BIOMI 2600 final study guide
On one of your powerpoint slides, you saw a protein complex denoted C3b2Bb. Can you decipher what is meant by each letter and each number?
"C3b" refers to a fragment of the complement C3 protein that is created by proteolysis. The other fragment is C3a. "2" refers to two C3b fragments. "Bb" refers to a fragment of complement protein B that is created by proteolysis. Two C3b fragments and one Bb fragment form a complex that converts more C3 proteins in the C3b and C3a.
In the context of polio vaccines, described what is meant by "tOPV", "bOPV", and "nOPV2". Where is each currently used?
"tOPV" is the trivalent vaccine, which contains attenuated type 1, 2, and 3 polioviruses. It is no longer used, as wild type 2 poliovirus has been eradicated, and the type 2 strain in the vaccine can revert to a pathogenic form. "bOPV" is a bivalent vaccine containing attenuated type 1 and type 3 poliovirus. It is widely used in the developing world "nOPV2" is a "novel" attenuated Type 2 poliovirus that cannot revert (we hope) and is used in parts of the world where circulating vaccine-derived poliovirus (cVDPV) is found.
Caps of host mRNA are cut off by the RNA polymerase of influenza and used as primers of (+) strands destined to be translated (+) strands that are destined to serve as templates for (-) strands (-) strands that are packaged into virions. A and B A, B, and C)
(+) strands destined to be translated
What is the estimated case fatality rate for 20-29 year olds in mainland China? 0.2% 0.4% 1.3% 3.6% 8% 14.8%
0.2%
If protein has 12 signal sequences (or start-transfer sequences) and 12 stop-transfer sequences, how many cytoplasmic loops ought it have? "Loops" would exclude the extreme N terminus and extreme C terminus 5 9 11 13 22
11
IgG has _ heavy chains while IgM can form complexes that have _ heavy chains and IgA can form complexes that have ______ heavy chains 2, 10, 4 1, 5, 2 2, 4, 10 1, 10, 4 2, 4, 4
2, 10, 4
How many proteases (or "proteinases") are required to convert the viral polyprotein to mature proteins? How many cleavage sites are shown in the figure on slide 32? 1, 13 2, 13 3, 13 4, 14 2, 12 2, 11 2, 10
2, 13
Order the following events in quorum sensing by Staphylococcus aureus: 1. Exotoxin expression increases, while expression of surface adhesins decreases. 2. AgrB-D-C-A operon is expressed at low levels. 3. RNA III accumulates. 4. AgrD peptide is processed and secreted by AgrB, creating the mature pheromonE) 5. Pheromone accumulates when population densities are higH) 6. AgrC phosphorylates AgrA) 7. AgrA-P binds to promoters P2 and P3, activating botH) 8. Pheromone binds to the sensory kinase AgrC. 5, 8, 1, 3, 6, 7, 2, 4 2, 4, 5, 8, 6, 7, 3, 1 4, 2, 7, 3, 8, 1, 5, 6 4, 8, 1, 6, 2, 3, 5, 7 4, 6, 5, 3, 1, 7, 8, 2
2, 4, 5, 8, 6, 7, 3, 1
An icosahedral capsid has how many sides? 20 8 40 6 10
20
Open the nextstrain link (I'll send you the link separately). Scroll down to a graph entitled Frequencies (colored by Clade). It shows three different clades of Delta strains (21J, 21I, and 21A). Approximately when were these clades first detected? If you add them together, what fraction of current infections are caused by delta variants?
21J: 3/7/21 21I: 3/7/21 21A: 3/15/21 97%
If a PCR reaction were carried out for N cycles and no reagents were depleted, how many DNA fragments could be created per input DNA? N 2N 2^N (2 raised to the power of N) 10N N2 N! (N factorial)
2^N (2 raised to the power of N)
List the correct order of the following events in phagocytosis: (1) discharge of waste material with presentation of antigen on the surface of the phagocytic cell; (2) fusion of the phagosome with a lysosome; (3) adherence of the microbe to phagocytes; (4) digestion of the ingested microbe; (5) formation of a phagosome; (6) ingestion of the microbe by the phagocyte. 3, 6, 5, 2, 4, 1 5, 2, 3. 6, 4, 1 3, 4, 6, 5, 2, 1 6, 5, 2, 4, 3, 1 none of the above
3, 6, 5, 2, 4, 1
The first and second bases of RNA that are polymerized by RNA polymerase are joined by a ______ bond A. 5'-5' triphosphate B. 5'-3' triphosphate C. 3'-3' triphosphate D. 5'-5' diphosphate E. 5'-3' diphosphate F. 3'-3' diphosphate G. 5'-5' monophosphate H. 5'-3' monophosphate I. 3'-3' monophosphate J. None of the above
5'-3' monophosphate
Mammalian and most mRNA's have a "cap" at their 5' end. Caps consist of an extra G residue fused to the rest of the molecule by a _____ linkage 5'-5' diphosphate 5'-3' diphosphate 3'-5' diphosphate 3'-3' diphosphate 5'-5' triphosphate 5'-3' triphosphate 3'-5' triphosphate 3'-3' triphosphate
5'-5' triphosphate
The Cap of eukaryotic mRNAs have a non-templated G residue in a 5'-5' triphosphate linkage 3'-5' triphosphate linkage 5'-3' triphosphate linkage 5'-5' monophosphate linkage 3'-5' monophosphate linkage 5'-3' monophosphate linkage None of the above
5'-5' triphosphate linkage
Order the follow steps in immunoprecipitation of the RecA protein. 1) Combine the lysate with the antibody-protein A-sepharose beads. 2) Identify the proteins in the pellet. 3) Centrifuge the beads to separate the beads (pellet) from the supernatant. 4) Lyse a culture of E. coli expressing RecA protein. 5) Purify anti-RecA antibodies from a rabbit. 6) Add antibodies to Protein A-sepharose beads. 7) Wash the pellet. 5, 6, 4, 1, 3, 7, 2 5, 1, 3, 4, 7, 2, 6 1, 3, 5, 7, 2, 6, 4 1, 3, 4, 7, 2, 5, 6 6, 7, 3, 1, 4, 5, 2
5, 6, 4, 1, 3, 7, 2
Order the following steps in export and maturation of cell-wall-associated protein A. 1. As Protein A secretion begins, the signal sequence is removed by a signal peptidase. 2. Secretion stops at the stop-transfer sequence. 3. The distal glycine residue of the pentaglycine of lipid II attacks the bond that links sortase to Protein A. A covalent bond is formed between the lipid II and Protein A. 4. Lipid II with bound Protein A is incorporated into cell wall. 5. Sortase attacks the sortase signal near the stop-transfer sequence of Protein A. Sortase forms a covalent bond with Protein A and stop-transfer sequence is removed. 6. Protein A is synthesized in cytoplasm 1, 2, 3, 4, 5, 6 6, 1, 2, 5, 3, 4 5, 6, 1, 3, 2, 4 4, 2, 3, 1, 5, 6 3, 4, 5, 6, 1, 2
6, 1, 2, 5, 3, 4
How many major groups of viruses are described in the Baltimore classification scheme? 9 5 7 6 8
7
Which of the following could serve as an invitation point for DNA synthesis? A. A 3' OH group of RNA B. A 3' OH group of RNA that has a bound phosphate group C. A 5' OH group of RNA that has a bound phosphate group D. A 5' OH group of RNA E. A 5' group of DNA F. None of the above
A 3' OH group of RNA
Within two weeks after a woman becomes pregnant, the fetus and placenta begin to produce human chorionic gonadotropin (hCG), which can be detected in the blood and urine of the mother. Pregnancy test kits have been developed to facilitate the detection of hCG) By analogy to the malaria test kit described in class, which of the following antibodies would you expect to bind directly to hCG? Detecting antibody Capture antibody Control antibody A and B A and C B and C A, B, and C
A and B
The vaccine for yellow fever is A live attenuated virus A wild type virus that is inactivated using formaldehyde Purified viral adhesin Nucleic acid of the virus converted to double-stranded DNA A virus-like particle containing a fusion between the viral adhesin and the Hepatitis B surface antigen. None of the above; there is no effective vaccine for yellow fever.
