ASCP TECHNOLOGIST IN MOLECULAR
BIOLOGY BOARD EXAM PREP WITH
CORRECT SOLUTIONS
How are nucleotides joined together? - ANSWER-Condensation to form phosphodiester
bond
Functions of mRNA - ANSWER-Carries genetic info out of nucleus
Transcript translated to protein
Functions of tRNA - ANSWER-Carries amino acid to ribosome
Anticodon pairs with codon on mRNA strand
Functions of rRNA - ANSWER-part of ribosome structure
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - ANSWER-Product of pathway is noncompetitive inhibitor
Binds to allosteric site to slow down reaction because too much product
Exonucleases - ANSWER-Degrades nucleic acids by removing one terminal nucleotide
at a time
Cleaves phosphodiester bond at end of chain
Endonucleases (Prok) - ANSWER-Restriction enzymes
Cleaves phosphodiester bonds within polynucleotide chain
Recognition site is palindromic sequence
ORI sites - ANSWER-nucleotide sequence where replication is initiated
topoisomerase I - ANSWER-Induces single strand breaks
Remove DNA supercoils during transcription and DNA replication; for strand breakage
during recombination; for chromosome 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 - ANSWER-Unwinds supercoiling caused by unwinding at the replication fork
Helicase - ANSWER-Breaks H-bonds of double helix at the replication fork
Primase - ANSWER-DNA pol α (alpha)
,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 transcription, replication, repair, and recombination
Reverse transcriptase - ANSWER-enzyme that transcribes RNA to cDNA (lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Pleiotrophy - ANSWER-a single gene controls the expression of many phenotypic traits
ie Sickle Cell Anemia
cDNA - ANSWER-intron free complementary DNA
can be inserted into a plasmid
Vector - ANSWER-helps carry DNA into cell
ie plasmids, virus
Open Reading Frame (ORF) - ANSWER-sections of DNA that begin with start codons
and end with stop codons
DNA: 5' --> 3'
transcription: 3' --> 5' DNA --> RNA (promoter)
translation: 5' --> 3' mRNA
Okazaki fragments - ANSWER-Short fragments of DNA synthesized by DNApol δ
(delta) using the lagging strand (3'->5') as a template
Ligase - ANSWER-Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
Steps in DNA replication - ANSWER-Initiate
Elongate
Terminate
Telomeres - ANSWER-Repeat sequence (TTAGGG) at the ends of chromosome,
protect chromosome from degradation
RNA polymerase - ANSWER-Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Enhancers - ANSWER-Short regions of DNA that bind proteins (transcription factors)
that enhance transcription 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 translation apparatus
aminoacyl tRNA - ANSWER-tRNAs that carry amino acids
Ribosomes - ANSWER-location that translation occurs
Catalyzes peptide bond between amino acid's
Path of a tRNA in a ribosome - ANSWER-Acceptor > Peptidyl > Exit
How is translation initiated? - 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? - ANSWER-Occurs when stop codon enters A site
Release factor recognizes stop codon, hydrolyzes ester bond with P site, releasing
amino acid chain
Wavelength that DNA and RNA absorb - ANSWER-260 nm
Wavelength that protein absorb - ANSWER-280 nm
How do you inactivate RNases? - ANSWER-200C for 2 hrs
30 min in 1M NaOH or quanidinum isothiocyanate
Hybridization - ANSWER-2 ssDNA molecules of complementary base sequence can
form a ds hybrid (duplex)
Blocking DNA (in Hybridization) - ANSWER-minimizes probe binding to nonspecific
sequence
ie salmon sperm DNA, Human LINE-1
Blocking Proteins (in Hybridization) - ANSWER-minimize nonspecific binding of probe to
membrane
ie casein (milk), Denhardt's sol
Stringency - ANSWER-conditions of hybridization that control the specificity of binding
of the probe to the target sequence
Formamide acts as a __________ in a hybridization. - ANSWER-denaturing agent
Line Probe Assay (LiPA) - ANSWER-reverse hybridization assay using sequence-
specific oligonucleotide probes (reverse SSOP)
multi-parameter testing --> single strip
