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97 Cards in this Set
- Front
- Back
Central Dogma of Molecular Genetics
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The DNA self replicates and directs the production of proteins
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Three parts of the nucleotide
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Deoxyribose Sugar, Nitrogen BASE , and phosphate group.
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What forms the core of the nucelotide.
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The deoxyribose sugar.
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Two categories of Nitrogen bases
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Purines = Double RInged
Pyrimidines = Single Rined |
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Purines
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Adenine and Guanine
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Pyrimidines
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Cytosine and Thymine
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Why does the ribose sugar have the name 'deoxy' on it?
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Because on the 2' position, it has an H rather than and OH.
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The sugar side chain is bound by what kind of bonds?
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Hydrogen Bonds
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Inner and outer structure of the DNA molecule.
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The inner part is the NITROGEN BASE while the outer part is the RIBOSE SUGAR which forms the backbone of the DNA molecule
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G-C Bonds
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G-C bonds are the strongest bonds that exists in the DNA molecule
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Bonding between bases in the DNA molecule.
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Purines will bond with Pyrimidines and vice versa. Also, for each type of base there is, there will be an equal amount of the other base
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Anti Parallel
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The fact that one DNA strand will exhibit 3→5 polarity while the other will exhibit 5→3 polaity. This is important because enzymes can only move in the 5→3 direction.
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DNA Base Pairing
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Adenine - Thymine
Guanine - Cytosine |
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Semiconservative Replication
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The method of DNA replication in which each new DNA molecule is composed on one parent strand and one strand that has been newly synthesized.
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How can you tell the new strand from the old one?
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The new strands have not undergone methlyation and will not show methyl group while the older ones will.
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Origin of Replication
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The point on the DNA molecule where the DNA starts replicating. There need to be a number of origins of replication in order for the DNA to replicate at a sustainable pace.
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Replication Fork
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The split between the two DNA strands during the replication process.
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Helicase
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Unwinds the two strands of DNA
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The bonds between the two strands of DNA.
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Hydrogen Bonds
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This protein makes sure that the single strand of DNA does not rebind to other strand during the replication process. They accomplish this by stabilizing the single strand of the DNA
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Single Strand Binding Proteins
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This molecule relieves the strain on the single strand of the molecule as a result of the POSITIVE SUPERCOILING by introducing NEGATIVE SUPERCOILING to compensate
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DNA Gyrase
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Coiling
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A feature of the DNA in which the DNA literally wraps into a coil. Negative and postive refer the the direction of the coil.
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DNA Polymerase
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Adds nucleotides to the single strand of DNA.
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RNA Primer
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DNA Polymerase can only work if it knows where to go. RNA primer is a segment of RNA that guides DNA Polymerse to where it needs to be.
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Pimase
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An RNA polymer enzyme that creates the RNA primers
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DNA Ligase
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Will fill in the points between the okazaki fragments with the missing nucleotides.
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Which strand is more likely to find errors?
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The lagging strand since the DNA molecules need to add and remove from the strand more ofter leading to a higher liklihood of error.
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Leading Strand - Lagging Strand
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The enzyme that place neucleotides on the parent strand of the DNA can only do so in the 5 → 3 direction. This is fine for the leading strand becayse the DNA polymerase can move inward in the 5 →3 as the helicase opens th DNA strand. The other strand cannot do this. The DNA polymerase can only move in a 5 → 3 direction if it's moving outward. This is the lagging strand. As such the strand can only take nucelotides in a step by step manner; constantly moving back as the helicase opens the DNA
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Okazaki Fragments
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The sections of DNA that are added to the lagging strand of the DNA.
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Where is RNA found?
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Cytoplasm and the nucleus
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Base pairing of the RNA.
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Adenine - Uracil
Guanine - Cytosine |
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Four types of RNA
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mRNA, tRNA, rRNA, hnRNA
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Major Function of cytoplasmic RNA
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Transcription and Translation
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mRNA
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Carries genetic message from the nucelus to the cytoplsm so that it can be tranlated into a PROTEIN
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Monocistronic - Polycistronic
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The former means that the RNA can only be used to make one product while the latter means that one RNA molecule can be used to make many products. The latter are generally found in prokaryotes
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What received the RNA to make proteins
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The ribsome
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tRNA
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Links RNA together to form a polypeptide chain
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Codon
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Selects for different amino acids
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rRNA
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Ribosomal RNA. Made in the NUCLEOLOUS and forms an integral part of the ribsome
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hnRNA
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Heterogeneous Nuclear RNA. A precursor to mRNA
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Antisense strand
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During RNA synthesis, only one strand is used which is known as the antisense strand
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Transcription
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The encoding of mRNA
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RNA Polymerase
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Synthesizes the production of RNA from the DNA template
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Promoters
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Signel to the RNA polmerase where to begin transcription.
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Termination Sequences
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Sequences on the DNA that signal to the RNA Polymerase to stop transcription
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Three steps that hnRNA undergoes to become mRNA
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- 5-Guanosyl is added to cap one end in order to stabilize molecule
- Poly Adenine cap is added to 3' of molecule -Removal of INTRONS which are the NON CODING PARTS of te hnRNA |
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In the genetic language________are the letters and_______are the words.
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Letters: A,C,T/U, G
Words: All 20 Amino Acids |
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Degeneracy/Redundancy
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The fact that the genetic code, give the number of permutations that it has, will have a segment of the code that is redundant
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The forming of proteins from mRNA and Amino Acids
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Translation
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During the translation process, what molecule a) recognizes the codon and b) the amino acid that the codon specifies?
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tRNA has one region that recognizes the codon and another region that will bind the correct Amino acid specified by the codon.
