Biology Final

7/28/2019 Biology Final

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(1) Chapter title: The Molecular Basis of Inheritance

(a) [the molecular basis inheritance (Google Search)] [index]

(2) Chromosomes

(a) Chromosomes consist ofDNA andprotein

(b) Which is the hereditary material? The history of our understanding is

outlined in the efforts of the following:(i) Griffith, 1928

(ii) Avery, MacLeod, and McCarty, 1944

(iii) Hershey and Chase, 1952(iv) Chargaff

(v) Franklin and Wilkins

(vi) Watson and Crick, 1953

(c) [chromosomes (Google Search)] [index]

(3) Griffith, 1928

(a) Griffith discovered a hereditary molecule that was transmittable between

bacteria

(b) See Figure 16.1, Transformation of bacteria(c) [Griffith 1928 (Google Search)] [index]

(4) Avery, MacLeod, and McCarty, 1944

(a) Avery et al. found that Griffithstransmittable hereditary molecule is

DNA

(b) In particular, they showed that the transmittable hereditary molecule wassusceptible to the DNA hydrolyzing enzyme known generically as DNAse

(c) [Avery MacLeod McCarty,DNAse OR DNAase,DNAse,DNAase

(Google Search)] [index]

(5) Hershey and Chase, 1952

(a) Hershey and Chase showed that the hereditary material in T2

bacteriophages is DNA, thereby generalizing Avery, MacLeod, andMcCartysobservation

(b) See Figure 16.2, The Hershey-Chase experiment

(c) [Hershey Chase,Alfred Day Hershey (Google Search)] [the bacteriophage

ecology group (Microdude)] [index]

(6) Chargaff (Chargaffs rule)

(a) Chargaff found that different species of organisms have different DNA

nucleotide compositions

(b) Chargaffs rule states that the fraction of nucleotides that makes up anorganisms DNA always behaves the rule: the fraction ofAs = the

fraction ofTs, and the fraction ofGs = the fraction ofCs (i.e., the

fractions of A + T + G + C = 1; A = T and G = C; 2 * (A + G) = 1, etc.)(c) [Chargaff,Chargaff's rule (Google Search)] [index]

(7) Franklin and Wilkins

(a) Franklin and Wilkins are responsible for supplying an X-ray diffraction ofDNA, essentially an in-this-case crude molecular picture of the molecule,

that indicated the basic structural features that DNA possesses:

(i) The periodicity of DNA

(ii) The molecules uniform width
http://www.google.com/search?q=the+molecular+basis+inheritance&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl13.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#griffith_1928%23griffith_1928http://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://mansfield.osu.edu/~sabedon/campbl16.htm#hershey_and_chase_1952%23hershey_and_chase_1952http://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#watson_and_crick_1953%23watson_and_crick_1953http://www.google.com/search?q=chromosomes&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/search?q=Griffith+1928&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#griffith_1928%23griffith_1928http://mansfield.osu.edu/~sabedon/campbl16.htm#griffith_1928%23griffith_1928http://www.google.com/search?q=Avery+MacLeod+McCarty&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAse+OR+DNAase&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAse+OR+DNAase&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAsehttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAsehttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAase&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAase&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://www.google.com/search?q=Hershey+Chase&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=Hershey+Chase&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=Alfred+Day+Hershey&btnG=Google+Searchhttp://www.google.com/http://www.phage.org/http://www.phage.org/http://mansfield.osu.edu/~sabedon/homepage_index.htmhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#adeninehttp://mansfield.osu.edu/~sabedon/campbl05.htm#thyminehttp://mansfield.osu.edu/~sabedon/campbl05.htm#guaninehttp://mansfield.osu.edu/~sabedon/campbl05.htm#guaninehttp://mansfield.osu.edu/~sabedon/campbl05.htm#cytocinehttp://mansfield.osu.edu/~sabedon/campbl05.htm#cytocinehttp://www.google.com/search?hl=en&lr=&safe=off&q=Chargaffhttp://www.google.com/search?hl=en&lr=&safe=off&q=Chargaff%27s+Rule&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=Chargaff%27s+Rule&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl13.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#griffith_1928%23griffith_1928http://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://mansfield.osu.edu/~sabedon/campbl16.htm#hershey_and_chase_1952%23hershey_and_chase_1952http://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#watson_and_crick_1953%23watson_and_crick_1953http://www.google.com/search?q=chromosomes&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/search?q=Griffith+1928&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#griffith_1928%23griffith_1928http://www.google.com/search?q=Avery+MacLeod+McCarty&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAse+OR+DNAase&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAsehttp://www.google.com/search?hl=en&lr=&safe=off&q=DNAase&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://mansfield.osu.edu/~sabedon/campbl16.htm#avery_macleod_and_mccarty_1944%23avery_macleod_and_mccarty_1944http://www.google.com/search?q=Hershey+Chase&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=Alfred+Day+Hershey&btnG=Google+Searchhttp://www.google.com/http://www.phage.org/http://www.phage.org/http://mansfield.osu.edu/~sabedon/homepage_index.htmhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#adeninehttp://mansfield.osu.edu/~sabedon/campbl05.htm#thyminehttp://mansfield.osu.edu/~sabedon/campbl05.htm#guaninehttp://mansfield.osu.edu/~sabedon/campbl05.htm#cytocinehttp://www.google.com/search?hl=en&lr=&safe=off&q=Chargaffhttp://www.google.com/search?hl=en&lr=&safe=off&q=Chargaff%27s+Rule&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/search?q=the+molecular+basis+inheritance&hq=&hl=en&lr=&safe=off


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(iii) That the nitrogenous bases stacked 0.34 nm apart

(b) See Figure 16.4, Rosalind Franklin and her X-ray diffraction photo of

DNA

(c) [Franklin Wilkins DNA,DNA X-ray diffraction(Google Search)] [index]

