Biology. DNA Replication. Slide 1 / 111 Slide 2 / 111. Slide 4 / 111. Slide 3 / 111. Slide 5 / 111. Slide 6 / 111. Genes. Genes Unit Topics.

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1 Slide 1 / 111 Slide 2 / 111 iology Genes Slide 3 / 111 Vocabulary lick on each word below to go to the definition. P site 3' end polymerase chain reaction 5' end parent strand site promoter anti-parallel replicate anticodon ribosome central dogma RN polymerase codon rrn daughter strand semi-conservative N polymerase template strand elongation termination gene terminator sequence gene expression transcription initiation translation mrn trn Slide 5 / 111 Genes Unit Topics Slide 4 / 111 N Replication Transcription Overview of Gene Expression Translation Slide 6 / 111 lick on the topic to go to that section Genes gene is a segment of N needed to make a specific protein. N Replication Return to Table of ontents The complementary base pairs of N are: guanine (G) with () and () with thymine (T). The nucleotides of one strand bond to matching nucleotides in a second strand, to create the double stranded helix. N is a good archive for genetic information since the bases are protected on the inside of the helix.

2 Slide 7 / What is the shape of N called? Slide 7 (nswer) / What is the shape of N called? single helix double helix it has many shapes circle single helix double helix it has many shapes circle nswer Slide 8 / In N, adenine pairs with... Slide 8 (nswer) / In N, adenine pairs with... uracil guanine thymine cytosine uracil guanine thymine cytosine nswer Slide 9 / In N, guanine pairs with... Slide 9 (nswer) / In N, guanine pairs with... uracil adenine thymine cytosine uracil adenine thymine cytosine nswer

3 Slide 10 / If one strand of N is GGT, the complementary strand would be: Slide 10 (nswer) / If one strand of N is GGT, the complementary strand would be: GTG GTG GGT GGT TGT GTG TGT GTG nswer Slide 11 / If one strand of N is GTG, the complementary strand would be: Slide 11 (nswer) / If one strand of N is GTG, the complementary strand would be: TGU TGU TGT TGT GTG GTG GTG GTG nswer Slide 12 / 111 Replication The functions of a cell are determined by its N. ells have to reproduce many times. In complex organisms, trillions of copies are made from one original cell. ut when cells reproduce, they must replicate (or copy) their N. The structure of N reveals how trillions of copies of the N in one of your cells can be made, and be almost exactly the same each time. Slide 13 / 111 Watson & rick Francis rick and James Watson discovered the structure of N in This breakthrough was on a par with Newton's work in physics...but in our recent past. When Watson and rick published the structure of N in a short article in 1953 they stated: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." The fact that there are two N strands that are mirror images of one another suggested how copies could be made of each N sequence. lick here to see the letter Francis rick wrote to his son about the structure of N

4 Slide 14 / 111 N Molecule as Template Each molecule of N is made of a template strand and a new strand. The template is used to make the new strand. The template strand is also known as the parent strand since it came from the original N molecule. The new strand is also known as the daughter strand. template strand The 5' end has a phosphate group at the end. The 3' end has an -OH group at the end. Slide 15 / 111 N is nti-parallel Each strand has two ends: a 5' end and a 3' end. The two strands of N always run in opposite directions. They are said to be anti-parallel to each other. Slide 16 / 111 Slide 17 / 111 Separation of Strands The template strands of the N molecule separate and the new strands are made on the inside. dding New Nucleotides Nucleotides can only be added to the -OH end (3`), not the 5`so all new strands are made in the 5' - 3' direction. The result of this process is 2 new N molecules each having an old template strand and new strand. This is called semi-conservative because it "conserves" some of the old N in each copy. lick here to see an animation of the mechanism of replication Slide 18 / 111 Replication Practice 3' TGGGTTGGT 5' template strand 5' 3' new strand Slide 19 / The 3' end of a N strand has a phosphate at the end. True False What is the sequence of the new strand? 3' GGTTTTGGT 5' template strand 5' 3' new strand What is the sequence of the new strand?

