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

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1 Slide 1 / 111 Slide 2 / 111 New Jersey enter for Teaching and Learning Progressive Science Initiative This material is made freely available at and is intended for the non-commercial use of students and teachers. These materials may not be used for any commercial purpose without the written permission of the owners. NJTL maintains its website for the convenience of teachers who wish to make their work available to other teachers, participate in a virtual professional learning community, and/or provide access to course materials to parents, students and others. Genes lick to go to website: Slide 3 / 111 Slide 4 / 111 Vocabulary lick on each word below to go to the definition. 3' end P site 5' end polymerase chain reaction site parent strand anti-parallel promoter lick on the topic to go to that section N Replication anticodon replicate central dogma ribosome codon RN polymerase daughter strand rrn semi-conservative N polymerase elongation Genes Unit Topics gene template strand termination gene expression terminator sequence initiation transcription mrn translation Transcription Overview of Gene Expression Translation trn Slide 5 / 111 Slide 6 / 111 Genes gene is a segment of N needed to make a specific protein. The complementary base pairs of N are: guanine (G) with () and () with thymine (T). N Replication The nucleotides of one strand bond to matching nucleotides in a second strand, to create the double stranded helix. Return to Table of ontents N is a good archive for genetic information since the bases are protected on the inside of the helix.

2 Slide 7 / 111 What is the shape of N called? 1 What is the shape of N called? single helix single helix double helix double helix it has many shapes circle it has many shapes circle 1 Slide 7 () / 111 Slide 8 / In N, adenine pairs with... uracil uracil guanine guanine thymine thymine cytosine cytosine In N, adenine pairs with... 2 Slide 8 () / 111 Slide 9 / In N, guanine pairs with... uracil uracil adenine adenine thymine thymine cytosine cytosine In N, guanine pairs with... 3 Slide 9 () / 111

3 Slide 10 / If one strand of N is GGT, the complementary strand would be: GTG GTG GGT GGT TGT TGT GTG GTG If one strand of N is GGT, the complementary strand would be: 4 Slide 10 () / 111 Slide 11 / If one strand of N is GTG, the complementary strand would be: TGU TGU TGT TGT GTG GTG GTG GTG If one strand of N is GTG, the complementary strand would be: 5 Slide 11 () / 111 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.

4 Slide 14 / 111 Slide 15 / 111 N is nti-parallel N Molecule as Template template strand Each molecule of N is made of a template strand and a new strand. 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. The template is used to make the new strand. The 5' end has a phosphate group at the end. 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. The 3' end has an -OH group at the end. Slide 16 / 111 Slide 17 / 111 dding New Nucleotides Separation of Strands 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 template strands of the N molecule separate and the new strands are made on the inside. 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 Replication Practice Slide 19 / 111 3' TGGGTTGGT 5' template strand The 3' end of a N strand has a phosphate at the end. True 5' 3' False new strand 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? 6 Slide 18 / 111

5 Slide 19 () / 111 False 7 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 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' FLSE Slide 20 () / 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 5' TGTTGTG 3' 3' TGTT 5' because N can only add nucleotides to the 5' end of the molecule 5' UGUUGUG 3' because mrn can only read a N molecule from 5' to 3' 3' TGTTGTG 5' because mrn can only read a N molecule from 3' to 5' Slide 21 () / 111 If the parent N strand is 5' TGTT 3', what will the daughter stand be? 5' TGTTGTG 3' 3' TGTT 5' 5' UGUUGUG 3' 3' TGTTGTG 5' 8 Slide 22 / 111 Enzyme atalyzed Reaction N nucleotide monomers are made ahead of time and stored in the cell. The 3' end of a N strand has a phosphate at the end. True 6 Slide 20 / 111 N polymerase is the enzyme responsible for adding each new nucleotide to the growing strand.

6 Slide 23 / 111 Slide 24 / 111 Polymerase hain Reaction iotech pplication 1. N is heated to high temperature, the N strands denature, separating the double helix 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. 2. N is cooled, primers and polymerase in the mixture stick to the N 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. 3. The temperature is increased slightly to increase the rate of replication lick here to see an animation of the mechanism of PR The cycle is repeated, doubling the amount of N each cycle. Slide 25 / 111 Slide 25 () / single N molecule is placed in a PR machine. fter 5 cycles, how many copies of N will be present? 9 single N molecule is placed in a PR machine. fter 5 cycles, how many copies of N will be present? 32 Slide 26 () / single N molecule is placed in a PR machine. fter 10 cycles, how many copies of N will be present? 10 single N molecule is placed in a PR machine. fter 10 cycles, how many copies of N will be present? Slide 26 /

