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2010-10-18 03:42:02

test#2 part 2
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  1. What are heterotrophs?
    • • Must obtain carbon in an organic form made by otherliving organisms
    • • Such as proteins, carbohydrates, lipids, and nucleicacids
  2. What are Autotroph?
    • • An organism that uses CO2 as its carbon source
    • • Not nutritionally dependent on other living things
  3. What are Chemotroph?
    gain energy from chemical compounds
  4. What are Phototrophs?
    gain energy through photosynthesis
  5. What are Photoautotrophs?
    • • Oxygenic photosynthesis
    • • Anoxygenic photosynthesis
  6. What are Chemoautotrophs?
    • • lithoautotrophs
    • • survive totally on inorganic substances
  7. What are lithoautotrophs?
    eats rocks
  8. What are Methanogens?
    • • A kind of chemoautotroph
    • • Produce methane gas under anaerobic conditions
  9. What are chemoheterotrophs?
    • Majority of hetertrophes
    • • Aerobic respiration
    • – Two categories
    • • Saprobes
    • • Parasite
  10. What are Saprobes?
    • – Free-living microorganisms that feed on organic detritusfrom dead organisms
    • – Opportunistic pathogen
    • – Facultative parasite
  11. What are Parasite?
    • – Derive nutrients from host
    • – Pathogens
    • – Some are obligate parasites
  12. What are pathogens?
    they are parasites that cause damage to cells (disease) or death.
  13. What is Passive transport?
    does not require energy; substancesexist in a gradient and move from areas of higherconcentration toward areas of lower concentration
  14. What is Diffusion?
    molecules propelled down a concentration gradient by random thermal motion.
  15. What is Osmosis?
    diffusion of water
  16. What is Facilitated diffusion?
    requires a carrier
  17. What is Active transport?
    requires energy and carrier proteins;gradient independent
  18. What is Group translocation?
    transported molecule chemically altered
  19. What is Bulk transport?
    endocytosis, exocytosis, pinocytosis
  20. What is endocytosis?
    solid and liquids materials are taken into the cell through membrane invagination or engulfment into a vesicle
  21. What is exocytosis?
    releases enveloped viruses from the membrane of the host's cytoplasm
  22. What is pinocytosis?
    engulfment or endocytosis of liquid by extensions(microvilli) of the cell membrane
  23. What is phagocytosis?
    type of endocytosis in which the cell membrane actively engulfs large particles or cells into vesicles
  24. When is a cell hypotonic?
    When it has less solute outside the cell causing the cell to take in water and push against cell wall
  25. When is a cell hypertonic?
    when the cell has more solute outside the cell causing the cell to lose water and shrink.
  26. When is a cell isotonic?
    When the cell has the same solute concentration inside and outside the cell
  27. What is symbiosis?
    the relationship between two organisms that live together in a close partnership
  28. What is Mutualism?
    members are obligatory, dependent; both members benefit
  29. What is Commensalism?
    commensal member benefits,other member neither harmed nor benefited
  30. What is Parasitism?
    parasite is dependent and benefits;host is harmed
  31. What are biofilms?
    • result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers
    • • Dominate the structure of most natural environments on earth
    • • Communicate and cooperate in the formation and function of biofilms – quorum sensing
  32. binary fission (transverse)
    Parent cell enlarges, duplicates its chromosome, and forms a central transverse septum dividing the cell into two daughter cells
  33. What is generation, or doubling time?
    Time required for a complete fission cycle
  34. What is exponential growth?
    Each new fission cycle increases the population by a factor of 2
  35. What is Lag phase?
    “flat” period of adjustment, enlargement; little growth
  36. What is Exponential growth phase?
    a period of maximum growth will continue as long as cells have adequate nutrients and a favorable environment
  37. What is Stationary phase?
    rate of cell growth equals rate of celldeath caused by depleted nutrients and O2, excretion of organic acids and pollutants
  38. What is Death phase?
    as limiting factors intensify, cells die exponentially
  39. What is a growth curve?
    a graphical representation of the change in population size over time. It has 4 periods known as lag phase, exponential phase, stationary phase and death phase.
