the cytoplasm! hey protect from hydrolytic enzymes! hey help ribosomes attach to the end 9 modified guanine nucleotide added to the end P P P ap R Region that includes protein-coding segments Start codon codon Polyadenylation signal R 00 adenine nucleotides added to the end Poly- tail 0! Most eukaryotic genes and their RN s have long noncoding stretches of nucleotides that lie between coding regions! hese noncoding regions are called intervening sequences, or introns! he other regions are called exons because they are eventually expressed, usually translated into amino sequences! RN splicing removes introns and joins exons, creating an molecule with a continuous coding sequence Pre- ap 0 0 s cut out and exons spliced together 0 ap Poly- tail R R oding segment Poly- tail 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure. Spliceosome RNs Ribozymes! In some cases, RN splicing is carried out by spliceosomes! Spliceosomes consist of a variety of proteins and several small nuclear ribonucleoproteins (snrnps) that recognize the splice sites! he RNs of the spliceosome also catalyze the splicing reaction Pre- xon Spliceosome components xon xon xon ut-out intron! Ribozymes are catalytic RN molecules that function as enzymes and can splice RN! he discovery of ribozymes rendered obsolete the belief that all biological catalysts were proteins! hree properties of RN enable it to function as an enzyme! It can form a three-dimensional structure because of its ability to base-pair with itself! Some bases in RN contain functional groups that may participate in catalysis! RN may hydrogen-bond with other nucleic molecules 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. he Functional and volutionary Importance of s! Some introns contain sequences that may regulate gene expression! Some genes can encode more than one kind of, depending on which segments are treated as exons during splicing! his is called alternative RN splicing! s often have a modular architecture consisting of discrete regions called domains! In many cases, different exons code for the different domains in a protein! xon shuffling may result in the evolution of new proteins Figure. ene xon xon xon ranscription RN processing ranslation Domain oncept.: ranslation is the RN-directed synthesis of a : closer look! enetic information flows from to protein through the process of translation! onsequently, the number of different proteins an organism can produce is much greater than its number of genes Domain Domain Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Molecular omponents of ranslation Figure. he Structure and Function of ransfer RN! cell translates an message into protein with the help of transfer RN (trn)! trns transfer amino s to the growing in a ribosome! ranslation is a complex process in terms of its biochemistry and mechanics rp Phe mino s trn with amino attached ly trn! Molecules of trn are not identical! ach carries a specific amino on one end! ach has an anticodon on the other end; the anticodon base-pairs with a complementary codon on! trn molecule consists of a single RN strand that is only about 80 nucleotides long! Flattened into one plane to reveal its base pairing, a trn molecule looks like a cloverleaf nticodon odons 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.

5 Figure.! Because of hydrogen bonds, trn actually twists and folds into a three-dimensional molecule! trn is roughly L-shaped Figure.a mino attachment site mino attachment site mino attachment site Hydrogen bonds Hydrogen bonds nticodon nticodon nticodon (a) wo-dimensional structure (b) hree-dimensional structure (c) Symbol used in this book 0 Pearson ducation, Inc. mino attachment site Hydrogen bonds Hydrogen bonds 8 0 Pearson ducation, Inc. Figure.- Figure.- yrosine (yr) (amino ) mino and trn enter active site. yr-trn yrosyl-trn yr-trn! Second: a correct match between the trn anticodon and an codon yrosine (yr) (amino ) mino and trn enter active site. yrosyl-trn! ccurate translation requires two steps! First: a correct match between a trn and an amino, done by the enzyme aminoacyl-trn omplementary trn anticodon 9 Figure.- mino and trn enter active site. MP + P i omplementary trn anticodon minoacyl-trn MP + P i minoacyl trn released. trn mino sing P, catalyzes covalent bonding. omputer model omputer model xit tunnel rowing trn molecules xit tunnel P site (Peptidyl-tRN binding site) 0 Pearson ducation, Inc. xit tunnel P rowing Next amino to be added to chain mino end site (minoacyltrn binding site) site (xit site) P (b) Schematic model showing binding sites (a) omputer model of functioning ribosome! Bacterial and eukaryotic ribosomes are somewhat similar but have significant differences: some antibiotic drugs specifically target bacterial ribosomes without harming eukaryotic ribosomes Figure.a rowing P! he two ribosomal s (large and small) are made of proteins and ribosomal RN (rrn) Figure.b trn odons (c) Schematic model with and trn 0 Pearson ducation, Inc. (a) omputer model of functioning ribosome 0 Pearson ducation, Inc. Figure.c P site (Peptidyl-tRN binding site) rowing mino end xit tunnel site (minoacyltrn binding site) site (xit site) P Building a Next amino to be added to chain! he three stages of translation! he P site holds the trn that carries the growing chain! he site holds the trn that carries the next amino to be added to the chain! Initiation! longation! ermination! he site is the exit site, where discharged trns leave the ribosome odons (c) Schematic model with and trn 0 Pearson ducation, Inc.! ribosome has three binding sites for trn trn (b) Schematic model showing binding sites 0 Pearson ducation, Inc. trn molecules binding site 0 Pearson ducation, Inc. mino 0 Pearson ducation, Inc.! s facilitate specific coupling of trn anticodons with codons in protein synthesis P omplementary trn anticodon 0 Pearson ducation, Inc. Figure. yr-trn binding site 0 s yrosyl-trn trn sing P, catalyzes covalent bonding. 0 Pearson ducation, Inc. yrosine (yr) (amino ) minoacyl-trn P! Flexible pairing at the third base of a codon is called wobble and allows some trns to bind to more than one codon 0 Pearson ducation, Inc. (c) Symbol used in this book (b) hree-dimensional structure 0 Pearson ducation, Inc. Video: Stick and Ribbon Rendering of a trn nticodon nticodon nticodon (a) wo-dimensional structure 0 Pearson ducation, Inc. Figure.b! ll three stages require protein factors that aid in the translation process! nergy is required for some steps also Pearson ducation, Inc Pearson ducation, Inc.