7 Slide 27 / 111 Slide 27 () / 111 Enzymes from thermophilic bacteria are stable at high temperatures Most polymerases do not work in different organisms - scientists discovered that Taq polymerase is universal. Ethical objections exist to the use of human macromolecules, such as N polymerase Polymerases from thermophilic bacteria are not denatured at high ph. 11 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 Most polymerases do not work in different organisms - scientists discovered that Taq polymerase is universal. 11 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? Ethical objections exist to the use of human macromolecules, such as N polymerase bacteria are not Polymerases from thermophilic 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 strand with bases in the sequence: UGGUUG has a different shape, and functions differently, than a strand with the sequence: UGGU Letter changes result in a new shape, and new functions. 12 RN is more stable than N. True False RN Slide 31 / 111

8 Slide 31 () / 111 Slide 32 / 111 Transcription 12 RN is more stable than N. True 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. FLSE 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 Slide 34 / 111 Transcription - Initiation Template vs. Non-Template Strands 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. 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. olymerase NonTemplate Promotor Region 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 Slide 36 / 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. non-template strand of N template strand of N transcription of template strand RN Note: the non-template strand of N (the gene) matches the new RN strand 13 The strand that is transcribed into RN is called the strand. Template Non Template RN mino cid False

9 Slide 36 () / The transfer of genetic material from N to RN is called: Template translation Non Template RN transcription mino cid elongation promotion 13 The strand that is transcribed into RN is called the strand. Slide 37 / 111 Slide 37 () / The transfer of genetic material from N to RN is called: Slide 38 / Genes are located on the strand. Non Template transcription RN elongation mino cid promotion Template translation Slide 38 () / 111 Template Non Template RN mino cid 16 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 15 Genes are located on the strand. Slide 39 / 111

10 Slide 39 () / 111 it where transcription terminates it is where the RN polymerase binds to on the 3' end of the N initiating transcription it is where the RN polymerase recognizes and binds to initiate transcription it is where the RN gets copied 17 The strand that is NOT transcribed into RN is called the strand. Template Non Template RN mino cid 16 What is the function of the promoter sequence on the N? Slide 40 / 111 Slide 40 () / 111 Slide 41 / 111 Transcription - Elongation 17 The strand that is NOT transcribed into RN is called the strand. Template Non Template RN mino cid 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! NonTemplate new mrn Slide 42 / 111 Slide 43 / 111 Transcription ase Pairing Transcription is made possible by the fact that the different bases are attracted to one another in pairs. 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. Just like in N replication, RN is made from the 5' end to the 3' end. N ("template strand") RN 3' TGGTT5' 5' UGGUU 3' (being made in 5' >3' direction)

11 Slide 44 / 111 If the template strand of N is 5' TGTTG 3', which isthe RN strand produced from transcription? 18 If the template strand of N is 5' TGTTG 3', which isthe RN strand produced from transcription? 5' UUUUGGU 3' 5' UUUUGGU 3' 5' TTTTGGT 3' 5' TTTTGGT 3' 3' UUUUGGU 5' 3' UUUUGGU 5' 3' TTTTGGT 5' 3' TTTTGGT 5' 18 Slide 44 () / 111 Slide 45 / 111 Slide 45 () / If the template strand of N is 5' GTTT 3', which is the RN strand produced from transcription? 5' UUUUGUGU 3' 19 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' UUUUGUGU 5' 3' TTTTGTGT 5' 3' TTTTGTGT 5' 5' TTTTGTGT 3' Slide 46 / 111 Slide 46 () / 111 3' TGTTG 5' 3' UGUUG 5' 5' UGUUG 3' 3' GUUU 5' 20 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' 20 If the non-template strand of N is 3'GTTT5', which is the RN strand produced through transcription? 3' GUUU 5'

12 Slide 47 / 111 Slide 48 / 111 Transcription - Termination 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. NonTemplate Termination Sequence 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 Slide 49 / 111 N Replication Transcription Two new stranded N are produced One new stranded RN is produced denine from the parent strand bonds with on the new daughter strand of N denine on the N strand bonds with on the new RN strand. The whole molecule is replicated Only the strand with the code for the is transcribed. Synthesis of both occur in the ' to ' direction 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 Slide 51 / 111 Gene Expression 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 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 Slide 54 / 111 The Universal Genetic ode odons 61 of the codons code for an amino acid The mrn "message" is read in 3-letter words called codons. Each codon codes for an amino acid or tells the process to stop. 3 of the remaining codons are "STOP" codons that do not code for an amino acid. They just signal that translation is over. There are 64 codons (4x4x4) but only 20 amino acids. So some codons code for the same amino acid. 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 Slide 56 / 111 What is a codon? 21 a 3 base sequence on trn a 3 base sequence on mrn This tells us that this code goes back billions of years, in the first cell...or even before that. a 3 base sequence on N and E, and 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. If there were alternative codes that could work, they would have appeared in nature. There are very minor alterations, but they are rare and insignificant in their effect. Slide 56 () / 111 What is a codon? 21 a 3 base sequence on trn a 3 base sequence on mrn a 3 base sequence on N and E, and Slide 57 / 111

