Exam (elaborations)
ASCP Molecular Biology Certification Exam Questions and Answers
- Institution
- ASCP Molecular Biology Certification
ASCP Molecular Biology Certification Exam Questions and Answers
[Show more]
Content preview
ASCP Molecular Biology CertificationExam Questions and Answers
Pyrimidine - -One carbon ring
Cytosine, Thymine, Uracil
-Purine - -Two carbon rings
Adenine, Guanine
-How are nucleotides joined together? - -Condensation to form
phosphodiester bond
-What is the function of mRNA? - -Carries genetic info out of nucleus
Transcript translated to protein
-What is the function of tRNA? - -Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
-What is the function of rRNA? - -part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
-Feedback inhibition - -Product of pathway is noncompetitive inhibitor
Binds to allosteric site to slow down rxn b/c too much product
-Exonucleases - -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) - -Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
-ORI sites - -nt sequence where replication is initiated
-Topoisomerase I - -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 - -cuts both strands of one DNA double helix, passes
another unbroken DNA helix through it, and then reanneals the cut strands
, -Gyrase (topoisomerase II) - -Unwinds supercoiling caused by unwinding at
the rep fork by introducing DSBs
-Helicase - -Breaks H-bonds of double helix at the replication fork
-Primase - -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) - -Binds ssDNA and prevents it
from re-annealing during TXN, replication, repair, and recombination
-Okazaki fragments - -Short fragments of DNA synthesized by DNApol δ
using the lagging strand (3'->5') as a template
-Ligase - -Closes gaps in DNA
Catalyzes phosphodiester bond between 3'OH and 5'P
-What are the steps in DNA replication? - -1. Initiate
2. Elongate
3. Terminate
-Telomeres - -Repeat sequence (TTAGGG) at the ends of chr, protect chr
from degradation
-RNA polymerase - -DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
-Splicesomes - -Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
-Enhancers - -Short regions of DNA that bind proteins (TXN factors) that
enhance TXN of a gene
-Poly-A tail - -Prevents mRNA from being degraded in cytoplasm
100-250 A's at 3' end
-5' cap - -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 - -tRNAs that carry amino acids
-Ribosomes - -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? - -Acceptor > Peptidyl > Exit
-How is translation initiated? - -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? - -Occurs when stop codon enters A site
Release factor recognizes stop codon, hydrolyzes ester bond with P site,
releasing aa chain
-Reverse transcriptase - -enzyme that transcribes RNA to cDNA (lacks
introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
-Pleiotrophy - -a single gene controls the expression of many phenotypic
traits
ie Sickle Cell Anemia
-cDNA - -intron free complementary DNA
can be inserted into a plasmid
-Vector - -helps carry DNA into cell
ie plasmids, virus
-Open Reading Frame (ORF) - -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 - -Measures amount of light absorbed
Quantitative measurement of [DNA/RNA]
-At what wavelength does DNA and RNA absorb? - -260 nm
-At what wavelength does protein absorb? - -280 nm
-Organic isolation method - -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? - -200C for 2 hrs
30 min in 1M NaOH or quanidinum isothiocyanate
-Hybridization - -2 ssDNA molecules of comp base sequence can form a ds
hybrid (duplex)
-What does the incubation step in hybridization do? - -Allows formation of
ds molecules
-Blocking DNA (Hybridization) - -minimizes probe binding to nonspecific
sequence
ie salmon sperm DNA, Human LINE-1
-Blocking Proteins (Hybridization) - -minimize nonspecific binding of probe
to membrane
ie casein (milk), Denhardt's sol
-Stringency - -conditions of hybridization that control the specificity of
binding of the probe to the target sequence
-How can you increase strigency in a hybridization? - -decrease [salt]
increase [formamide]
increase temp
-Formamide acts as a __________ in a hybridization. - -denaturing agent
-Line Probe Assay (LiPA) - -reverse hybridization assay using sequence-
specific oligonucleotide probes (reverse SSOP)
multi-parameter testing --> single strip
-Line Probe Assay steps - -1. Isolate nucleic acid (RNA)
2. Amplify
3. Hybridization
4. Strigent wash
5. Incubate with conjugate
6. Incubate with substrate
7. Detect
-What method would you use if you knew the gene sequence and the
mutation? - -Reverse Dot Blot
-Microarrays - -Used for unknown gene and mutation
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Victorious23. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £13.20. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
81531 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now