BIOLOGY BOARD EXAM PREP WITH
CORRECT SOLUTIONS
How are nucleotides joined together? - ANSWER-Condensation to form phosphodiester
bond
Functions of mRNA - ANSWER-Carries genetic info out of nucleus
Transcript translated to protein
Functions of tRNA - ANSWER-Carries amino acid to ribosome
Anticodon pairs with codon on mRNA strand
Functions of rRNA - ANSWER-part of ribosome structure
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - ANSWER-Product of pathway is noncompetitive inhibitor
Binds to allosteric site to slow down reaction because too much product
Exonucleases - ANSWER-Degrades nucleic acids by removing one terminal nucleotide
at a time
Cleaves phosphodiester bond at end of chain
Endonucleases (Prok) - ANSWER-Restriction enzymes
Cleaves phosphodiester bonds within polynucleotide chain
Recognition site is palindromic sequence
ORI sites - ANSWER-nucleotide sequence where replication is initiated
topoisomerase I - ANSWER-Induces single strand breaks
Remove DNA supercoils during transcription and DNA replication; for strand breakage
during recombination; for chromosome 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 - ANSWER-Unwinds supercoiling caused by unwinding at the replication fork
Helicase - ANSWER-Breaks H-bonds of double helix at the replication fork
Primase - ANSWER-DNA pol α (alpha)
,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 transcription, replication, repair, and recombination
Reverse transcriptase - ANSWER-enzyme that transcribes RNA to cDNA (lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Pleiotrophy - ANSWER-a single gene controls the expression of many phenotypic traits
ie Sickle Cell Anemia
cDNA - ANSWER-intron free complementary DNA
can be inserted into a plasmid
Vector - ANSWER-helps carry DNA into cell
ie plasmids, virus
Open Reading Frame (ORF) - ANSWER-sections of DNA that begin with start codons
and end with stop codons
DNA: 5' --> 3'
transcription: 3' --> 5' DNA --> RNA (promoter)
translation: 5' --> 3' mRNA
Okazaki fragments - ANSWER-Short fragments of DNA synthesized by DNApol δ
(delta) using the lagging strand (3'->5') as a template
Ligase - ANSWER-Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
Steps in DNA replication - ANSWER-Initiate
Elongate
Terminate
Telomeres - ANSWER-Repeat sequence (TTAGGG) at the ends of chromosome,
protect chromosome from degradation
RNA polymerase - ANSWER-Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Enhancers - ANSWER-Short regions of DNA that bind proteins (transcription factors)
that enhance transcription 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 translation apparatus
aminoacyl tRNA - ANSWER-tRNAs that carry amino acids
Ribosomes - ANSWER-location that translation occurs
Catalyzes peptide bond between amino acid's
Path of a tRNA in a ribosome - ANSWER-Acceptor > Peptidyl > Exit
How is translation initiated? - 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? - ANSWER-Occurs when stop codon enters A site
Release factor recognizes stop codon, hydrolyzes ester bond with P site, releasing
amino acid chain
Wavelength that DNA and RNA absorb - ANSWER-260 nm
Wavelength that protein absorb - ANSWER-280 nm
How do you inactivate RNases? - ANSWER-200C for 2 hrs
30 min in 1M NaOH or quanidinum isothiocyanate
Hybridization - ANSWER-2 ssDNA molecules of complementary base sequence can
form a ds hybrid (duplex)
Blocking DNA (in Hybridization) - ANSWER-minimizes probe binding to nonspecific
sequence
ie salmon sperm DNA, Human LINE-1
Blocking Proteins (in Hybridization) - ANSWER-minimize nonspecific binding of probe to
membrane
ie casein (milk), Denhardt's sol
Stringency - ANSWER-conditions of hybridization that control the specificity of binding
of the probe to the target sequence
Formamide acts as a __________ in a hybridization. - ANSWER-denaturing agent
Line Probe Assay (LiPA) - ANSWER-reverse hybridization assay using sequence-
specific oligonucleotide probes (reverse SSOP)
multi-parameter testing --> single strip
