Microbiology FINAL EXAM-Fa25Bio

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

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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

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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

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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

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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

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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

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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

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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.

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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

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Question 13

Nitrous acid causes a mutation by converting adenine to __.

• guanine
• cytosine
• hypoxanthine
• thymine
• hypoxanthine. Microbiology FINAL EXAM-Fa25 Bio

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Question 14

Mutations that are caused by exposure to X-rays are called __ mutations.

• induced
• missense
• spontaneous
• nonsense
• induced

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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

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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

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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

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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

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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

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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

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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

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Question 43

Which of the following is a nucleotide analog?

• hydroxylamine
• acridine
• 5-bromouracil
• ethidium bromide
• nitrous acid

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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

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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

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Question 46

Which of the following is NOT a viral disease?

• rabies
• smallpox
• AIDS
• viruses are involved in ALL these diseases
• influenza

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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

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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

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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

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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.

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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

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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.

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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

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Question 55

West Nile virus is an example of a

• direct-contact infection.
• non-communicable disease.
• zoonosis.
• systemic infection.

Answer: zoonosis.

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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.

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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.

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Question 58

Rhabdoviridae is at which level of the viral taxonomic hierarchy?

• order
• species
• genus
• family

Answer: family