5 Slide 19 (nswer) / The 3' end of a N strand has a phosphate at the end. True False Slide 20 / Why does a N strand only "grow" in the 5' to 3' direction? because N can only add nucleotides to the 3' end of the molecule nswer FLSE because N can only add nucleotides to the 5' end of the molecule because mrn can only read a N molecule from 5' to 3' because mrn can only read a N molecule from 3' to 5' Slide 20 (nswer) / Why does a N strand only "grow" in the 5' to 3' direction? Slide 21 / If the parent N strand is 5' TGTT 3', what will the daughter stand be? because N can only add nucleotides to the 3' end of the molecule because N can only add nucleotides to the 5' end of the molecule nswer because mrn can only read a N molecule from 5' to 3' because mrn can only read a N molecule from 3' to 5' 5' TGTTGTG 3' 3' TGTT 5' 5' UGUUGUG 3' 3' TGTTGTG 5' Slide 21 (nswer) / If the parent N strand is 5' TGTT 3', what will the daughter stand be? Slide 22 / 111 Enzyme atalyzed Reaction 5' TGTTGTG 3' 3' TGTT 5' 5' UGUUGUG 3' nswer 3' TGTTGTG 5' N nucleotide monomers are made ahead of time and stored in the cell. N polymerase is the enzyme responsible for adding each new nucleotide to the growing strand.

6 Slide 23 / 111 iotech pplication Slide 24 / 111 Polymerase hain Reaction Polymerase hain Reaction(PR) is a technique which uses the principles of N replication to amplify the amount of N available for testing and manipulation. This reaction is carried out by a special machine that utilizes repeating cycles of heat, N polymerase, N primers and free nucleotides to build copies of the N fragment. This technology enables small amounts of N to be turned into large amounts. lick here to see an animation of the mechanism of PR 1. N is heated to high temperature, the N strands denature, separating the double helix 2. N is cooled, primers and polymerase in the mixture stick to the N 3. The temperature is increased slightly to increase the rate of replication The cycle is repeated, doubling the amount of N each cycle. Slide 25 / single N molecule is placed in a PR machine. fter 5 cycles, how many copies of N will be present? Slide 25 (nswer) / single N molecule is placed in a PR machine. fter 5 cycles, how many copies of N will be present? nswer 32 Slide 26 / single N molecule is placed in a PR machine. fter 10 cycles, how many copies of N will be present? Slide 26 (nswer) / single N molecule is placed in a PR machine. fter 10 cycles, how many copies of N will be present? nswer 1024

7 Slide 27 / Taq polymerase is typically used in polymerase chain reactions. This polymerase enzyme is found in thermophilic bacteria, Thermus aquaticus. What is the best explanation for the use of this enzyme? Slide 27 (nswer) / Taq polymerase is typically used in polymerase chain reactions. This polymerase enzyme is found in thermophilic bacteria, Thermus aquaticus. What is the best explanation for the use of this enzyme? Enzymes from thermophilic bacteria are stable at high temperatures Enzymes from thermophilic bacteria are stable at high temperatures Most polymerases do not work in different organisms - scientists discovered that Taq polymerase is universal. Most polymerases do not work in different organisms - scientists discovered that Taq polymerase is universal. nswer Ethical objections exist to the use of human macromolecules, such as N polymerase Ethical objections exist to the use of human macromolecules, such as N polymerase Polymerases from thermophilic bacteria are not denatured at high ph. Polymerases from thermophilic bacteria are not denatured at high ph. Slide 28 / 111 Slide 29 / 111 RN RN is essential for bringing the genetic information stored in the N to where it can be used in the cell. Transcription Recall that RN is made up of a sugar molecule and phosphate group "backbone" and a sequence of nitrogen bases: Return to Table of ontents These bases hydrogen bond in pairs: bonds to U and G bonds to. Slide 30 / 111 RN strand with bases in the sequence: UGGUUG Slide 31 / RN is more stable than N. True False has a different shape, and functions differently, than a strand with the sequence: UGGU Letter changes result in a new shape, and new functions.

