MOLECULAR DIAGNOSTICS 3RD EDITION
BUCKINGHAM TEST BANK EXAM SCRIPT
2026 TESTED QUESTIONS AND VERIFIED
SOLUTIONS
⩥ What are two ways to break down cell walls for DNA extraction?
Answer: 1. homogenization through physical grinding
2. treatment of detergent (SDS) with strong base (NaOH) in ethylene-
diaminetetraacetic acid (EDTA)
⩥ Ficoll Answer: Highly branched sugar Solution w/ specific density
that allows only RBCs and neutrophils to pass through
Mononuclear cells (monocytes and lymphocytes) form a band on top
⩥ What are two methods for separating nucleated cells? Answer: 1.
density-gradient centrifugation of whole blood or bone marrow with
ficoll
2. incubation of whole blood or bone marrow in hypotonic water which
will lyse RBC's prior to WBC's, and then centrifuged to pellet the
WBC's
⩥ Which fixative is the worst for DNA recover? Answer: Bouin's and B-
5
, ⩥ Which fixative is the best for DNA recovery? Answer: buffered
formalin
⩥ Steps of Organic DNA Extraction Answer: 1. lyse cells in suspension
using alkaline (NaOH) and a detergent (SDS)
2. treat lysed debris with acetic acid and salt, centrifuge to pellet
3. add phenol and chloroform to separate solution into two layers an
upper aqueous phase which contains the DNA and a lower organic phase
which contains the cell debris ie proteins
4. precipitate DNA with ethanol, centrifuge, remove ethanol and
reprecipitate with water/buffer, can add RNAse
⩥ What can be used to help precipitate low amounts of DNA? Answer:
carrier molecules such as yeast, RNA, glycogen
⩥ In inorganic DNA isolation, or "salting out" procedures, in the
presence of low-pH and high-salt concentrations, which intracellular
component precipitates out of solution? Answer: proteins
⩥ inorganic DNA isolation Answer: 1. lyse suspended cells using
detergent and tris buffer
2. add high salt and low pH, sodium acetate to precipitate protein from
solution and leave DNA in solution, centrifuge
3. remove aqueous layer and precipitate DNA with isopropanol,
centrifuge, remove ethanol and add buffer or water
BUCKINGHAM TEST BANK EXAM SCRIPT
2026 TESTED QUESTIONS AND VERIFIED
SOLUTIONS
⩥ What are two ways to break down cell walls for DNA extraction?
Answer: 1. homogenization through physical grinding
2. treatment of detergent (SDS) with strong base (NaOH) in ethylene-
diaminetetraacetic acid (EDTA)
⩥ Ficoll Answer: Highly branched sugar Solution w/ specific density
that allows only RBCs and neutrophils to pass through
Mononuclear cells (monocytes and lymphocytes) form a band on top
⩥ What are two methods for separating nucleated cells? Answer: 1.
density-gradient centrifugation of whole blood or bone marrow with
ficoll
2. incubation of whole blood or bone marrow in hypotonic water which
will lyse RBC's prior to WBC's, and then centrifuged to pellet the
WBC's
⩥ Which fixative is the worst for DNA recover? Answer: Bouin's and B-
5
, ⩥ Which fixative is the best for DNA recovery? Answer: buffered
formalin
⩥ Steps of Organic DNA Extraction Answer: 1. lyse cells in suspension
using alkaline (NaOH) and a detergent (SDS)
2. treat lysed debris with acetic acid and salt, centrifuge to pellet
3. add phenol and chloroform to separate solution into two layers an
upper aqueous phase which contains the DNA and a lower organic phase
which contains the cell debris ie proteins
4. precipitate DNA with ethanol, centrifuge, remove ethanol and
reprecipitate with water/buffer, can add RNAse
⩥ What can be used to help precipitate low amounts of DNA? Answer:
carrier molecules such as yeast, RNA, glycogen
⩥ In inorganic DNA isolation, or "salting out" procedures, in the
presence of low-pH and high-salt concentrations, which intracellular
component precipitates out of solution? Answer: proteins
⩥ inorganic DNA isolation Answer: 1. lyse suspended cells using
detergent and tris buffer
2. add high salt and low pH, sodium acetate to precipitate protein from
solution and leave DNA in solution, centrifuge
3. remove aqueous layer and precipitate DNA with isopropanol,
centrifuge, remove ethanol and add buffer or water
