ASU BIO 340 EXAM 3 QUESTIONS
WITH CORRECT SOLUTIONS||A+
GRADED||UPDATED 2026/2027
SYLLABUS||<<RECENT VERSION>>
Match the function with the correct enzyme (prokaryotes):
A. Helicase
B. Ligase
C. Primase
1. Seals the gaps between the Okazaki fragments to create one continuous DNA
strand
2.Opens the DNA helix by breaking hydrogen bonds between nitrogenous bases
3. Synthesizes RNA primers needed to start replication - ANSWER ✓ A.->2.
B.->1.
C.->3.
Match the function with the correct enzyme (prokaryotes):
A. Sliding clamp
B. Topoisomerase
C. Single-strand binding proteins
1. Binds to single-stranded DNA to avoid DNA rewinding back
2. Helps relieve the stress on DNA when unwinding by causing breaks and then
resealing the DNA
3. Helps to hold the DNA pol in place when nucleotides are being added -
ANSWER ✓ A.->3
B.-> 2.
C.->1
DNA helicase - ANSWER ✓ An enzyme that unwinds the DNA double helix
during DNA replication
single-stranded binding protein - ANSWER ✓ proteins that bind to the freshly
split DNA molecule to keep the two strands apart.
,supercoiling - ANSWER ✓ twisting in the opposite direction to the turns of the
double helix during the first stage of mitosis.
DNA gyrase - ANSWER ✓ relaxes supercoiling ahead of the replication fork
DNA topoisomerase - ANSWER ✓ relieve torsional strain by winding and
unwinding DNA
primase - ANSWER ✓ An enzyme that joins RNA nucleotides to make the
primer using the parental DNA strand as a template.
continuous DNA synthesis - ANSWER ✓ Occurs only in the leading strand
towards the replication fork
leading strand - ANSWER ✓ strand synthesized continuously in the direction of
the replication fork
discontinuous DNA synthesis - ANSWER ✓ The synthesis of DNA in fragments
on the lagging strand during replication. The fragments, known as Okazaki
fragments, are subsequently joined by DNA ligase to form a continuous strand.
lagging strand - ANSWER ✓ A discontinuously synthesized DNA strand that
elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction
away from the replication fork.
okazaki fragments - ANSWER ✓ Small fragments of DNA produced on the
lagging strand during DNA replication, joined later by DNA ligase to form a
complete strand.
DNA ligase - ANSWER ✓ A linking enzyme essential for DNA replication;
catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end
of a growing chain.
proofreading - ANSWER ✓ function of DNA pol in which it reads the newly
added base before adding the next one
telomere - ANSWER ✓ repetitive DNA at the end of a eukaryotic chromosome
, end-replication problem - ANSWER ✓ polymerase cannot replicate the 5'
(beginning) end of the new strand because that's where the primer was. DNA
strands lose 50-200 bases per replication
telomerase - ANSWER ✓ An enzyme that catalyzes the lengthening of telomeres
in eukaryotic germ cells.
codon - ANSWER ✓ A specific sequence of three adjacent bases on a strand of
DNA or RNA that provides genetic code information for a particular amino acid
frameshift mutation - ANSWER ✓ mutation that shifts the "reading" frame of the
genetic message by inserting or deleting a nucleotide
reading frame - ANSWER ✓ The way a cell's mRNA-translating machinery
groups the mRNA nucleotides into codons
anticodon - ANSWER ✓ group of three bases on a tRNA molecule that are
complementary to an mRNA codon
wobble hypothesis - ANSWER ✓ initial two ribonucleotides of triplet codes are
often more critical than the third member in attracting the correct tRNA
ordered genetic code - ANSWER ✓ the pattern of triplet code sequences whereby
chemically similar amino acids often share one or two middle bases
start codon - ANSWER ✓ AUG (methionine)
stop codon - ANSWER ✓ punctuation signals that do not code for any amino acid
nonsense mutation - ANSWER ✓ partial polypeptide is synthesized
open reading frame - ANSWER ✓ any DNA sequence that produces a functional
mRNA, one with a start and stop codon between which is a series of triplet codons
specifying the amino acids making up a polypeptide
RNA polymerase - ANSWER ✓ Enzyme similar to DNA polymerase that binds
to DNA and separates the DNA strands during transcription
, core enzyme - ANSWER ✓ prokaryotic RNA polymerase consisting of α, α, β,
and β' but missing σ; this complex performs elongation
holoenzyme - ANSWER ✓ proteins with multiple subunits, complex formed by
the union of all subunits necessary for all functions of the enzyme
sigma factor - ANSWER ✓ controls the binding of RNA polymerase to the
promoter
template strand - ANSWER ✓ The DNA strand that provides the template for
ordering the sequence of nucleotides in an mRNA transcript.
coding strand - ANSWER ✓ the strand of DNA that is not used for transcription
and is identical in sequence to mRNA, except it contains uracil instead of thymine
template binding - ANSWER ✓ The initial step in prokaryotic gene transcription
promoter - ANSWER ✓ specific region of a gene where RNA polymerase can
bind and begin transcription
What is a gene? - ANSWER ✓ Fundamental unit of inheritance
Origin of the word "gene" - ANSWER ✓ greek: genos (origin), and genesis
(birth)
Gregor Mendel Experiment - ANSWER ✓ -pea plants
-traits do not blend in offspring
-traits are discreet, distinct entities
Thomas Hunt Morgan Experiment - ANSWER ✓ -genes are arranged linearly
-crossing over is proportional to gene distance
Frederick Griffith's Transformation Experiment - ANSWER ✓ -heat-killed
virulent strain transformed avirulent strain into virulent
-supported bacterial transformation of form and function
-coined phenomenon "transformation"
-*a chemical component of cells could introduce new, heritable trait to cell*
WITH CORRECT SOLUTIONS||A+
GRADED||UPDATED 2026/2027
SYLLABUS||<<RECENT VERSION>>
Match the function with the correct enzyme (prokaryotes):
A. Helicase
B. Ligase
C. Primase
1. Seals the gaps between the Okazaki fragments to create one continuous DNA
strand
2.Opens the DNA helix by breaking hydrogen bonds between nitrogenous bases
3. Synthesizes RNA primers needed to start replication - ANSWER ✓ A.->2.
B.->1.