A live attenuated virus
Shiga toxin genes are found on A lysogenic phage A lytic phage A plasmid An integron A transposon
A lysogenic phage
The B subunit of shiga toxin binds a host receptor consisting of A membrane-localized protein A membrane-localized glycoprotein containing neutral sugar residues A membrane-localized glycolipid that contains two fatty acyl groups and several neutral (uncharged) sugar residues You Answered A membrane-localized glycolipid that contains two fatty acyl groups, several neutral sugars, and sialic acid A membrane-localized glycoprotein containing neutral sugars and sialic acid.
A membrane-localized glycolipid that contains two fatty acyl groups and several neutral (uncharged) sugar residues
The ability of a B cell to switch from synthesizing IgM to IgG requires Differential splicing of the mRNA encoding the antibody heavy chain Differential splicing of the mRNA encoding the antibody light chain A programmed deletion of a portion of the gene that encodes the antibody heavy chain A programmed deletion of a portion of the gene that encodes the antibody light chain Expression of an entirely new gene encoding the IgG heavy chain Expression of an entirely new gene encoding the IgG light chain
A programmed deletion of a portion of the gene that encodes the antibody heavy chain
An EHEC strain, when exposed to antibiotics that interfere with DNA replication, might be expected to release A) A lysogenic bacteriophage B) Heat-labile enterotoxin C) Typhoid toxin D) Shiga toxin E) A type 3 injectisome
A) A lysogenic bacteriophage D) Shiga toxin
When hemagglutinin is first synthesized on host ribosomes, it contains (multiple correct answers) A) A signal sequence B) A stop transfer sequence C) A site that will be cleaved by a host protease D) A sequence that will become the "fusion peptide" E) None of the above.
A) A signal sequence B) A stop transfer sequence C) A site that will be cleaved by a host protease D) A sequence that will become the "fusion peptide"
When the spike protein of HIV is first synthesized on host ribosomes, it contains (multiple correct answers) A) A signal sequence B) A stop transfer sequence C) A site that will be cleaved by a host protease D) A sequence that will become the "fusion peptide" E) A domain that will bind to CD4 and CCR5 F) None of the above.
A) A signal sequence B) A stop transfer sequence C) A site that will be cleaved by a host protease D) A sequence that will become the "fusion peptide" E) A domain that will bind to CD4 and CCR5
What functions in the SARS life cycle are carried out by the Spike protein? (Multiple correct answers) A) Adhesion to the host receptor angiotensin converting enzyme (ACE2) B) Adhesion to angiotensin C) Fusion of the viral envelope to the mitochondrial membrane D) Synthesis of a 5' Cap E) Synthesis of a poly-A tail F) Fusion of the viral envelope with the endosomal membrane
A) Adhesion to the host receptor angiotensin converting enzyme (ACE2) F) Fusion of the viral envelope with the endosomal membrane
Staphylococcus aureus (multiple correct answers) A) Along with Bacillus, Listeria, and Clostridium is a member of the Firmicutes. B) Along with Bacillus, Listeria, and Clostridium is a member of the Proteobacteria C) Along with Bacillus, Listeria, and Clostridium is a member of the Bacterioidetes. D) Colonizes a large proportion of humankind, most often as a commensal without any adverse consequences
A) Along with Bacillus, Listeria, and Clostridium is a member of the Firmicutes. D) Colonizes a large proportion of humankind, most often as a commensal without any adverse consequences
Which of the following can opsonize a microbe? (multiple correct answers) A) Antibodies B) Complement C3b C) Complement C6-C10 D) Complement C3a E) MHC-I F) MHC-II
A) Antibodies B) Complement C3b
To make an RNA vaccine against SARS-CoV2, one must (multiple correct answers) A) Assemble the full length spike protein from synthetic DNA fragments B) Clone the gene into a bacterial plasmid adjacent to a strong promoter C) Introduce the recombinant plasmid into bacteria for propagation D) Purify the plasmid DNA E) To the plasmid DNA, add RNA polymerase and substrates for mRNA F) Purify the mRNA G) Encase mRNA in a lipid nanodrop H) Place a drop of vaccine on a sugar cube for oral administration.