  40. What is Metabolism?
    all chemical and physical workings of a cell
  41. What is Catabolism?
    degradative;breaks the bonds of larger molecules forming smaller molecules; releases energy
  42. What is Anabolism?
    biosynthesis;process that forms larger macromolecules from smaller molecules;requires energy input
  43. What are Enzymes?
    • Enzymes are biological catalysts
    • –Lower the energy of activation
    • – The energy of activation is the resistance to a reaction
    • – The enzyme is not permanently altered in the reaction
    • • Enzymes use a specific lock and key fit with substrate
  44. Simple enzymes
    consist of protein alone
  45. Holoenzymes
    • – contain protein and nonprotein molecules
    • – Apoenzyme is proteinportion
    • – Cofactors is nonprotein portion
    • • Metallic cofactors:iron,copper,magnesium
    • – Coenzymes,organic molecules:vitamins
  46. What is the Enzyme Specificity and the Active Site?
    • – Site for substrate binding is active site,or catalytic site
    • – A temporary enzyme-­‐substrate union occurs when substrate moves into active site=induced fit
    • – Appropriate reaction occurs;product is formed and released
  47. What are Exoenzymes?
    • • Transported extracellularly
    • • They breakdown large food molecules or harmful chemicals
    • • Cellulase,amylase,penicillinase
  48. What are Endoenzymes?
    • • retained intracellularly and function there
    • • Most enzymes are endoenzymes
  49. What are Constitutive enzymes?
    • – Always present
    • – Always produced in equal amounts or at equal rates
    • – Enzymes involved in glucose metabolism
  50. What are Regulated enzymes?
    • – Not constantly present
    • – Production is turned on(induced)or turned off(repressed) in response to changes in concentration of the substrate
  51. What is Synthesis or condensation reactions?
    • –Anabolic reactions to form covalent bonds
    • – Between smaller substrate molecules
    • – Require ATP
    • – Release one molecule of water for each bond formed
  52. What are Hydrolysis reactions?
    • – Catabolic reactions that breakdown substrates into small molecules
    • – Requires the input of water to break bonds
  53. Activity of an enzyme is influenced by what in a cell’s environment?
    • • Temperature
    • – Reduce activity
    • – Denature
    • • pH
    • – Reduce activity
    • – Denature
    • • Substrate concentration
    • – Reaches a saturation point
  54. What is Competitive inhibition?
    Competition for the active site. Inhibitor blocks the active site.
  55. What is Noncompetitive inhibition?
    • • Allosteric enzymes
    • • The binding by a substance to a site other than the active site which blocks the substrate from active substrate
  56. What is Enzyme repression?
    • • Inhibits at the genetic level by controlling synthesis of key enzymes
    • when too much product is being made, the product binds to another protein which binds to promoter and turns gene off
  57. What is Enzyme induction?
    • Enzymes are made only when suitable substrates are present
    • protein keeps geen off until a certain protein or sugar is present and binds to promoter and turns gene on causing it to start making the product. once enough product is made the protein or sugar breaks off and the gene turns off. this helps preserve energy.
  58. What do Endergonic reactions do?
    consume energy
  59. What do Exergonic reactions do?
    release energy
  60. What is Redox reactions?
    • – Always occur in pairs
    • – There is an electron donor and electron acceptor which constitute a redox pair
    • – Process salvages electrons and their energy
    • – Released energy can be captured to phosphorylate ADP or another compound
    • Na + e- + Cl » Na+oxidized Cl- reduced
    • everytime you add on an e- and H+ to a molecule it is reduced
  61. What are and what do Electron and Proton Carriers do?
    • – Repeatedly accept and release electrons and hydrogen to facilitate the transfer of redox energy
    • – Most carriers are coenzymes:
    • • NAD+
    • • FAD
    • • NADP
    • • coenzymeA
    • • Compounds of the respiratory chain
  62. What is AdenosineTriphosphate:ATP?
    • – Metabolic“currency”
    • – Three part molecule consisting of
    • • Adenine–anitrogenous base
    • • Ribose–a 5-­‐carbonsugar
    • • 3phosphate groups– ATP utilization and replenishment is a constant cycle in active cells