(8) Watson and Crick, 1953

(a) Watson and Crick, in 1953, published the double helix model of DNAsstructure

(b) J. D. Watson and F. H. C. Crick (1953). Molecular Structure of Nucleic

Acids.Nature, vol. 171 (25 April 1953), pages 737-738(c) This paper was, arguably, the single most important contribution to

biology (and perhaps even chemistry as well) of the twentieth century

(d) See Figure 16.5, The double helix

(e) The Watson and Crick model:(i) Explains DNAs periodicity

(ii) Explains DNAs uniform width

(iii) Explains Chargaffs rule

(iv) Explains how DNA is replicated(f) (you will not be held responsible for the above history)

(g) [Watson Crick,double helix (Google Search)] [annotated version ofWatson & Crick, 1953!, (nice index of gifs and html files but I have no

idea who the author is)] [index]

(9) Base sequence

(a) The sequence of bases in a DNAmolecule represent information

(b) This sequence is effectively unconstrained by the structure of the double

helix

(c) As a consequence, much of the DNA in a chromosome (i.e., that whichmakes upgenes) represents unique nucleotidesequences

(d) The rest consists of various repeated sequences which typically arespecies

specific(e) [base sequence(Google Search)] [index]

(10) Strand complementarity

(a) Because of base pairingand the making up of adouble helix ofDNA oftwo separate strands, there exists a redundancy of information carried by

the double helix

(b) Note, however, that the two DNAs do not possess the same sequence

(c) Instead, each possesses the complementary sequence of the other(d) Another way of saying this is that throughbase pairing one strand is

capable of specifying the sequence of the other strand, and vice versa

(e) This sequence complementarity forms the basis of DNA-templated DNApolymerization (i.e., DNA replication)

(f) [strand complementarity (Google Search)] [index]

(11) Semiconservative DNA replication

(a) The specific mechanism by which DNA is replicated is termed

semiconservative
http://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://www.google.com/search?q=Franklin+Wilkins+DNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNA+X-ray+diffraction&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNA+X-ray+diffraction&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNA+X-ray+diffraction&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#chromosomes%23chromosomeshttp://www.google.com/search?q=Watson+Crick&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=Watson+Crick&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=double+helixhttp://www.google.com/http://millenium.salem.k12.va.us/shs/science/biochem/watcri.htmhttp://millenium.salem.k12.va.us/shs/science/biochem/watcri.htmhttp://millenium.salem.k12.va.us/shs/science/biochem/http://millenium.salem.k12.va.us/shs/science/biochem/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl11.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl12.htm#geneshttp://mansfield.osu.edu/~sabedon/campbl12.htm#geneshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl24.htm#specieshttp://mansfield.osu.edu/~sabedon/campbl24.htm#specieshttp://www.google.com/search?q=base+sequence&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=base+sequence&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#base_pairinghttp://mansfield.osu.edu/~sabedon/campbl05.htm#base_pairinghttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#base_pairinghttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://www.google.com/search?q=strand+complementarity&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://www.google.com/search?q=Franklin+Wilkins+DNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=DNA+X-ray+diffraction&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#franklin_and_wilkins%23franklin_and_wilkinshttp://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#chromosomes%23chromosomeshttp://www.google.com/search?q=Watson+Crick&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?hl=en&lr=&safe=off&q=double+helixhttp://www.google.com/http://millenium.salem.k12.va.us/shs/science/biochem/watcri.htmhttp://millenium.salem.k12.va.us/shs/science/biochem/watcri.htmhttp://millenium.salem.k12.va.us/shs/science/biochem/http://millenium.salem.k12.va.us/shs/science/biochem/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl11.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl12.htm#geneshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl24.htm#specieshttp://www.google.com/search?q=base+sequence&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#base_pairinghttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#base_pairinghttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://www.google.com/search?q=strand+complementarity&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dna


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(b) Despite the long, confusing word used to describe it, this is actually the

simplest mechanism by which template-dependent DNA replication might

occur(c) In short, semiconservative DNA replication consists of each strand of

DNA in adouble helixspecifying thepolymerization of a new strand

which, in turn, remains attached to its parent strand(d) This parent-daughter strand forms a new double helix that consists of both

a parental strand of DNA and a newly synthesized strand of DNA

(e) (note that above I am using the term strand synonymous to singlemolecule of DNA, i.e., half of a double helix)

(f) See Figure 16.7, A model for DNA replication: the basic concept

(g) [semiconservative DNA replication (Google Search)] [index]

(12) 5 3 polarity(a) Recall that the sugars of nucleic acids are numbered with primes (i.e., 1

through 5)(b) Recall additionally that the backbone of polymerizednucleic acids consists

of the 3 through 5 carbons alternating with a covalently bondedphosphate group

(c) See Figure 16.11, Incorporation of a nucleotide into a DNA strand

(d) [5' 3' polarity (Google Search)] [index]

(13) Antiparallel strands

(a) Recall additionally that the twoDNA strands that make up a double helixare arranged antiparallelly

(b) That is, starting from one end of the double helix, one strand runs in the 5

3 direction while the other runs in the 3 5 direction

(c) See Figure 16.12, The two strands of DNA are antiparallel

(d) This antiparallel nature of DNA impacts on DNA replication

(e) [antiparallel strands (Google Search)] [index](14) 5 3 direction of synthesis

(a) During DNA synthesis, incoming subunits arrive with phosphates

(b) They attach to the 3 OH exposed at the end of the growing new strand

(c) This supplies the phosphate making up the sugar-phosphate backbone ofDNA

(d) It also constrains the growth of the new DNA strand to the 5 to 3

direction(e) That is, for each DNA molecule there exists a 5 end at which no synthesis

is occurring (directly, anyway) and a 3 end at which synthesis may occur

(f) See Figure 16.11, Incorporation of a nucleotide into a DNA strand

(g) [5' 3' direction of synthesis (Google Search)] [index](15) Nucleosides

(a) The incoming subunit, in fact, does not carry just one phosphate

(b) Instead it carries three phosphates (i.e., their structure is analogous to thatofATP)