8 Slide 31 (nswer) / RN is more stable than N. Slide 32 / 111 Transcription True False nswer FLSE Transcription is the process by which RN strands are synthesized from N strands. This is the first step in the transport of the genetic information contained in N. Transcribe means to write out or rewrite, you can remember that the process of making RN from N is called transcription because the N sequence of nucleotides is being rewritten into the RN sequence of nucleotides, which differ only slightly. The process of transcription is very similar to that of N replication. Slide 33 / 111 Transcription - Initiation To begin, an enzyme called RN Polymerase attaches to the Promoter region on the N. The Promoter is a specific sequence of bases that the RN polymerase recognizes. olymerase Slide 34 / 111 Template vs. Non-Template Strands The RN polymerase never attaches to the strand that actually contains the gene. The strand with the genes is called the "non-template strand." This IS NOT the strand that is transcribed. Promotor Region Non- Template The other strand is the mirror image of the first, it carries the mirror image of the gene, not the gene itself. It is called the "template strand." This IS the strand where the RN polymerase attaches. Slide 35 / 111 Transcription: N Strands This makes sense in that the RN will be the mirror image of the N it is transcribed from. nd the non-coding strand is the mirror image of the gene. transcription of template strand non-template strand of N template strand of N Slide 36 / The strand that is transcribed into RN is called the strand. Template Non Template RN mino cid RN Note: the non-template strand of N (the gene) matches the new RN strand

9 Slide 36 (nswer) / The strand that is transcribed into RN is called the strand. Slide 37 / The transfer of genetic material from N to RN is called: Template Non Template RN mino cid nswer translation transcription elongation promotion Slide 37 (nswer) / The transfer of genetic material from N to RN is called: translation transcription elongation promotion nswer Slide 38 / Genes are located on the strand. Template Non Template RN mino cid Slide 38 (nswer) / Genes are located on the strand. Template Non Template RN mino cid nswer Slide 39 / What is the function of the promoter sequence on the N? it is where the RN polymerase recognizes and binds to initiate transcription it is where the RN gets copied it where transcription terminates it is where the RN polymerase binds to on the 3' end of the N initiating transcription

10 Slide 39 (nswer) / What is the function of the promoter sequence on the N? Slide 40 / The strand that is NOT transcribed into RN is called the strand. it is where the RN polymerase recognizes and binds to initiate transcription it is where the RN gets copied it where transcription terminates it is where the RN polymerase binds to on the 3' end of the N initiating transcription nswer Template Non Template RN mino cid Slide 40 (nswer) / 111 Slide 41 / The strand that is NOT transcribed into RN is called the strand. Template Non Template RN mino cid nswer Transcription - Elongation To make the RN strand, RN Polymerase runs down the N template strand reading the bases and bringing in the new RN nucleotides with the proper complementary bases. s the RN Polymerase runs down the N, it actually unwinds the N! Non- Template new mrn Slide 42 / 111 ase Pairing Slide 43 / 111 Transcription Transcription is made possible by the fact that the different bases are attracted to one another in pairs. Just like in N replication, RN is made from the 5' end to the 3' end. Note: In N replication adenine paired with thymine, in N transcription uracil is now paired with adenine. Remember that RN does not contain thymine as a nucleotide base. N ("template strand") 3' TGGTT 5' RN 5' UGGUU 3' (being made in 5' >3' direction)

