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38 Cards in this Set
- Front
- Back
depurination is hydrolysis of ______ from ________.
What kind of drugs do this? |
depurination is hydrolysis of RIBOSE from a purine (A or G).
Alkylating drugs induce this. |
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In _________, NH2 falls off of ________ and is replaced by a _______ group.
So _____ is replaced by ______. |
In deamination, NH2 falls off of CYTOSINE and is replaced by a carboxyl group.
So cytosine is replaced by URACIL. |
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Does deamination occur spontaneously?
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yes. but chemicals make it deaminate faster.
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What kind of damage does UV radiation do to DNA?
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UV radiation causes formation of pyrimidine bases. (Especially Thymine dimers).
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Oxidation is the kind of damage to DNA caused by?
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ROS resulting from normal metabolism.
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Why is radiation so bad for DNA?
What repairs this? |
Radiation breaks the double strand creating reactive ends = rearrangements, inversions, translocations.
NON-HOMOLOGOUS END-JOINING PROTEINS |
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What is the inheritance pattern of a PROTOONCOGENE?
What do protooncogenes do? |
AUTOSOMAL DOMINANT
Increase activity in cell growth |
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What is the inheritance pattern of tumor supressor genes?
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recessive
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What seals the nicks in DNA repair? How does it get the energy for this?
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DNA Ligase seals the nicks - it uses ATP.
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What are two specific DNA repair pathways?
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Nucleotide Excision Repair (NER)
Mismatch Repair |
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What removes the bad DNA in the NER pathway?
What disease did we study that is caused by problems with this pathway? |
helicase
XP |
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What removes the bad DNA in the Mismatch repair pathway?
What disease that we studied is caused by problems in this pathway? |
exonuclease
Hereditary Non-Polyposis Colon Cancer |
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What is the inheritance pattern of XP?
Why does uv radiation create problems for XP patients? |
Recessive
UV radiation hits the skin - causes formation of Thymine dimers and NER can't fix it. |
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What inheritance pattern does a mutated MSH2 gene follow?
What does the gene do? |
mediates repair of mismatched bases.
autosomal dominant |
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Which needs a primer, DNAP or RNAP?
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DNA Polymerase needs a primer.
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What do snRNA's do? Where are snRNA's found? Why?
These are an example of _______. |
They remove introns in pre-mRNA. In the NUCLEUS - because that's where pre-mRNA is found as an initial transcript of DNA.
SPLICEOSOMES |
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What is an anticodon?
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found on tRNA (one the inferior loop) - it "reads" the mRNA codon bc it matches it.
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this kind of mutation changes a codon into a stop-codon specifically.
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nonsense mutation.
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this kind of mutation causes the insertion or deletion of a number of base pairs not divisible by 3.
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frameshift mutation
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this kind of mutation changes the identity of one AA to another.
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missense mutation
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B-Thalassemia cap site degradation by exonuclease is called what?
What is the result? |
Promoter Mutation - the gene never begins
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B-Thalessemia mutation point: what kind of mutations cause introns to not be removed like they should?
What is the result? |
splice site mutations - makes non-functional proteins
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B-Thalessemia mutation point: what mutation causes change to the AAUAAA site?
What is the result? |
Polyadenylation Signal mutation - makes the strands way too long bc they don't know to stop.
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What enzyme makes NTP out of NMP?
Does this require ATP? What does that mean for AMP? |
Nucleotide Kinase = REQUIRES ATP
futile cycle for AMP |
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What enzyme makes NMP?
Can bases cross the cell membrane? |
Nucleoside kinase
bases alone can cross cell membrane |
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if you start with ribose-5-phosphate what enzyme do you use to make 5-phosphoriboxyl-1-pyrophosphate? (PRPP).
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PRPP syntheTase.
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what enzyme makes NMP's from PRPP?
How does it do this? |
NPRT (nucleotide phosporibosyl transferase).
It does this by removing the pyrophosphate and putting a base in its place. |
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excess amp pathway.
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amp (PHOSPHATASE)-->Adenosine (ADENOSINE DEAMINASE) --> inosine (NUCLEOSIDE PHOSPHORYLASE) --> hypoxanthine
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what rxn does nucleoside phosphorylase catalyze?
how? |
inosine --> hypoxanthine
it removes the ribose backbone inosine is the "nucleoside" and hypoxanthine is the "base". |
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SCID is caused by what?
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deficiency in Adenosine Deaminase
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excess guanine pathway
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guanine (GUANASE)--> hypoxanthine (XANTHINE OXIDASE)--> xanthine (XANTHINE OXIDASE)-->uric acid
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what enzyme does allopurinol inhibit?
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xanthine oxidase
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what's a nucleotide precursor to ATP and GTP?
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IMP
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What enzyme lack/deficiency causes Lesch-Nyhan Syndrome?
What is the inheritance pattern of this disease? |
HGPRT
X-linked recessive |
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Sx of Lesch-Nyhan Syndrome?
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Bad gout, mental retardation, spastic CP, self-mutilation
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what enzyme makes deoxyribonucleotides from ribonucleotides?
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ribonucleotide reductase
****ONLY WORKS ON NDP'S (not NMP'S) (diphosphates only) |
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what takes useless dUDP and makes it into DTMP?
in the presence of what coenzyme? |
Thymidylate Synthase
folate is the coenzyme |
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how does 5-flourouracil work?
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irreversible inhibitor of Thymidylate Synthase.
dTMP never gets made from dUMP |