(c) Nucleosides that carry a single phosphate are called nucleotides and this is

what remains following the addition of a nucleoside triphosphates to agrowing DNA (or RNA) polymer
http://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#polymerizationhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://www.google.com/search?q=semiconservative+DNA+replication&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/black02.htm#covalent_bondshttp://www.google.com/search?q=5%27+3%27+polarity&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://www.google.com/search?q=antiparallel+strands&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/search?q=5%27+3%27+direction+of+synthesis&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/black05.htm#atphttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://mansfield.osu.edu/~sabedon/campbl05.htm#polymerizationhttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://www.google.com/search?q=semiconservative+DNA+replication&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/black02.htm#covalent_bondshttp://www.google.com/search?q=5%27+3%27+polarity&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#double_helixhttp://www.google.com/search?q=antiparallel+strands&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://www.google.com/search?q=5%27+3%27+direction+of+synthesis&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/black05.htm#atphttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotides


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(d) The hydrolytic removal of two of these phosphates supplies the energy

employed to attach the subunit to the 3 OH of the growing DNA strand

(e) See Figure 16.11, Incorporation of a nucleotide into a DNA strand

(f) [nucleoside -HIV (Google Search)] [index]

(16) DNA polymerase

(a) Theenzyme that catalyzes this template-directed conversion ofnucleosides into an elongated DNA strand is called DNA polymerase

(b) Note that DNA polymerase can elongate a strand of DNA only in the 5

3 direction

(c) See Figure 16.11, Incorporation of a nucleotide into a DNA strand

(d) See Figure 16.12, The two strands of DNA are antiparallel

(e) [DNA polymerase(Google Search)] [index]

(17) RNA priming

(a) DNA polymerase attaches new nucleotides with high fidelity (thus

reducing errors)(b) This high-fidelity nucleotideaddition requires the existence of a 3 OH

(c) This means that DNA polymerase cannot initiate DNA replication since, atthe start of DNA replication, the to-be-synthesized DNA strand does not

yet possess a 3 OH (i.e., the strand does not yet exist)(d) This problem of how to initiate DNA replication in the absence of a 3

OH is solved by priming using RNA

(e) See Figure 16.14, Priming DNA synthesis with RNA

(f) [RNA priming(Google Search)] [index]

(18) Primase

(a) DNA replication is initiated with RNA by anenzyme called primase(b) Primase can initiate template-directedpolymerization without a 3 OH

(c) Thus, DNA polymeraseuses a RNA 3 OH to initiate replication

(d) The RNA is then eventually replaced by DNA(e) Note that replacing the RNA with DNA at the very ends of linearchromosomes is a problem (no matter what, the very end will never have a

3 OH), thus explaining, in part, the problem oftelomere erosion in

eukaryotes

(f) See Figure 16.14, Priming DNA synthesis with RNA

(g) [primase (Google Search)] [index]

(19) Origins of replication

(a) One place thatprimaseacts is at certain DNAsequences called origins of

replication

(b) This is the site of priming of the leading strand of DNA replication

(c) See Figure 16.10: Origins of replication in eukaryotes(d) [origins of replication (Google Search)] [index]

(20) Replication fork

(a) One role of these replication origin proteins is to open up the double helixso that both strands are exposed as single-strand DNA, i.e., as potential

templates

(b) The local bubble created by this separation of strands about the origin isbordered at each end with a replication fork
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(c) It is at these replication forks that the parent double helix is unwound and

daughter DNA strands are synthesized, thus converting one double helix

into two

(d) See Figure 16.10: Origins of replication in eukaryotes

(e) [replication fork(Google Search)] [index]

(21) Leading strand(a) Note that because of the antiparallel nature of thedouble helix, as the

replication forkopens, for one DNA strand the opening occurs in the 3

5 direction while for the other DNA strand the opening occurs in the 5

3 direction

(b) See Figure 16.12, Synthesis of leading and lagging strands during

DNA replication

(c) Note that both new daughter strands are laid down in a 5 3 direction

antiparallel to each template (parent) strand

(d) As a consequence, for only one daughter strand will the replication fork be

opening such as to allow unimpeded 5 3 synthesis

(e) This unimpeded strand is called the leading strand(f) [leading strand (Google Search)] [index]

(22) Lagging strand

(a) The other strand must be replicated in the direction leading away from the

replication fork

(b) Consequently, the replication of this other strand is discontinuous(c) Its replication must wait for the replication fork to sufficiently open up the

DNA so that a reasonably large number ofnucleotides are exposed (on the

order of 100 to 1000 depending on system)(d) Then at the replication fork RNA synthesis must beprimed, thus priming

DNA synthesis which then proceeds in the 5 3 direction

(e) At the other endDNA polymerase eventually (a fraction of a second later)bumps into the RNA from a previous priming

(f) This RNA is stripped away by the DNA polymerase and replaced with

DNA

(g) The new segment of DNA is then ligated to the downstream DNA strand(h) This represents the complex synthesis of the lagging strand

(i) See Figure 16.12, Synthesis of leading and lagging strands during

DNA replication

(j) [lagging strand(Google Search)] [index]

(23) Okazaki fragments

(a) The fragments of DNA synthesized to make up thelagging strand are

called Okazaki fragments for their discoverer(b) [okazaki fragment or fragments (Google Search)] [index]

(24) DNA ligase

(a) Theenzyme that ligates together the Okazaki fragments is called DNA

ligase

(b) [DNA ligase (Google Search)] [index]

(25) The replication fork, a summary

(a) See Figure 16.16, A summary of DNA replication
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(b) Note:

(i) The helicase enzyme

(ii) Single-stranded binding protein(iii) Proofreading

(c) [replication fork(Google Search)] [index]

(26) Helicase(a) Theenzyme that opens the replication fork is called helicase

(b) This name refers to the fact that the double helix is unwound (helically, get

it?) at the replication fork(c) [helicase (Google Search)] [index]

