molecular_genetics_ms1.txt

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molecular_genetics_ms1.txt
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genetics ms1
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molecular genetics ms1
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  1. A nucleotide monomer contains:
    1.
    2.
    3.
    • 1. nitrogen base
    • 2. sugar
    • 3. phosphate
  2. What is the structure of mRNA?
    A. double helix
    B. clover leafed shaped
    C. globular
    D. linear
    D. linear
    (this multiple choice question has been scrambled)
  3. What is the structure of rRNA?
    a. double helix
    b. linear
    c. clover leafed shaped
    d. globular
    globular
  4. Topoisomerases are what type of enzymes?
    isomerases
  5. DNA polymerase synthesizes in the ____________ direction.
    5' --- 3'

    *leading strand
  6. During mRNA processing, a 5' cap is added to the 5' end of the mRNA.
    What does this capping provide?
    • Capping provides stability to the mRNA
    • * made up of guanine nucleotide with 2 phosphate
  7. The Poly-A tail is attached the ______ end of the mRNA.
    3' end
  8. What does the poly-A tail mainly composed of?
    Adenine bases -- approx. 200
  9. What does the Poly-A tail do ?
    provides stability to the mRNA and also appears to control the movement of the mRNA across the nuclear envelope.
  10. __________ are sequences that express a code for a polypeptide.
    A. extrons
    b. introns
    extrons
  11. Before the mRNA moves to the cytoplasm, _________________ delete the introns and splice the exons.
    small nuclear ribonucleoproteins or snRNP's
  12. 3 MAJOR STRUCTURE FORMS OF DNA
    A - RIGHT HANDED; ASSOCIATED WITH DNA/RNA HYBRIDS

    B - RIGHT HANDED; MOST COMMON IN HUMANS.

    Z - LEFT HANDED; FORMS ZIG-ZAG PATTERN.
  13. CENTROMERE
    USED DURING CELL DIVISION AS THE ATTACHMENT POINT FOR SPINDLE FIBERS
  14. TELOMERE
    USED TO MAINTAIN CHROM INTEGRITY BY CAPPING OFF THE ENDS OF THE LINEAR CHROM
  15. HISTONES
    OCTAMER CONSISTING OF 2 COPIES EACH OF THE CORE HISTONES H2A, H2B, H3, H4, AND LINKER HISTONE H1.

    RICH IN BASIC AMINO ACIDS (LYS, ARG) AND ARE POSITIVELY CHARGED AT PHYS PH ALLOWING THEM TO BIND TO NEGATIVE CHARGED DNA

    STABLE IN PRESENCE OF DNA
  16. CHROMATIN STRUCTURE ALTERATIONS (2)
    COVALENT METHYLATION OF THE CYTOSINE BASES IN DNA

    REVERSIBLE MODIFICAITONS OF HISTONES BY ACYLATION OF N-TERMINAL AMINO ACIDS

    INVOLVED IN GENE SILENCING AND CONSIDERED EPIGENETIC
  17. ALPHA GLOBIN GENE CLUSTER
    CHROM 16 CONTAIN DIFFERENT TYPES OF ALPHA HEMOGLOBIN

    DEFECTIVE ALPHA GENES CAUSE THALASSEMIA RESULTING IN MILD TO SEVERE ANEMIA AND EVEN DEATH
  18. BETA GLOBIN GENE CLUSTER
    CHROM 11, SLIGHT CHANGE CAUSES DISASTEROUS EFFECTS

    SICKLE-CELL ANEMIA
  19. MINISATELLITE DNA
    SHORT REGION OF 20-50 REPEATS.

    DIFFERENCES IN THESE REPEATS IS THE BASIS FOR DNA FINGERPRINTING
  20. MICROSATELLITE REPEATS
    POLYMORPHIC WITH 1-15 REPEATS.

