Bio 325
BIO 325 Exam 3 Practice Questions and
Answers Graded A+ 2025-2026
Some restriction endonucleases produce 'sticky' ends. What makes an end sticky?
A) blunt ends
B) single-stranded complementary tails
C) poly-A sequences
D) 5' cap
E) Interference -Correct Answers ✔-B (single-stranded complementary tails)
List two especially useful characteristics of cloning vector
A) high copy number and antibiotic-resistance gene
B) virulence and lysogenecity
C) ability to integrate into host chromosome and cause lysis of the host cell
D) nonautonomous replication and transposition
E) reverse transcriptase and ligase activity -Correct Answers ✔-A (high copy
number and antibiotic-resistance gene)
Vectors such as pUC18 contain a large number of restriction enzyme sites
clustered in one region. What is that site called?
A) palindrome
B) consensus sequence
C) polylinker
D) beta-galactosidase
E) complementation -Correct Answers ✔-C (polylinker)
In a southern-blot, one generally
A) hybridizes filter-bound DNA with a DNA probe
B) hybridizes filter-bound RNA with a DNA probe
Bio 325
, Bio 325
C) examines amino acid substitutions with radioactive probe
D) cleaves RNA with restriction endonuclease
E) ligates DNA with DNA ligase -Correct Answers ✔-A (hybridizes filter-bound
DNA with a DNA probe)
ddNTPs are used in which of the following biochemical reaction?
A) restriction digestion
B) DNA sequencing
C) Electron transport
D) PCR
E) Plaque hybridization -Correct Answers ✔-B (DNA sequencing)
Taq polymerase, a heat-stable DNA polymerase, is used in PCR, because
A) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that allows
the primer to anneal to the target DNA
B) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that sterilize
the culture
C) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that activates
the Taq polymerase
D) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that separates
the hydrogen bonds which hold the strands of DNA together
E) A and C are correct -Correct Answers ✔-D (each PCR cycle includes a 'hot' (95
degree C) denaturation phase, that separates the hydrogen bonds which hold the
strands of DNA together)
ddNTP lacks ..............at the ........end.
A) methyl group, 3'
B) OH group, 3'
C) OH group, 5'
D) Carboxyl group, 3'
E) None of the above -Correct Answers ✔-B (OH group, 3')
Bio 325
BIO 325 Exam 3 Practice Questions and
Answers Graded A+ 2025-2026
Some restriction endonucleases produce 'sticky' ends. What makes an end sticky?
A) blunt ends
B) single-stranded complementary tails
C) poly-A sequences
D) 5' cap
E) Interference -Correct Answers ✔-B (single-stranded complementary tails)
List two especially useful characteristics of cloning vector
A) high copy number and antibiotic-resistance gene
B) virulence and lysogenecity
C) ability to integrate into host chromosome and cause lysis of the host cell
D) nonautonomous replication and transposition
E) reverse transcriptase and ligase activity -Correct Answers ✔-A (high copy
number and antibiotic-resistance gene)
Vectors such as pUC18 contain a large number of restriction enzyme sites
clustered in one region. What is that site called?
A) palindrome
B) consensus sequence
C) polylinker
D) beta-galactosidase
E) complementation -Correct Answers ✔-C (polylinker)
In a southern-blot, one generally
A) hybridizes filter-bound DNA with a DNA probe
B) hybridizes filter-bound RNA with a DNA probe
Bio 325
, Bio 325
C) examines amino acid substitutions with radioactive probe
D) cleaves RNA with restriction endonuclease
E) ligates DNA with DNA ligase -Correct Answers ✔-A (hybridizes filter-bound
DNA with a DNA probe)
ddNTPs are used in which of the following biochemical reaction?
A) restriction digestion
B) DNA sequencing
C) Electron transport
D) PCR
E) Plaque hybridization -Correct Answers ✔-B (DNA sequencing)
Taq polymerase, a heat-stable DNA polymerase, is used in PCR, because
A) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that allows
the primer to anneal to the target DNA
B) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that sterilize
the culture
C) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that activates
the Taq polymerase
D) each PCR cycle includes a 'hot' (95 degree C) denaturation phase, that separates
the hydrogen bonds which hold the strands of DNA together
E) A and C are correct -Correct Answers ✔-D (each PCR cycle includes a 'hot' (95
degree C) denaturation phase, that separates the hydrogen bonds which hold the
strands of DNA together)
ddNTP lacks ..............at the ........end.
A) methyl group, 3'
B) OH group, 3'
C) OH group, 5'
D) Carboxyl group, 3'
E) None of the above -Correct Answers ✔-B (OH group, 3')
Bio 325