11 Slide 44 / If the template strand of N is 5' TGTTG 3', which is the RN strand produced from transcription? Slide 44 (nswer) / If the template strand of N is 5' TGTTG 3', which is the RN strand produced from transcription? 5' UUUUGGU 3' 5' TTTTGGT 3' 3' UUUUGGU 5' 3' TTTTGGT 5' 5' UUUUGGU 3' 5' TTTTGGT 3' nswer 3' UUUUGGU 5' 3' TTTTGGT 5' Slide 45 / If the template strand of N is 5' GTTT 3', which is the RN strand produced from transcription? Slide 45 (nswer) / If the template strand of N is 5' GTTT 3', which is the RN strand produced from transcription? 5' UUUUGUGU 3' 5' TTTTGTGT 3' 3' UUUUGUGU 5' 3' TTTTGTGT 5' 5' UUUUGUGU 3' 5' TTTTGTGT 3' 3' UUUUGUGU 5' nswer 3' TTTTGTGT 5' Slide 46 / If the non-template strand of N is 3'GTTT5', which is the RN strand produced through transcription? Slide 46 (nswer) / If the non-template strand of N is 3'GTTT5', which is the RN strand produced through transcription? 3' TGTTG 5' 3' UGUUG 5' 5' UGUUG 3' 3' GUUU 5' 3' TGTTG 5' nswer 3' UGUUG 5' 5' UGUUG 3' 3' GUUU 5'

12 Slide 47 / 111 Transcription - Termination Slide 48 / 111 N Replication vs. Transcription RN Polymerase gets to a sequence on the N called a Termination Sequence. This sequence signals the RN Polymerase to STOP transcription. Termination Sequence Non- Template N Replication Two new stranded N are produced denine from the parent strand bonds with on the new daughter strand of N Transcription One new stranded RN is produced denine on the N strand bonds with on the new RN strand. The RN Polymerase falls off the N. The new RN strand separates from the N. The N recoils into a helix. lick here to see an animation of transcription The whole molecule is replicated Only the strand with the code for the is transcribed. Synthesis of both occur in the ' to ' direction Slide 49 / 111 Slide 50 / 111 Evolution Remember that eventually, the functions performed directly by RN were taken over by. Gene Expression Overview The shapes of proteins are determined by the sequence of their. Proteins must be "coded" with the correct sequence of amino acids to have the right shape. There has to be a way to translate from the sequences of bases in RN to a sequence of amino acids in a protein. Return to Table of ontents Gene expression is the process of taking the "code" in the nucleic acid and making the product it codes for - the protein. Gene expression occurs whenever a specific protein is needed by the cell. Slide 51 / 111 Gene Expression Slide 52 / 111 N to RN to Protein Expressing the information stored on a gene into a protein requires two things to happen. First, the information must be translated from the 4 letter language of N to RN. Then from the 4 letter language of RN, it must be translated to the 20 letter language of proteins (their amino acid sequence).

13 Slide 53 / 111 odons The mrn "message" is read in 3-letter words called codons. Each codon codes for an amino acid or tells the process to stop. There are 64 codons (4x4x4) but only 20 amino acids. So some codons code for the same amino acid. 61 of the codons code for an amino acid Slide 54 / 111 The Universal Genetic ode 3 of the remaining codons are "STOP" codons that do not code for an amino acid. They just signal that translation is over. 1 codon that codes for the amino acid "methionine" is also the "STRT" codon. Methionine is always the first amino acid in a protein. Slide 55 / 111 The Universal Genetic ode 21 What is a codon? Slide 56 / 111 This is called a "universal" code because LL LIFE uses the same genetic code... from the smallest bacteria or virus to the largest animal or tree. This tells us that this code goes back billions of years, in the first cell...or even before that. If there were alternative codes that could work, they would have appeared in nature. E a 3 base sequence on trn a 3 base sequence on mrn a 3 base sequence on N and, and There are very minor alterations, but they are rare and insignificant in their effect. Slide 56 (nswer) / 111 Slide 57 / What is a codon? E a 3 base sequence on trn a 3 base sequence on mrn a 3 base sequence on N and, and nswer

14 Slide 58 / The codon U specifies: Slide 58 (nswer) / The codon U specifies: E denine Glycine (Gly) STOP rginine Valine Refer to the codon table E denine Glycine (Gly) STOP rginine Valine nswer Refer to the codon table Slide 59 / The codon GGG specifies: Slide 59 (nswer) / The codon GGG specifies: E denine Glycine STOP rginine Valine Refer to the codon table E denine Glycine STOP rginine Valine nswer Refer to the codon table Slide 60 / The codon G specifies: Slide 60 (nswer) / The codon G specifies: E denine Glycine STOP rginine spartic cid Refer to the codon table E denine Glycine STOP rginine spartic cid nswer Refer to the codon table E

