ASCP Molecular Biology Certification
Exam 2026 QUESTIONS AND ANSWERS
Pyrimidine - Correct Answer -One carbon ring
Cytosine, Thymine, Uracil
Purine - Correct Answer -Two carbon rings
Adenine, Guanine
How are nucleotides joined together? - Correct Answer -Condensation to form
phosphodiester bond
What is the function of mRNA? - Correct Answer -Carries genetic info out of
nucleus
Transcript translated to protein
What is the function of tRNA? - Correct Answer -Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
What is the function of rRNA? - Correct Answer -part of ribosome structure
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,most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - Correct Answer -Product of pathway is noncompetitive
inhibitor
Binds to allosteric site to slow down rxn b/c too much product
Exonucleases - Correct 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) - Correct Answer -Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
ORI sites - Correct Answer -nt sequence where replication is initiated
Topoisomerase I - Correct Answer -Induces ss breaks
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,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 - Correct 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) - Correct Answer -Unwinds supercoiling caused by
unwinding at the rep fork by introducing DSBs
Helicase - Correct Answer -Breaks H-bonds of double helix at the replication fork
Primase - Correct 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) - Correct Answer -Binds ssDNA and
prevents it from re-annealing during TXN, replication, repair, and recombination
Okazaki fragments - Correct Answer -Short fragments of DNA synthesized by
DNApol δ using the lagging strand (3'->5') as a template
Ligase - Correct Answer -Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
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, What are the steps in DNA replication? - Correct Answer -1. Initiate
2. Elongate
3. Terminate
Telomeres - Correct Answer -Repeat sequence (TTAGGG) at the ends of chr,
protect chr from degradation
RNA polymerase - Correct Answer -DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Splicesomes - Correct Answer -Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
Enhancers - Correct Answer -Short regions of DNA that bind proteins (TXN
factors) that enhance TXN of a gene
Poly-A tail - Correct Answer -Prevents mRNA from being degraded in cytoplasm
100-250 A's at 3' end
5' cap - Correct 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
aminoacyl tRNA - Correct Answer -tRNAs that carry amino acids
©COPYRIGHT 2025 ALL RIGHTS RESERVED 4
Exam 2026 QUESTIONS AND ANSWERS
Pyrimidine - Correct Answer -One carbon ring
Cytosine, Thymine, Uracil
Purine - Correct Answer -Two carbon rings
Adenine, Guanine
How are nucleotides joined together? - Correct Answer -Condensation to form
phosphodiester bond
What is the function of mRNA? - Correct Answer -Carries genetic info out of
nucleus
Transcript translated to protein
What is the function of tRNA? - Correct Answer -Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
What is the function of rRNA? - Correct Answer -part of ribosome structure
©COPYRIGHT 2025 ALL RIGHTS RESERVED 1
,most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - Correct Answer -Product of pathway is noncompetitive
inhibitor
Binds to allosteric site to slow down rxn b/c too much product
Exonucleases - Correct 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) - Correct Answer -Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
ORI sites - Correct Answer -nt sequence where replication is initiated
Topoisomerase I - Correct Answer -Induces ss breaks
©COPYRIGHT 2025 ALL RIGHTS RESERVED 2
,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 - Correct 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) - Correct Answer -Unwinds supercoiling caused by
unwinding at the rep fork by introducing DSBs
Helicase - Correct Answer -Breaks H-bonds of double helix at the replication fork
Primase - Correct 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) - Correct Answer -Binds ssDNA and
prevents it from re-annealing during TXN, replication, repair, and recombination
Okazaki fragments - Correct Answer -Short fragments of DNA synthesized by
DNApol δ using the lagging strand (3'->5') as a template
Ligase - Correct Answer -Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
©COPYRIGHT 2025 ALL RIGHTS RESERVED 3
, What are the steps in DNA replication? - Correct Answer -1. Initiate
2. Elongate
3. Terminate
Telomeres - Correct Answer -Repeat sequence (TTAGGG) at the ends of chr,
protect chr from degradation
RNA polymerase - Correct Answer -DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Splicesomes - Correct Answer -Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
Enhancers - Correct Answer -Short regions of DNA that bind proteins (TXN
factors) that enhance TXN of a gene
Poly-A tail - Correct Answer -Prevents mRNA from being degraded in cytoplasm
100-250 A's at 3' end
5' cap - Correct 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
aminoacyl tRNA - Correct Answer -tRNAs that carry amino acids
©COPYRIGHT 2025 ALL RIGHTS RESERVED 4