    • – Removal of the terminal phosphate releases energy
  63. How is ATP can be formed three different mechanisms?
    • • Substrate-­ level phosphorylation – transfer of phosphate group from a phosphorylated compound(substrate) directly to ADP
    • • Oxidative phosphorylation – series of redox reactions occurring during respiratory pathway
    • • Photophosphorylation – ATP is formed utilizing the energy of sunlight
  64. What three catabolic pathways convert glucose to CO2 and gives off energy in Aerobic respiration?
    glycolysis, the Kreb’s cycle, respiratory chain
  65. What three catabolic pathways convert glucose to CO2 and gives off energy Anaerobic respiration?
    glycolysis, the TCA cycle, respiratory chain; molecular oxygen is not final electron acceptor
  66. What catabolic pathway convert glucose to CO2 and gives off energy Fermentation?
    glycolysis, organic compounds are the final electron acceptors
  67. What is Glycolysis?
    glucose(6C) is oxidized and split into 2molecules of pyruvic acid (3C), NADH is generated
  68. What is TCA?
    processes pyruvic acid and generates 3CO2 molecules, three NADH and one FADH2 are generated
  69. What is Electron transport chain?
    accepts electrons from NADH and FADH; generates energy through sequential redox reactions called oxidative phosphorylation
  70. What is the Electron Transport and Oxidative Phosphorylation?
    • – Final processing of electrons and hydrogen and the major generator of ATP
    • – Chain of redox carriers that receive electrons from reduced carriers (NADHandFADH2)
    • – ETS shuttles electrons down the chain, energy is released and subsequently captured and used by ATP synthase complexes to produce ATP which is Oxidative phosphorylation
  71. Chemiosmosis
    • as the electron transport carriers shuttle electrons, they actively pump hydrogen ions(protons) across the membrane setting up a gradient of hydrogen ions–proton motive force
    • Hydrogen ions diffuse back through the ATP synthase complex causing it to rotate, causing a 3-dimensional change resulting in the production of ATP
  72. What are the ATP Totals?
    Glycolysis ?
    Pyruvate to Acetyl CoA ?
    Kreb’s cycle ?
    • • Glycolysis
    • – 2 NADH = 6 ATP
    • – Plus 2 ATP
    • • Pyruvate to Acetyl CoA
    • – 2 NADH = 6 ATP
    • • Kreb’s cycle
    • – 6 NADH = 18 ATP
    • – 2 FADH2 = 4 ATP
    • – Plus 2 ATP
    • • Total = 38 ATP
  73. What is Anaerobic Respiration?
    • – Functions like aerobic respiration
    • •Except it utilizes other electron acceptors rather than oxygen
    • • Nitrate(NO3-­‐) and nitrite(NO2-­‐)
    • • Used by anaerobes and facultative anaerobes
  74. What is Fermentation?
    • – Incomplete oxidation of glucose or other carbohydrates in the absence of oxygen
    • – Uses organic compounds as terminal electron acceptors
    • – Yields a small amount of ATP
    • – Recycles the NADH
    • – Produces
    • • Ethyl alcohol by yeasts acting on glucose
    • • Formation of acid or acid and gas by bacteria
  75. What is Genetics?
    • the study of heredity
    • • The science of genetics explores
    • – Transmission of biological traits from parent to offspring
    • – Expression and variation of those traits
    • – Structure and function of genetic material
    • – How this material changes
  76. What is the Genome?
    • sum total of genetic material of a cell(chromosomes+mitochondria/chloroplasts and/or plasmids)
    • • Genome of cells – DNA
    • • Genome of viruses – DNA or RNA
    • – DNA complexed with protein constitutes the genetic material as chromosomes
    • – Bacterial chromosomes are a single circular loop
    • – Eukaryotic chromosomes are multiple and linear
  77. What are genes?
    • • Chromosome is subdivided into genes
    • – The fundamental unit of heredity responsible for a given trait
    • – Site on the chromosome that provides information for a certain cell function
    • – Segment of DNA that contains the necessary code to make a protein or RNA molecule