(27) Single-strand binding protein

(a) An unwound double helix is unstable

(b) To prevent the individual strand from reannealing prior to the synthesis ofthe new daughter strand, aproteinis employed to stabilize the single-

stranded DNA

(c) This protein is called single-strand binding protein

(d) [single strand binding protein (Google Search)] [index](28) Proofreading(a) In addition to all of the above (and much not mentioned) another problem

run into during DNA replicationis that template directed replication is not

sufficient to achieve the high fidelity of DNA replication that organisms

achieve(b) That is, the interaction between complementary bases is not precise

enough to allow the level of DNA replication fidelity most organisms

shoot for

(c) An additional level of fidelity is achieved by what is known asproofreading

(d) During DNA replication, the newly attached bases are checked to make

sure they really are the correct, complementary bases(e) Those that are not are removed and replaced

(f) In prokaryotes this is yet another function of the DNA polymerase while

eukaryotes (in all their complexity) use additional proteins(g) RNA viruses, like HIV and influenza virus, by the way, do not employ

proofreading and consequently possess much higher mutation rates than do

most DNA-based organisms; this high mutation rate allows HIV (and

influenza virus, etc.) to evolve maddeningly quickly(h) Finally, note that your text on page 290 seems to confuse mutation and

DNA damage (as in Fortunately, these changes, or mutations, are usually

corrected); try not to let this get to you(i) [proofreading replication(Google Search)] [index]

(29) Telomeres (telomerase)

(a) The end of a linear chromosome presents an additional DNA replicationproblem: At the end of a chromosome RNA priming cannot supply a 3

OH

(b) Why not? There is no sequence beyond the end of the chromosome to

template the polymerization of the priming RNA sequence
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(c) As a consequence, the ends of linear chromosomes tend to erode with

every replication (i.e., the very ends arent replicated so are lost, and this

effect is cumulative so that each chromosomal replication results in a lossof additional DNA)

(d) To guard against this erosion, eukaryotes possess regions of DNA at the

end of their chromosomes called telomeres that serve essentially as DNA-erosion buffers

(e) That is, the telomeres, which are otherwise not important for chromosome

functioning, erode rather important parts (e.g., protein-coding regions)(f) To replace eroded telomeres, eukaryotes employ an enzyme called

telomerase

(g) Telomerase, however, is mostly found in cells that are immortal (e.g.,

germ line cells) or in the developing organism(h) The absence of telomerase places an upper limit on how many times the

cells in your body may divide, thus providing an additional level of

protection against uncontrolled cell growth such as that seen with cancer

(i) See Figure 16.19, Telomeres and telomerase(j) [telomere or telomeres,telomerase (Google Search)] [index]

(30) (Review transcription if you have time)(31) Vocabulary [index]

(a) Antiparallel strands

(b) Base sequence(c) Chargaff

(d) Chromosomes

(e) DNA ligase

(f) DNA polymerase(g) Helicase

(h) Lagging strand

(i) Leading strand(j) Nucleosides

(k) Okazaki fragments

(l) Origins of replication(m) Primase

(n) Proofreading

(o) Replication fork

(p) RNA priming(q) The replication fork, a summary

(r) Semiconservative DNA replication

(s) Single-strand binding protein(t) Strand complementarity

(u) Telomerase

(v) Telomeres

(w) 5 3 direction of synthesis

(x) 5 3 polarity
http://www.google.com/search?q=telomere+OR+telomeres&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=telomerase&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=telomerase&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htmhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#antiparallel_strands%23antiparallel_strandshttp://mansfield.osu.edu/~sabedon/campbl16.htm#base_sequence%23base_sequencehttp://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#chromosomes%23chromosomeshttp://mansfield.osu.edu/~sabedon/campbl16.htm#dna_ligase%23dna_ligasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#dna_polymerase%23dna_polymerasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#helicase%23helicasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#lagging_strand%23lagging_strandhttp://mansfield.osu.edu/~sabedon/campbl16.htm#leading_strand%23leading_strandhttp://mansfield.osu.edu/~sabedon/campbl16.htm#nucleosides%23nucleosideshttp://mansfield.osu.edu/~sabedon/campbl16.htm#okazaki_fragments%23okazaki_fragmentshttp://mansfield.osu.edu/~sabedon/campbl16.htm#origins_of_replication%23origins_of_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#primase%23primasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#proofreading%23proofreadinghttp://mansfield.osu.edu/~sabedon/campbl16.htm#replication_fork%23replication_forkhttp://mansfield.osu.edu/~sabedon/campbl16.htm#rna_priming%23rna_priminghttp://mansfield.osu.edu/~sabedon/campbl16.htm#the_replication_fork_a_summary%23the_replication_fork_a_summaryhttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#single_strand_binding_protein%23single_strand_binding_proteinhttp://mansfield.osu.edu/~sabedon/campbl16.htm#strand_complementarity%23strand_complementarityhttp://mansfield.osu.edu/~sabedon/campbl16.htm#telomerase%23telomerasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#telomeres%23telomereshttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_3_prime_synthesis%23five_prime_to_3_prime_synthesishttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_3_prime_synthesis%23five_prime_to_3_prime_synthesishttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_3_prime_synthesis%23five_prime_to_3_prime_synthesishttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_three_prime_polarity%23five_prime_to_three_prime_polarityhttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_three_prime_polarity%23five_prime_to_three_prime_polarityhttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_three_prime_polarity%23five_prime_to_three_prime_polarityhttp://www.google.com/search?q=telomere+OR+telomeres&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=telomerase&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htmhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htm#antiparallel_strands%23antiparallel_strandshttp://mansfield.osu.edu/~sabedon/campbl16.htm#base_sequence%23base_sequencehttp://mansfield.osu.edu/~sabedon/campbl16.htm#chargaff%23chargaffhttp://mansfield.osu.edu/~sabedon/campbl16.htm#chromosomes%23chromosomeshttp://mansfield.osu.edu/~sabedon/campbl16.htm#dna_ligase%23dna_ligasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#dna_polymerase%23dna_polymerasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#helicase%23helicasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#lagging_strand%23lagging_strandhttp://mansfield.osu.edu/~sabedon/campbl16.htm#leading_strand%23leading_strandhttp://mansfield.osu.edu/~sabedon/campbl16.htm#nucleosides%23nucleosideshttp://mansfield.osu.edu/~sabedon/campbl16.htm#okazaki_fragments%23okazaki_fragmentshttp://mansfield.osu.edu/~sabedon/campbl16.htm#origins_of_replication%23origins_of_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#primase%23primasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#proofreading%23proofreadinghttp://mansfield.osu.edu/~sabedon/campbl16.htm#replication_fork%23replication_forkhttp://mansfield.osu.edu/~sabedon/campbl16.htm#rna_priming%23rna_priminghttp://mansfield.osu.edu/~sabedon/campbl16.htm#the_replication_fork_a_summary%23the_replication_fork_a_summaryhttp://mansfield.osu.edu/~sabedon/campbl16.htm#semiconservative_dna_replication%23semiconservative_dna_replicationhttp://mansfield.osu.edu/~sabedon/campbl16.htm#single_strand_binding_protein%23single_strand_binding_proteinhttp://mansfield.osu.edu/~sabedon/campbl16.htm#strand_complementarity%23strand_complementarityhttp://mansfield.osu.edu/~sabedon/campbl16.htm#telomerase%23telomerasehttp://mansfield.osu.edu/~sabedon/campbl16.htm#telomeres%23telomereshttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_3_prime_synthesis%23five_prime_to_3_prime_synthesishttp://mansfield.osu.edu/~sabedon/campbl16.htm#five_prime_to_three_prime_polarity%23five_prime_to_three_prime_polarity