6 0 Pearson ducation, Inc. ssociation and Initiation of ranslation! Initiation brings together, a trn with the first amino, and the two ribosomal s! First, a small ribosomal binds with and a special initiator trn! hen the small moves along the until it reaches the start codon ()! s called initiation factors bring in the large that completes the translation initiation complex 8 Figure.8 Initiator trn Start codon binding site P ribosomal P i + DP P site ribosomal ranslation initiation complex ribosomal binds ribosomal to. completes the initiation complex. 8 longation of the hain! During elongation, amino s are added one by one to the -terminus of the growing chain! ach addition involves proteins called elongation factors and occurs in three steps: codon recognition, peptide bond formation, and translocation! nergy expenditure occurs in the first and third steps! ranslation proceeds along the in a direction 8 Figure.9- mino end of P site site odon recognition P DP + P! i! P 8 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.9- mino end of P site site odon recognition P Figure.9- mino end of ready for next aminoacyl trn P site site odon recognition P ermination of ranslation! ermination occurs when a stop codon in the reaches the site of the ribosome Figure.0- Release factor DP + P! i! DP + P! i!! he site accepts a protein called a release factor P Peptide bond formation P DP + ranslocation P P! i! P Peptide bond formation! he release factor causes the addition of a water molecule instead of an amino! his reaction releases the, and the translation assembly comes apart codon (,, or ) reaches a stop codon on. P 8 P Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.0- Release Free factor codon (,, or ) reaches a Release factor stop codon on. promotes hydrolysis. Figure.0- Release Free factor P codon (,, or ) DP + P i reaches a Release factor Ribosomal s stop codon on. promotes hydrolysis. and other components dissociate. ompleting and argeting the Functional! Often translation is not sufficient to make a functional protein! chains are modified after translation or targeted to specific sites in the cell Folding and Post-ranslational Modifications! During its synthesis, a chain begins to coil and fold spontaneously to form a protein with a specific shape a three-dimensional molecule with secondary and tertiary structure! gene determines primary structure, and primary structure in turn determines shape! Post-translational modifications may be required before the protein can begin doing its particular job in the cell Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. argeting s to Specific Locations! wo populations of ribosomes are evident in cells: free ribosomes (in the cytosol) and bound ribosomes (attached to the R)! Free ribosomes mostly synthesize proteins that function in the cytosol! Bound ribosomes make proteins of the endomembrane system and proteins that are secreted from the cell! s are identical and can switch from free to bound 9! synthesis always begins in the cytosol! Synthesis finishes in the cytosol unless the signals the ribosome to attach to the R! s destined for the R or for secretion are marked by a signal peptide 9! signal-recognition particle (SRP) binds to the signal peptide! he SRP brings the signal peptide and its ribosome to the R 9 Figure. synthesis begins. SRP Signal peptide YOSOL R LMN SRP binds to signal peptide. SRP binds to receptor protein. SRP receptor protein ranslocation complex SRP detaches and synthesis resumes. Signalcleaving enzyme cuts off signal peptide. Signal peptide removed ompleted folds into final conformation. R membrane 9 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.