    DI, TRI, OR VNTR (VARIABLE # TANDEM REPEATS)

    HUNTINGTON'S CHORIA (TRI CAG REPEAT >30)
  21. INTERSPERSED REPETITIVE DNA
    FOUND IN ALL EUK GENOMES

    PROPAGATE BY RNA MEDIATED TRANSPOSITION
  22. LINES
    LONG INTERSPERSED NUCLEAR ELEMENTS

    TRANSCRIBED INTO RNA USING RNA POL I PROMOTER LOCATED INSIDE GENE

    CODE FOR ENZYME REVERSE TRANSCRIPTASE AND ENDONUCLEASE (RNase)

    COPY THEMSELVES AND ENLARGE GENOME (21% IS ARE LINES)
  23. SINES
    SMALL INTERSPERSED NUCLEAR ELEMENTS

    REVERSE TRANSCRIBED RNA ORIGINALLY TRANSCRIBED BY RNA POL III INTO tRNA, rRNA, and other small nuclear RNA

    DO NOT CONTAIN ANY CODING SEQUENCES

    31% OF GENOME
  24. HIGHLY REPETITIVE SEQUENCE
    REPEATED PATERN CAN BE 1 TO SEVERAL THOUSAND BP LONG AND IN TOTAL CAN BE SEVERAL MEGA BP

    MOSTLY IN TELOMERIC AND CENTROMERIC REGIONS
  25. 3'UTR REGULATORY SEQUENCES
    3'-UNTRANSLATED REGION

    POLY-A SIGNAL FOR POST TRANSCRIPTIONAL MODIFICATION

    BINDING SITES FOR PROTEINS

    BINDING SITES FOR miRNA
  26. tRNA COMPONENTS (6)
    (1) 5'-TERMINAL PHOSPHATE GROUP

    (2) ACCEPTOR STEM FOR ADDITION OF 3' CCA SEQUENCE

    (3) CCA TAIL ON 3' END ADDED POST-TRANSCRIPTIONALLY. WHERE AMINO ACID ATTACHES

    (4) D ARM. 4 BP LOOP OFTEN CONTAINING DIHYDRURIDINE

    (5) ANTICODON ARM

    (6) T ARM CONTAINING PSEUDO-URIDINE
  27. EUK rRNA
    28S, 18S, 5.8S, AND 5S + 82 PROTEINS

    MAKE 80S RIBOSOMES (60S LARGE AND 40S SMALL)

    60S (28S, 5.8S, 5S + 49 PROTEINS)

    40S (18S + 33 PROTEINS)

    80-85% OF TOTAL RNA FOUND IN AVERAGE EUK CELL
  28. snRNA
    SMALL NUCLEAR RNA FOUND WITHIN NUCLEUS OF EUK CELLS

    TRANSCRIBED BY RNA POL II OR III

    INVOLVED IN RNA SPLICING, REGULATION OF TRANSCRIPTION FACTORS, AND MAINTAINING TELOMERES
  29. miRNA
    microRNA POST-TRANSCRIPTIONAL REGULATORS THAT BIND TO COMPLEMENTARY SEQUENCES IN THE 3' UTR OF TARGET mRNA

    USUALLY BLOCK TRANSLATION OR ACCELERATE DEGRADATION

    CAN CAUSE METHYLATION OF GENES

    TARGET ABOUT 60% OF MAMMALIAN GENES
  30. FIRST STEP IN DNA REPLICATION
    FORMATION OF PRE-INITIATION REPLICATION COMPLEX (pre-RC = ORC + MCM) REFERED TO AS LICENSING

    Cdc6 LOADS MCM COMPLEX TO ORIGIN. MADE ONLY DURING G1 PHASE, PHOSPHORYLATED AT S PHASE AND DEACTIVATED.

    MCM IS A DNA HELICASE
  31. SSB PROTEINS
    SINGLE STRANDED BINDING PROTEINS BIND TO DNA DURING SYNTHESIS TO KEEP FROM ANNEALING AND STABILIZE DNA TO ALLOW 100X FASTER REPLICATION
  32. EUK LAGGING STRAND SYNTHESIS ENZYME
    DNA POL ALPHA AND DELTA

    DNA POL ALPHA ADDS RNA PRIMERS

    PRIMERS REMOVED BY RNAse H & FLAP ENDONULEASES (FENs)

    REPLACED BY DNA POL DELTA & LINKED BY DNA LIGASE
  33. DNA POL ALPHA
    SYNTHS AN RNA PRIMER AT INITIATION SITES FOR LEADING/LAGGING STRAND