  78. What are the Three basic categories of genes?
    • – Genes that code for proteins which are structural genes
    • – Genes that code for RNA
    • – Genes that control gene expression which are regulatory genes
  79. What is a genotype?
    All types of genes constitute the genetic makeup
  80. What is a phenotype?
    The expression of the genotype creates observable traits
  81. What is a nucleotide?
    • Basic unit of DNA structure
    • • Each nucleotide consists of 3 parts
    • :– A 5 carbon sugar which is deoxyribose
    • – A phosphate group
    • – A nitrogenous base of adenine,guanine,thymine,cytosine
    • • Nucleotides joined by phosphodiester bond
    • • Two strands twisted into a doublehelix
    • – They are anitiparallel
  82. What are the enzymes of DNA Replication?
    • • Helicase-­‐unwinds and unzips the double helix by binding hydrogen bonds
    • • Topoimerase-­‐relieves supercoiling
    • • Single Stranded Binding proteins
    • • Primase-­‐makes a short RNA primer
    • • DNA polymerase III-­‐adds nucleotides in a 5 ' to 3' directions
    • • DNA polymerase I-­‐removes the primer and fills in the gaps
    • • DNA polymerase II– has no known function
    • • DNA Ligase-­‐joins the two ends after DNA Pol I
  83. What diriction is DNA synthesized?
    • DNA synthesis is always towards the replication fork
    • – Leading strand is Synthesized continuously in 5'to3' direction
    • – Lagging strand is synthesized 5'to 3' in short segments
    • • Over all direction is 3' to 5'
    • • Segments are called Okazaki Fragments
  84. Why is DNA replication is semiconservative?
    because each chromosome ends up with one new strand of DNA and one old strand.
  85. What is Transcription and Translation?
    • – Transcription
    • • Is used to make RNA ( mRNA, tRNA, rRNA)
    • – Translation
    • • Is used to make protein from mRNA
  86. What are 3 the steps of Transcription?
    • – Initiation
    • • RNA polymerase finds the promoter before the gene and unwinds the DNA
    • – Elongation
    • starts 10 base pairs down from the promoter
    • • NTPs are added in the 5’to 3‘ direction
    • – Termination
    • • Self termination with a stem loop
    • • Enzyme dependent
  87. What are the genetic codes for mRNA, tRNA, rRNA?
    • mRNA is composed of codons and the genetic code is universal, the genetic code is redundant
    • • There is more than one codon per amino acid
    • • There are 64 codons
    • • Three are stop codons
    • The tRNA is a stem loop structure and brings amino acids to the ribosome on the 3’end containing the anticodon
    • The rRNA is used to make ribosomes
  88. What are the 3 steps of Translation?
    • – Initia-on
    • • mRNA and ribosomes come together
    • • Starts at the P site with the AUG start codon
    • • First amino acid is methionine
    • – Elongation
    • • Add amino acids and form a peptide bond
    • • Ribosome moves down them RNA to next codon
    • – Termination
    • • Ribosome reaches the stop codon
    • – Causes them all to come apart
  89. Facts about Eukaryotic Transcription and Translation
    • – Transcription occurs in the nucleus
    • – Translation occurs in the cytoplasm
    • – Eukaryotic mRNA starts as premessenger RNA
    • • Contains introns or intervening sequences
    • • Contains exons that are expressed
    • • Spliced by ribosomes
    • • 3’PolyA tail is added
    • • 5’methyl cap
    • • Now it can leave the nucleus
    • – Eukaryotic start codon is AUG, but it does not use formyl‐methionine
  90. Facts about Genetics of Animal Viruses
    • – One or more pieces of DNA or RNA
    • – Contains only genes needed for production of new viruses
    • – Viral can have overlapping
    • • Requires access to host cell’s genetics and metabolic machinery
  91. Facts about Genetics of bacteria
    • – Can perform transcription and translation at the same time
    • – Poly cistronic mRNA
    • • Genes are clustered together
    • • In groups called operons
    • • operons, a set of genes,all of which are regulated as a single unit
  92. What are operons?
    what are the 2 types of operons?
    • operons, a set of genes,all of which are regulated as a single unit
    • – Inducible operon
    • •Operon is turned ON by substrate
    • – Repressible operon
    • • genes in a series are turned OFF by the product synthesized
  93. What is Lac operon?
    • Lactose Operon : Inducible Operon
    • Made of 3 segments:
    • • Regulator–gene that codes for repressor
    • • Control locus–composed of promoter and operator
    • • Structural locus–made of 3 genes each coding for an enzyme needed to catabolize lactose
