Question 4
Microbiology FINAL EXAM-Fa25 Bio. Which of the following prevents the attachment of pathogens to host cell binding sites?
- siderophores
- folic acid
- lysozyme
- bacteria of the human microbiome
- B cells and T cells
Question 5
Some pathogens produce the enzyme hyaluronidase to break down __________ that holds cells together in the body.
- hyaluronic acid
- connective tissue
- clotting factors
- epithelial tissue
- keratin
Question 6
An integrated prophage is “induced” to enter the lytic cycle when the bacterial host is stressed by:
- high nutrient levels
- excessive binary fission
- exposure to UV light
- competition from other bacteria
- presence of a different virus
Question 7
Which of the following statements about transposons is FALSE?
- transposons are capable of being transferred between different species
- transposons are prevalent in bacteria but absent in humans
- all transposons contain the gene for the enzyme transposase
- transposons can cause mutations by inserting into a gene
- transposons are prevalent in bacteria but absent in humans
Question 8
The specificity of a virus is determined by the:
- host cell’s ability to produce viral toxins
- number of capsomeres in the viral capsid
- receptor proteins embedded within the viral envelope. Microbiology FINAL EXAM- Fa25 Bio
- types of receptors possessed by the host cell
- types of receptors possessed by the host cell
Question 9
Naked viruses are usually released by __ whereas enveloped viruses are usually released by __.
- budding or exocytosis … lysis
- lysis … budding or exocytosis
- lysis … binary fission
- endocytosis … budding or exocytosis
- lysis … budding or exocytosis
Question 10
The epithelial cells of a mucous membrane are:
- widely spaced and in contact with a basement membrane
- tightly packed and in contact with a basement membrane
- tightly packed and in contact with extracellular matrix
- widely spaced and in contact with extracellular matrix
- tightly packed and in contact with a basement membrane
Question 11
Which of the following explains why a human does not develop a tobacco mosaic virus infection?
- The human body produces blood clots that trap the virus.
- The human body produces hemolysins that destroy the virus.
- Human cells lack the ability to produce the viral toxins.
- The human body’s normal microbiota outcompetes the virus.
- NONE of these statements accurately explain the reason for this species resistance.
Question 12
Which of the following is NOT an example of a single-gene mutation?
- missense mutation
- frameshift mutation
- nonsense mutation
- chromosomal inversion
- chromosomal inversion
Question 13
Nitrous acid causes a mutation by converting adenine to __.
- guanine
- cytosine
- hypoxanthine
- thymine
- hypoxanthine. Microbiology FINAL EXAM-Fa25 Bio
Question 14
Mutations that are caused by exposure to X-rays are called __ mutations.
- induced
- missense
- spontaneous
- nonsense
- induced
Question 15
The first step in clonal selection is:
- the production of antibodies by a plasma cell
- interaction between a lymphocyte and an antigen
- the differentiation of a lymphocyte into a memory cell
- the division of a lymphocyte into a clone of cells
- interaction between a lymphocyte and an antigen
Question 16
Which of the following is NOT a consequence of localized vasodilation during inflammation?
- increased delivery of oxygen and nutrients to the injury site
- redness and heat at the injury site
- increased delivery of phagocytes to the injury site
- redistribution of blood to the kidneys and digestive system
- redistribution of blood to the kidneys and digestive system
Question 17
In the process of clonal selection, what is the “selection” step?
- the production of antibodies by a plasma cell
- the division of a lymphocyte into a clone of cells
- the binding of an antigen to its corresponding receptor
- the differentiation of a lymphocyte into a memory cell
- the binding of an antigen to its corresponding receptor
Question 36
Which of the following statements about mutations is TRUE?
- Mutation rates differ between species
- Mutation rates differ between genes
- Mutagens can increase mutation rates
- Mutations are either spontaneous or induced
- Mutations are permanent change in the nucleotide sequence of DNA
- all these statements are TRUE
Question 38
Which of the following statements about the nitrogenous base thymine is FALSE?
- at equilibrium, thymine’s keto form is more prevalent than its enol form
- a carboxyl (C=O) group is present in thymine’s keto form, but absent in the enol form
- when in the keto form, thymine normally pairs with adenine
- when in the enol form, thymine can pair with guanine or cytosine
- keto/enol tautomerism can result in base-pairing mutations. Microbiology FINAL EXAM-Fa25 Bio
Question 40
Which of the following statements accurately describes both specificity and inducibility of adaptive immunity?
- immune cells can recognize and respond to any pathogen
- a pathogen activates cells involved in an immune response to that particular pathogen
- immune cells that recognize a pathogen expand greatly in number
- the adaptive immune system is capable of eliminating virally-infected cells
- the adaptive immune system can respond more quickly to a pathogen it has encountered previously
Question 40 (Skin Anatomy)
Which of the following does NOT accurately represent a difference between the dermis and the epidermis?