C.->3.
Match the function with the correct enzyme (prokaryotes):
A. Sliding clamp
B. Topoisomerase
C. Single-strand binding proteins
1. Binds to single-stranded DNA to avoid DNA rewinding back
2. Helps relieve the stress on DNA when unwinding by causing breaks and then
resealing the DNA
3. Helps to hold the DNA pol in place when nucleotides are being added -
ANSWER ✓ A.->3
B.-> 2.
C.->1
DNA helicase - ANSWER ✓ An enzyme that unwinds the DNA double helix
during DNA replication
single-stranded binding protein - ANSWER ✓ proteins that bind to the freshly
split DNA molecule to keep the two strands apart.
,supercoiling - ANSWER ✓ twisting in the opposite direction to the turns of the
double helix during the first stage of mitosis.
DNA gyrase - ANSWER ✓ relaxes supercoiling ahead of the replication fork
DNA topoisomerase - ANSWER ✓ relieve torsional strain by winding and
unwinding DNA
primase - ANSWER ✓ An enzyme that joins RNA nucleotides to make the
primer using the parental DNA strand as a template.
continuous DNA synthesis - ANSWER ✓ Occurs only in the leading strand
towards the replication fork
leading strand - ANSWER ✓ strand synthesized continuously in the direction of
the replication fork
discontinuous DNA synthesis - ANSWER ✓ The synthesis of DNA in fragments
on the lagging strand during replication. The fragments, known as Okazaki
fragments, are subsequently joined by DNA ligase to form a continuous strand.
lagging strand - ANSWER ✓ A discontinuously synthesized DNA strand that
elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction
away from the replication fork.
okazaki fragments - ANSWER ✓ Small fragments of DNA produced on the
lagging strand during DNA replication, joined later by DNA ligase to form a
complete strand.
DNA ligase - ANSWER ✓ A linking enzyme essential for DNA replication;
catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end
of a growing chain.
proofreading - ANSWER ✓ function of DNA pol in which it reads the newly
added base before adding the next one
telomere - ANSWER ✓ repetitive DNA at the end of a eukaryotic chromosome
, end-replication problem - ANSWER ✓ polymerase cannot replicate the 5'
(beginning) end of the new strand because that's where the primer was. DNA
strands lose 50-200 bases per replication
telomerase - ANSWER ✓ An enzyme that catalyzes the lengthening of telomeres
in eukaryotic germ cells.
codon - ANSWER ✓ A specific sequence of three adjacent bases on a strand of
DNA or RNA that provides genetic code information for a particular amino acid
frameshift mutation - ANSWER ✓ mutation that shifts the "reading" frame of the
genetic message by inserting or deleting a nucleotide
reading frame - ANSWER ✓ The way a cell's mRNA-translating machinery
groups the mRNA nucleotides into codons
anticodon - ANSWER ✓ group of three bases on a tRNA molecule that are
complementary to an mRNA codon
wobble hypothesis - ANSWER ✓ initial two ribonucleotides of triplet codes are
often more critical than the third member in attracting the correct tRNA
ordered genetic code - ANSWER ✓ the pattern of triplet code sequences whereby
chemically similar amino acids often share one or two middle bases
start codon - ANSWER ✓ AUG (methionine)
stop codon - ANSWER ✓ punctuation signals that do not code for any amino acid
nonsense mutation - ANSWER ✓ partial polypeptide is synthesized
open reading frame - ANSWER ✓ any DNA sequence that produces a functional
mRNA, one with a start and stop codon between which is a series of triplet codons
specifying the amino acids making up a polypeptide
RNA polymerase - ANSWER ✓ Enzyme similar to DNA polymerase that binds
to DNA and separates the DNA strands during transcription
, core enzyme - ANSWER ✓ prokaryotic RNA polymerase consisting of α, α, β,
and β' but missing σ; this complex performs elongation
holoenzyme - ANSWER ✓ proteins with multiple subunits, complex formed by
the union of all subunits necessary for all functions of the enzyme
sigma factor - ANSWER ✓ controls the binding of RNA polymerase to the
promoter
template strand - ANSWER ✓ The DNA strand that provides the template for
ordering the sequence of nucleotides in an mRNA transcript.
coding strand - ANSWER ✓ the strand of DNA that is not used for transcription
and is identical in sequence to mRNA, except it contains uracil instead of thymine
template binding - ANSWER ✓ The initial step in prokaryotic gene transcription
promoter - ANSWER ✓ specific region of a gene where RNA polymerase can
bind and begin transcription
What is a gene? - ANSWER ✓ Fundamental unit of inheritance
Origin of the word "gene" - ANSWER ✓ greek: genos (origin), and genesis
(birth)
Gregor Mendel Experiment - ANSWER ✓ -pea plants
-traits do not blend in offspring
-traits are discreet, distinct entities
Thomas Hunt Morgan Experiment - ANSWER ✓ -genes are arranged linearly
-crossing over is proportional to gene distance
Frederick Griffith's Transformation Experiment - ANSWER ✓ -heat-killed
virulent strain transformed avirulent strain into virulent
-supported bacterial transformation of form and function
-coined phenomenon "transformation"
-*a chemical component of cells could introduce new, heritable trait to cell*
