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WorksheetsDNA Extraction & Gel Electrophoresis
Total questions: 16
Worksheet time: 5mins
DNA extraction requires _________to lyse the epithelial cells and to degrade compounds inhibitory to amplification
freezing
heat treatment
enzyme
mechanical shearing
What can you observe on the agarose gel after electrophoresis if you do not treat your sample with RNAse ?
protein
RNA
mitochondria
phospholipids
The ratio of absorption at 260nm to absorption at 280nm is commonly used to assess….
Whether your DNA or RNA is contaminated with organic substances.
The purity of DNA and RNA with respect to protein.
The concentration of protein in your sample.
Put the following types of naturally occurring RNA in order according to their abundance in cellular or total RNA. (First listed is most abundant)
mRNA, rRNA, tRNA
rRNA, tRNA, mRNA
tRNA, rRNA, mRNA
tRNA, mRNA, rRNA
When evaluating the purity of extracted DNA, deoxyribonucleic acid, what should the optical density, or its light-blocking ability, be at 260nm and 280nm be? (The 260nm/280nm ratio)
< 1.6
2.0 - 2.3
>2.0
1.6 - 2.0
What is the purpose of a buffer system in electrophoresis?
Alternate the current
Carry the current, maintain a stable pH for the separation of molecules and protect the sample
disrupt the contaminants
stop the migration process
How can DNA fragments be separated using gel electrophoresis ?
DNA carries a negative charge and large fragments are pulled more strongly than small fragments towards the positive electrode
DNA carries a negative charge and small fragments are able to travel more quickly than large towards the positive electrode
DNA carries a positive charge and large fragments are pulled more strongly than small fragments towards the negative electrode
DNA carries a positive charge and small fragments are able to travel more quickly than large towards the negative electrode
Where would you find DNA, the genetic material, in an animal cell?
In the centriole
Only in the mitochondria
In the mitochondria and the nucleus
In the cytoplasm
Eukaryotic chromosomes are thousands of times longer than a typical cell. How can chromosomes fit inside a eukaryotic nucleus?
The genetic material remains distributed in the nucleus, mitochondria, and chloroplast.
The genome is present in a looped structure; thus, it fits the size of the nucleus.
The DNA remains coiled around proteins to form nucleosomes.
The genetic material remains bound to the nuclear envelope, forming invaginations.
What is the first step in isolating DNA?
Generating genomic DNA fragments with restriction endonucleases
Introducing recombinant DNA into an organism by any means
Overexpressing proteins in E. coli
Lysing the cells in the sample
What is the role of ethanol in DNA extraction?
To break down cell walls
To precipitate DNA from the solution
To neutralize the pH
To increase the solubility of the DNA
The basic principle behind separating DNA from a cell lysate relies on the difference in properties between:
Nucleic acid and proteins
Proteins and lipids
DNA & RNA
Nucleotides & enzyme
Silica membranes in DNA extraction columns primarily bind to which molecule based on its charge?
DNA
Protein
Enzyme
Lipid
Which of the following statements accurately describes the role of centrifugation in DNA extraction?
It lyses the cells to release DNA.
It selectively precipitates DNA from the solution.
It separates DNA fragments based on size.
It separates heavier cellular components from the DNA suspension.
What is the main purpose of a wash buffer used with silica membrane columns?
lyse cells and release DNA
remove proteins and other contaminants
elute purified DNA from the column
precipitate DNA from solution
During elution in silica membrane column extraction, what property allows DNA to be released from the membrane?
High ionic strength of the elution buffer
Lower affinity of DNA for the membrane at low ionic strength
Change in pH of the elution buffer
Heat treatment of the column