14 Slide 58 / 111 Slide 58 () / 111 The codon U specifies: 22 The codon U specifies: 22 denine Glycine (Gly) Glycine (Gly) STOP STOP rginine E Valine Refer to the codon table rginine E Valine denine to the Refer codon table Slide 59 / 111 denine Glycine STOP rginine Refer to the codon table E Valine 23 The codon GGG specifies: denine Glycine STOP rginine The codon GGG specifies: 23 Slide 59 () / 111 Refer to the codon table E Valine Slide 60 / 111 The codon G specifies: 24 denine Glycine E spartic cid STOP rginine Refer to the codon table Refer to the codon table E spartic cid STOP rginine The codon G specifies: denine Glycine 24 Slide 60 () / 111 E

15 Slide 61 / 111 Why is Methionine the very first amino acid in all proteins? 25 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 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 Methionine is coded for by more than one codon none of the above none of the above 25 Slide 61 () / 111 Slide 62 / 111 Slide 63 / 111 The entral ogma Steps of Gene Expression Gene expression occurs in two steps: N transcription N translation RN PROTEIN 1. The gene is copied from N into RN through a process called RN. 2. The RN builds a protein in a process Protein called. replication 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 The entral ogma The entral ogma is a one way process. hanges in N affect mrn and protein. transcription N Steps of Transcription & Translation Transcription and Translation both have 3 steps called: Initiation - the beginning translation mrn Slide 65 / 111 Protein ut changes in proteins or mrn do not affect the N. This will have important implications when we study genetics. 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 () / 111 folding of the protein 26 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 26 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 Slide 66 / 111 folding of the protein Slide 67 / 111 Slide 67 () / Which one of the following sequences best describes the entral ogma of biology? 27 Which one of the following sequences best describes the entral ogma of biology? RN to N to RN to Protein N to RN to Protein N to RN to Protein Protein to RN to N Protein to RN to N N to mino cid to RN to Protein N to mino cid to RN to Protein RN to N to RN to Protein Slide 68 / 111 Slide 69 / 111 Translation Translation is the process by which RN strands are read to build proteins. 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. Translation Return to Table of ontents

17 Slide 70 / 111 Slide 71 / 111 Three Types of RN Messenger RN (mrn) Translation requires 3 types of RN that are created using transcription. 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. 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 Slide 72 / 111 Slide 73 / 111 Ribosomal RN (rrn) Ribosomal RN (rrn) and some additional proteins make up the ribosome. 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. Large subunit RN, being single stranded, can fold in on itself. In trn, the RN folds into a t-shape. The ribosome includes two subunits: one small, and one large. Small subunit The mino cid ttachment Siteis where the amino acid will attach to the trn. uring translation, the ribosome catalyzes the reaction that makes covalent bonds between amino acids, thus building the protein. The nticodon Loop is a 3 base sequence on the tip that is complementary to the codon on the mrn. Slide 74 / 111 What 2 components is a ribosome made of? 28 What 2 components is a ribosome made of? rrn and N rrn and carbohydrates rrn and proteins both b and c rrn and carbohydrates rrn and proteins both b and c rrn and N 28 Slide 74 () / 111

18 Slide 75 / 111 to make RN 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 29 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 What is the function of the ribosome? 29 Slide 75 () / 111 Slide 76 / 111 "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 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 What does the "t" in trn stand for? 30 Slide 76 () / 111 Slide 77 / 111 Why does trn fold into its specific shape? 31 Why does trn fold into its specific shape? The sequence and bonding of its amino acids The sequence and bonding of its amino acids The sequence of and bonding of nucleotides The sequence of and bonding of nucleotides Its protein structure Its protein structure and and E and E and 31 Slide 77 () / 111

19 Slide 78 / 111 Translation - n Overview Slide 79 / 111 Translation - n Overview trns bond to the amino acid specified by their anti-codon. 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. Slide 81 / 111 Translation - Initiation 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 82 / 111 Translation - Initiation 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. lso notice that there are 2 sites within the ribosome. 3' 5' The P-site where the new protein will emerge The -site where the mino cids are delivered in 3' 5' Slide 83 / 111 Translation - Initiation The trns, hydrogen bonded to their specific amino acids, surround the ribosome. 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. Me t 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. U ll the pieces are ready to begin translation: UG

20 Slide 84 / 111 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. 32 How does the anticodon on the trn and the codon on the mrn match up? by hydrogen bonding/complimentary base pairing by ionic bonding 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. by peptide bonds none of the above Translation - Initiation Slide 85 / 111 ecause each trn has an anticoding sequence it complimentary base pairs with the codon on the mrn. Slide 85 () / 111 by hydrogen bonding/complimentary base pairing by ionic bonding by peptide bonds none of the above What is the P site of the ribosome? 33 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 () / 111 What is the P site of the ribosome? 33 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 87 / 111 Translation - Elongation 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. 32 How does the anticodon on the trn and the codon on the mrn match up? Slide 86 / 111