A) Assemble the full length spike protein from synthetic DNA fragments B) Clone the gene into a bacterial plasmid adjacent to a strong promoter C) Introduce the recombinant plasmid into bacteria for propagation D) Purify the plasmid DNA E) To the plasmid DNA, add RNA polymerase and substrates for mRNA F) Purify the mRNA G) Encase mRNA in a lipid nanodrop
Staphylokinase is very similar to a protein called Streptokinase, which is isolated from a bacterium (Streptococcus) that is a relative of Staphylococcus. By analogy to Staphylokinase, Streptokinase (multiple correct answers) A) Binds to plasminogen B) Converts Plasminogen to an inactive form C) Is sometimes prescribed to patients that have excessive blot clotting in an effort to disrupt blood clots D) Might plausibly help Streptococcus to protect itself from neutrophils and macrophages by walling itself off from them
A) Binds to plasminogen C) Is sometimes prescribed to patients that have excessive blot clotting in an effort to disrupt blood clots
The CHIPS protein of S. aureus (multiple correct answers) A) Blocks binding of C5a to the C5a receptor B) Blocks binding of F-met-peptides to the Fmet-peptide receptor C) Releases Protein A from the bacterial envelope D) Directly blocks extravasation of neutrophils from the capillaries E) Forms pores in the membranes of neutrophils.
A) Blocks binding of C5a to the C5a receptor B) Blocks binding of F-met-peptides to the Fmet-peptide receptor
Natural substrates of Pla include (multiple correct answers) A) Blood clotting enzymes B) Streptokinase C) Antimicrobial peptides (i.E) defensins) D) Complement 3b E) Coagulase F) Actin G) All of the above.
A) Blood clotting enzymes C) Antimicrobial peptides (i.E) defensins) D) Complement 3b
Which bacteria are depicted in the powerpoint as causing elevated levels of cAMP? (multiple correct answers) A) Bordetella pertussis (via pertussis toxin) B) Bordetella pertussis (via adenylate cyclase toxin) C) Vibrio cholerae D) Mycobacterium tuberculosis E) Staphylococcus aureus F) Yersinia pestis
A) Bordetella pertussis (via pertussis toxin) B) Bordetella pertussis (via adenylate cyclase toxin) C) Vibrio cholerae D) Mycobacterium tuberculosis
Hemolysins (multiple correct answers) A) Can cause lysis of red blood cells that are embedded in agar B) Evolved specifically to lysis red blood cells C) Assemble into a multiprotein complex on the membrane of host cells and then form a pore D) Are vaguely reminiscent of a variety of proteins that can form pores in membranes, including defensins, membrane attack complex (MAC), gramicidin, and polymyxins.
A) Can cause lysis of red blood cells that are embedded in agar C) Assemble into a multiprotein complex on the membrane of host cells and then form a pore D) Are vaguely reminiscent of a variety of proteins that can form pores in membranes, including defensins, membrane attack complex (MAC), gramicidin, and polymyxins.
Harvoni (multiple correct answers) A) Contains two antivirals, Sofosbuvir and Ledipasvir B) Contains an analog of ATP C) Might plausibly be effective against yellow fever D) Blocks the addition of a cap to progeny viruses E) Costs $94,000 for a complete course F) Can be purchased from the internet for $1300
A) Contains two antivirals, Sofosbuvir and Ledipasvir C) Might plausibly be effective against yellow fever E) Costs $94,000 for a complete course F) Can be purchased from the internet for $1300
Cyclic-di-GMP (multiple correct answers) A) Contains two molecules of guanine. B) Contains two molecules of ribose. C) Contains two molecules of sulfate. D) Is destroyed by enzymes called diguanylate cyclases. E) Is synthesized by enzymes called phosphodiesterases. F) At high levels, causes cells to adopt a motile lifestyle. G) At high levels, causes cells to adopt a sessile (non-motile) lifestyle.
A) Contains two molecules of guanine. B) Contains two molecules of ribose. G) At high levels, causes cells to adopt a sessile (non-motile) lifestyle.
Rhinovirus inhibits the synthesis of host proteins by (multiple correct answers) A) Destroying proteins that are required for CAP-dependent translation initiation B) Destroying host Capping enzymes C) Destroying host mRNA D) Destroying host DNA E) Destroying host ribosomes. F) Blocking the function of nuclear pores that normally allow host mRNA to enter the cytoplasm
A) Destroying proteins that are required for CAP-dependent translation initiation F) Blocking the function of nuclear pores that normally allow host mRNA to enter the cytoplasm
In the Rapid Diagnostic Test, which antibodies bind to Plasmodium falciparum proteins (multiple correct answers)? A) Detecting antibody B) Capture antibody C) Control antibody D) All of the above E) None of the above
A) Detecting antibody B) Capture antibody
Of the following, which is detectable earliest? Which would be detectable last? (multiple correct answers) A) HIV RNA in plasma (first) B) HIV proviral DNA in PBMCs (peripheral blood mononuclear cells, also known as monocytes) C) HIV proteins D) Anti-HIV IgM E) Anti-HIV IgG (last)
A) HIV RNA in plasma (first) D) Anti-HIV IgM E) Anti-HIV IgG (last)
Synthesis of measles virus proteins requires mRNA that (multiple correct answers) A) Has a Cap made by the viral L protein B) Has a Cap that is made by host capping enzymes C) Has a Cap that is "snatched" from host mRNA's D) Has an IRES and no Cap. E) Has a long poly-A tail made by transcript slippage
A) Has a Cap made by the viral L protein E) Has a long poly-A tail made by transcript slippage
Members of the herpes family of viruses (multiple correct answers) A) Have DNA genomes B) Are naked C) Have 100-160 kilobases of nucleic acid D) Include a virus that causes smallpox E) Include a virus that cause mononucleosis ("mono" or "kissing disease") F) Include a virus that causes genital infections that can be sexually acquired
A) Have DNA genomes C) Have 100-160 kilobases of nucleic acid E) Include a virus that cause mononucleosis ("mono" or "kissing disease") F) Include a virus that causes genital infections that can be sexually acquired
Nucleoside Analog Reverse Transcriptase Inhibitors (multiple correct answers) A) Have a nitrogenous base identical or similar to adenine, guanine, cytosine, or thymine B) Are converted to a triphosphate by host cells C) Can be incorporated by reverse transcriptase into a growing DNA polymer D) Have a ribose analog that is incompatible with further chain elongation E) Can be removed from the DNA polymer by the RNase H activity of Reverse Transcriptase.
