FIRST AID USMLE STEP 1: BIOCHEMISTRY
1. What is a nucleoside?: Side = base + (deoxy)ribose [sugar]
2. Which are the pyrimidines?: "CUT the pyramid" = Cytosine, Uracil,
Thymine
3. What is a nucleotide?: Tide = base + (deoxy)ribose [sugar] +
phosphate
4. Which are the purines?: "pure as gold" = Adenosine, Guanosine
5. Drugs that Disrupt pyrimidine synthesis: Leflunomide,
Methotrexate, Trimethoprim, and Pyrimethamine
6. Leflunomide: inhibits dihydroorate dehydrogenase
7. Methotrexatem Trimethoprim and Pyrimethamine Effect on DNA: inhibit
di- hydrofolate reductase
8. 5- uorouracil (5-FU) MOA: inhibits thymidylate synthase
9. 6-mercaptopurine (6-MP) MOA: Inhibit de novo purine synthesis
10.Mycophenolate and ribavirin MOA: inhibit
inosine monophosphate dehydrogenase
11.Hydroxyurea effect on DNA: 1) inhibits ribonucleotide reductase
2) Effects Purine/Pyrimidine Synthesis
12. Adenosine deaminase deficiency
1) Function of ADA
2) Problem: 1) Degradation of Adenosine and Deoxyadenosine
2) Toxicity of Lymphocytes (MCC of SCID)
,13.Lesch-Nyhan Syndrome: Pattern of Inheritance? Enzyme
Defect? Process Affected? Results in?: 1) X-Linked Recessive
2) Defective Purine Salvage Due To Absence Of Hgprt Which Converts
Hypoxan- thine To Imp And Guanine To Gmp
3) Excess Uric Acid Production
14.Lesch-Nyhan Syndrome Sx: HGPRT
- Hyperuricemia
- Gout
- Pissed off (aggression)
- Retarded (intellectual disability)
- DsyTonia
15.DNA Polymerase III Function? Found in?: 1) Elongates Leading Strand
2) 32 52 Exonuclease Activity "Proofreads"
3) Prokaryotes
,16.DNA polymerase I Function? Compared to DNA Pol III?
Found in?: 1) Degrades RNA primer and Replaces it
with DNA
2) Similar to Pol III w/ 5' to 3' Exonuclease Activity
3) Prokaryotes
17.DNA Nucleotide Excision Repair Function? Problems seen in?: 1)
Repairs bulky Helix-Distorting lesions
2) Xeroderma Pigmentosum (pyrimidine dimers aggregated due to UV
light expo- sure)
18.Base Excision Repair: Process? Function?: 1) Base Specific
Glyxosylase removes Altered Base and Creates AP Site
2) Base is replaced
3) Repair Spontaneous/Toxic Deamination
19.Mismatch Repair: Function? Problem leads to what disease?: 1)
Mis- matched Nucleotides are Removed
2) Lynch Syndrome (Heriditary Nonpolyposis Colorectal Cancer) HNPCC
20.mRNA Start Codon: AUG
21.Eukaryote and Prokaryote Start Codon codes for?: 1) Eukaryote:
Methion- ine
2) Prokaryote: fMet (formyl)
22.mRNA Stop Codons: UGA: U Go
Away UAA: U Are Away
UAG: U are Gone
, 23.Eukaryote: RNA Pol I Function: Makes Rrna (Ribosomal Rna)
24.Eukaryote: RNA Pol II Function: mRNA
25.Eukaryote: RNA Pol III Function: tRNA
26.Alpha-Amantin effects which RNA Pol: RNA Polymerase II
27.How many RNA polymerases do Prokaryotes have?: 1 That Codes For
All Three Kinds Of RNA
28.Difference between hnRNA and mRNA: 1) 5' Capping (Guanosine
Cap_ 2) PolyA Tail
3) Splicing out of Introns
29.Polyadenylation Signal: AAUAAA
30.mRNA quality control in cytoplasm: P-Bodies (Processing Bodies)
31.Function of Small Nuclear Ribonucleoproteins (snRNPs): Spliceosomes