8/47

Course-external links are in

brackets

Click [index] to access site indexClickhere to access texts website

Vocabulary wordsare found below

(1) Chapter title: From Gene to Protein

(a) The DNA inherited by an organism leads to specific traits by dictating the

synthesis of certainproteins. Proteins are the links between genotypeandphenotype.

(b) [from gene to protein(Google Search)] [index]

(2) Central dogma of molecular genetics

(a) The central dogma of molecular genetics is typically depicted as ashorthand review of how genetic information moves around a cell, or from

parent to offspring.

(b) The central dogma looks like this:

(i) DNA

DNA

RNA

protein(c) Note that we can give names to these various steps:

(i) DNA DNA = replication(direction of arrow is arbitrary)

(ii) DNA RNA = transcription (direction of arrow is not arbitrary)

(iii) RNA protein = translation (ditto)

(d) This chapter deals particularly with the last two, transcription andtranslation

(e)

(f) (reverse transcription serves as an exception to the central dogma as

originally conceived; it consists of DNA RNA, i.e., RNA DNA, and

is employed by such things asretrovirusesincluding the virusthat causesAIDS; note in the above figure that, of course, proteins also serve as

enzymes)

(g) [central dogma,central dogma molecular genetics (Google Search)]

[index]
http://mansfield.osu.edu/~sabedon/biology.htmhttp://occ.awlonline.com/bookbind/pubbooks/campbell_awl/chapter2/deluxe.htmlhttp://mansfield.osu.edu/~sabedon/campbl17.htm#vocabulary%23vocabularyhttp://mansfield.osu.edu/~sabedon/campbl17.htm#vocabulary%23vocabularyhttp://mansfield.osu.edu/~sabedon/campbl013.htm#traithttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl14.htm#genotypehttp://mansfield.osu.edu/~sabedon/campbl14.htm#genotypehttp://mansfield.osu.edu/~sabedon/campbl14.htm#phenotypehttp://www.google.com/search?hl=en&lr=&safe=off&q=from+gene+to+protein&btnG=Google+Searchhttp://www.google.com/search?hl=en&lr=&safe=off&q=from+gene+to+protein&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/cambl05.htm#dnahttp://mansfield.osu.edu/~sabedon/cambl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl16.htmhttp://mansfield.osu.edu/~sabedon/campbl16.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl18.htm#retroviruseshttp://mansfield.osu.edu/~sabedon/campbl18.htm#retroviruseshttp://mansfield.osu.edu/~sabedon/campbl18.htm#retroviruseshttp://mansfield.osu.edu/~sabedon/campbl18.htm#virus_distinguishing_characteristicshttp://mansfield.osu.edu/~sabedon/campbl18.htm#virus_distinguishing_characteristicshttp://mansfield.osu.edu/~sabedon/black18.htm#aidshttp://www.google.com/search?q=central+dogma&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=central+dogma&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=central+dogma+molecular+genetics&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://ntri.tamuk.edu/homepage-ntri/lectures/biology/central-dogma.gifhttp://www.phage.org/http://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://occ.awlonline.com/bookbind/pubbooks/campbell_awl/chapter2/deluxe.htmlhttp://mansfield.osu.edu/~sabedon/campbl17.htm#vocabulary%23vocabularyhttp://mansfield.osu.edu/~sabedon/campbl013.htm#traithttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl14.htm#genotypehttp://mansfield.osu.edu/~sabedon/campbl14.htm#phenotypehttp://www.google.com/search?hl=en&lr=&safe=off&q=from+gene+to+protein&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/cambl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl16.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl18.htm#retroviruseshttp://mansfield.osu.edu/~sabedon/campbl18.htm#virus_distinguishing_characteristicshttp://mansfield.osu.edu/~sabedon/black18.htm#aidshttp://www.google.com/search?q=central+dogma&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=central+dogma+molecular+genetics&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htm


9/47

(3) RNA (uracil)

(a) See Figure 17.2, Overview: the roles of transcription and translation

in the flow of genetic information

(b) RNAis anucleic acidpolymerthat resembles DNAexcept

(i) RNA uses the sugarribose instead of deoxyribose

Ribose has an OH group at the 2 carbon instead of the H seenwith deoxyribose found in DNA