A) Have a nitrogenous base identical or similar to adenine, guanine, cytosine, or thymine B) Are converted to a triphosphate by host cells C) Can be incorporated by reverse transcriptase into a growing DNA polymer D) Have a ribose analog that is incompatible with further chain elongation
Which Influenza proteins are found at least partly on the surface of the virus particle? A) Hemagglutinin B) Matrix C) M2 D) Neuraminidase E) NP F) NS1 G) NEP H) Polymerase acidic I) Polymerase basic 1 J) Polymerase basic 2
A) Hemagglutinin C) M2 D) Neuraminidase
The fact that the H5N1 influenza virus binds preferentially to 2-3 sialic acids makes the H5N1 bind only in the lower respiratory tract of humans, making these viruses (multiple correct answers) A) Highly lethal but poorly contagious B) Seldom lethal but poorly contagious C) Highly lethal and highly contagious D) Seldom lethal and highly contagious E) Evolvable by antigenic drift to a highly lethal and highly contagious form that binds both 2-3 and 2-6 sialic acids.
A) Highly lethal but poorly contagious E) Evolvable by antigenic drift to a highly lethal and highly contagious form that binds both 2-3 and 2-6 sialic acids.
Herd Immunity could provide some protection against (multiple correct answers) A) Influenza virus B) Measles virus C) Whooping cough, caused by a contagious bacterium, Bordetella pertussis D) Chicken pox virus E) Tetanus, a noncontagious disease that is caused by the soil bacterium Clostridium tetani.
A) Influenza virus B) Measles virus C) Whooping cough, caused by a contagious bacterium, Bordetella pertussis D) Chicken pox virus
Most viral genomes include encode proteins that are required for replication of viral nucleic acid. Which of the following ALSO contain the replicase protein in the virus particle? A) Influenza virus B) Measles virus C) Rhinovirus D) Ebola Virus E) Polio virus F) Coronaviruses
A) Influenza virus B) Measles virus D) Ebola Virus
Preventative measures against malaria include which of the following (multiple correct answers) A) Insect netting B) Spraying with DDT C) Draining stagnant pools of water D) Removing alternative mammalian hosts
A) Insect netting B) Spraying with DDT C) Draining stagnant pools of water
Measles Virus (multiple correct answers) A) Is Enveloped B) Is Naked C) Is (+) stranded D) Is (-) stranded E) Virion contains RNA F) Virus infection cycle closely resembles that of Poliovirus G) Virus infection cycle closely resembles that of Ebolavirus H) Has one nucleic acid strand per virion I) Has multiple nucleic acids strands per virion
A) Is Enveloped D) Is (-) stranded E) Virion contains RNA G) Virus infection cycle closely resembles that of Ebolavirus H) Has one nucleic acid strand per virion
Coagulase (multiple correct answers) A) Is made early in infection B) Is made late in infection C) Stimulates blood clotting D) Stimulates fibrinolysis E) Binds to Prothrombin and converts it to an active form F) Binds to Plasminogen and converts it to an active form G) Directly converts fibrinogen into fibrin
A) Is made early in infection C) Stimulates blood clotting E) Binds to Prothrombin and converts it to an active form
One of the leading candidates for an Ebola vaccine is called VSV-Zebov. Which of the follow statements are correct? (multiple correct answers) A) It contains the GP protein of the Zaire strain of Ebola B) The VSV virus is related to Vaccinia virus C) Native VSV is well tolerated in humans, though it can cause temporary flu-like symptoms D) VSV-Zebov might be poorly tolerated in severely immunocompromised individuals, as it is a viable virus that can replicate in humans E) VSV-Zebov might be predicted to stimulate a strong cellular immunity.
A) It contains the GP protein of the Zaire strain of Ebola C) Native VSV is well tolerated in humans, though it can cause temporary flu-like symptoms D) VSV-Zebov might be poorly tolerated in severely immunocompromised individuals, as it is a viable virus that can replicate in humans E) VSV-Zebov might be predicted to stimulate a strong cellular immunity.
Which of the following statements about HIV integrase are correct (multiple correct answers) A) It is encoded by HIV B) It is found in the shorter of the two polyproteins C) Its proteolytic activity is present even before it has excised from its polyprotein. D) It causes HIV integration as a specific site of the human genome. E) It can mediate excision from the genome.
A) It is encoded by HIV C) Its proteolytic activity is present even before it has excised from its polyprotein.
Which of the following proteins is created by digestion by HIV protease (multiple correct answers)? A) MA B) CA C) NC D) PR E) RT F) IN G) SU H) TM
A) MA B) CA C) NC D) PR E) RT F) IN
What factors caused the pandemic to end abruptly in 1919? (multiple correct answers) A) Many had survived an infection and had strong immunity B) Those with strong immunity protected their neighbors by herd immunity C) Immune mothers may have protected their infants by donating maternal antibodies against influenza D) The viruses evolved to a more benign form. E) Cessation of hostilities
A) Many had survived an infection and had strong immunity B) Those with strong immunity protected their neighbors by herd immunity C) Immune mothers may have protected their infants by donating maternal antibodies against influenza E) Cessation of hostilities
In examining large numbers of S. aureus isolates from hospital patients, it has been found that most isolates encode only a subset of the toxins, adhesins, and other proteins that are important in host colonization. The genes encoding these proteins (multiple correct answers) A) Might plausibly be carried on lysogenic bacteriophage B) Might plausibly be carried on plasmids C) Might plausibly be carried on genomic islands D) Should be considered part of the core gene pool (as described at the beginning of handout #2) E) Should be considered part of the flexible gene pool (sometimes called the "pan genome")
A) Might plausibly be carried on lysogenic bacteriophage B) Might plausibly be carried on plasmids C) Might plausibly be carried on genomic islands E) Should be considered part of the flexible gene pool (sometimes called the "pan genome")
Which of the following is true of Type IV pili (circle all correct answers)? A) Pilus subunits are assembled and disassembled at the inner membrane B) Pilus subunits are assembled and disassembled at the outer membrane C) Assembly and disassembly are driven by hydrolysis of NTP (ATP, GTP, etc) D) Assembly and disassembly requires periplasmic chaperones. E) Can pull a cell across a solid surface.
A) Pilus subunits are assembled and disassembled at the inner membrane C) Assembly and disassembly are driven by hydrolysis of NTP (ATP, GTP, etc) E) Can pull a cell across a solid surface.
