MOLBIO - MIDTERM Flashcards
Which of the following statement is FALSE?
The PCR is usually done in a reaction volume of 10 – 200 ml in small tubes in a thermal cycler.
SNPs are detected by Allele-Specific PCR by
using Allele-specific primers
Which is INCORRECT about SNPs?
They usually affect health and development.
This is added to determine if you have contaminants on your DNA
Controls
Principle of separation in Capillary zone electrophoresis
C
Statements below describes polyacrylamide gel EXCEPT
Mobility does not depend on DNA sequence
Extension time is set for () base pairs of DNA per minute
1000
In array-based CGH, what is the sample used?
mRNA
In Gel Electrophoresis, how do we make the DNA migrate through the gel?
We place a positive electrode away from the wells
This is a type of PRGE in which two fields are arranged in separated straight angle
FIELD INVERSION GE ELECTRO
After heating and cooling the mixture, which of the following catalyzes the synthesis of complementary strands of DNA?
Taq polymerase
Low annealing temperature leads to some mismatches
True
Pfu polymerase is superior over Taq polymerase because:
of more accurate amplification
Which is INCORRECT about ASO hybridization?
The result is analyzed using gel electrophoresis.
When setting up a Sanger sequencing reaction, each reaction should include template DNA, deoxyribonucleotides, dideoxyribonucleotides, buffer, DNA polymerase, and
Forward OR reverse primer
What would be the effect on the PCR reaction if any of the following circumstances arose: 1) there are no primers in the reaction, 2) enough dNTPs in the reaction, 3) there is Taq polymerase in the reaction?
Amplicons will not be produced, false negative result.
Nonspecific amplification may be a result of adding:
5.5 mM MgCl2+
The PCR technique was developed by
Mullis
Among those listed below, which is most common mutation effect that leads to the development on cancer?
Increase in the activity of a protein
TRUE for agarose gels
High voltage in a high agarose concentration can resolve small DNAs
Why do you need to prepare an extra volume in your Master Mix?
To compensate pipetting errors
What will happen if too much enzyme is added to the reaction?
Digestion reaction may fail
At what temperature does annealing of primers to the template takes place?
- 47-60˚C
-10-20˚C below the melting point of primer
-5˚C below the melting point of primer
LAMP PCR requires this range of temperature:
60-65°
What is a palindromic restriction endonuclease?
The sequence recognized by the enzyme is the same in the forward and reverse sense.
Example of spontaneously generated mutation:
Uncorrected error committed by DNA polymerase
Which of the following is not a practice for autoclaving?
All items should have a masking tape
What makes Sanger technique superior over Maxam-Gilbert technique for DNA sequencing?
-Uses less hazardous reagents
-Can sequence longer DNA
-It is widly used for sequencing
DNA length is measured in units called
base pairs
Sickle cell anemia is caused by a point mutation in the hemoglobin gene, resulting in the substitution of a single amino acid in the mature protein. This mutation could be detected by all of the following methods EXCEPT:
Western blot analysis
It uses pressurized steam to kill infectious agents
Autoclaving
It is the standard concentration used in staining DNA in gels
0.5 – 1 ug/ml
Acts as a cofactor to create the DNA chain
Magnesium ions
Match the following chemical reagents of Maxam-Gilbert with their correct use.
Piperidine
-After chemical modification of bases, this reagent will generate breaks on the strands
Hydrazine + Salt
-Inhibits the reaction of thymine for the C- only reaction
Hydrazine
-Hydrolyzes pyrimidines Formic acid
-Modifies purine bases in the template
Dimethylsulphate
-Adds methyl group to Guanine
Fidelity in amplification may be decreased in which of the following conditions?
Increased concentrations of dNTPs
Which of the following IS NOT a biological activity of Reverse transcriptase?
DNA ligase activity
It is routinely used to stain DNA in agarose and polyacrylamide gels
Ethidium bromide
Which is INCORRECT regarding Restriction Endonucleases applied in molecular techniques?
They have modification activity.
It protects the host DNA from being cleaved.
Methyltransferase
Which of the following is TRUE for optimizing a primer?
Optimal G-C content should range between 40-60%.
Which stage of a PCR is affected by the primers’ melting temperature?
Annealing
What is the most widely used sequencing technique principle?
Chain termination sequencing
Which is the easiest, fastest and most economical method of detecting mutation?
