front 1 What is the role of DNA helicase in DNA replication? | back 1 It uses the energy created by ATP to break the hydrogen bonds between two DNA strands, thereby "unzipping" the molecule. |
front 2 The replication fork __________________. | back 2 is the point where DNA helicase is "unzipping" the double-stranded DNA molecule. |
front 3 What is the function of stabilizing proteins? | back 3 They hold the separated strands apart and prevent their degredation. |
front 4 The replication fork moves ___________. | back 4 ahead of the newly synthesized DNA. |
front 5 What must occur for an organism to pass its genetic information on to its offspring? | back 5 The parent must copy its own DNA and provide a copy to its offspring. |
front 6 The process of copying DNA prior to cell replication is known as _____________. | back 6 DNA replication. |
front 7 What is meant by semiconservative replication? | back 7 The new copies of DNA contain one original strand of DNA and one new strand of DNA |
front 8 What serves as the template for DNA replication? | back 8 each of the original DNA strands |
front 9 Which enzyme(s) can synthesize new strands of DNA? | back 9 DNA polymerase |
front 10 Why is primase essential for DNA replication? | back 10 It provides a 3' end of the newly synthesized strand, allowing DNA polymerase to begin copying DNA. |
front 11 DNA synthesis occurs in which direction? | back 11 From 5' to 3' on both the leading and lagging strands. |
front 12 How does the DNA polymerase know which nucleotide triphosphate to add to the growing strand? | back 12 It hydrogen-bonds the nucleotide to the parental strand, pairing adenines to thymines and guanines to cytosines. |
front 13 What might happen if the cell does not have RNAse? | back 13 The newly made chromosome would consist of DNA and RNA molecules. |
front 14 How many RNA primers are required for the leading strand of DNA replication?
| back 14 One RNA primer
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front 15 What is the function of the connector proteins? | back 15 They link the leading strand DNA polymerase and the lagging strand DNA polymerase together. |
front 16 Okazaki fragments are typically ____ nucleotides in length and are found on the ______ strand of DNA replication. | back 16 1000 and Lagging |
front 17 Name the 4 steps of lagging strand DNA replication. | back 17 1. Primase adds an RNA primer
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front 18 Name the three products of transcription | back 18 mRNA, rRNA, tRNA |
front 19 The role of transcription is ___________________. | back 19 to copy the information stored in DNA into RNA. |
front 20 _______ is used to make ribosomes | back 20 rRNA |
front 21 _______ is involved in bringing amino acids to the ribosomes | back 21 tRNA |
front 22 _______ is a copy of a DNA sequence used to make protein | back 22 mRNA |
front 23 In general, higher levels of transcription lead to ______________________. | back 23 higher amounts of protein. |
front 24 Name three functions of RNA polymerase | back 24 It binds to the promoter region of the gene prior to starting RNA synthesis, adds nucleotides to the 3' end of the growing RNA molecule, and reads the template strand of DNA. |
front 25 How does protein-dependent termination differ from protein-independent termination? | back 25 Protein-dependent termination involves the use of a protein to end transcription. |
front 26 Translation | back 26 the process of making protein from RNA. |
front 27 Ribosomes move along the mRNA in which direction? | back 27 5' to 3' |
front 28 Name three things involved in translation | back 28 ribosomes, amino acids, and mRNA |
front 29 What is the order of ribosomal sites that a charged tRNA molecule passes through? | back 29 A site, P site, E site |
front 30 The anticodon sequence is found on the __________. | back 30 tRNA. |
front 31 An amino acid is considered charged ____________. | back 31 when it is bound to its correct tRNA. |
front 32 mRNA is not a part of the initiation process.
| back 32 True |
front 33 Release factors _______________________and ________________________. | back 33 bind to the A site
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front 34 Name 3 genetic elements found in an operon | back 34 operator region, structural genes, and promoter |
front 35 Where does the activation and repression of an operon occur? | back 35 operator region |
front 36 Inducible operons are transcribed only ____________________. | back 36 when they are activated. |
front 37 Repressible operons are always transcribed unless
| back 37 they are deactivated by a repressor |
front 38 The structural genes of an operon typically have the same biochemical function in the cell.