What major virulence genes were acquired by Y. pseudotuberculosis as it evolved into Y. pestis (multiple correct answers) A) Pla B) YopH C) Ycs genes D) Murine toxin E) F1 pilus (encoded by caf genes)
A) Pla D) Murine toxin E) F1 pilus (encoded by caf genes)
Which of the following proteins are covalently bound to peptidoglycan via sortase? (multiple correct answers) A) Protein A B) Pili C) Elastin-binding protein D) Collagen-binding protein E) Fibronectin-binding protein F) Enterotoxin B G) TSST-1 H) Alpha Toxin
A) Protein A B) Pili C) Elastin-binding protein D) Collagen-binding protein E) Fibronectin-binding protein
Antimalarial medicines include (multiple correct answers). A) Quinine B) DDT C) Chlorquinine D) Artemisinin E) Bacitracin
A) Quinine C) Chlorquinine D) Artemisinin
One of Robert Koch's significant achievements is to develop strategies to isolate pure clones of bacteria Which of the following approaches did he try? (multiple correct answers) A) Repeated subculturing of single bacteria into the clear fluid from an ox eye B) Streaking bacteria against the surface of a sterile, sliced potato C) Streaking bacteria across a petri dish that contained medium solidified with gelatin D) Streaking bacteria across a petri dish that contained medium solidified with agar. E) Requesting strains from the American Type Culture Collection
A) Repeated subculturing of single bacteria into the clear fluid from an ox eye B) Streaking bacteria against the surface of a sterile, sliced potato C) Streaking bacteria across a petri dish that contained medium solidified with gelatin D) Streaking bacteria across a petri dish that contained medium solidified with agar.
Which of the following statements about coronavirus protein expression is accurate? (multiple correct answers) A) Some ribosomes that start synthesizing protein at "ns1" synthesize a polyprotein whose digestion yields approximately 10 mature proteins B) Some ribosomes that start synthesizing protein at "ns1" make a longer polyprotein whose digestion yields approximately 15 mature proteins. C) This longer polyprotein requires a -1 frameshift in the translation of the mRNA. D) This -1 frameshift occurs directly upstream of the RdRp gene. E) This frameshift requires a folded mRNA structure called a "pseudoknot" in the mRNA directly downstream of the frameshift. F) This frameshift ensures that more RdRp (RNA dependent RNA polymerase) is synthesized than either of the two proteases.
A) Some ribosomes that start synthesizing protein at "ns1" synthesize a polyprotein whose digestion yields approximately 10 mature proteins B) Some ribosomes that start synthesizing protein at "ns1" make a longer polyprotein whose digestion yields approximately 15 mature proteins. C) This longer polyprotein requires a -1 frameshift in the translation of the mRNA. D) This -1 frameshift occurs directly upstream of the RdRp gene. E) This frameshift requires a folded mRNA structure called a "pseudoknot" in the mRNA directly downstream of the frameshift.
What factors might cause the contagiousness of a pathogen to decrease over the course of an epidemic? (multiple correct answers) A) Survivors become immune and therefore are not infectious B) Evolution of the pathogen to a more benign form C) Vaccines or antiviral medications may decrease transmission D) Quarantining of the sick E) Tendency of healthy individuals to minimize human contact
A) Survivors become immune and therefore are not infectious C) Vaccines or antiviral medications may decrease transmission D) Quarantining of the sick E) Tendency of healthy individuals to minimize human contact
Reverse transcriptase A) Synthesizes DNA B) Synthesizes RNA C) If provided with a (+) stranded molecule, will synthesize the (-) strand D) If provided with a (+) stranded molecule, will synthesize the (+) strand E) Requires rNTPs for substrates F) Requires dNTPs for substrates. G) Generates pyrophosphate as a side product.
A) Synthesizes DNA C) If provided with a (+) stranded molecule, will synthesize the (-) strand F) Requires dNTPs for substrates. G) Generates pyrophosphate as a side product.
Which of the following statements about the Spike protein are correct? (multiple correct answers) A) The 2003 strain of SARS has a monobasic cleavage site. B) The monobasic cleavage site is cleaved during entry of the virus into the host cell. C) SARS-CoV-2 has a polybasic cleavage site. D) The polybasic cleavage site is cleaved by furin before viruses are released from the infected host cell. E) The monobasic cleavage site is reminiscent of the hemagglutinin cleavage site of the most contagious strains of influenza.
A) The 2003 strain of SARS has a monobasic cleavage site. B) The monobasic cleavage site is cleaved during entry of the virus into the host cell. C) SARS-CoV-2 has a polybasic cleavage site. D) The polybasic cleavage site is cleaved by furin before viruses are released from the infected host cell.
Expression of the vanH vanA vanX and vanY genes are regulated by (multiple correct answers) A) The VanS membrane-spanning sensory kinase B) A vancomycin-detecting riboswitch C) The VanR response regulator D) A vancomyin-detecting transcriptional repressor
A) The VanS membrane-spanning sensory kinase C) The VanR response regulator
Protein A can be either covalently bound to the bacterial peptidoglycan or can be released into the cell supernatant. What causes a portion of Protein A to be released from the cell surface? (multiple correct answers) A) The stop-transfer sequences sometimes fail to stop secretion of the protein. In this case, the C terminus of the protein is intact and unprocessed by sortase B) The mRNA of protein A can be spliced in two different ways, one of which encodes a secreted protein that lacks the stop-transfer sequencE) C) In some cases, the sortase-Protein A bond is stable and resistant to attack by Lipid II. D) In some cases, the sortase-protein A bond is attacked by a pentapeptide that is not bound to lipid II. E) Protein A that is covalently attached to peptidoglycan can be released by cell wall hydrolytic enzymes. In this case the protein has cell wall fragments attached to it.
A) The stop-transfer sequences sometimes fail to stop secretion of the protein. In this case, the C terminus of the protein is intact and unprocessed by sortase E) Protein A that is covalently attached to peptidoglycan can be released by cell wall hydrolytic enzymes. In this case the protein has cell wall fragments attached to it.
Which of the following has been used to suppress overactive immune systems (multiple correct answers) A) Tocilizumab B) REGN10987 C) Ebselen D) Remdesivir E) Dexamethasone F) REGN10933
A) Tocilizumab E) Dexamethasone
Yersinia survive within macrophages by (multiple correct answers) A) Upregulating their iron-uptake systems B) Using Pla to destroy defensins (also known as antimicrobial peptides, AMPS) C) Blocking fusion between phagosomes and lysosomes D) Escaping from the phagosome into the host cell cytoplasm E) Using enzymes such as superoxide dismutase and catalase to detoxify reactive oxygen species.