    • –» β-­‐galactosidase–hydrolyzes lactose
    • » permease–brings lactose across cell membrane
    • » β-­‐galactosidasetransacetylase–uncertain function
  94. How does Lac operon work?
    • • Lac Operon is normally off
    • – When there is no lactose
    • • The repressor binds with the operator locus
    • •Blocks transcription of downstream structural genes
    • – Lactose turns the operon on
    • • Lactose binds to repressor and changes its shape
    • • Repressor comes off the operator
    • • Now, RNA polymerase can bind to the promoter
  95. How does Arginine Operon work?
    • • Arginine Operon:Repressible
    • – Normally on
    • – Will be turned off when the product of the pathway is no longer required
    • – When excess arginine is present it will bind to the repressor and changes its shape or the repressor binds to the operator and blocks arginine synthesis
  96. DNA Recombination Events
    • • Genetic recombination– Occurs when an organism acquires and expresses genes that originated in another organism
    • • Horizontal genetic transfer:
    • – Conjugation
    • – Transformation
    • – Transduction
  97. What is conjugation?
    • – Transfer of a plasmid
    • • Plasmid is called a factor
    • • Example is the F factor, which meands fertility factor
    • – Done through pili
    • – Can transfer factors for many different functions
    • • Antibiotic resistance
    • • Fertility
    • • Enzymes
  98. What is transformation?
    • – Can take up DNA from the environment
    • – Chromosome fragments from alysed cell are accepted by a recipient cell
    • – The genetic code of the DNA fragment is acquired by the recipient
    • – Donor and recipient cells can be unrelated
    • – Useful tool in recombinant DNA technology
  99. What is Transduction?
    Bacteriophage serves as a carrier of DNA from a donor cell to a recipient cell
  100. What are Transposons?
    • • Special DNA segments that have the capability of moving from one location in the genome to another – “jumping genes”
    • • Cause rearrangement of the genetic material
    • • Can move from one chromosome site to another, from a chromosome to a plasmid, or from a plasmid to a chromosome
    • • Maybe beneficial or harmful
  101. What is Biotechnology?
    Use of an organism’s biochemical and metabolic pathways for industrial production
  102. What are the Tools and Techniques of Genetic Engineering?
    • – Intrinsic properties of DNA hold true even in a test tube
    • • DNA heated from 90°C to 95°C
    • – The two strands separate
    • – The nucleotides can be identified, replicated,or transcribed
    • • Slowly cooling the DNA
    • –Allows complementary nucleotides to hydrogen bond
    • – DNA will regain double-­stranded form
  103. What are the Enzymes for Dicing, Splicing, and Reversing Nucleic Acids?
    • • Restriction Endonucleases
    • • Ligase
    • • Reverse transcriptase
  104. What does Restriction Endonucleases do?
    • – Recognize specific sequences of DNA
    • – Break phosphodiester bonds between adjacent nucleotides
    • – The enzymes can be used to cleave DNA at desired sites
    • – Recognize and clip the DNA at palindrome base sequences
    • – Used in the lab to cut DNA into smaller pieces
    • – restriction fragments
  105. What does Ligase do?
    • – Rejoins phosphate‐sugar bonds
    • – Sticky ends‐cut by endonucleases
    • – Used for final splicing of genes into plasmids and chromosomes
  106. What does Reverse transcriptase do?
    • – makes a DNA copy of RNA = cDNA
    • – cDNA can be made from mRNA, tRNA,or rRNA
    • – Provides a means of synthesizing eukaryotic genes
  107. What are Methods for Analysis of DNA?
    • • Gel Electrophoresis
    • •Nucleic Acid Hybridization and Probes
  108. How does Gel Electrophoresis work?
    • – Separates DNA fragments based on size
    • – DNA samples are placed on soft agar gel and subjected to an electric current
    • – Negative charge of molecule causes DNA to move toward positive pole
    • – Rate of movement is dependent on size of fragment
    • – larger fragments move more slowly
    • – Fragments are stained for observation
    • – Useful in characterizing DNA fragments and comparing for genetic similarities
  109. How does Nucleic Acid Hybridization and Probes work?
    • – Hybridization
    • – Foundation for gene probes
    • • Short fragments of DNA of a known sequence
    • • Will base-­pair with a stretch of DNA with a complementary sequence,if one exists in the sample
    • – Useful in detecting specific nucleotide sequences in unknown samples
    • • DNA fragments are separated by electrophoresis
    • • Southern blot is performed on the gel
    • • Membrane from southern blot is incubated with probes
    • • If probes are complimentary they will bind to DNA
    • • This will isolate fragments from a mix of fragments and find specific gene sequences