(ii) RNA employs the nitrogenous base uracil (U) instead of the

pyrimidinethymine

For the latter point, that is, T U

The analogous base-pairing is U-A

Note that U is energetically cheaper to make than T but that U is

also less stable than T

(c) [RNA,uracil (Google Search)] [index]

(4) One gene-one polypeptide hypothesis

(a) Beadle and Tatum developed the one gene-one enzyme hypothesis in the

1940s(b) The idea is that Mendels hereditary units are found in DNA but work by

specifying enzymes

(c) This hypothesis was modified to one gene-one protein since not all

proteins are enzymes but genes work by specifying proteins(d) Finally, this hypothesis was modified to one gene-one polypeptide since

many proteins consist of more than one polypeptide

(e) Genes specify the construction of specific polypeptides(f) (in fact, to deconstruct things further, genes specify thetranscription of

specific RNAs)

(g) See Figure 17.1, Beadle and Tatums evidence for the one geneone

enzyme hypothesis(h) ["one gene one protein", "one gene one polypeptide", "one gene one

peptide" (Google Search)] [index]

TRANSCRIPTION

(5) Transcriptionintroduction (template strand)

(a) TheDNARNA flow of genetic information is termed transcription(b) The term transcription reflects that the information in DNA (i.e.,

nucleotide sequence) is copied into a similar code in RNA

(c) Only one strand of the two possible strands of DNA is typically copied(always one strand per transcriptional unit)

(d) In different places on achromosome the other strand may be copied

(e) The DNA strand that provides the complementary template to RNApolymerization is called the template strand

(f) The RNA can be of a number of types including:

(i) Messenger RNA (mRNA)

(ii) Transfer RNA(tRNA)
http://mansfield.osu.edu/~sabedon/campbl05.htm#rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#polymerhttp://mansfield.osu.edu/~sabedon/campbl05.htm#polymerhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#sugarshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://mansfield.osu.edu/~sabedon/campbl05.htm#pyrimidinehttp://mansfield.osu.edu/~sabedon/campbl05.htm#thyminehttp://mansfield.osu.edu/~sabedon/campbl05.htm#adeninehttp://www.google.com/search?q=RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=uracil&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl06.htm#enzymeshttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://www.google.com/search?q=%22one+gene+one+protein%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+polypeptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+peptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+peptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl11.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl11.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl17.htm#messenger_rna%23messenger_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_1%23transfer_rna_1http://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_1%23transfer_rna_1http://mansfield.osu.edu/~sabedon/campbl05.htm#rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleic_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#polymerhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#sugarshttp://mansfield.osu.edu/~sabedon/campbl05.htm#nitrogenous_baseshttp://mansfield.osu.edu/~sabedon/campbl05.htm#pyrimidinehttp://mansfield.osu.edu/~sabedon/campbl05.htm#thyminehttp://mansfield.osu.edu/~sabedon/campbl05.htm#adeninehttp://www.google.com/search?q=RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=uracil&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl06.htm#enzymeshttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://www.google.com/search?q=%22one+gene+one+protein%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+polypeptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+peptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/search?q=%22one+gene+one+peptide%22&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl11.htm#chromosomehttp://mansfield.osu.edu/~sabedon/campbl17.htm#messenger_rna%23messenger_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_1%23transfer_rna_1


10/47

(iii) Ribosomal RNA (rRNA)

(iv) Etc. (e.g.,spliceosomes)

(g) See Figure 17.2, Overview: the roles of transcription and translation


(h) (see transcription in detail, below)

(i) [RNA transcription, template strand (Google Search)] [index](6) Messenger RNA (mRNA)(a) If theRNA produced bytranscriptionis to be used to code for the

synthesis of proteins, it is called messenger RNA (a.k.a., mRNA)(b) [messenger RNA, mRNA (Google Search)] [index]

(7) Transfer RNA (1) (tRNA)

(a) Another category of RNA, used duringprotein synthesisto ferry amino

acids to growing peptide chains, is called transfer RNA (a.k.a., tRNA)(b) (for more information, seetransfer RNA, below)

(c) [transfer RNA, tRNA (Google Search)] [index]

(8) Ribosomal RNA (rRNA)

(a) Another category of RNA that together constitute about 60% of the massofribosomesis called ribosomal RNA or rRNA

(b) (inEscherichia coli cells, ribosomes make up 25% of the dry weight ofcells)

(c) [ribosomal RNA,rRNA (Google Search)] [index]

(9) Translationintroduction

(a) TheRNAprotein flow of genetic information is termed translation

(b) The term translation reflects that the information in mRNAs (i.e.,

nucleotide sequence) is translated into a new language, i.e., amino acidsequence

(c) See Figure 17.2, Overview: the roles of transcription and translation

in the flow of genetic information(d) (see translation in detail, below)(e) [protein translation (Google Search)] [index]

(10) Eucaryotic segregation of transcription and translation

(a) Note that due to the existence of the nuclear membrane in eucaryotes,there exists a temporal and spatial separation oftranscription and

translation

(b) See Figure 17.2, Overview: the roles of transcription and translation


(c) Transcription occurs within the nucleus, where the DNA resides

(d) Translation occurs within the cytosol, where the functionalribosomes

reside(e) There is no such segregation of transcription and translation in prokaryotes

(f) [segregation of translation and transcription (Google Search)] [index]

(11) Codons

(a) The DNA and RNA nucleotide sequence code consists of one of four types

of nucleotides (4 each, that is)