A) Upregulating their iron-uptake systems B) Using Pla to destroy defensins (also known as antimicrobial peptides, AMPS) E) Using enzymes such as superoxide dismutase and catalase to detoxify reactive oxygen species.
Soluble Protein A can bind to B cell receptors causing a capping reaction that leads to Proliferation Differentiation into plasma cells and memory cells Excessive release of cytokines A and B A, B, and C.
A, B, and C.
Bacterial plasmids (multiple correct answers) A. Are usually double-strand circular DNA molecules B. Are found in all bacteria C. Are never essential for host cell survival D. Sometimes have genes that confer useful new phenotypes E. Sometimes transfer copies of themselves to recipient bacterial cells via conjugative transfer
A. Are usually double-strand circular DNA molecules C. Are never essential for host cell survival D. Sometimes have genes that confer useful new phenotypes E. Sometimes transfer copies of themselves to recipient bacterial cells via conjugative transfer
Heliobacter pylori (multiple correct answers) A. Colonizes the human stomach B. Colonizes 50% of humanity C. Can survive at pH=1 D. Can cause ulcers and gastric cancer E. Is harmless to most people F. Is an example of a "commensal pathogen" a microbe that can be harmless or can be harmful, depending on many factors
A. Colonizes the human stomach B. Colonizes 50% of humanity C. Can survive at pH=1 D. Can cause ulcers and gastric cancer E. Is harmless to most people F. Is an example of a "commensal pathogen" a microbe that can be harmless or can be harmful, depending on many factors
Which of the following is true about conjugative DNA transfer? (multiple correct answers) A. Conjugal donors make a plasmid-encoded conjugal pilus B. Conjugal pili can bind to recipient cells and retract, drawing the donor and recipient C. A protein called a "relaxosome" binds to a DNA site called the oriT (origin or transfer) D. Relaxosome cuts one strand of the oriT and remains bound to the 5' end of the cut DNA E. Relaxosome moves into the recipient cell, dragging DNA behind it F. As the DNA leaves the donors cell, it is replaced by new DNA synthesis G. The DNA entering the recipient cells serves H. During conjugation both DNA strands leaves the donor cell, causing it to lose the plasmid
A. Conjugal donors make a plasmid-encoded conjugal pilus B. Conjugal pili can bind to recipient cells and retract, drawing the donor and recipient C. A protein called a "relaxosome" binds to a DNA site called the oriT (origin or transfer) D. Relaxosome cuts one strand of the oriT and remains bound to the 5' end of the cut DNA E. Relaxosome moves into the recipient cell, dragging DNA behind it F. As the DNA leaves the donors cell, it is replaced by new DNA synthesis G. The DNA entering the recipient cells serves
As you know, the spike protein is cleaved into two fragments, S1 and S2. Which fragment contains each of the following? (indicate by writing "S1" or "S2" next to each answer) A. Cytoplasmic Domain B. Receptor binding motif C. fusion peptide D. Transmembrane domain E. Signal sequence (before removal) F. receptor binding domain
A. Cytoplasmic Domain--> S2 B. Receptor binding motif --> S1 C. fusion peptide--> S2 D. Transmembrane domain --> S2 E. Signal sequence (before removal)--> S1 F. receptor binding domain --> S1
As you know, hemagglutinin is cleaved into two fragments, HA1 and HA2. Which fragment contains each of the following? (indicate by writing "HA1" or "HA2" next to each answer) A. Cytoplasmic domain B. Sialic acid binding site C. Fusion peptide D. Transmembrane domain E. Signal sequence (before removal)
A. Cytoplasmic domain--> HA2 B. Sialic acid binding site--> HA1 C. Fusion peptide--> HA2 D. Transmembrane domain--> HA2 E. Signal sequence (before removal)--> HA1
"Degranulation" refers to (multiple correct answers) A. Fusion of intracellular vesicles with the cytoplasmic membrane of neutrophils (and other cell types) B. Release of proteases C. Release of Lysozyme D. Release of defensins E. Release of enzymes that synthesize reactive oxygen species F. Release of nuclear DNA to trap the microbes
A. Fusion of intracellular vesicles with the cytoplasmic membrane of neutrophils (and other cell types) B. Release of proteases C. Release of Lysozyme D. Release of defensins E. Release of enzymes that synthesize reactive oxygen species
C3a and/or C5a (multiple correct answers) A. Increase the permeability of blood vessels B. Inhibit the release of proteins of the immune system such as IgG, IgM, and complement C. Allow the migration of neutrophils and macrophages from blood vessels into the site of infections D. Increase the ability of macrophages to engulf pathogens E. Are created by methylation of the complement proteins C3 and C5
A. Increase the permeability of blood vessels C. Allow the migration of neutrophils and macrophages from blood vessels into the site of infections D. Increase the ability of macrophages to engulf pathogens
Pyrophosphate (multiple correct answers) A. Is synthesized during DNA synthesis B. Is synthesized during RNA synthesis C. Is converted to two phosphate molecules by the enzyme pyrophosphatase D. If allowed to accumulate, could cause DNA polymerase to remove bases from an elongating RNA polymer E. If allowed to accumulate, could cause DNA polymerase to remove bases from an elongating DNA polymer
A. Is synthesized during DNA synthesis B. Is synthesized during RNA synthesis C. Is converted to two phosphate molecules by the enzyme pyrophosphatase D. If allowed to accumulate, could cause DNA polymerase to remove bases from an elongating RNA polymer E. If allowed to accumulate, could cause DNA polymerase to remove bases from an elongating DNA polymer
What events occur before a neutrophil reaches the site of infection (multiple correct answers) A. It detects proinflammatory cytokines B. It binds to proteins such a V-CAM-1 AND I-CAM-1 and selectins C. It undergoes extravasation D. It detects f-Met peptides E. It travels along an increasing gradient of chemokines
A. It detects proinflammatory cytokines B. It binds to proteins such a V-CAM-1 AND I-CAM-1 and selectins C. It undergoes extravasation D. It detects f-Met peptides E. It travels along an increasing gradient of chemokines
What are the three main goals of the complement system? (multiple correct answers) A. Opsonize the microbe (ie) coat its surface with a protein to facilitate phagocytosis by macrophages B. Decorate the surface of a microbe with C3a so that macrophages avoid phagocytosing them C. Assemble a membrane attack complex D. Recruit macromolecules and cells of the immune system to the site of the infection E. Kill host cells that have been infected or are cancerous F. Destroy and dispose of unneeded C3 and C5 by proteolysis
