ASCP Molecular Biology
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Pyrimidine - Answer✅✅ One carbon ring
Cytosine, Thymine, Uracil
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
aminoacyl tRNA - Answer✅✅ tRNAs that carry amino acids
Ribosomes - 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? - 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 aa
chain
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
Spectrophotometer - Answer✅✅ Measures amount of light absorbed
Quantitative measurement of [DNA/RNA]
At what wavelength does DNA and RNA absorb? - Answer✅✅ 260 nm
At what wavelength does protein absorb? - Answer✅✅ 280 nm
Organic isolation method - Answer✅✅ 1. Lyse
2. Add phenol/ chloroform > vortex/spin
3. Transfer aqueous layer (top) to new tube
4. Add chloroform:IAA (removes phenol) > vortex/spin
5. Transfer aqueous layer to new tube
6. Add NaOAc and EtOH > vortex/spin
7. Decant
8. Resuspend
How do you inactivate RNases? - Answer✅✅ 200C for 2 hrs
30 min in 1M NaOH or quanidinum isothiocyanate
Hybridization - Answer✅✅ 2 ssDNA molecules of comp base sequence can form a
ds hybrid (duplex)
What does the incubation step in hybridization do? - Answer✅✅ Allows formation
of ds molecules
Blocking DNA (Hybridization) - Answer✅✅ minimizes probe binding to nonspecific
sequence
ie salmon sperm DNA, Human LINE-1
Blocking Proteins (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
How can you increase strigency in a hybridization? - Answer✅✅ decrease [salt]
Certification Exam| Brand New
Exam Questions with 100% Correct
Clear Verified Answers| All Graded
A+|Latest Premium Update|100%
Guaranteed Success.
Pyrimidine - Answer✅✅ One carbon ring
Cytosine, Thymine, Uracil
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
aminoacyl tRNA - Answer✅✅ tRNAs that carry amino acids
Ribosomes - 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? - 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 aa
chain
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
Spectrophotometer - Answer✅✅ Measures amount of light absorbed
Quantitative measurement of [DNA/RNA]
At what wavelength does DNA and RNA absorb? - Answer✅✅ 260 nm
At what wavelength does protein absorb? - Answer✅✅ 280 nm
Organic isolation method - Answer✅✅ 1. Lyse
2. Add phenol/ chloroform > vortex/spin
3. Transfer aqueous layer (top) to new tube
4. Add chloroform:IAA (removes phenol) > vortex/spin
5. Transfer aqueous layer to new tube
6. Add NaOAc and EtOH > vortex/spin
7. Decant
8. Resuspend
How do you inactivate RNases? - Answer✅✅ 200C for 2 hrs
30 min in 1M NaOH or quanidinum isothiocyanate
Hybridization - Answer✅✅ 2 ssDNA molecules of comp base sequence can form a
ds hybrid (duplex)
What does the incubation step in hybridization do? - Answer✅✅ Allows formation
of ds molecules
Blocking DNA (Hybridization) - Answer✅✅ minimizes probe binding to nonspecific
sequence
ie salmon sperm DNA, Human LINE-1
Blocking Proteins (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
How can you increase strigency in a hybridization? - Answer✅✅ decrease [salt]