15 Slide 61 / Why is Methionine the very first amino acid in all proteins? because it is coded by the stop codon because it is coded for by UG which is the start codon Methionine is coded for by more than one codon none of the above Slide 61 (nswer) / Why is Methionine the very first amino acid in all proteins? because it is coded by the stop codon because it is coded for by UG which is the start codon Methionine is coded for by more than one codon nswer none of the above Slide 62 / 111 Steps of Gene Expression Slide 63 / 111 The entral ogma Gene expression occurs in two steps: 1. The gene is copied from N into RN through a process called. 2. The RN builds a protein in a process called. N RN Protein translation N RN PROTEIN replicatio n transcription The processes of replication, transcription and translation are so critical that they are called the entral ogma of iology. "ogma" is a postulate; an idea; a philosophy. It is "entral" because it is what life is based on. Slide 64 / 111 Slide 65 / 111 The entral ogma The entral ogma is a one way process. hanges in N affect mrn and protein. transcription translation N mrn Protein ut changes in proteins or mrn do not affect the N. This will have important implications when we study genetics. Steps of Transcription & Translation Transcription and Translation both have 3 steps called: Initiation - the beginning Elongation - the RN (transcription) or protein (translation) is made longer Termination - the end The activities that occur at each step are different for transcription and translation, but you should aware that they have the same names.

16 Slide 66 / What is meant by "gene expression"? making the protein or RN coded in the nucleic acid making amino acids so they can be made into protein making trn only folding of the protein Slide 66 (nswer) / What is meant by "gene expression"? making the protein or RN coded in the nucleic acid making amino acids so they can be made into protein making trn only nswer folding of the protein Slide 67 / Which one of the following sequences best describes the entral ogma of biology? Slide 67 (nswer) / Which one of the following sequences best describes the entral ogma of biology? RN to N to RN to Protein RN to N to RN to Protein N to RN to Protein N to RN to Protein Protein to RN to N N to mino cid to RN to Protein Protein to RN to N N to mino cid to RN to Protein nswer Slide 68 / 111 Slide 69 / 111 Translation Translation is the process by which RN strands are read to build proteins. Translation Translate means to convert something from one language to another, you can remember that the process of making protein from RN is called translation because the "language" of nucleotides" is being changed to the "language" of amino acids. Return to Table of ontents

17 Slide 70 / 111 Three Types of RN Slide 71 / 111 Messenger RN (mrn) Translation requires 3 types of RN that are created using transcription. 1. mrn or messenger RN, carries the information for protein synthesis. This type of RN is key to The entral ogma. 2. rrn or ribosomal RN, is a catalyst for protein synthesis 3. trn or transfer RN, helps in the assembly of amino acids during protein synthesis The specific RN that contains the protein's information from N is called Messenger RN (mrn); it carries the genetic message to ribosomes, where it is translated. Ribosomal RN (rrn) and some additional proteins make up the ribosome. The ribosome includes two subunits: one small, and one large. uring translation, the ribosome catalyzes the reaction that makes covalent bonds between amino acids, thus building the protein. Slide 72 / 111 Ribosomal RN (rrn) Small subunit Large subunit RN, being single stranded, can fold in on itself. In trn, the RN folds into a t-shape. The mino cid ttachment Site is where the amino acid will attach to the trn. The nticodon Loop is a 3 base sequence on the tip that is complementary to the codon on the mrn. Slide 73 / 111 Transfer RN (trn) Transfer RN (trn) carries amino acids to the ribosome so that the ribosome can covalently bond them together to form the protein. Slide 74 / What 2 components is a ribosome made of? Slide 74 (nswer) / What 2 components is a ribosome made of? rrn and N rrn and N rrn and carbohydrates rrn and carbohydrates rrn and proteins rrn and proteins both b and c both b and c nswer