(b) Theamino acid sequence code consists of 20 amino acids
http://mansfield.osu.edu/~sabedon/campbl17.htm#ribosomal_rna%23ribosomal_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#spliceosome%23spliceosomehttp://mansfield.osu.edu/~sabedon/campbl17.htm#spliceosome%23spliceosomehttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_in_detail%23transcription_in_detailhttp://www.google.com/search?q=RNA+transcription&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=template+strand&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://www.google.com/search?q=messenger+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=mRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_2%23transfer_rna_2http://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_2%23transfer_rna_2http://www.google.com/search?q=transfer+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=tRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=ribosomal+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=ribosomal+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=rRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_in_detail%23translation_in_detailhttp://www.google.com/search?q=protein+translation&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl07.htm#nuclear_membranehttp://mansfield.osu.edu/~sabedon/campbl07.htm#eukaryotehttp://mansfield.osu.edu/~sabedon/black07.htm#transcriptionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl07.htm#nucleushttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl07.htm#cytosolhttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=segregation+of+translation+and+transcription&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#ribosomal_rna%23ribosomal_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#spliceosome%23spliceosomehttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_in_detail%23transcription_in_detailhttp://www.google.com/search?q=RNA+transcription&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=template+strand&hq=&hl=en&lr=&safe=off&btnG=Google+Searchhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://www.google.com/search?q=messenger+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=mRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transfer_rna_2%23transfer_rna_2http://www.google.com/search?q=transfer+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=tRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=ribosomal+RNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=rRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/black02.htm#proteinshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_in_detail%23translation_in_detailhttp://www.google.com/search?q=protein+translation&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl07.htm#nuclear_membranehttp://mansfield.osu.edu/~sabedon/campbl07.htm#eukaryotehttp://mansfield.osu.edu/~sabedon/black07.htm#transcriptionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://mansfield.osu.edu/~sabedon/campbl07.htm#nucleushttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl07.htm#cytosolhttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=segregation+of+translation+and+transcription&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#nucleotideshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acids


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(c) In translating from nucleotide sequence to amino acid sequence there

cannot be a one-to-one correspondence (4 < 20)

(d) There also cannot be a two-to-one correspondence (42 < 20)(e) Instead there exists a three to one correspondence (43 > 20)

(f) The three nucleotides that specify an amino acid during translation are

called codons(g) See Figure 17.3, The triplet code

(h) See Figure 17.4, The dictionary of the genetic code

(i) [codons or codon(Google Search)] [the genetic code (the table of codonsand what that means) (Shaun D. Black)] [index]

(12) Codons are a property of mRNA

(a) Note that codonsexist in mRNA, but only their complement exists on the

template strand of DNA(b) (though note, additionally, that on the non-template strand of DNA the

analogous DNA codonsthough without uracilexists)

(c) See Figure 17.4, The dictionary of the genetic code

(d) [codons mRNA (Google Search)] [index](13) Redundancy of triplet code(a) 43 = 64 >> 20(b) Consequently, there are many more codons than there are amino acids

(c) However, 61 of the 64 possible codons do code for an amino acid

(d) This is because many amino acids are specified by more than one codon

(e) See Figure 17.4, The dictionary of the genetic code

(f) (no, you dont have to memorize the figure)

(g) [triplet code redundancy OR redundant (Google Search)] [index]

(14) Lack of ambiguity in the triplet code

(a) Note that while the code is redundant, it is not ambiguous

(b) That is, each codon specifies for one and only one amino acid, not

more than one

(c) [triplet code ambiguity (Google Search)] [index]

(15) Codons dont overlap

(a) Another property of codons is that they are arrayed one after another in themRNA

(b) That is, they do not overlap

(c) (note that there is an only slightly related exception in which codons can

overlap and this is whenreading framesof different genes overlap)

(d) See Figure 17.3, The triplet code

(e) [codons overlap (Google Search)] [index]

(16) There is no punctuation between codons

(a) Furthermore, codons do not have gaps between them (i.e., there is no

punctuation)

(b) See Figure 17.3, The triplet code

(c) [punctuation codons (Google Search)] [index]

(17) Start codon (AUG, methionine)

(a) The codon AUG codes for the amino acid methionine

(b) See Figure 17.4, The dictionary of the genetic code
http://www.google.com/search?q=codons+OR+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=codons+OR+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://psyche.uthct.edu/shaun/SBlack/geneticd.htmlhttp://psyche.uthct.edu/shaun/SBlack/SDB-Home.htmlhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#template_strand%23template_strandhttp://www.google.com/search?q=codons+mRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://www.google.com/search?q=triplet+code+redundancy+OR+redundant&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://www.google.com/search?q=triplet+code+ambiguity&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://www.google.com/search?q=codons+overlap&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://www.google.com/search?q=codons+punctuation&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://www.google.com/search?q=codons+OR+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://psyche.uthct.edu/shaun/SBlack/geneticd.htmlhttp://psyche.uthct.edu/shaun/SBlack/SDB-Home.htmlhttp://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#template_strand%23template_strandhttp://www.google.com/search?q=codons+mRNA&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://www.google.com/search?q=triplet+code+redundancy+OR+redundant&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://www.google.com/search?q=triplet+code+ambiguity&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#m_rna%23m_rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://www.google.com/search?q=codons+overlap&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://www.google.com/search?q=codons+punctuation&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acids


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(c) AUG also specifies the initiationof translation

(d) Thus, all polypeptides initially begin with methionine (Met)

(e) Note that as a part of post-translational protein processing the Met aminoacid is often clipped off

(f) (though I dont expect you to learn all of the codons and their assignments,

you should memorize AUG, methionine, and the fact that it serves as thestart codon ofreading frames)

(g) [start codon, methionine (Google Search)] [index]

(18) Stop codons

(a) Only 61 of the 64 possible codons specifyamino acids

(b) The other three specify what are known as stop codons

(c) (or nonsense codons to distinguish them from the other 61 sense codons)

(d) See Figure 17.4, The dictionary of the genetic code

(e) Stop codons instruct theribosometo stop adding amino acids to the

growing peptide chain

(f) [stop codon(Google Search)] [index]

(19) Reading frame(a) The sequence of codons beginning with AUG and ending with astop

codonis called the reading frame(b) Note that the reading frame consists of (x + 1) * 3 nucleotides wherex is

the number ofamino acids found in the resulting polypeptide (prior to

post-translational modification) and the additional 1 is a stop codon(c) [reading frame, open reading frame(Google Search)] [index]