    PROVIDES 3'OH FOR ELONGATION WITH DNA NUCLEOTIDES
  34. DNA POL BETA
    IMPLICATED IN DNA BASE EXCISION REPAIR
  35. DNA POL GAMMA
    REPLICATES AND REPAIRS MITOCHONDRIAL DNA

    HAS PROOFREADING 3'-5' EXONUCLEASE ACTIVITY
  36. DNA POL DELTA
    HIGHLY PROCESSIVE 5'-3' SYNTH

    PROOFREADING 3'-5' EXONUCLEASE ACTIVITY

    MAIN POL FOR DNA LEADING/LAGGING STRAND SYNTH AND GAP FILLING AFTER REMOVAL
  37. CLAMP PROTEINS
    CONTRIBUTE TO DNA SYNTH BY FORMING A SLIDING CLAMP AROUND DNA

    HELPS RELEASE DNA POL
  38. PCNA
    PROLIFERATING CELL NUCLEAR ANTIGENS

    PROTEIN THAT ACTS AS A PROCESSIVITY FACTOR FOR DNA POL DELTA IN EUK CELLS

    TYPE OF DNA CLAMP
  39. TELOMERASE
    EXTENDS REPETITIVE SEQUENCES OF THE TELOMERE TO PREVENT DEGRADATION AND CHROM FUSION

    REVERSE TRANSCRIPTASE THAT CARRIES OWN RNA MOLECULE, WHICH IS USED AS TEMPLATE DURING ELONGATION

    REGULATED DURING DEVELOPMENT AND HAS VERY LOW ACTIVITY IN SOMATIC CELLS (AGING, CANCER)
  40. PROK DNA REPLICATION
    BIDIRECTIONAL

    SINGLE ORIGIN
  41. PROCARYOTIC DNA POLS
    POL I -- DNA REPAIR, HAS 5'-3' ACTIVITY AND BOTH 3'-5' AND 5'-3' EXONUCLEASE ACTIVITY (REMOVING DNA PRIMERS) AND FILLS GAPS AFTER REMOVAL OF RNA PRIMERS

    POL II -- REPAIR OF DAMAGED DNA. HAS 3'-5' EXONUCLEASE ACTIVITY

    POL III -- MAIN POL IN PROC SYNTH. HAS 5'-3' SYNTH AND 3'-5' PROOFREADING
  42. NOVOBIOXIN
    ANTIBIOTIC

    TARGET DNA GYRASE (TOPO I & II) AND BLOCK SYNTH

    USED TO TREAT MRSA
  43. NALADIXIC ACID
    ANTIBIOTIC

    EFFECTIVE AGAINST BOTH GRAM + & -

    PREVENTS REANNEALING OF DOUBLE-SRTANDED BREAK

    TREAT AGAINST URINARY TRACT INFECTIONS
  44. CIPROFLOXIN
    ANTIBIOTIC

    ACTS ON TOPOs

    TREATS ANTHRAX
  45. REVERSE TRANSCRIPTASE
    CAN TRANSCRIBE BOTH DNA AND RNA

    RNase ACTIVITY REMOVES RNA FROM DNA/RNA HYBRIDS AND MAKES 2X STRANDED DNA

    LACKS PROOFREADING & MAKES LOTS OF MISTAKES (1 IN 2,000 -- ABOUT 5X)
  46. MATURE VIRUS PROTEINS
    (GAG) GROUP SPECIFIC PROTEINS MAKES CORE AND STRUCTURAL PROTEINS (VIRAL CAPSID)

    • POLIMERASE CODES FOR:
    • --REVERSE TRANSCRIPTASE
    • --PROTEASE CLEAVES PROTEINS TO MAKE GAG AND POL
    • --INTEGRASE FOR INTEGRATION INTO HOST DNA

    ENV CODES FOR ENVELOPE PROTEINS ESSENTIAL FOR VIRAL ENTRY INTO CELL

    LTR LONG TERMINAL REPEATS

    POL POLYMERASE GENE

    ENV ENVELOPE GENE

    TAT TRANSACTIVATOR PROTEIN

    REV REGULATOR OF EXPRESSION

    VIF VIRAL INFECTIVITY

    VPU VIRAL PROTEIN U

    VPR VIRAL PROTEIN R

    NEF NEGATIVE-REGULATION PROTEIN
  47. VIRAL RNA
    DIMER RNA

    5' CAP AND 3'POLLY A TAIL

    TERMINAL NONCODING REGIONS IMPORTANT FOR REPLICATION AND INTERNAL REGIONS THAT ENCODE VIRAL PROTEINS
  48. CAMPTOTHECIN
    BINDS TO TOPO I AND DNA COMPLEX