18 Slide 75 / What is the function of the ribosome? Slide 75 (nswer) / What is the function of the ribosome? to make an ionic bond between amino acids to make a covalent/peptide bond between amino acids thus building the protein to make hydrogen bonds to make RN to make an ionic bond between amino acids to make a covalent/peptide bond between amino acids thus building the protein to make hydrogen bonds to make RN nswer Slide 76 / 111 Slide 76 (nswer) / What does the "t" in trn stand for? 30 What does the "t" in trn stand for? "transfer"- it transfers the amino acid to the ribosome and mrn codon it refers to the shape "transfer"- it transfers the protein to the N oth and "transfer"- it transfers the amino acid to the ribosome and mrn codon it refers to the shape "transfer"- it transfers the protein to the N nswer oth and Slide 77 / 111 Slide 77 (nswer) / Why does trn fold into its specific shape? 31 Why does trn fold into its specific shape? E The sequence and bonding of its amino acids The sequence of and bonding of nucleotides Its protein structure and and E The sequence and bonding of its amino acids The sequence of and bonding of nucleotides Its protein structure and and nswer

19 Slide 78 / 111 Translation - n Overview Slide 79 / 111 Translation - n Overview trns bond to the amino acid specified by their anti-codon. ll the pieces are ready to begin translation: a coded strand of mrn a set of 20 amino acids ribosomes trn to match all the amino acids The opposite side of each trn, the anti-codon, bonds to the matching codon on the mrn, creating a string of amino acids in the proper sequence. The ribosome makes covalent bonds between the amino acids. The result is a protein chain with the specified sequence of amino acids. Slide 80 / 111 Proteins: Words mino cids :: Letters The length and sequence of these amino acids allow all the proteins in the world to be created from only 20 amino acids. This is very similar to how all the words can be created from only 26 letters in the alphabet. The small subunit of the ribosome attaches to the mrn at the bottom of the start codon(at the 5' end). Then the large subunit of the ribosome comes in over the top. The result is that the mrn is "sandwiched" between the mrn at the start codon (and the second codon as well!) Slide 81 / 111 Translation - Initiation 5' 3' Slide 82 / 111 The ribosome goes to the 5' end of the mrn because the 5' end is the beginning of where the gene on the N was transcribed into mrn. 5' Translation - Initiation 3' lso notice that there are 2 sites within the ribosome. The P-site - where the new protein will emerge The -site - where the mino cids are delivered in s the leading edge of the mrn, with the starting code UG, is exposed in the site, the trn with the code U enters the site and hydrogen bonds with it, carrying methionine into the ribosome. Slide 83 / 111 Translation - Initiation The trns, hydrogen bonded to their specific amino acids, surround the ribosome. Met U UG

20 Slide 84 / 111 Translation - Initiation The methonine is removed from the trn and stays in the ribosome to be bonded with the next amino acid. The trn leaves the ribosome so another trn can enter. Each trn will carry the appropriate amino acid into the ribosome to be bonded in the proper sequence, since each trn anticoding site matches the coding site on the mrn, which is located at the site of the ribosome. Slide 85 / How does the anticodon on the trn and the codon on the mrn match up? by hydrogen bonding/complimentary base pairing by ionic bonding by peptide bonds none of the above ecause each trn has an anticoding sequence it complimentary base pairs with the codon on the mrn. Slide 85 (nswer) / How does the anticodon on the trn and the codon on the mrn match up? by hydrogen bonding/complimentary base pairing by ionic bonding by peptide bonds nswer none of the above Slide 86 / What is the P site of the ribosome? it is where the amino acids are delivered in it is where the protein or peptide will emerge it where the trn's will deliver in the next amino acid after each translocation it is where the proteins fold into their 3-d shape Slide 86 (nswer) / What is the P site of the ribosome? it is where the amino acids are delivered in it is where the protein or peptide will emerge it where the trn's will deliver in the next amino acid after each translocation it is where the proteins fold into their 3-d shape nswer The 2nd trn with its amino acid is delivered into the -site in the ribosome. The ribosome catalyzes a covalent bond between the amino acids. Slide 87 / 111 Translation - Elongation