7 Figure. Figure.a ompleted rowing s Making Multiple s in Bacteria and ukaryotes Figure.b Incoming ribosomal s! Multiple ribosomes can translate a single simultaneously, forming a polyribosome (or polysome) Polyribosom Start of ( end) e Incoming ribosomal s (a) Several ribosomes simultaneously translating one molecule! Polyribosomes enable a cell to make many copies of a very quickly ompleted rowing s nd of ( end) s Start of ( end) s Polyriboso me nd of ( end) (a) Several ribosomes simultaneously translating one molecule (b) large polyribosome in a bacterial cell (M) 9 0 Pearson ducation, Inc. 0. µm 98 0 Pearson ducation, Inc. (b) large polyribosome in a bacterial cell (M) 99 0 Pearson ducation, Inc. Figure. 0. µm 00 0 Pearson ducation, Inc. Figure.a RN! bacterial cell ensures a streamlined process by coupling ion and translation! In this case the newly made protein can quickly diffuse to its site of function! In eukaryotes, the nuclear envelop separates the processes of ion and translation Polyribosome RN! RN undergoes processes before leaving the nucleus 0. µm Direction of ion RN Polyribosome Polyribosome 0. µm (amino end) ( end) 0 0 Pearson ducation, Inc. 0 0 Pearson ducation, Inc. Figure. Figure.a Figure.b RN RN RN (pre-) mino RN minoacyl-trn RN PROSSIN MINO ID IVION trn RN P P xon Ribosomal s mino minoacyl (charged) trn 0 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. nimation: ranslation oncept.: Mutations of one or a few nucleotides can affect protein structure and function nticodon MINO ID IVION trn odon nticodon odon minoacyl (charged) trn Ribosomal s minoacyl-trn minoacyl (charged) trn rowing RN (pre-) BioFlix: Synthesis xon RN PROSSIN 0 0 Pearson ducation, Inc. 0 0 Pearson ducation, Inc Pearson ducation, Inc Pearson ducation, Inc. Figure.! Mutations are changes in the genetic material of a cell or virus! Point mutations are chemical changes in just one base pair of a gene Wild-type β-globin! If a mutation has an adverse effect on the phenotype of the organism the condition is referred to as a genetic disorder or hereditary disease 09 0 Pearson ducation, Inc. Normal hemoglobin lu 0 0 Pearson ducation, Inc. Mutant β-globin! he change of a single nucleotide in a template strand can lead to the production of an abnormal protein 0 Pearson ducation, Inc. Sickle-cell β-globin Wild-type β-globin Sickle-cell hemoglobin Val 0 Pearson ducation, Inc.

8 0 Pearson ducation, Inc. ypes of -Scale Mutations! Point mutations within a gene can be divided into two general categories! Nucleotide-pair substitutions! One or more nucleotide-pair insertions or deletions Substitutions! nucleotide-pair substitution replaces one nucleotide and its partner with another pair of nucleotides! Silent mutations have no effect on the amino produced by a codon because of redundancy in the genetic code! Missense mutations still code for an amino, but not the correct amino! Nonsense mutations change an amino codon into a stop codon, nearly always leading to a nonfunctional protein Figure.a template strand Lys Phe ly mino end Nucleotide-pair substitution: silent instead of arboxyl end instead of Lys Phe ly Insertions and Deletions! Insertions and deletions are additions or losses of nucleotide pairs in a gene! hese mutations have a disastrous effect on the resulting protein more often than substitutions do! Insertion or deletion of nucleotides may alter the reading frame, producing a frameshift mutation 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.b template strand Lys Phe ly mino end Nucleotide-pair substitution: missense instead of instead of Lys Phe Ser arboxyl end New Mutations and Mutagens! Spontaneous mutations can occur during replication, recombination, or repair! Mutagens are physical or chemical agents that can cause mutations What Is a ene? Revisiting the Question! he idea of the gene has evolved through the history of genetics! We have considered a gene as! discrete unit of inheritance! region of specific nucleotide sequence in a chromosome! sequence that codes for a specific chain! gene can be defined as a region of that can be expressed to produce a final functional product that is either a or an RN molecule Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure. Figure.c Figure.d Figure.e template strand Lys Phe ly mino end arboxyl end (a) Nucleotide-pair substitution (b) Nucleotide-pair insertion or deletion instead of xtra instead of xtra Lys Phe ly Silent Frameshift ( nucleotide-pair insertion) instead of missing instead of missing Lys Phe Ser Lys Leu la Missense Frameshift ( nucleotide-pair deletion) instead of missing instead of missing Phe ly Nonsense nucleotide-pair deletion template strand Lys Phe ly mino end Nucleotide-pair substitution: nonsense instead of arboxyl end instead of template strand Lys Phe ly mino end arboxyl end Nucleotide-pair insertion: frameshift causing immediate nonsense xtra template strand Lys Phe ly mino end arboxyl end Nucleotide-pair deletion: frameshift causing extensive missense missing missing Lys Leu la 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. Figure.f Figure.N0 Figure.N0 Figure.N0 template strand mino end Lys Phe ly arboxyl end nucleotide-pair deletion: no frameshift, but one amino missing missing missing Phe ly Pre- Pre- 8 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.

9 0 Pearson ducation, Inc. Figure.N0a Figure.N0b Figure.N0c Figure.N0 thr lac lacy lacz lacl rec galr metj lex trpr 8 0 Sequence alignment Sequence logo 0 Pearson ducation, Inc Pearson ducation, Inc Promoter RN ranscription unit RN emplate strand of 0 Pearson ducation, Inc. Figure.N0 Figure.N08 Figure.N09 Figure.N0 ap xon xon Pre- Poly- tail xon trn mino ype of RN Messenger RN () ransfer RN (trn) Functions R oding R segment odon nticodon Primary RNs in the spliceosome Plays catalytic (ribozyme) roles and structural roles in ribosomes 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc. 0 Pearson ducation, Inc.