21 Slide 88 / 111 Slide 89 / 111 Translation - Elongation Translation - Elongation The ribosome moves the mrn using chemical energy. Elongation continues by adding one amino acid after another. 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. 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... Notice the protein emerging from the Psite! Slide 90 / 111 Slide 91 / 111 Translation - Termination Translation - Termination The Result- protein in its "primary sequence". The ribosome reaches a STOP codon. Remember that STOP codons do not code for amino acids. This signals the end of translation. Remember that Primary level (10 ) of protein structure is the sequence of amino acids. The protein is complete. The 2 subunits (large and small) separate from each other. U is 1 of the 3 lick here to see an animation of translation possible STOP codons. Slide 92 / 111 What is the first event of translation? 34 What is the first event of translation? the trn comes in the small subunit of the ribosome and the 1st trn brings in Methionine to the start codon elongation happens the large subunit of the ribosome comes in the large subunit of the ribosome comes in the trn comes in the small subunit of the ribosome and the 1st trn brings in Methionine to the start codon elongation happens 34 Slide 92 () / 111

22 Slide 93 / 111 Slide 93 () / 111 What is the first step of translation called? 35 transcription elongation termination initiation termination initiation transcription elongation What is the first step of translation called? 35 Slide 94 / 111 What is the function of the ribosome in translation? 36 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 What is the function of the ribosome in translation? it makes a peptide/covalent bond between codons it makes hydrogen bonds between the codons 36 Slide 94 () / 111 it makes covalent/peptide bonds between amino acids none of the above Slide 95 / 111 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 RN polymerase falls off the N a trn brings in an amino acid a trn brings in an amino acid 37 Slide 95 () / 111

23 Slide 96 / 111 What is translation? 38 What is translation? 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 the assembly of the amino acids from the protein code assembly of amino acids coded for by the mrn codons the making of mrn 38 Slide 96 () / 111 Slide 97 / 111 Slide 97 () / 111 What is a gene? 39 What is a gene? 39 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 segment on the RN that codesfor codons segment on the amino acid 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: TTT GGG T TTT GGG Resulting Transcript: UUU GGG UU GGG Resulting Polypeptide: Phe - Lys - Gly - Pro -Tyr - Lys - Gly - Pro

24 Slide 100 / 111 Slide 101 / 111 Reading Frame Shifts Insertion and eletion Mutations We can think about the N sequence of a gene as a sentence made up entirely of three-letter words. Thesunwashot 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. 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 orrect NSequence: RN Transcript: orrect Polypeptide: Insertion mutation: Resulting Transcript: Resulting Polypeptide: TT T GG G UUU U GG G Phe - STOP eletion mutation: Resulting Transcript: Resulting Polypeptide: T TT G GG_ UU G GG _ Leu - Lys - Gly? Slide 102 / 111 Silent Mutations TTT GGG UUU GGG Phe - Lys - Gly - Pro Slide 103 / hanging one nucleotide in a N sequence can change in a protein. mutation is "silent" if it has no affect on the protein coded by the gene. The redundancy in the genetic code makes this possible. a polypeptide 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. the secondary structure the primary structure the tertiary structure E all of the above If you were to split this sentence into individual three-letter words, you would probably read it like this: The sun was hot la - GU, G, G, GG Leu - UU, UUG, UU, U, U, UG rg - GU, G, G, GG, G, GG Slide 103 () / 111 a polypeptide the primary structure the secondary structure the tertiary structure E E all of the above 41 Using TTT GGG as an example, which of the following would be an example of a substitution mutation? TTT GGG TT T GGG T TTT GGG TTT GGG hanging one nucleotide in a N sequence can change in a protein. 40 Slide 104 / 111

25 Slide 104 () / 111 TTT GGG TT T GGG T TTT GGG TTT GGG 42 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 Using TTT GGG as an example, which of the following would be an example of a substitution mutation? 41 Slide 105 / 111 Slide 105 () / 111 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 42 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 Slide 107 / 111 Spontaneous Mutations Slide 108 / 111 re mutations always bad? 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. This shows a N strand slipping out of place during replication, causing a mutation in the N once it has been repaired. Not necessarily... 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.

26 Slide 109 / 111 temporary always fatal permanent always beneficial 43 The change a mutation causes to N is: temporary always fatal permanent always beneficial The change a mutation causes to N is: 43 Slide 109 () / 111 Slide 110 / 111 ll mutations are caused by mutagens. 44 ll mutations are caused by mutagens. True False True False 44 Slide 110 () / 111 FLSE Slide 111 / 111