ASCP Technologist In Molecular Biology
Board Exam Prep UPDATED Actual Exam
Questions and CORRECT 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
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
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
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
Ribosomes - CORRECT ANSWER- ✔✔Where TLN occurs
Prok: 30s and 50s
, Euk: 40s and 60s
Catalyzes peptide bond between a.a.'s
What is the path of a tRNA in a ribosome? - CORRECT ANSWER- ✔✔Acceptor > Peptidyl
> Exit
How is translation initiated? - CORRECT ANSWER- ✔✔small rRNA (40S) subunit binds
mRNA and scans for start codon (AUG)
Met-tRNA is brought to the P site
Large rRNA (60S) subunit binds
How is translation terminated? - CORRECT ANSWER- ✔✔Occurs when stop codon enters
A site
Release factor recognizes stop codon, hydrolyzes ester bond with P site, releasing aa chain
Reverse transcriptase - CORRECT ANSWER- ✔✔enzyme that transcribes RNA to cDNA
(lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Pleiotrophy - CORRECT ANSWER- ✔✔a single gene controls the expression of many
phenotypic traits
ie Sickle Cell Anemia
cDNA - CORRECT ANSWER- ✔✔intron free complementary DNA
can be inserted into a plasmid
Vector - CORRECT ANSWER- ✔✔helps carry DNA into cell
ie plasmids, virus
Open Reading Frame (ORF) - CORRECT ANSWER- ✔✔sections of DNA that begin with
start codons and end with stop codons
DNA: 5' --> 3'
Board Exam Prep UPDATED Actual Exam
Questions and CORRECT 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
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
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
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
Ribosomes - CORRECT ANSWER- ✔✔Where TLN occurs
Prok: 30s and 50s
, Euk: 40s and 60s
Catalyzes peptide bond between a.a.'s
What is the path of a tRNA in a ribosome? - CORRECT ANSWER- ✔✔Acceptor > Peptidyl
> Exit
How is translation initiated? - CORRECT ANSWER- ✔✔small rRNA (40S) subunit binds
mRNA and scans for start codon (AUG)
Met-tRNA is brought to the P site
Large rRNA (60S) subunit binds
How is translation terminated? - CORRECT ANSWER- ✔✔Occurs when stop codon enters
A site
Release factor recognizes stop codon, hydrolyzes ester bond with P site, releasing aa chain
Reverse transcriptase - CORRECT ANSWER- ✔✔enzyme that transcribes RNA to cDNA
(lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Pleiotrophy - CORRECT ANSWER- ✔✔a single gene controls the expression of many
phenotypic traits
ie Sickle Cell Anemia
cDNA - CORRECT ANSWER- ✔✔intron free complementary DNA
can be inserted into a plasmid
Vector - CORRECT ANSWER- ✔✔helps carry DNA into cell
ie plasmids, virus
Open Reading Frame (ORF) - CORRECT ANSWER- ✔✔sections of DNA that begin with
start codons and end with stop codons
DNA: 5' --> 3'