1. What is a nucleoside?: Side = base + (deoxy)ribose [sugar]
2. Which are the pyrimidines?: "CUT the pyramid" = Cytosine, Uracil,
Thymine
3. What is a nucleotide?: Tide = base + (deoxy)ribose [sugar] +
phosphate
4. Which are the purines?: "pure as gold" = Adenosine, Guanosine
5. Drugs that Disrupt pyrimidine synthesis: Leflunomide,
Methotrexate, Trimethoprim, and Pyrimethamine
6. Leflunomide: inhibits dihydroorate dehydrogenase
7. Methotrexatem Trimethoprim and Pyrimethamine Effect on DNA: inhibit
di- hydrofolate reductase
8. 5- uorouracil (5-FU) MOA: inhibits thymidylate synthase
9. 6-mercaptopurine (6-MP) MOA: Inhibit de novo purine synthesis
10.Mycophenolate and ribavirin MOA: inhibit
inosine monophosphate dehydrogenase
11.Hydroxyurea effect on DNA: 1) inhibits ribonucleotide reductase
2) Effects Purine/Pyrimidine Synthesis
12. Adenosine deaminase deficiency
1) Function of ADA
2) Problem: 1) Degradation of Adenosine and Deoxyadenosine
2) Toxicity of Lymphocytes (MCC of SCID)
,13.Lesch-Nyhan Syndrome: Pattern of Inheritance? Enzyme
Defect? Process Affected? Results in?: 1) X-Linked Recessive
2) Defective Purine Salvage Due To Absence Of Hgprt Which Converts
Hypoxan- thine To Imp And Guanine To Gmp
3) Excess Uric Acid Production
14.Lesch-Nyhan Syndrome Sx: HGPRT
- Hyperuricemia
- Gout
- Pissed off (aggression)
- Retarded (intellectual disability)
- DsyTonia
15.DNA Polymerase III Function? Found in?: 1) Elongates Leading Strand
2) 32 52 Exonuclease Activity "Proofreads"
3) Prokaryotes
,16.DNA polymerase I Function? Compared to DNA Pol III?
Found in?: 1) Degrades RNA primer and Replaces it
with DNA
2) Similar to Pol III w/ 5' to 3' Exonuclease Activity
3) Prokaryotes
17.DNA Nucleotide Excision Repair Function? Problems seen in?: 1)
Repairs bulky Helix-Distorting lesions
2) Xeroderma Pigmentosum (pyrimidine dimers aggregated due to UV
light expo- sure)
18.Base Excision Repair: Process? Function?: 1) Base Specific
Glyxosylase removes Altered Base and Creates AP Site
2) Base is replaced
3) Repair Spontaneous/Toxic Deamination
19.Mismatch Repair: Function? Problem leads to what disease?: 1)
Mis- matched Nucleotides are Removed
2) Lynch Syndrome (Heriditary Nonpolyposis Colorectal Cancer) HNPCC
20.mRNA Start Codon: AUG
21.Eukaryote and Prokaryote Start Codon codes for?: 1) Eukaryote:
Methion- ine
2) Prokaryote: fMet (formyl)
22.mRNA Stop Codons: UGA: U Go
Away UAA: U Are Away
UAG: U are Gone
, 23.Eukaryote: RNA Pol I Function: Makes Rrna (Ribosomal Rna)
24.Eukaryote: RNA Pol II Function: mRNA
25.Eukaryote: RNA Pol III Function: tRNA
26.Alpha-Amantin effects which RNA Pol: RNA Polymerase II
27.How many RNA polymerases do Prokaryotes have?: 1 That Codes For
All Three Kinds Of RNA
28.Difference between hnRNA and mRNA: 1) 5' Capping (Guanosine
Cap_ 2) PolyA Tail
3) Splicing out of Introns
29.Polyadenylation Signal: AAUAAA
30.mRNA quality control in cytoplasm: P-Bodies (Processing Bodies)
31.Function of Small Nuclear Ribonucleoproteins (snRNPs): Spliceosomes