(20) (nearly) Universal triplet code

(a) The language of codons is nearly universal among extant organisms

(b) (e.g., AUG specifies Met and is thestart codon in all or nearly all livingorganisms)

(c) This near-universality is taken as evidence that all extant organisms share

a common ancestor(d) Furthermore, the divergence from this common ancestor must have

occurred at a time after the implementation of the triplet code

(e) Since the triplet code is somewhat arbitrary, the converse hypothesis, thatall organisms somehow independently adopted the samecodons for each

amino acid, is much less likely

(f) As a consequence of the near-universality of the triplet code, genes from

one organism may be transferred into unrelated organisms and still express(i.e., be transcribedthen translated)

(g) [universal triplet code(Google Search)] [index]

(21) Transcription in detail

(a) Transcription takes place in three steps

(i) DNAbinding and initiation

(ii) Elongation of theRNA strand(iii) Termination oftranscription

(b) The primaryenzyme involved is calledRNA polymerase

(c) See Figure 17.6, The stages of transcription: initiation, elongation, and

termination
http://mansfield.osu.edu/~sabedon/campbl17.htm#initiation%23initiationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#initiation%23initiationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://www.google.com/search?q=start+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=methionine&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=stop+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=stop+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://www.google.com/search?q=reading+frame&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=open+reading+frame&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=open+reading+frame&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#start_codon%23start_codonhttp://mansfield.osu.edu/~sabedon/campbl17.htm#start_codon%23start_codonhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://www.google.com/search?q=universal+triplet+code&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=universal+triplet+code&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/black07.htm#transcriptionhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#initiation%23initiationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#elongation_1%23elongation_1http://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#termination%23terminationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl06.htm#enzymeshttp://mansfield.osu.edu/~sabedon/campbl06.htm#enzymeshttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna_polymerase%23rna_polymerasehttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna_polymerase%23rna_polymerasehttp://mansfield.osu.edu/~sabedon/campbl17.htm#initiation%23initiationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#reading_frame%23reading_framehttp://www.google.com/search?q=start+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=methionine&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl07.htm#ribosomeshttp://www.google.com/search?q=stop+codon&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#stop_codons%23stop_codonshttp://www.google.com/search?q=reading+frame&hq=&hl=en&lr=&safe=offhttp://www.google.com/search?q=open+reading+frame&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl17.htm#start_codon%23start_codonhttp://mansfield.osu.edu/~sabedon/campbl17.htm#codons%23codonshttp://mansfield.osu.edu/~sabedon/campbl05.htm#amino_acidshttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl17.htm#translation_introduction%23translation_introductionhttp://www.google.com/search?q=universal+triplet+code&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/black07.htm#transcriptionhttp://mansfield.osu.edu/~sabedon/campbl05.htm#dnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#initiation%23initiationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#elongation_1%23elongation_1http://mansfield.osu.edu/~sabedon/campbl17.htm#rna%23rnahttp://mansfield.osu.edu/~sabedon/campbl17.htm#termination%23terminationhttp://mansfield.osu.edu/~sabedon/campbl17.htm#transcription_introduction%23transcription_introductionhttp://mansfield.osu.edu/~sabedon/campbl06.htm#enzymeshttp://mansfield.osu.edu/~sabedon/campbl17.htm#rna_polymerase%23rna_polymerase


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(d) See Figure 17.25, A summary of transcription and translation in a

eukaryotic cell

(e) [RNA transcription (Google Search)] [index]

(22) RNA polymerase

(a) RNA polymerase works similarly to DNA polymerase

(b) Like DNA polymerase, RNA polymerase employs a DNA template (i.e.,thetemplate strand) but, of course,polymerizes RNA

(c) Just as with DNA polymerase, RNA polymerase synthesizes in the 5

3 direction(d) [RNA polymerase (Google Search)] [index]

(23) Promoter binding (transcription factor)

(a) The first step intranscriptionis DNAbinding(b) In prokaryotes this involves the recognition of specific DNA sequences

(promoters) by the RNA polymerase

(c) See Figure 17.7, The initiation of transcription in a eukaryotic

promoter

(d) In either case, the promoter is found upstream from thestart codon(e) Once bound the RNA polymerase begins transcribing (i.e., polymerizing

RNA from a DNA template)(f) In eukaryotes this involves the binding of RNA polymerase toproteins,

called transcription factors, that are involved in sequence recognition

(g) [promoter binding (Google Search)] [index]

(24) Elongation (1)

(a) To initiatetranscription, the RNA polymerase must separate the DNA

strands of thedouble helix(b) Throughout the elongation of the RNA transcript, the DNA strand is kept

open approximately 10 bases

(c) Note that a given gene may be transcribed by more than one RNApolymerase simultaneously, with one RNA polymerase following anotheralong on the transcribed DNA

(d) See Figure 17.6, The stages of transcription: initiation, elongation, and

termination

(e) [transcription elongation(Google Search)] [index]

(25) Termination of transcription

(a) Just astranscriptionis initiated at certain base sequences, it is similarlyterminated at specificbase sequences

(b) With terminationthe RNA transcript is released from the RNA polymerase

and DNA template strand, and the RNA polymerase from the DNA

(c) See Figure 17.6, The stages of transcription: initiation, elongation, andtermination

(d) [transcription termination (Google Search)] [index]

(26) mRNA processing

(a) The compartmentalization of the eukaryotic cell results in a separation of

transcription and translation, both spatially and temporally

(b) Eukaryotic cells take advantage of this compartmentalization to modifyRNAs prior to translation
http://www.google.com/search?q=RNA+transcription&hq=&hl=en&lr=&safe=offhttp://www.google.com/http://mansfield.osu.edu/~sabedon/biology.htmhttp://mansfield.osu.edu/~sabedon/campbl15.htm#dna_polymerasehttp://mansfield.osu.edu/~sabedon/campbl17.htm#template_strand%23templat

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