DNA Isolation and Analysis Techniques

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Questions and Answers

What are the four nitrogenous bases found in DNA?

Adenine, Guanine, Uracil, Thymine
Adenine, Guanine, Cytosine, Thymine (correct)
Adenine, Guanine, Cytosine, Uracil
Cytosine, Guanine, Uracil, Thymine

What type of bond connects the sugar and phosphate residues in DNA?

Phosphodiester bond (correct)
Hydrogen bond
Glycosidic bond
Ionic bond

What is the name of the five-carbon sugar found in DNA?

Fructose
Glucose
Ribose
Deoxyribose (correct)

How many hydrogen bonds form between a guanine (G) and a cytosine (C) base pair?

Three (B) Signup and view all the answers

Which of the following statements about DNA structure is FALSE?

The sugar and phosphate residues are oriented towards the interior of the helix. (C) Signup and view all the answers

What term describes the relationship between the nitrogenous bases of the two strands of DNA?

Complementary (A) Signup and view all the answers

Why are G-C bonds stronger than A-T bonds?

G-C bonds form more hydrogen bonds than A-T bonds. (B) Signup and view all the answers

What is the primary function of DNA in living organisms?

To carry genetic information (D) Signup and view all the answers

What is the primary goal of DNA isolation?

To obtain a high-molecular-weight preparation of DNA, purified from proteins and DNA enzyme inhibitors. (D) Signup and view all the answers

Which of the following is NOT a factor influencing the choice of DNA isolation method?

The research budget for the project. (C) Signup and view all the answers

Why is EDTA used when collecting blood for DNA isolation?

EDTA inhibits the activity of enzymes that degrade DNA. (A) Signup and view all the answers

In addition to peripheral blood, DNA can also be isolated from which of the following human materials?

Amniotic fluid cells. (A) Signup and view all the answers

What is the purpose of the 'cell disintegration and lysis' stage of DNA isolation?

To release DNA from the cell into a solution where it can be protected from degradation. (C) Signup and view all the answers

Which of these is NOT a typical stage in the DNA isolation process?

Translation. (B) Signup and view all the answers

Why is it important to remove low-molecular-weight impurities during DNA isolation?

Both A and B are correct. (C) Signup and view all the answers

What is the main purpose of the concentration stage of DNA isolation?

To increase the amount of DNA present in the sample. (D) Signup and view all the answers

What is the purpose of adding Proteinase K in step 2?

To degrade proteins and release DNA. (D) Signup and view all the answers

What is the role of Sol S buffer in step 3?

To precipitate the DNA. (A) Signup and view all the answers

Why is the tube incubated at 70°C in step 4?

To inactivate the Proteinase K. (B) Signup and view all the answers

What is the purpose of centrifuging the tube with the swab in step 6?

To separate the DNA from the cell debris. (C) Signup and view all the answers

What is the main purpose of adding ethanol in step 5?

To precipitate the DNA. (B) Signup and view all the answers

Why is the spin-column transferred to a new collection tube in step 14?

To prevent contamination with other solutions. (A) Signup and view all the answers

What does the purity ratio 260/280nm indicate?

The amount of protein contamination in the DNA sample. (A) Signup and view all the answers

What is the expected yield of DNA isolation in this procedure?

1 to 10 µg DNA. (D) Signup and view all the answers

What is the purpose of the activation buffer (Buffer S) in the GeneMATRIX Swab-Extract DNA Purification Kit?

To saturate the membranes of the mini-column and prepare it for DNA binding (B) Signup and view all the answers

Why is it important to avoid eating, drinking, smoking, or brushing teeth 1-2 hours before collecting cheek epithelial cells?

To avoid contamination of the sample with foreign DNA (A) Signup and view all the answers

What is the recommended time for rubbing the cotton swab against the inner cheeks for optimal cell collection?

30-40 seconds (B) Signup and view all the answers

Why is it important to use a different side of the cotton swab for each cheek?

To avoid cross-contamination between the cheeks (D) Signup and view all the answers

What is the role of the laboratory centrifuge in the DNA isolation procedure?

To separate the DNA from other cellular debris (C) Signup and view all the answers

What is the likely purpose of using a spectrophotometer in the DNA isolation procedure?

To determine the purity of the isolated DNA (B), To measure the concentration of the isolated DNA (D) Signup and view all the answers

What is the purpose of the thermal block in the DNA isolation procedure?

To incubate the sample with enzymes that break down proteins (B) Signup and view all the answers

What is the primary function of the swab stick in the DNA isolation procedure?

To collect epithelial cells from the inner cheek surface (D) Signup and view all the answers

What is the typical A260/A280 ratio for pure, double-stranded DNA?

1.8 (D) Signup and view all the answers

What does an A260/A280 ratio below 1.8 indicate?

Presence of proteins (B) Signup and view all the answers

What is the primary purpose of using a spectrophotometer in DNA analysis?

To determine the purity and concentration of DNA (B) Signup and view all the answers

Which of these is NOT a method for DNA isolation?

Electroporation (D) Signup and view all the answers

Which enzyme is used to degrade proteins during DNA isolation?

Proteinase K (B) Signup and view all the answers

What is the role of detergents like SDS and Triton-X100 in DNA isolation?

To disrupt cell membranes (D) Signup and view all the answers

What is the optimal storage temperature for isolated DNA for long-term preservation?

-80 °C (B) Signup and view all the answers

At what wavelength does DNA absorb maximum UV light?

260 nm (D) Signup and view all the answers

What is the primary purpose of using phenol and chloroform during DNA isolation?

To extract lipids from the solution (D) Signup and view all the answers

What is the role of proteinase K in DNA isolation?

To digest proteins and improve DNA isolation efficiency (D) Signup and view all the answers

Which of the following is NOT a characteristic of DNA isolation using the magnetic method?

The DNA is precipitated using ethanol or isopropanol (D) Signup and view all the answers

In the column-based DNA isolation method, what is the purpose of the wash steps?

To remove impurities from the column (A) Signup and view all the answers

What is the role of buffers in DNA isolation, specifically during lysis?

To denature proteins and break down cell structures (B) Signup and view all the answers

In the initial steps of DNA isolation, why is the obtained lysate vigorously shaken in the presence of phenol and chloroform?

To remove proteins and lipids (D) Signup and view all the answers

During column-based DNA isolation, what is the principle behind DNA binding to the GeneMATRIX column during centrifugation?

DNA is negatively charged and binds to the positively charged column matrix (D) Signup and view all the answers

In the magnetic method of DNA isolation, what is the role of the magnet?

To immobilize the magnetic beads with bound DNA (C) Signup and view all the answers

Flashcards

DNA Isolation

The process of extracting DNA from biological samples.

Applications of Isolated DNA

Using isolated DNA to detect diseases and develop treatments.