    PREVENTS RELIGATION

    WORKS WITH CTP
  49. ARABINOSYL CYTOSINE (AraC)
    DNA POL INHIBITOR

    CONVERTED TO TRI-PHOS FORM THEN ACTS AS CHAIN TERMINATOR

    BLOCKS RIBONUCLEOTIDE REDICTASE IN CDP FORM

    REPLACES RIBOSE SUGAR WITH ARABINOSE
  50. CISPLATIN
    CANCER DRUG

    PLATINUM COMPLEXES CAUSE CROSSLINKING OF DNA AND TRIGGERS APOPTOSIS
  51. AZIDODEOXYTHYMIDINE (AZT)
    ANTIRETROVIRAL DRUG

    NUCLEOSIDE ANALOG REVERSE TRANSCRIPTASE INHIBITOR (NRTI)

    RESULTS IN CHAIN TERMINATION

    SHOWS SELECTIVITY FOR HIV CELLS
  52. EFAVIRENZ
    HIGHLY ACTIVE ANTIRETROVIRAL THERAPY (HAART)

    HIV
  53. LAMIVUDINE
    (3TC) HIV

    REVERSE TRANS INHIBITOR
  54. ACYCLOVIR
    HERPES REPLICATION BLOCKER

    SUGAR RING REPLACED BY OPEN CHAIN STRUCTURE

    RESULTS IN ACYLCO-GTP HAVING HIGHER AFFINITY FOR VIRAL POL, CAUSING CHAIN TERMINATION
  55. 3 GENERAL PROPERTIES OF RNA POLS
    1) REQUIRE DNA TEMPLATE

    2) REQUIRE ALL 4 NUCLEOTIDE TRIPHOSPHATES AS SUBSTRATES

    3) CATALYZE THE SYNTHESIS OF NEW RNA MOLECULE IN A 5' TO 3' DIRECTION
  56. HOW DOES TRANSCRIPT INITIATION OCCUR?
    REARRANGEMENT OF CHROMATIN CONTAINING THE PROMOTER SEQUENCE

    BINDING OF TRANSCRIPTION FACTORS TO PROMOTER AND ENHANCER (NOT ALL GENES CONTAIN ENHANCER)

    BINDING OF RNA POL TO PROMOTER FOR INITIATION OF TRNASCRIPTION
  57. CHROMATIN REARRANGEMENT
    REVERSIBLE MODIFICATIONS OF HISTONES

    ACETYLATION CREATES WEAKER INTERACTION BETWEEN HISTONE(+) AND DNA (-)

    LYSINE IN HISTONE --> HAT --> ACETYL-LYSINE RESIDUES IN HISTONE. HDAC REVERSES
  58. WHAT ARE THE CHARACTERISTICS OF SPECIFIC TRANSCRIPTION FACTORS? (5)
    (1) BIND DISITALLY FROM DNA PROMOTER

    (2) MODULATE EFFICIENCY OF INITIATION (ENHANCER)

    3) MEDIATE SIGNAL RESPONSE (e.g. HORMONE RESPONSE)

    (4) REGULATE GENE EXPRESSION (TIME-DEPENDENT, TISSUE SPECIFIC)

    (5) CAN ACT AS CO-ACTIVATORS RESULTING IN ENHANCEMENT
  59. WHAT ARE THE MAJOR STEPS OF tRNA SYNTHESIS?
    BINDING TRANSCRIPTION FACTORS TO PROMOTER. 2 PROMOTERS WITHIN TRANSCRIBED GENE.