A. Opsonize the microbe (ie) coat its surface with a protein to facilitate phagocytosis by macrophages C. Assemble a membrane attack complex D. Recruit macromolecules and cells of the immune system to the site of the infection
Homology-dependent recombination requires (multiple correct answers) A. RecA, RecB, RecC, RecD, and a number of other host-encoded proteins B. An integrase protein C. At least 300 nucleotide pairs of "homologous" DNA D. AttP and AttB sites
A. RecA, RecB, RecC, RecD, and a number of other host-encoded proteins C. At least 300 nucleotide pairs of "homologous" DNA
Which of the following describes the SARS-CoV-2 coronavirus? A. Spherical B. Filamentous C. Enveloped D. Naked E. Genome RNA F. Genomic DNA G. Genome double-stranded H. Genome (+) single-stranded I. Genome (-) single-stranded
A. Spherical C. Enveloped E. Genome RNA H. Genome (+) single-stranded
Which of the following accurately describes proteins that are exported from the cell by a Type 2 mechanism? (multiple correct answers) A. These proteins are synthesized on cytoplasmic ribosomes B. They have signal sequences that are removed by the signal peptidase C. They accumulate transiently in the periplasm D. They have domain that forms a pore (or "beta barrel") in the outer membrane E. They cross the outer membrane via a complex of proteins that act by a piston-like mechanism that requires polymerization and depolymerization F. The "linker" and "passenger" exits from the periplasm through the pore G. Some "passengers" are released by proteolysis, while some members of this family are not released and reside stably on the outer face of the outer membrane
A. These proteins are synthesized on cytoplasmic ribosomes B. They have signal sequences that are removed by the signal peptidase C. They accumulate transiently in the periplasm E. They cross the outer membrane via a complex of proteins that act by a piston-like mechanism that requires polymerization and depolymerization
Which of the following statements about defensins are correct? (multiple correct answers) A. They are produced by skin, GI-tract, white blood cells and lung epithelial cells B. They form channels in bacterial cytoplasmic membranes, ultimately killing the bacterial cell C. The transmembrane electrical potential allows defensins to penetrate and kill cells D. Like antibodies, each defensin is highly specific and can attack only a narrow range of bacteria E. Variation in defensins produced by different animals partially explains the varying susceptibility of these animals to pathogens
A. They are produced by skin, GI-tract, white blood cells and lung epithelial cells B. They form channels in bacterial cytoplasmic membranes, ultimately killing the bacterial cell C. The transmembrane electrical potential allows defensins to penetrate and kill cells E. Variation in defensins produced by different animals partially explains the varying susceptibility of these animals to pathogens
Lysozyme (multiple correct answers) A. can hydrolyze peptidoglycan and chitin B. can hydrolyze cellulose C. is found in extracellular secretions including tears and breast milk D. is found in lysosomes and phagolysosomes E. cannot readily pass through the outer membrane of proteobacteria F. was discovered by Alexander Fleming, who later discovered penicillin
A. can hydrolyze peptidoglycan and chitin C. is found in extracellular secretions including tears and breast milk D. is found in lysosomes and phagolysosomes E. cannot readily pass through the outer membrane of proteobacteria F. was discovered by Alexander Fleming, who later discovered penicillin
fMLF (multiple correct answers) A. is an abbreviation for N-formyl-Met-Leu-Phe B. is a MAMP (or PAMP) and a DAMP C. contains formyl-Methionine, which is the first amino acid of all bacterial and mitochondrial proteins D. must contain Leu and Phe to be active E. is detected by formyl-peptide receptors (FPR)
A. is an abbreviation for N-formyl-Met-Leu-Phe B. is a MAMP (or PAMP) and a DAMP C. contains formyl-Methionine, which is the first amino acid of all bacterial and mitochondrial proteins E. is detected by formyl-peptide receptors (FPR)
We learned about two types of electron microscopy, transmission EM and scanning EM. Which of these creates images that most closely resemble atomic force micrographs? Explain your answer.
AFM creates images of the surface topology of a sample. SEM creates an image of the outer surface of a sample, while TEM creates images of cross sections of a sample. AFM is therefore more similar to SEM than to TEM.
Mycobacterium tuberculosis is a member of the Gammaproteobacteria Betaproteobacteria Firmicutes Actinobacteria Bacterioidetes
Actinobacteria
Defensins are converted to an __ form by ___ Inactive, proteolysis Active, phosphorylation Inactive, acylation Active, proteolysis Inactive, binding bacterial LPS
Active, proteolysis
Which portion of NAD does pertussis toxin transfer to a host G protein? Adenine Adenine + ribose Adenine + ribose + phosphate Adenine + ribose + phosphate + phosphate Adenine + ribose + phosphate + phosphate + ribose Adenine + ribose + phosphate + phosphate + ribose + nicotinamide
Adenine + ribose + phosphate + phosphate + ribose
Which RNA strands are identical in all vaccine strains? None All but H and N All but H All but N All but H, N, and M All but H, N and PB
All but H and N
Which of the following influenza RNA fragments of the Spanish flu strain are thought to contribute to its enhanced pathogenicity? (multiple correct answers) A. PB1 B. PB2 C. PA D. HA E. NA F. NP G. M H. NS
All of the above
In 2009, a new influenza virus appeared and evolved by antigenic shift. Its eight fragments can ultimately be traced back to H1N1 Eurasian "Avian-like" swine virus H1N1 Classical swine virus H1N1 Avian virus H3N2 seasonal human virus A and C B and D A, B and D All of the above.
All of the above.
Injection of convalescent serum into a patient is An example of natural active immunity An example of natural passive immunity An example of artificial active immunity An example of artificial passive immunity
An example of artificial passive immunity
Injection of monoclonal antibodies into a patient is An example of natural active immunity An example of natural passive immunity An example of artificial active immunity An example of artificial passive immunity
An example of artificial passive immunity
Pertussis toxin modifies __ by addition of ___, causing ____ An inhibitory G protein, ADP-ribose, elevated cAMP. An inhibitory G protein, AMP, elevated cAMP. An inhibitory G protein, NAD, elevated cAMP. An inhibitory G protein, ADP-ribose, decreased cAMP. A stimulatory G protein, ADP-ribose, elevated cAMP. A stimulatory G protein, AMP, elevated cAMP. A stimulatory G protein, NAD, elevated cAMP. A stimulatory G protein, ADP-ribose, decreased cAMP.
