PORTAGE LEARNING MICROBIOLOGY FINAL
EXAM 2026 EXAM SCRIPT FULL QUESTIONS
AND VERIFIED SOLUTIONS
◉ In most women, which is the most common acid-producing
bacterial genus in the vagina? Answer: Lactobacillus
◉ Which of the following is not true of biofilms? Answer: Nutrients
are equally distributed throughout a biofilm, so all the cells are
healthy and resistant.
◉ Which of the following is true of the normal skin microbiota?
Answer: It varies depending on microenvironment and is an
important part of the nonspecific immune system.
◉ Common cold viruses can often be differentiated from influenza
by which of the following? Answer: absence of a high fever
◉ In the United States, which sexually transmitted infection is
especially common in individuals between the ages of 15 and 24
years? Answer: gonorrhea
,◉ How does sebum affect microbial growth on the skin? Answer: It
may aid growth by providing nutrients but also has components that
inhibit microbial growth.
◉ Which type of microbes thrive in the Great Salt Lake. Answer:
extreme halophiles
◉ The central dogma describes which of the following? Answer: the
steps of gene expression
◉ Stop codons are also known as: Answer: nonsense codons
◉ Which of the following is another name for generation time?
Answer: doubling time
◉ There has been considerable concern about finding good ways to
treat infections involving biofilms, such as those that develop on
medical devices. What characteristics of biofilms complicate the
treatment of infections involving biofilms? Answer: Biofilms contain
certain pathogens that increase the antibiotic resistance. Biofilms
also allows for the exchange of extrachromosomal DNA, which also
leads to antibiotic resistance.
The proposed hypotheses include at least three possibilities. First,
microbes in biofilms may be less metabolically active and bacteria
,that are less metabolically active are generally affected less by
medications. Second, the extracellular polymeric substances may
inhibit the ability of medications and other chemicals to penetrate
the biofilm to affect the deeper cells. In addition, microbes in
biofilms may have metabolic abilities that help to counteract
medications. For example, they may be able to pump out antibiotics
using efflux pumps. Finally, microbes in biofilms can exchange
resistance genes through horizontal gene transfer.
◉ Mutations may be harmful but may also be beneficial or neutral.
Explain some examples of neutral and beneficial mutations. Answer:
Some examples of beneficial mutations are HIV resistance , lactose
tolerance, and trichromatic vision. Neutral mutations are blood type
and eye color.
Neutral mutations have no effect on fitness (i.e., the ability of an
organism to reproduce). They are not harmful or helpful. If the
mutation occurs in the third base of a codon, the amino acid may not
be changed (a silent mutation). Even if a single amino acid is
changed, the protein may still function in some cases. Additionally,
mutations may occur in noncoding regions and be neutral. Beneficial
mutations may give an organism a new ability, such as antibiotic
resistance. The text describes how a mutation may help to protect
against HIV in the Micro Connections box "A Beneficial Mutation." In
this case, a mutation in the gene for a receptor causes an abnormal
receptor to be produced and this interferes with the ability of HIV to
bind to the cell.
, ◉ Which of the following are enzymes that break down proteins?
Answer: proteases
◉ Which best describes bacterial growth during the log phase of the
growth curve? Answer: exponential
◉ ATP is produced through oxidative phosphorylation when which
of the following occurs? Answer: H+ moves through ATP synthase
◉ Which of the following is not a product of the Krebs cycle?
Answer: Pyruvate
◉ Bacteria typically divide by: Answer: binary fission
◉ The noncoding, repetitive sequences at the end of eukaryotic
chromosomes are called which of the following? Answer: telomeres
◉ The reaction breaks down ATP into ADP and inorganic phosphate
is classified as: Answer: exergonic
◉ If you grow two species of bacteria on mannitol salt agar to
determine which can ferment mannitol, and you know both species
can grow on the medium, which type of medium is the agar?
Answer: differential
EXAM 2026 EXAM SCRIPT FULL QUESTIONS
AND VERIFIED SOLUTIONS
◉ In most women, which is the most common acid-producing
bacterial genus in the vagina? Answer: Lactobacillus
◉ Which of the following is not true of biofilms? Answer: Nutrients
are equally distributed throughout a biofilm, so all the cells are
healthy and resistant.
◉ Which of the following is true of the normal skin microbiota?
Answer: It varies depending on microenvironment and is an
important part of the nonspecific immune system.
◉ Common cold viruses can often be differentiated from influenza
by which of the following? Answer: absence of a high fever
◉ In the United States, which sexually transmitted infection is
especially common in individuals between the ages of 15 and 24
years? Answer: gonorrhea
,◉ How does sebum affect microbial growth on the skin? Answer: It
may aid growth by providing nutrients but also has components that
inhibit microbial growth.
◉ Which type of microbes thrive in the Great Salt Lake. Answer:
extreme halophiles
◉ The central dogma describes which of the following? Answer: the
steps of gene expression
◉ Stop codons are also known as: Answer: nonsense codons
◉ Which of the following is another name for generation time?
Answer: doubling time
◉ There has been considerable concern about finding good ways to
treat infections involving biofilms, such as those that develop on
medical devices. What characteristics of biofilms complicate the
treatment of infections involving biofilms? Answer: Biofilms contain
certain pathogens that increase the antibiotic resistance. Biofilms
also allows for the exchange of extrachromosomal DNA, which also
leads to antibiotic resistance.
The proposed hypotheses include at least three possibilities. First,
microbes in biofilms may be less metabolically active and bacteria
,that are less metabolically active are generally affected less by
medications. Second, the extracellular polymeric substances may
inhibit the ability of medications and other chemicals to penetrate
the biofilm to affect the deeper cells. In addition, microbes in
biofilms may have metabolic abilities that help to counteract
medications. For example, they may be able to pump out antibiotics
using efflux pumps. Finally, microbes in biofilms can exchange
resistance genes through horizontal gene transfer.
◉ Mutations may be harmful but may also be beneficial or neutral.
Explain some examples of neutral and beneficial mutations. Answer:
Some examples of beneficial mutations are HIV resistance , lactose
tolerance, and trichromatic vision. Neutral mutations are blood type
and eye color.
Neutral mutations have no effect on fitness (i.e., the ability of an
organism to reproduce). They are not harmful or helpful. If the
mutation occurs in the third base of a codon, the amino acid may not
be changed (a silent mutation). Even if a single amino acid is
changed, the protein may still function in some cases. Additionally,
mutations may occur in noncoding regions and be neutral. Beneficial
mutations may give an organism a new ability, such as antibiotic
resistance. The text describes how a mutation may help to protect
against HIV in the Micro Connections box "A Beneficial Mutation." In
this case, a mutation in the gene for a receptor causes an abnormal
receptor to be produced and this interferes with the ability of HIV to
bind to the cell.
, ◉ Which of the following are enzymes that break down proteins?
Answer: proteases
◉ Which best describes bacterial growth during the log phase of the
growth curve? Answer: exponential
◉ ATP is produced through oxidative phosphorylation when which
of the following occurs? Answer: H+ moves through ATP synthase
◉ Which of the following is not a product of the Krebs cycle?
Answer: Pyruvate
◉ Bacteria typically divide by: Answer: binary fission
◉ The noncoding, repetitive sequences at the end of eukaryotic
chromosomes are called which of the following? Answer: telomeres
◉ The reaction breaks down ATP into ADP and inorganic phosphate
is classified as: Answer: exergonic
◉ If you grow two species of bacteria on mannitol salt agar to
determine which can ferment mannitol, and you know both species
can grow on the medium, which type of medium is the agar?
Answer: differential