    BINDING OF POL III

    PROCESSING OF tRNA PRECURSOR (REMOVING INTRONS)

    POST-TRANSCRIPTIONAL MODIFICATIONS. TRINUCLEOTIDE SEQUENCE 'CCA' ADDED TO 3' END
  60. WHAT ARE THE MAJOR STEPS OF EUK rRNA SYNTHESIS?
    BINDING OF TRANSCRIPTION FACTORS TO PROMOTERS LOCATED ON 2 DIFFERENT GENES (5.8 18 28 SEQUENCE AND 5 SEQUENCE)

    TRANSCRIPTION TO MAKE rRNA PRECURSERS

    REMOVING INTRONS FROM PRECURSERS

    POST-TRANSCRIPTIONAL MODIFICATIONS (METHYLATION)

    BINDING OF RIBOSOMAL PROTEINS TO FORM THE 2 SUBUNITS (40 & 60)
  61. WHAT ARE THE MAJOR STEPS IN EUK mRNA SYNTHESIS?
    RECOGNITION OF UPSTREAM CIS-ACTING ELEMENTS (PROMOTERS & ENHANCERS)

    BINDING OF TRANS ACTING ELEMENTS (TRANSCRIPTION FACTORS)

    BINDING OF RNA POLYMERASE
  62. WHAT ARE THE GENERAL CHARACTERISTICS OF ENHANCERS (CIS-ACTING ELEMENTS)?
    CANNOT INITIATE TRANSCRIPTION WITHOUT PROMOTER

    FUNCITON ONLY WHEN LOCATED ON THE SAME DNA MOLECULE AS PROMOTER THEY AFFECT

    CAN FUNCTION AT GREAT DISTANCE FROM THEIR PROMOTER AND IN EITHER ORIENTATION

    BINDING SITES FOR ENHANCER OR SILENCER PROTEINS (TRANS-ACTING ELEMENTS OR TRANSCRIPTIONAL TRANSACTIVATORS)
  63. WHAT ARE THE 2 TYPES OF PROMOTER SEQUENCES?
    CORE PROMOTER SEQUENCES OR PROXIMAL ELEMENTS DETERMINE PRECISELY WHERE TRANSCRIPTION WILL INITIATE (TATA BOX 25 BP UPSTREAM OF START SITE)

    UPSTREAM PROMOTER ELEMENTS ARE GENERALLY FIXED WITH RESPECT TO POSITION NEAR START SITE (CAAT BOX)
  64. WHAT ARE THE EUK AND PROK TRANS-ACTING FACTORS OF mRNA SYNTHESIS?
    PROKARYOTES -- CLUSTERED RELATIVELY CLOSE TO START SITE. AT-RICH SEQUENCE AT -7 TO -10 BINDS SIGMA FACTOR WHICH IS IMPORTANT FOR RNA POL BINDING

    EUK -- TATA BOX BINDING PROTEIN (TBP) IS PART OF LARGE TRANS-ACTING COMPLEX CALLED TFIID.

    TBP OF THE TFIID BINDS TO TATA BOX, THEN RNA POL II AND BASAL TRANSCRIPTION FACTORS (TAFs) CREATING BASAL COMPLEX.

    OTHER TAFs BIND TO STABILIZE THE BASAL COMPLEX (e.g. HELIX TURN HELIX AND ZINC FINGERS)
  65. HELIX-TURN-HELIX
    REGULATORY TRANSCRIPTION FACTOR FOR EUK

    2 ALPHA HELICES SEPARATED BY BETA TURN.

    ONE BINDS TO SPECIFIC DNA SEQUENCE AND THE OTHER INTRACTS WITH OTHER TFs
  66. ZINC FINGERS
    REGULATORY TRANSCRIPTIONFACTOR IN EUK

    ONE OR MULTI MOTIFS WITH ZINC ATOM LINKED TO 2 CYSTEINE RESIDUES AND 2 HISTIDINE SIDE CHAINS

    MOTIF FLANKED BY AN ALPHA HELIX AND A BETA SHEET. HELIX BINDS TO TARGET SEQUENCE
  67. LEUCINE ZIPPER
    REGULATORY TRANSCRIPTION FACTORS IN EUK

    ALPHA HELIX CONTAINING AT LEAST 4 LEUCINE RESIDUES WHICH ALIGN ON ONE EDGE

    BINDS WITH ANOTHER LEUCINE HELIX VIA HYDROPHOBIC INTERACTIONS

    DIMER FORMED (HOMO OR HETERO) AND BASIC SIDE HELIX ADJACENT TO ZIPPER BINDS TO DNA
  68. HELIX-LOOP-HELIX
    REGULATORY TRANSCRITION FACTOR IN EUK TRANSCRIPTION