| back 38 True |
front 39 What does the inducer bind to in the lac operon system? | back 39 repressor proteins |
front 40 Which genetic element codes for the repressor protein? | back 40 the regulatory gene |
front 41 ___________ _______ bind to the operator, preventing RNA polymerase from transcribing the structural genes. | back 41 Repressor proteins |
front 42 When is the regulatory gene transcribed? | back 42 Always |
front 43 What ceases when lactose is absent from the system. | back 43 Induction of the operon |
front 44 The inducer acts by ________? | back 44 turning off the repressor |
front 45 Allolactose serves as ___________? | back 45 an inducer |
front 46 The trp operon is always activated unless __________________________________________. | back 46 deactivated by a repressor |
front 47 What is the role of tryptophan in the trp operon? | back 47 It activates the repressor proteins. |
front 48 Why is the transcription of structural genes of the trp operon turned off in the presence of tryptophan? | back 48 The structural genes are used to make tryptophan, which would not be needed if tryptophan is available. |
front 49 What is the target of the activated repressor protein? | back 49 the operator region of the operon |
front 50 The repressor gene is always _____________. | back 50 transcribed |
front 51 Activated repressor proteins bind to the operator region, preventing ______________________________. | back 51 RNA polymerase from transcribing the structural genes |
front 52 Which mutation is the least likely to be harmful to a cell? | back 52 silent mutation |
front 53 A mutation that results in the presence of a stop codon in the middle of the genetic code is a _____________. | back 53 nonsense mutation |
front 54 What type of mutation can change all subsequent amino acids following it? | back 54 fragment mutation |
front 55 A chemical that can increase the rate of mutations. | back 55 mutagen |
front 56 Base pair substitutions that can result in what 3 types of mutations | back 56 silent, nonsense, and missense |
front 57 How frequently does an error occur in DNA replication in the absence of a mutagen? | back 57 one error for every 1,000,000,000 nucleotides copied |
front 58 What is a potential source of mutations from ionizing radiation? | back 58 The resulting Ions and free radicals can break chromosomes. |
front 59 Ethidium bromide can result in _________________. | back 59 frameshift mutations via insertion or deletion of nucleotides. |
front 60 X-rays would be considered which type of mutagen? | back 60 ionizing radiation |
front 61 5-bromouracil is an example of a ___________ _______. | back 61 nucleoside analog |
front 62 Enzymes known as photolyases are involved in which type of repair? | back 62 light repair mechanism |
front 63 How can a mismatch repair enzyme detect which strand contains the correct DNA sequence? | back 63 The original strand will likely have a methyl group attached, while the newly mutated strand will not. |
front 64 Name the 2 repair mechanisms that require assistance from DNA polymerase to make the correction? | back 64 excision-repair mechanism AND mismatch-repair mechanism |
front 65 Light repair mechanism does not involve the removal of nucleotides?
| back 65 True |
front 66 Name 2 repair mechanisms that might be involved in repairing a mutation that results from exposure to UV light | back 66 light-repair mechanism AND
|
front 67 The transfer of DNA from one bacterium to another is an example of ______________ _________ _____________. | back 67 Horizontal gene transfer |
front 68 Transcription is NOT a type of horizontal gene transfer.
| back 68 True |
front 69 Name 3 types of horizontal gene transfer. | back 69 conjugation, transformation, and transduction |
front 70 Recombinant | back 70 A cell that has incorporated new DNA as part of its own |
front 71 Cells that are naturally able to take up DNA from their environment | back 71 competent |
front 72 Why do S strains escape killing by host phagocytes? | back 72 They are encapsulated. |
front 73 What reason most likely explains the recovery of S strain from a mouse injected with heat-killed S strain mixed with living R strain? | back 73 The R strain picked up the S-strain DNA, enabling it to produce capsules. |
front 74 T or F?