  110. What are the Methods Used to Size, Synthesize, and Sequence DNA?
    • • DNA sequencing
    • • PCR
  111. What is DNA sequencing and how does it work?
    • – Determining the actual order and type of bases for all types of DNA
    • – Most common sequencing technique is Sange rtechnique
    • • Test strands are denatured to serve as a template to synthesize complementary strands
    • • Fragments are divided into tubes that contain:
    • –Primers
    • – DNA polymerase
    • –All 4 nucleotides
    • –dideoxynucleotide
    • » A different one in each tube
  112. What is Polymerase Chain Reaction (PCR) and how does it work?
    • – Method to amplify DNA
    • – Ingredients
    • • DNA to be amplified
    • • Taq Polymerase(fromThermusaquaticus)
    • • Nucleotides
    • – Repetitively cycled
    • • Denaturation(94oC)
    • • Priming(50to65oC)
    • • Extension(72oC)
    • – Each cycle doubles the number of copies for analysis
  113. what are the Methods in Recombinant DNA Technology?
    • • Recombinant DNA technology
    • • Cloning Vectors
  114. What is Recombinant DNA technology?
    • – The intentional removal of genetic material from one organism and combining it with that of a different organism
    • – Requirements to make RecDNA
    • • Restriction endonucleases
    • • Desired gene
    • • Ligase
    • • Vector(plasmidorvirus)
    • • Cloning host(bacteriaoryeast)
  115. What are the Characteristics of Cloning Vectors?
    • – Origin of replication is needed so it will be replicated
    • – Vector must accept DNA of the desired size
    • – Gene which confers drug resistance to their cloning host
  116. What are Desirable Features in a Cloning Host?
    • – Rapid overturn, fast growth rate
    • – Can be grown in large quantities using ordinary culture methods
    • – Nonpathogenic
    • – Genome that is well delineated
    • – Capable of accepting plasmid or bacteriophage vectors
    • – Maintains foreign genes through multiple generation
    • – Will secrete a high yield of proteins frome xpressed foreign genes
    • • Producing a synthetic peptide using recombinant DNA technology and transformation
  117. What are Biochemical Products of Recombinant DNA Technology?
    • • Enables large scale manufacturing of life‐saving hormones, enzymes, vaccines
    • – Insulin for diabetes
    • – Human growth hormone for dwarfism
    • – Erythropoietin for anemia
    • – Factor VIII for hemophilia
    • – HBV vaccine
  118. What is Genome Analysis?
    • • DNA Finger printing –Every individual has a unique sequence of DNA
    • • Methods used include restriction endonucleases, electrophoresis, hybridization, and Southernblot
    • • Types of analysis
    • • SNP – single nucleotide polymorphism
    • • Markers
    • • VNTRs
    • • Microsatellite polymorphisms
  119. What is DNA Fingerprinting is used for?
    • • Identify hereditary relationships
    • • Study inheritance of patterns of diseases
    • • Study human evolution
    • • Identify criminals or victims of disaster
    • • Analysis of mitochondrial DNA isused to trace evolutionary origins
    • • Micro array analysis – track the expression of thousands of genes
  120. Describe the process of glycosis.
    start with 6 c glucose which gains 2 phosphates from ATP which becomes ADP. this results in a 6c sugar phosphate which splits into 2 3c sugar phosphates. An electron and NAD+ is added to each 3c sugar phosphate this produces NADH then ADP picks up 2 phosphates becoming 2ATP and lose of 1 H20 molecule and formation of pyruvate. in aerobic respiration the pyruvate with Co2 is converted to acetyl CoA in the transition step before entering the Krebs cycle. in fermentation the pyruvate with Co2 is converted to acid and gas with no fnal electron receptor. Net results is 2NADH which equals 6 ATP and 2 ATP.
  121. What is the differences between eukayote, prokaryote and virus genomes?
    • Viral genes can be RNA or DNA and overlap
    • Eukaryote have introns and exons, introns have to be taken out with rbosomes then the exons ned to be put back together wth a 5' prime cap and a 3' polyA tail end then leave the nucleus.