    ONE DNA BINDING HELIX AND TWO DIMERIZED HELICES SEPARATED BY A NON-HELICAL LOOP
  69. BASIC CHARACTERISTICS OF LAC OPERON
    CONSISTS OF PROMOTER, OPERATOR, REPRESSOR (SEPARATE GENE), AND 3 STRUCTURAL GENES

    REPRESSOR BINDS TO OPERATOR AND BLOCKS RNA POL IN THE ABSENCE OF LACTOSE

    IF LAC IS PRESENT AND GLUCOSE IS DEPLETED, LAC CONVERTED TO INDUCER (ALLOLACTOSE) WHICH INACTIVATES REPRESSOR AND STARTS SYNTHESIS OF cAMP

    cAMP BINDS TO CRP, WHICH BINDS TO REGULATORY SEQUENCE

    RNA POL BINDS AND TRANSCRIPTION OCCURS
  70. GIVE AN EXPAMPLE OF TISSUE SPECIFIC REGULATION OF TRANSCRIPTION
    ALBUMIN GENE IN LIVER MODULATED BY TFs

    LIVER PROTEIN TRANSTHYRETIN (PREALBUMIN) ACTS AS TF SPECIFIC TO HEPATOCYTES
  71. MEDICAL RELAVENCE OF RNA BINDING PROTEINS
    NEURODEGENERATIVE DISEASES IN PRE-mRNA (POMA PARANEOPLASTIC NEUROPATHIES DUE TO MUTATION IN hnRNP-P2 WHICH BINDS TO PRE-mRNA)
  72. WHAT ARE SOME DISEASES ASSOCIATED WITH POLY-A SIGNAL
    (AAUAAA) IN mRNA?
    COLORECTAL CANCER

    INSULIN-LIKE GROWTH FACTOR 1 DEFICIENCY

    SCID

    • ALPH/BETA THALASSEMIA FROM REDUCED GLOBIN CHAIN SYNTHESIS. MAJOR DEFICIENCY CAUSES
    • CHRONIC ANEMIA. TREAT BY BLOOD TRANSFUSION AND IRON CHELATION WITH DEFEROXAMINE
  73. WHAT ARE SOME DISEASES ASSOCIATED WITH mRNA cleavage site?
    • THROMBOPHILIA (HYPERCOAGULABILITY) INCLUDING DVT AND
    • PULMONARY EMBOLISM PE)
  74. DESCRIBE RNA SPLICING
    snRNPs BASE PAIR WITH THE 5’ SPLICE JUNCTION AND SEQUENCE WITHIN INTRON TERMED THE BRANCH POINT (ENTIRE COMPLEX CALLED SPLICEOSOME)

    5’ END IS GU AND 3’ END IS AG

    2’, 5’-PHOSPHODIESTER LINKAGE BETWEEN EXON 1 AND INTRON CALLED LARIAT.

    EXON 1, INTRON, AND EXON 2 JOIN AND INTRON/snRNP RELEASED
  75. SYSTEMATIC LUPUS ERYTHEMATOSUS (SLE)
    DISORDER OF SPLICING CHARACTERIZED BY DEGENERATION OF SEVERAL TISSUES AND ORGANS INCLUDING SKIN, JOINTS, KIDNEYS, AND NERVOUS SYSTEM

    CONTAIN ANTIBODIES TO SELF snRNP INHIBITING RNA SPLICING (AUTOIMMUNE DISEASE)
  76. BRCA1 GENE
    DEFECT IN ALTERNATIVE SPLICING CAN CAUSE BREAST AND OVARIAN CANCER

    INVOLVED IN DNA DAMAGE REPAIR
  77. DESCRIBE CHARACTERISTICS AND ASSOCIATED DISEASES INVOLVED WITH mRNA STABILITY
    ALTERING DEGRADATION OF mRNA ALSO REGULATES mRNA LEVELS

    Ex, TRANSFERRIN RECEPTOR – WHEN IRON INSIDE CELL IS LOW THEN TRANSFERRIN RECEPTOR INCREASES. LACK OF IRON CAUSES IRE-BP TO BIND TO 3’UTR AND PROTECT TRANSFERRIN RNA FROM DEGRADATION