21 The trn that was in the -site moves to the P-site and the trn that was in the P-site separates from its amino acid. Notice the protein emerging from the P- site! Slide 88 / 111 Translation - Elongation The ribosome moves the mrn using chemical energy. Slide 89 / 111 Translation - Elongation Elongation continues by adding one amino acid after another. Each amino acid is delivered to the -site by its matching trn. The ribosome makes a peptide bond between the 2 amino acids in the P and sites. until... Slide 90 / 111 Translation - Termination The ribosome reaches a STOP codon. Remember that STOP codons do not code for amino acids. This signals the end of translation. The protein is complete. Slide 91 / 111 Translation - Termination The Result- protein in its "primary sequence". Remember that Primary level (1 0 ) of protein structure is the sequence of amino acids. The 2 subunits (large and small) separate from each other. U is 1 of the 3 possible STOP codons. lick here to see an animation of translation Slide 92 / 111 Slide 92 (nswer) / What is the first event of translation? 34 What is the first event of translation? the trn comes in the trn comes in the small subunit of the ribosome and the 1st trn brings in Methionine to the start codon the small subunit of the ribosome and the 1st trn brings in Methionine to the start codon elongation happens elongation happens the large subunit of the ribosome comes in the large subunit of the ribosome comes in nswer

22 Slide 93 / What is the first step of translation called? Slide 93 (nswer) / What is the first step of translation called? transcription elongation termination initiation transcription elongation termination initiation nswer Slide 94 / What is the function of the ribosome in translation? Slide 94 (nswer) / What is the function of the ribosome in translation? it makes a peptide/covalent bond between codons it makes hydrogen bonds between the codons it makes covalent/peptide bonds between amino acids none of the above it makes a peptide/covalent bond between codons it makes hydrogen bonds between the codons it makes covalent/peptide bonds between amino acids nswer none of the above Slide 95 / 111 Slide 95 (nswer) / What does termination in translation involve? 37 What does termination in translation involve? translocation of the ribosome translocation of the ribosome the ribosome gets to a stop codon and the small and large subunits of the ribosome separate the ribosome gets to a stop codon and the small and large subunits of the ribosome separate RN polymerase falls off the N a trn brings in an amino acid RN polymerase falls off the N nswer a trn brings in an amino acid

23 38 What is translation? Slide 96 / What is translation? Slide 96 (nswer) / 111 the assembly of the amino acids from the protein code assembly of amino acids coded for by the mrn codons the making of mrn the assembly of the amino acids from the protein code assembly of amino acids coded for by the mrn codons the making of mrn assembly of codons from N template assembly of codons from N template nswer Slide 97 / 111 Slide 97 (nswer) / What is a gene? 39 What is a gene? segment on the amino acid segment on the amino acid segment on the protein segment on the N that codes for a protein segment on the protein segment on the N that codes for a protein segment on the RN that codes for codons nswer segment on the RN that codes for codons Slide 98 / 111 Mutations mutation is a permanent change in the N sequence of a gene. Mutations in a gene's N sequence can alter the amino acid sequence of the protein encoded by the gene. Like words in a sentence, the N sequence of each gene determines the amino acid sequence for the protein it encodes. The N sequence is interpreted in groups of three nucleotide bases, codons. Each codon specifies a single amino acid in a protein. Slide 99 / 111 Substitution Mutations When a nucleotide in a gene is copied incorrectly during N replication, one nucleotide can be substituted with another. This results in the incorrect amino acid sequence, changing the structure of the protein. orrect NSequence: TTT GGG TTT GGG orrect RN Transcript: UUU GGG UUU GGG orrect Polypeptide: Phe - Lys - Gly - Pro - Phe - Lys - Gly - Pro Substitution mutation: Resulting Transcript: Resulting Polypeptide: TTT GGG T TTT GGG UUU GGG UU GGG Phe - Lys - Gly - Pro - Tyr - Lys - Gly - Pro

