ASCP CG CERTIFICATION COMPREHENSIVE
EXAM QUESTIONS WITH SOLUTIONS
◉ Purine . Answer: Two carbon rings
Adenine, Guanine
◉ How are nucleotides joined together? Answer: Condensation to form
phosphodiester bond
◉ What is the function of mRNA? Answer: Carries genetic info out of
nucleus
Transcript translated to protein
◉ What is the function of tRNA? Answer: Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
◉ What is the function of rRNA? Answer: part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
,◉ Feedback inhibition Answer: Product of pathway is noncompetitive
inhibitor
Binds to allosteric site to slow down rxn b/c too much product
◉ Exonucleases Answer: Degrades nucleic acids by removing one
terminal nt at a time
Cleaves phosphodiester bond at end of chain
5' --> 3' and 3' --> 5'
◉ Endonucleases (Prok) Answer: Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
◉ ORI sites Answer: nt sequence where replication is initiated
◉ Topoisomerase I Answer: Induces ss breaks
Remove DNA supercoils during TXN and DNA replication; for strand
breakage during recombination; for chr condensation; and to disentangle
intertwined DNA during mitosis
◉ topoisomerase II Answer: cuts both strands of one DNA double
helix, passes another unbroken DNA helix through it, and then reanneals
the cut strands
,◉ Gyrase (topoisomerase II) Answer: Unwinds supercoiling caused by
unwinding at the rep fork by introducing DSBs
◉ Helicase Answer: Breaks H-bonds of double helix at the replication
fork
◉ Primase Answer: DNApol α (DNA dep RNA pol)
adds short segments of complementary
RNA to ssDNA template (primers), serves as starting points for
replication
◉ single-strand DNA binding proteins (SSBPs) Answer: Binds ssDNA
and prevents it from re-annealing during TXN, replication, repair, and
recombination
◉ Okazaki fragments Answer: Short fragments of DNA synthesized by
DNApol δ using the lagging strand (3'->5') as a template
◉ Ligase Answer: Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
◉ What are the steps in DNA replication? Answer: 1. Initiate
2. Elongate
, 3. Terminate
◉ Telomeres Answer: Repeat sequence (TTAGGG) at the ends of chr,
protect chr from degradation
◉ RNA polymerase Answer: DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
◉ Splicesomes Answer: Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
◉ Enhancers Answer: Short regions of DNA that bind proteins (TXN
factors) that enhance TXN of a gene
◉ Poly-A tail Answer: Prevents mRNA from being degraded in
cytoplasm
100-250 A's at 3' end
◉ 5' cap Answer: 5'-5' pyrophosphate bridge to a methylated G added
to 5' end of a mRNA
Protects against degradation and as a recognition signal for TLN
apparatus
EXAM QUESTIONS WITH SOLUTIONS
◉ Purine . Answer: Two carbon rings
Adenine, Guanine
◉ How are nucleotides joined together? Answer: Condensation to form
phosphodiester bond
◉ What is the function of mRNA? Answer: Carries genetic info out of
nucleus
Transcript translated to protein
◉ What is the function of tRNA? Answer: Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
◉ What is the function of rRNA? Answer: part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
,◉ Feedback inhibition Answer: Product of pathway is noncompetitive
inhibitor
Binds to allosteric site to slow down rxn b/c too much product
◉ Exonucleases Answer: Degrades nucleic acids by removing one
terminal nt at a time
Cleaves phosphodiester bond at end of chain
5' --> 3' and 3' --> 5'
◉ Endonucleases (Prok) Answer: Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
◉ ORI sites Answer: nt sequence where replication is initiated
◉ Topoisomerase I Answer: Induces ss breaks
Remove DNA supercoils during TXN and DNA replication; for strand
breakage during recombination; for chr condensation; and to disentangle
intertwined DNA during mitosis
◉ topoisomerase II Answer: cuts both strands of one DNA double
helix, passes another unbroken DNA helix through it, and then reanneals
the cut strands
,◉ Gyrase (topoisomerase II) Answer: Unwinds supercoiling caused by
unwinding at the rep fork by introducing DSBs
◉ Helicase Answer: Breaks H-bonds of double helix at the replication
fork
◉ Primase Answer: DNApol α (DNA dep RNA pol)
adds short segments of complementary
RNA to ssDNA template (primers), serves as starting points for
replication
◉ single-strand DNA binding proteins (SSBPs) Answer: Binds ssDNA
and prevents it from re-annealing during TXN, replication, repair, and
recombination
◉ Okazaki fragments Answer: Short fragments of DNA synthesized by
DNApol δ using the lagging strand (3'->5') as a template
◉ Ligase Answer: Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
◉ What are the steps in DNA replication? Answer: 1. Initiate
2. Elongate
, 3. Terminate
◉ Telomeres Answer: Repeat sequence (TTAGGG) at the ends of chr,
protect chr from degradation
◉ RNA polymerase Answer: DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
◉ Splicesomes Answer: Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
◉ Enhancers Answer: Short regions of DNA that bind proteins (TXN
factors) that enhance TXN of a gene
◉ Poly-A tail Answer: Prevents mRNA from being degraded in
cytoplasm
100-250 A's at 3' end
◉ 5' cap Answer: 5'-5' pyrophosphate bridge to a methylated G added
to 5' end of a mRNA
Protects against degradation and as a recognition signal for TLN
apparatus