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The region of the tRNA that recognizes the codon.
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Anticodon region
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Sequence on the tRNA that will bind the Amino Acid
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CCA
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tRNA Synthetase
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Binds the correct amino acid to the tRNA forming an AMINOACYL-tRNA COMPLEX.
THIS PROCESS USES GTP NOT ATP!!!!! |
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Structure of Ribosome
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The ribsome has two units that come together during translation
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Ribosomal Binding Sites
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One site is for the mRNA. Another site is called the A SITE which holds the aminoacyl tRNA complex. The other is the P SITE which binds to the tRNA attached to the growing polypeptide chain.
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Three Stages of Protein Synthesis
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Initiation, Elongation, and Termination
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Codon Convention
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When the codon attached to the anti codon, it does so in a reverse order and always 5 → 3. If you have an 5- AUG- 3 codon, the anticodon wil be 5 - CAU -3
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Start Codon
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Start Codons are always AUG. They will also result in the synthesis of methionine.
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Methionine tRNA
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This tRNA has the anticodone sequence of 5 - CAU - 3 which will bind to the start codon of AUG.
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Peptdyl Transferas
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This enzyme will catalyze the formation of peptide bonds between the amino acids as the ribosome move along the mRNA
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Translocation
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As the ribosome moves along the mRNA, a peptide bond is formed between the two amino acids. When this bond is formed, the unchared tRNA molecule that was in the P SITE is not ejected to make room for the new tRNA molecule to elongate the chain.
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Termination Codon.
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This is a UAG codon which will stop the process totally. When the ribosome meets the stop codon it signal a release factor which will bind to the termination codon causing a water molecule to add to the polypeptide chain
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Polyribosome
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A ribosome that can translater a number of mRNA molecules at the same time
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What is the difference between transcription and Translation?
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Transcription uses the same language which means that it is something that will go from DNA to RNA. Translation goes from one language to the ther which means RNA can be translated into proteins.
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Things that can occur to the polypeptide chain after sythesis.
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-Phosphorylation
-Carboxylation -Methylation -Sugar Added -Cleavage into smaller parts or active form |
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Three type of genetic mutation
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Base Pair Mutaions, Insertions, Deletions
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Point Mutation
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Base Pair Mutation
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Frameshift Mutation
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Insertions and Deletions
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Silent Mutation
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Mutations that occur in non coding regions or regions where it will have no effect
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Missense Mutation
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A mutation in which one amino acid is replaced with another
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Transposons
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Elements that can insert and remove themselves from the genome.
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How do viruses violate a key tenet of Cell Theory
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Cell theory states that all living things reproduce. Viruses do not reproduce on their own but need a host to do so.
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Capsid and cell invasion
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A virus can only invade a cell is the protein coat of the virus can recognize a given cell and infect it.
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RNA Replicase
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In the case of a virus that has an RNA based genome, when it infects a cell it will bring with an enzyme known as RNA replicase which will replicate RNA. A normal cell cannot replicate RNA
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Retroviuses
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These viruses create DNA from RNA using REVERSE TRANSCRIPTASE. The virus will use this enzyme to turn its RNA genome into DNA which it will then integrate into the host genome.
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Virions
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Virus particle. When the DNA of the virus is transcribed by the hosts enzymes, it will create VIRAL PROTEINS. There viral proteins or virus particles are known as virions.
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Two ways in which viral progeny can be release
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One process is EXTRUSION in which the virus particles will bind with the host's cell membrane. A virus that does this is said to be in its PRODUCTIVE CYCLE. The other method is that the virus will create so many virus particles that it will simply lyse the cell.
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Bacteriophages
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Viruses that specifically target bacteria
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Lytic Cycle
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When a bacteriophage infects a cell and replicates to such an extent that it causes cell lysis
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Lysogenic Cycle
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When the bacteriophage integrates into the host DNA, the viral DNA is known as a provirus. As the cell replicates so will the bacteriophage DNA. Given certain environmental factors, the provirus will enter the lytic cycle, remove itself from the host DNA, and lyse the cell.
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Plasmids
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Extracellular DNA in Bacteria
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Episomes
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Plasmids that capable of integrating into the DNA.
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Polycistronic Character of Bacterial Proteins
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In bacteria, transcription and translation occur simultaneously. As such bacterial mRNA may have more than one function and can have varying effect on the cells
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Replication Origin in Bacteria
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Since their DNA is less extensive than human DNA, bacteria only need on origin of replication.
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Three methods of increasing genetic diversity in bacteria
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Transformation, Conjugation, and Transduction
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Transformation
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Results from the integration of foreign chromosome fragments into the DNA of the cell which confers a unique genetic identity
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Conjugation
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Occurs when a CYTOPLASMIC BRIDGE forms between DONE MALE and RECIPIENT FEMALE in which genetic material is passed from one to the other.
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What is the cytplasmic bridge formed from?
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Sex Pilus that are found on the Donor Males
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How do the males forms the sex pilus?
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The males need plasmids called SEX FACTORS in order to create the sex pilus.
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Term used to designate cells that have undergone conjugation?
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Hfr Recombinants
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Operons
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Proteins that regulate the RNA Polymerase's access to the genome.
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Three parts of the operon
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Structural Genes, Operator Genes, Promoter Genes
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Structural Gene
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Codes for the protein of interest
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Operator Site
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Capable of binding a repressor protein.
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Promoter
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Region where the RNA polymerase binds
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Repressor
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Serves as a roadblock to the RNA polymerase in the case where the protein could be transcribed
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Inducible - Repressible Systems
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An inducible system requires the presence of an INDUCER for the system to initiate transcription. A repressible system is one that is constantly transcribing unless a COREPERSSOR is present.
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