    MUTATIONS IN IRON RESPONSE ATTRIBUTED TO MITOCHONDRIAL AND METABOLIC DISORDERS

    TUMORS, BURKITT LYMPHOMA CAUSED BY TOO-STABLE Myc RNA WHICH IS A TRANSCRIPTION FACTOR
  78. RNA EDITING
    ADDITION OF A RESIDUES ON 3’ END OF VIRAL MRNA PROLONGS STABILITY (ex MEASLES & MUMPS)

    CHANGES IN BASE-PAIR SEQUENCING CAN CAUSE MAJOR MODIFICATIONS IN ORF (ex Apo B USED TO PRODUCE 2 TISSUE-SPECIFIC PROTEINS (LIVER & INTESTINE)
  79. DESCRIBE THE CHARACTERISTICS OF microRNA
    REGULATE THE STABILITY OF MRNA

    PRODUCED AS pre-miRNA THEN EXPORTED TO CYTOPLASM WHERE CLEAVED BY RNase TO MAKE SMALL 2X-STRANDED RNA

    2X-RNA DISSOCIATES INTO siRNA WHICH HYBRIDIZES TO TARGET MRNA FORMING A SILENCING COMPLEX (RISC) CAUSING DEGRADATION

    IF NOT HYBRIDIZED EXACTLY, TRANSLATION IS JUST INHIBITED

    MAY BE INVOLVED IN ALZHEIMERS, PARKINSONS, AND SUSTAINED CARDIAC HYPERTROPHY
  80. ANTIBIOTICS THAT INHIBIT RNA POLYMERASES
    • ACTINOMYCIN D & ADRIAMYCIN (DOXORUBICIN), CANCER CHEMOTHERAPY. INHIBITS BOTH DNA
    • REPLICATION AND RNA TRANSCRIPTION. HIGHLY TOXIC

    ALPHA-AMANITIN, FROM POISONOUS MUSHROOMS INHIBITS EUK RNA POL II AND LESSER EXTENT POL III

    RIFAMPICIN AND RIFAMYCIN B, INHIBIT ELONGATION BY BACTERIAL POL. TREATS INFECTION SUCH AS TB
  81. Cancer Chemotherapeutic Agents that inhibit DNA synthesis (59)
    Topoisomerase inhibitors: Camptothecin – inhibits human topoisomerase I by blocking the ligation of the DNA breaks made by the enzyme

    DNA Pol Inhibitors: Arabinosyl cytosine (AraC, cytosine arabinoside) Chain terminator: lacks a reactive 3’ OH so chain elongation stops when DNA Pol incorporates it into the replicating strand

    Agents that cross link strands: cisplatin
  82. Antibacterial agents that block DNA synthesis (2)
    • §
    • Novobiocin: inhibits bacterial topoisomerase (selective for bacteria)

    • §
    • Nalidixic acid: inhibits bacterial topoisomerase, treats MRSA and anthrax
  83. Antiviral drugs that block DNA synthesis (59)
    Reverse Transcriptase inhibitors:

    • Azidodeoxythymidine (AZT) and 2’,’3-dideoxycytidine (DDC)
    • Lack reactive OH’s so they stop chain elongation
    • Combined with other drugs for HAART (highly active retroviral therapy)
    • Have preferential affinity for RT and less for the host cell’s DNA polymerase

    Efavirenz – non-nucleotide RT inhibitor (NNRTI) – binds allosteric site to distort the catalytic asp residues and make RT nonfunctional

    • Acyclovir – used to block Herpes virus (HSV)
    • PO’d to monophosphate form by VIRAL thymidine kinase, then to di- and tri-
    • PO’d nucleotide is incorporated and acts as chain terminator
    • Specific only for the VIRAL kinase….very little side effects if HSV is not present
  84. THROMBOPHILIA (PIC)
  85. SYSTEMIC LUPUS ERYTHEMATOSIS SYMPTOMS (PIC)


  86. DRUGS THAT INHIBIT RNA POLS (PIC)
  87. ACUTE PROMYELOCYTIC LEUKEMIA (PIC)


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