WorksheetsMaxam-Gilbert Sequencing and Blotting Quiz
Total questions: 46
Worksheet time: 35mins
Which of the following is the primary principle behind Maxam-Gilbert sequencing?
Enzymatic DNA synthesis
Chemical modification and cleavage of DNA
Fluorescent dye incorporation
Single-molecule sequencing
What chemical is used in Maxam-Gilbert sequencing to methylate guanine (G) only?
Formic acid
Hydrazine
Dimethyl sulfate (DMS)
Piperidine
What is a key disadvantage of Maxam-Gilbert sequencing?
Requires DNA polymerase
High throughput
Use of toxic chemicals
Less accuracy in short sequences
What is the main purpose of Southern blotting?
To detect specific RNA sequences
To amplify DNA fragments
To determine the identity, size, and abundance of DNA sequences
To separate proteins based on their size
In Southern blotting, which step ensures the transfer of DNA from gel to a nylon membrane?
Denaturation
Blotting
Hybridization
PCR amplification
What is the purpose of restriction enzymes in Southern blotting?
To break down RNA molecules
To cut DNA at specific recognition sites
To denature proteins
To hybridize the probe
Who developed the Polymerase Chain Reaction (PCR) technique?
Kary Mullis
Edward Southern
Frederick Sanger
Walter Gilbert
What is the role of primers in PCR?
Act as templates for DNA synthesis
Bind to complementary sequences to initiate replication
Break the DNA strand
Replace nucleotides
What is the primary goal of DNA sequencing?
To create synthetic DNA
To determine the exact order of nucleotides in a DNA molecule
To clone genes
To modify genetic material
In Maxam-Gilbert sequencing, hydrazine + salt is used to cleave:
Thymine
Guanine
Cytosine
Adenine
What type of membrane is used in Southern blotting?
Cellulose
Nitrocellulose or nylon
Agarose
Polyvinyl chloride
What is the major difference between Southern and Northern blotting?
Northern blotting detects RNA instead of DNA
Southern blotting detects proteins
Northern blotting does not require hybridization
Southern blotting uses radioisotopes
What type of probe is used in Northern blotting?
DNA probe
RNA probe
Protein probe
Lipid probe
Which step in Southern blotting helps prevent rehybridization of DNA strands?
Blotting
Hybridization
Denaturation
Visualization
Northern blotting primarily measures:
Gene expression levels
DNA mutations
Protein folding
Enzyme activity
Which of the following statements about Taq polymerase is TRUE?
It is heat-sensitive
It is denatured at 50°C
It is thermostable
It degrades DNA
The purpose of a buffer system in PCR is to:
Prevent DNA degradation
Provide optimal conditions for polymerase activity
Stop the reaction
Denature proteins
In PCR, primers bind to complementary sequences during:
Denaturation
Annealing
Extension
Transcription
Which of the following is the correct order of PCR steps?
Denaturation → Extension → Annealing
Denaturation → Annealing → Extension
Annealing → Denaturation → Extension
Extension → Denaturation → Annealing
What is the typical temperature range for denaturation in PCR?
30-40°C
50-60°C
70-80°C
90-96°C
What occurs during the extension step of PCR?
DNA polymerase adds nucleotides to the growing strand
Primers bind to the template DNA
DNA strands separate
DNA ligase joins fragments
Which isotope is commonly used for labeling DNA in Maxam-Gilbert sequencing?
Carbon-14
Phosphorus-32
Sulfur-35
Phosphorous-31
The sequence of DNA is read from the gel:
Top to bottom
Bottom to top
Randomly
Left to right
What is the purpose of the membrane transfer step in Southern and Northern blotting?
To denature the DNA/RNA
To bind the DNA/RNA to a solid support for hybridization
To purify the DNA/RNA from contaminants
To visualize the DNA/RNA bands
What is the purpose of washing the membrane after hybridization in both Southern and Northern blotting?
To remove unbound probe
To denature the hybridized DNA or RNA
To enhance probe binding
To transfer the DNA or RNA to the membrane
Which of the following is NOT a step in Northern blotting?
RNA isolation
Gel electrophoresis
PCR amplification
Hybridization with a labelled probe
What is the role of piperidine in Maxam and Gilbert sequencing?
It acts as a probe
It cleaves the DNA backbone
It labels the DNA
It denatures proteins
How many primers are required in a standard PCR reaction?
1
2
3
4
Which labeling method is commonly used for probes in Southern blotting?
Radioactive labeling
Fluorescent labeling
Chemiluminescent labeling
All of the above
What does SDS stand for in SDS-PAGE?
Sodium Dihydrogen Sulfate
Sodium Dodecyl Sulfate
Sulfur Dichloride Solution
Sodium Dichromate Sulfate
What is the main function of SDS in SDS-PAGE?
To provide reducing conditions
To denature proteins and give them a negative charge
To stain proteins for visualization
To polymerize the gel
Which type of gel is used in SDS-PAGE?
Agarose
Polyacrylamide
Starch
Cellulose
SDS-PAGE separates proteins based on their:
Charge
Shape
Size
Function
Which reagent is commonly used to reduce disulfide bonds in SDS-PAGE?
Bromophenol blue
Tris buffer
β-Mercaptoethanol
Ethanol
What is the purpose of acrylamide in SDS-PAGE?
To denature proteins
To form a gel matrix
To act as a buffer
To stain proteins
What is the role of ammonium persulfate (APS) in SDS-PAGE?
It stains the proteins
It catalyzes polymerization
It provides reducing conditions
It stabilizes the gel
Which molecule is added as a cross-linker in SDS-PAGE?
TEMED
Urea
Bis-acrylamide
Tris
The stacking gel in SDS-PAGE has a:
Higher pH than resolving gel
Lower pH than resolving gel
Neutral pH
Same pH as resolving gel
The purpose of the stacking gel is to:
Separate proteins based on size
Concentrate proteins into a thin band
Stain the proteins
Act as a buffer
What dye is commonly used to visualize proteins after SDS-PAGE?
Bromophenol blue
Coomassie Brilliant Blue
Methylene blue
Safranin
Which buffer system is commonly used in SDS-PAGE?
Tris-Glycine
Phosphate buffer
Citrate buffer
HEPES buffer
What is the function of TEMED in SDS-PAGE?
Stains the gel
Catalyzes polymerization
Breaks disulfide bonds
Acts as a detergent
Which component in the SDS-PAGE loading buffer provides color tracking?
Tris-HCl
Bromophenol blue
Coomassie blue
Urea
Which factor determines the migration speed of proteins in SDS-PAGE?
Protein shape
Protein charge
Protein molecular weight
Protein function
In SDS-PAGE, proteins migrate toward the:
Cathode (-)
Anode (+)
Middle of the gel
None of the above
Which staining method is more sensitive than Coomassie Brilliant Blue?
Methylene blue staining
Silver staining
Bromophenol blue staining
Iodine staining