- blood vessels are present in the dermis, but absent in the epidermis
- most dermal cells are dead, whereas epidermal cells are alive
- epidermal cells are more tightly packed than dermal cells
- hyaluronic acid is more plentiful in the dermis than in the epidermis
- all these statements accurately represent a difference between the dermis and the epidermis
Question 41
Indirect selection would be particularly useful in selecting for:
- histidine auxotrophs (his-)
- penicillin-resistant bacteria
- lactose-fermenting bacteria
- revertants
- all of the above
Question 42
Phenotypic mixing is similar to genetic reassortment because in both cases:
- this occurs in DNA viruses only
- the viruses have multipartite (segmented) genomes
- a provirus is formed
- the progeny have genetic material from two “parent” viruses
- host range is altered
Question 43
Which of the following is a nucleotide analog?
- hydroxylamine
- acridine
- 5-bromouracil
- ethidium bromide
- nitrous acid
Question 44
The part of an antigen recognized by a T cell receptor is called a(n):
- Toll-like receptor
- constant region
- epitope
- MHC molecule
- paratope
Question 45
Which of the following are mechanisms for increasing the diversity of the antibody repertoire? (choose all that apply)
- first (somatic recombination/shuffling of gene segments)
- second (junctional diversity/imprecise joining of segments)
- third
- fourth
Question 46
Which of the following is NOT a viral disease?
- rabies
- smallpox
- AIDS
- viruses are involved in ALL these diseases
- influenza
Question 47
Unlike animal viruses, plant viruses can ONLY enter a host cell through:
- receptor-mediated endocytosis
- fusion of the viral envelope
- wound sites
- phagocytosis
- carrier proteins
Question 48
Nucleotide excision repair (NER) corrects which of the following? Microbiology FINAL EXAM-Fa25 Bio
- thymine dimers
- single-strand breaks
- mismatched bases
- methylation
- double-strand breaks
Question 49
How can humans produce billions of different antibodies with only a few hundred genes?
- alternative splicing of mRNA
- humans have many more genes than previously thought
- viruses use reverse transcriptase to add new genes
- the genes are cut and pasted differently in different B cells
- the antibodies are only made after the body sees an antigen
Question 50
A clear zone on a lawn of bacteria that results from the lysis of the bacteria by a bacteriophage is called a:
- colony
- prophage
- plaque
- clearing
- plaque
Question 51
Which of the following statements is TRUE regarding the difference between a silent mutation and a neutral mutation?
- a silent mutation does not change the amino acid sequence of the protein, while a neutral mutation changes the amino acid sequence but does not change the function of the protein
- a silent mutation is a type of point mutation, while a neutral mutation is a type of frameshift mutation
- a silent mutation occurs in a non-coding region of DNA, while a neutral mutation occurs in a coding region of DNA
- a silent mutation is caused by a base substitution, while a neutral mutation is caused by an insertion or deletion
- a silent mutation does not change the amino acid sequence of the protein, while a neutral mutation changes the amino acid sequence but does not change the function of the protein
Question 51
Compared to a neutral mutation, a silent mutation is different because
- Both involve a change in base sequence, but only a silent mutation involves a change in amino acid sequence.
- Both involve a change in base sequence, but only a neutral mutation involves a change in amino acid sequence.
- A silent mutation silences a gene while a neutral mutation does not.
- A silent mutation inactivates a start codon while a neutral mutation does not.
Answer: Both involve a change in base sequence, but only a neutral mutation involves a change in amino acid sequence.
Question 52
When guanine is in the enol form, it base-pairs with _______, and when it is in the form of 8-oxoguanine, it base-pairs with _______.
- C … T
- T … A
- T … C
- A … T
Answer: T … A
Question 53
Some pathogens have evolved to produce transferrin receptors. This allows them to have
- increased access to iron.
- increased access to water.
- increased access to vitamin B12.
- decreased access to oxygen.
Answer: increased access to iron.
Question 54
Which of the following causes the formation of covalent bonds between adjacent pyrimidine bases in a DNA molecule?
- x-rays
- ionizing radiation
- ultraviolet radiation
- gamma rays
Answer: ultraviolet radiation
Question 55
West Nile virus is an example of a
- direct-contact infection.
- non-communicable disease.
- zoonosis.
- systemic infection.
Answer: zoonosis.
Question 56
When a cell transfers its genes to its offspring through binary fission, this is called
- vertical gene transfer.
- transformation.
- transduction.
- horizontal gene transfer.
Answer: vertical gene transfer.
Question 57
One of the end products in the sequence of events that leads to blood clotting is the conversion of
- fibrin into fibrinogen.
- prothrombin into thrombin.
- fibrinogen into fibrin.
- platelets into a platelet plug.
Answer: fibrinogen into fibrin.
Question 58
Rhabdoviridae is at which level of the viral taxonomic hierarchy?
- order
- species
- genus
- family
Answer: family