24 Slide 100 / 111 Reading Frame Shifts We can think about the N sequence of a gene as a sentence made up entirely of three-letter words. Thesunwashot If you were to split this sentence into individual three-letter words, you would probably read it like this: The sun was hot If this sentence represents a gene then each letter corresponds to a nucleotide base, and each word represents a codon. If you shifted the three-letter reading frame it would result in a sentence which is not understandable... T hes unw ash ot_ Or _Th esu nwa sho t Slide 101 / 111 Insertion and eletion Mutations When a nucleotide in a gene is copied incorrectly during N replication, a nucleotide can be added or deleted. This results in a reading frame shift and the incorrect amino acid sequence, changing the structure of the protein. orrect NSequence: RN Transcript: orrect Polypeptide: Insertion mutation: Resulting Transcript: Resulting Polypeptide: TTT GGG UUU GGG Phe - Lys - Gly - Pro TT T GG G UUU U GG G Phe - STOP eletion mutation: T TT G GG_ Resulting Transcript: UU G GG _ Resulting Polypeptide: Leu - Lys - Gly? Slide 102 / 111 Silent Mutations mutation is "silent" if it has no affect on the protein coded by the gene. The redundancy in the genetic code makes this possible. Each amino acid has more than one possible codon. So, if a substitution occurs, the same amino acid may still be coded. This reduces the possibility of a mutation located in a gene causing a change in the protein. la - GU, G, G, GG Leu - UU, UUG, UU, U, U, UG rg - GU, G, G, GG, G, GG Slide 103 / hanging one nucleotide in a N sequence can change in a protein. a polypeptide the primary structure the secondary structure the tertiary structure E all of the above Slide 103 (nswer) / hanging one nucleotide in a N sequence can change in a protein. a polypeptide the primary structure the secondary structure nswer the tertiary structure E all of the above E Slide 104 / Using TTT GGG as an example, which of the following would be an example of a substitution mutation? TTT GGG TT T GG G T TTT GGG TTT GGG

25 Slide 104 (nswer) / Using TTT GGG as an example, which of the following would be an example of a substitution mutation? TTT GGG TT T GG G T TTT GGG TTT GGG nswer Slide 105 / Using TTT GGG as an example, which of the following would be an example of a frame-shift mutation? TTT GGG T TTT GGG TT T GG G TTT GGG Slide 105 (nswer) / Using TTT GGG as an example, which of the following would be an example of a frame-shift mutation? TTT GGG T TTT GGG TT T GG G TTT GGG nswer Slide 106 / 111 Mutagens mutagen is a physical or chemical agent that can change the N of an organism and thus increases the frequency of mutations. What examples can you think of? Ionizing radiation - X-rays, gamma rays Ultraviolet waves - sunlight (mild) lkaloid plants - tobacco, coca plant, poppy plant Sodium azide - a component in many car airbags enzene - solvent used in plastics, synthetic rubber Not all mutations are caused by mutagens. Spontaneous mutations occur due to errors involving: hanges to the hemistry of the N N replication, repair and recombination. Slide 107 / 111 Spontaneous Mutations Not necessarily... Slide 108 / 111 re mutations always bad? Very rarely a mutation will cause an individual to become stronger than the rest of its population. Sometimes a mutation can give a prokaryote resistance to a new antibiotic or toxin. These would be advantages to the individual and they may become better able to survive in their environment. This shows a N strand slipping out of place during replication, causing a mutation in the N once it has been repaired.

26 Slide 109 / The change a mutation causes to N is: temporary always fatal permanent always beneficial Slide 109 (nswer) / The change a mutation causes to N is: temporary always fatal permanent always beneficial nswer Slide 110 / ll mutations are caused by mutagens. True False Slide 110 (nswer) / ll mutations are caused by mutagens. True False nswer FLSE Slide 111 / 111