| back 74 True |
front 75 ___________ are unable to cause disease in mice. | back 75 R strains |
front 76 R strains do not produce a _________. | back 76 capsule |
front 77 Generalized transduction is initiated by ___________. | back 77 the lytic cycle of viral replication |
front 78 Transduction | back 78 the transfer of bacterial DNA from one host to another via a bacteriophage |
front 79 What would be a fate of a bacterium infected by a generalized transducing bacteriophage? | back 79 integration of the packaged DNA into the host chromosome |
front 80 The process of generalized transduction requires a _______ ______________. | back 80 lytic bacteriophage |
front 81 The process of generalized transduction utilizes any fragment of the bacterial chromosome.
| back 81 True |
front 82 Generalized transduction is the result of ________________________? | back 82 Sloppy packaging of the DNA by bacteriophage |
front 83 What 2 things initiate specialized phage transduction? | back 83 Prophage integrates into the host genome
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front 84 Two terms that could describe the newly infected host of a specialized transducing bacteriophage | back 84 recipient cell AND
|
front 85 What is packaged by the bacteriophage during induction? | back 85 the phage DNA with some of the host DNA |
front 86 What is the purpose of bacterial conjugation? | back 86 to transfer DNA between two living cells |
front 87 Why is E. coli considered the model of bacterial conjugation? | back 87 The process of conjugation is best characterized in E. coli. |
front 88 T or F?
| back 88 True |
front 89 What is unique about the DNA transferred between two cells during conjugation? | back 89 It is transferred by a single strand |
front 90 3 chronological events of conjugation | back 90 Pulling of donor and recipient cells together,
|
front 91 What characteristics do F+ and F- cells share? | back 91 each contain a chromosome |
front 92 Following conjugation between a donor and a recipient, what cell types are present? | back 92 two F+ cells |
front 93 F plasmid | back 93 fertility factor |
front 94 What DNA molecule is transferred between cells during conjugation between an F+ and an F- cell? | back 94 a single stranded F plasmid |
front 95 The 4 chronological events of conjugation | back 95 Attachment of the sex pilus,
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front 96 How does an F+ cell become an Hfr cell? | back 96 By integrating the F plasmid into the chromosome |
front 97 What typically results from conjugation between an Hfr cell and an F- cell? | back 97 one Hfr cell and one F- cell |
front 98 What does Hfr stand for? | back 98 high frequency of recombination |
front 99 Why are F- cells unable to spread the fertility factor? | back 99 F- cells rarely receive a complete copy of the fertility factor during conjugation. |
front 100 Name 3 characteristics of an F- cell | back 100 Cannot synthesize a sex pili
|
front 101 How long does it take an Hfr strain of E. coli to transfer its complete chromosome? | back 101 100 minutes |
front 102 Approximately how long would it take for the serA gene to transfer? | back 102 62 minutes |
front 103 If conjugation was allowed to be carried out for 42 minutes, which genes would be transferred to the recipient strain? | back 103 trp |
front 104 Which gene would transfer quickest during conjugation for this Hfr strain? | back 104 Fertility factor |
front 105 If gene X transferred at 99 minutes, what conclusion could you make about gene X? | back 105 Gene X is close to the fertility factor on the Hfr chromosome, but it is near the end of the chromosome transfer. |
front 106 Transposons | back 106 DNA fragments that can move from one location in the DNA to another |
front 107 Which type of transposon would contain an antibiotic resistance gene? | back 107 complex transposons |
front 108 Insertion sequences are composed of _____________. | back 108 a transposase gene flanked by inverted repeats |
front 109 A region of DNA in which the sequence of nucleotides is identical to an inverted sequence on the complementary strand | back 109 inverted repeat |
front 110 3 functions of the enzyme transposase | back 110 cuts the DNA so the transposon can leave its current position, cuts the DNA at the new site for a transposon, and covalently links the transposon to the new DNA site. |
front 111 How does replicative transposition differ from cut-and-paste transposition? | back 111 Replicative transposition results in multiple copies of the transposon in the DNA; cut-and-paste transposition has only one copy. |
front 112 What is unique about complex transposons? | back 112 They have two simple transposons with another DNA sequence between them |
front 113 Why is a complex transposon containing an antibiotic resistance gene more likely to be copied than a simple insertion sequence when the host reproduces? | back 113 They confer a survival advantage for the host. |