    • Prokaryotes have operons, more than 1 gene per promoter and operator. It translates and transcribes more than 1 gene at a time into protiens simutaneously. During transcription into mRNA, each gene has its own start codon.
    • [promoter ][ operator ]---[gene]--[gene]--[gene] »[ mRNA ] [gene] [gene] [gene]
    • -----------------operon---------------------- ==proteins= 1 ====2 -----3
  122. Describe Polymerase Chain Reaction (PCR)
    Method to amplify DNA. Ingredients primer, DNA to be amplified, Taq (DNA polymerase that works when heated up), nucleotides. Ingredients are put in tube then heated making a double strand copy then heated up again to denature to separate strands. It is then cooled down making primer bind, heated up again so Taq works making 2 double stranded DNA. This repeated over and over again.
  123. Describe how to make a synthetic peptide using Recombinant DNA methods.
    Ingredients needed restriction endonucleases (used to cut open plasmid), desired gene, ligase, plasmid (vector), bacteria or yeast (cloning host). Add cDNA or DNA from other pathogen and plasmid that has been cut open with restriction endonucleases plus contain the gene for antibodic resistance, then ligase which ligates genes together then add to bacteria or yeast (cloning host) and the plasmids will stick to bacteria. It is then heat shocked which cause transformation (bacteria suck up DNA). Plate bacteria on agar with antibodics where they will grow up (only bacteria with gene will grow). These bacteria are used to grow large batches of bacteria with new gene that can be used to make a synthetic peptide.
  124. What is Restriction Endonucleases?
    • – Recognize specific sequences of DNA
    • – Break phosphodiester bonds between adjacent nucleotides
    • – The enzymes can be used to cleave DNA at desired sites
    • – Recognize and clip the DNA at palindrome base sequences
    • – Used in the lab to cut DNA into smaller pieces called restriction fragments
  125. Describe an operon and how it works (Lac Operon).
    An operon is a set of genes that are regulated as a single unit. When there is no lactose present, a repressor protein from a repressor gene(located elsewhere on the chromosome) binds to the control locus(promoter and operator) blocking the transcription of downsteam structural genes. when lactose enters the cell it turns on the operon by binding to the repressor causing it to change shape and fall off the operator. This allows RNA polymerase to bind to the promoter and start transcription. The repression of the genes prevents the production of enzymes for breaking down lactose when lactose isn't present. This helps conserve energy by only producing enzymes when necessary.
  126. Describe DNA replication
    • 1.At the origin helicase unwinds the double helix asnd topimderase relieves supner coiling creating replicatieon forks at both of the replication bubble.
    • 2. single stranded binding proteins stops hydrogen bonding.
    • 3. leading strand is replicated in a continuous 5' to 3' strand by the laying down of primase making a RNA primer the DNA poly III adds nucleotides creating a new strand.
    • 4. lagging strand is made in discontinuous 5' to 3' short segment because it goes from 3' to 5' and DNA has to replicated from 5' to 3'. primase lays RNA primer then DNA poly III lays nucleotides to 3' primer end in short segments called Okazaki fragments.
    • 5. DNA I removes RNA primer and fills in gaps
    • 6. DNA ligase joins DNA poly I and DNA poly III fragments together.
    • 7. Process is terminated with either a stem loop or an enzyme causes RNA poly and RNA to come apart.
  127. Describe translation with all 3 steps.
    • Transcription is used to make RNA which occurs in the nucleus in 3 steps.
    • 1. Initiation - RNA polymerase fnds the promoter before the gene and unwinds the DNA
    • 2. Elongation - Starts 10 based pairs down from the promoter. NTPs are added in the 5' to 3' direction.
    • 3. Termination - Occurs at the end of the gene by self termination with a stem loop or an enzyme dependent action. Self termination occurs when RNA start to H+ bond with itself creating a stem loop causing RNA polymerase to stop then come off, setting the RNA free. An enzyme dependent action occurs when an enzyme attaches to the RNA then goes up the RNA this makes the DNA, RNA polymerase, and RNA come apart.
  128. Describe translation and all 3 steps.
    • Translation turns amino acids into protiens occurs in the cytoplasm in 3 steps.
    • 1. Initiation - The mRNA and ribosomes come together. Translation starts when a tRNA enters the P site and binds with the mRNA start codon AUG.
    • 2. Elongation - The next tRNA