DNA sequencing
It is a premixed solution that contains most of the components necessary to run a PCR assay
Master Mix
Which of the following is FALSE?
Check if there is a buffer that indicates 25% activity for each enzyme
This conformation is the fastest to migrate in an agarose gel
Form I
What is the volume of dNTPs in a 50ul reaction if the stock concentration = 10mM; Final concentration= 0.2mM?
1ul
In this type of electrophoresis, the mobility of DNA molecules is highly dependent on the electrical field applied to the gel
Pulsed-field electrophoresis
PCR variant that requires partitioning of the template:
Digital PCR
How many types of dDNTPs are used in Sanger technique?
4
Which of the following is a chemical sequencing method?
Maxam-Gilbert
What is the difference between a deoxyribonucleotide and a dideoxyribonucleotide?
A dideoxynucleotide is missing a 3’- hydroxyl group on its sugar.
This is a modification of PCR which is designed to improve sensitivity and specificity of amplification.
Nested PCR
What will happen if there is a low concentration of MgCl in the reaction?
No PCR product will be seen
Sickle cell anemia is an example of
Missense mutation
Which of the following statement is TRUE?
Reaction conditions will vary based on the enzyme.
PCR Supermix is a ready-to-use mixture of DNA polymerase, salts, magnesium and dNTPs for efficient amplification.
TRUE
This PCR method is also used to detect different viral, bacterial and other pathogens in a single reaction.
Multiplex PCR
Which technique uses southern blotting?
RFLP
Why do the restriction endonucleases NOT cleave the genome of the microorganism they belong to?
Because the sequences recognized by the endonuclease are appropriately methylated in the genomic DNA for their protection.
Single stranded nucleic acid primer sequences may form hairpin loop due to the presence of:
complementary sequences within its length
Which of the following is TRUE for EtBr?
Bands with DNA of less than 5 ng DNA may not be visible after staining
How many DNA duplex is obtained from one DNA duplex after 3 cycles of PCR?
8
Which statement is a FALSE statement?
All mutations have harmful effects on an individual.
The restriction enzyme SmaI recognizes a 6- base pair, “palindromic” sequence in double stranded DNA. The first three bases of one strand are given: 5´ C C C ()()() 3´. What are the last three bases of this restriction site?
G G G
To sequence DNA by Sanger method, the DNA must first be made in single stranded form.
True
Polymerase used for PCR is extracted from
Thermus aquaticus
Which is INCORRECT regarding restriction endonucleases?
Cleave methylated DNA
Which of the following recommended concentrations or volume is a mismatched?
MgCl2+ : 1.0-6.0 mM
A DNA fragment was cut by HaeIII into three fragments and PstI cuts into two fragments. How many DNA bands do you expect from a double digest in gel electrophoresis?
5
The recognition site of the restriction endonuclease BalI is 5’ T G G C C A 3’. If it cuts the site between G and C, what type ends will be produced?
Blunt ends
When a dideoxyribonucleotide is added to the DNA strands being synthesized:
replication of the strand stops
Which consists of primer molecules that have attached to each other because of strings of complementary bases in the primers?
Primer dimers
What type of bonds is present during gelation?
Hydrogen bond
What is the temperature that breaks apart hydrogen bonds during denaturing stage?
95°C
Which is INCORRECT regarding restriction endonucleases?
They degrade DNA completely
Agarose gel is matrix
Negatively charged
Which of the following statements is true about migration of biomolecules?
Rate of migration is directly proportional to current
Which of the following sequencing techniques requires strands amplification?
Chain termination sequencing
Which is INCORRECT regarding Allele- Specific PCR?
It requires blotting on a nylon membrane
Which DOES NOT use restriction endonucleases?
DNA microarray
Low to no yield of PCR products may be a result of which of the following?
Decreased MgCl2+ and decreased dNTPs
What are the factors to consider in choosing a DNA polymerase?
-Thermostability
-Specificity
-Fidelity
If a restriction endonuclease has only one cleavage site in a circular plasmid DNA, how many bands do you expect in gel electrophoresis?
one
It is the tracking dye to monitor the progress of gel electrophoresis
Bromphenol blue
To sequence DNA by Maxam-Gilbert method, the DNA must first be made in single stranded form.
True
Which of the following PCR Techniques is used for mass testing for COVID19 infection?
Reverse Transcription Real-Time PCR