An inhibitory G protein, ADP-ribose, elevated cAMP.
Malcolm Casadaban, a professor of genetics at the University of Chicago, died in 2011 after a laboratory-acquired infection of Yersinia pestis. This laboratory strain was supposedly rendered safe by to a mutation in _. Casadaban had an undiagnosed genetic anomaly called hemachromatosis, which causes _. An iron uptake system, elevated iron levels in blood and lymph. An iron efflux system, hypoferemia A manganese uptake system, anemia An iron efflux system, anemia A manganese uptake system, elevated iron levels in blood and lymph.
An iron uptake system, elevated iron levels in blood and lymph.
The "sandwich Elisa" used to test for TB requires immobilized IFN gamma Anti-IFN gamma antibodies Chromogenic enzyme ESAT4 CFP10 Anti ESAT4 antibodies Anti CFP4 antibodies
Anti-IFN gamma antibodies
Flaviviruses Have DNA genomes Have (-) stranded genomes Are filamentous Are Naked Are named for the "yellow" in yellow fever. Include yellow fever virus and poliovirus
Are named for the "yellow" in yellow fever.
Use of REGN-CoV2 antibodies is an example of Natural Active Immunity Natural Passive Immunity Artificial Active Immunity Artificial Passive Immunity
Artificial Passive Immunity
We mentioned in class that in 1895 diphtheria toxoid was injected into a horse, and the resulting anti-toxoid antibodies were purified and injected into diphtheria patients. It is now possible to destroy all of the B cells and T cells in a cow, then repopulate that cow with human B cells and T cells, then inject an antigen such as diphtheria toxoid into this poor cow, and later purify human antibodies for use in the clinic. If that cow were subsequently exposed to diphtheria toxin and was protected by these antibodies, this would be an example of A. Natural active immunity B. Natural passive immunity C. Artificial active immunity D. Artificial passive immunity
Artificial active immunity Artificial passive immunity
We mentioned in class that in 1895 diphtheria toxoid was injected into a horse, and the resulting anti-toxoid antibodies were purified and injected into diphtheria patients. It is now possible to destroy all the B cells and T cells in a cow, then repopulate that cow with human B cells and T cells, then inject an antigen such as diphtheria toxoid into this poor cow, and later purify human antibodies for use in the clinic. The use of these antibodies in the clinic would be an example of A. Natural active immunity B. Natural passive immunity C. Artificial active immunity D. Artificial passive immunity
Artificial passive immunity
What is the name of the DNA sequence on the viral genome that is required for integration into the host genome? AttP AttB AttL AttR Cos
Attp
Which types of cells display antigens complexed with MHC class II? (multiple correct answers) A. B cells B. Helper T cells C. Cytotoxic T cells D. Macrophages E. Dendritic cells F. Natural Killer cells G. Cells that have been infected by a virus
B cells Macrophages Dendritic cells
Recombination of V, D, and J regions occurs only in __ cells ______ B cells, in early development of the individual T cells, during infection Macrophages, in early development of the individual B cells, during infection Germ line cells, in early development of the individual
B cells, in early development of the individual
Bordetella pertussis is a member of the (multiple correct answers) A) Alphaproteobacteria B) Betaproteobacteria C) Vibrionales D) "gram negative" E) Firmicutes F) Proteobacteria
B) Betaproteobacteria D) "gram negative" F) Proteobacteria
The standard test for infection is to look for anti-Herpes antibodies in the blood. This test (multiple correct answers) A) Requires a heat-stable DNA polymerase and a thermocycler. B) Can distinguish Herpes type I from Herpes type 2 C) Can distinguish a genital infection from an oral infection D) Requires an herpes protein antigen that is immobilized on a plastic surface or a test stript E) Requires a secondary antibody that will bind to all human antibodies and contains an enzyme that can catalyze a chromogenic (color) reaction or a gold particle.
B) Can distinguish Herpes type I from Herpes type 2 D) Requires an herpes protein antigen that is immobilized on a plastic surface or a test stript E) Requires a secondary antibody that will bind to all human antibodies and contains an enzyme that can catalyze a chromogenic (color) reaction or a gold particle.
In the Rapid Diagnostic Test, which antibodies are immobilized (multiple correct answers)? A) Detecting antibody B) Capture antibody C) Control antibody D) All of the above E) None of the above
B) Capture antibody C) Control antibody
Oral polio vaccine (multiple correct answers) A) Was developed by Jonas Salk, who had a lifelong antipathy toward Albert Sabin. B) Consists of a live attenuated polio virus with an adenine residue at position 480 altered to a guanine C) Mimics a polio infection better than the earlier vaccine and therefore is more effective D) Can mutate back to the original fully virulent polio strain E) Is responsible for a small number of cases of vaccine-derived paralytic polio (VDPP). F) Is responsible for the elimination of wild type polio from all but two countries.
B) Consists of a live attenuated polio virus with an adenine residue at position 480 altered to a guanine C) Mimics a polio infection better than the earlier vaccine and therefore is more effective D) Can mutate back to the original fully virulent polio strain E) Is responsible for a small number of cases of vaccine-derived paralytic polio (VDPP). F) Is responsible for the elimination of wild type polio from all but two countries.
Wild type Y. pseudotuberculosis (Y. tb) fails to colonize the flea midgut, while Y. pestis does. To create a strain of Y. tb that can colonize the midgut, including the proventriculus, it was necessary to (multiple correct answers) A) Delete the "murine toxin" gene ymt. B) Create a nonfunctional mutation in the rscA gene C) Create a nonfunctional mutation in the PDE2 gene D) Created a nonfunctional mutation in the PDE3 gene E) Provide the pla gene
B) Create a nonfunctional mutation in the rscA gene C) Create a nonfunctional mutation in the PDE2 gene D) Created a nonfunctional mutation in the PDE3 gene
Which of the following terms describes Coronaviruses? (multiple correct answers) A) Naked B) Enveloped C) Filamentous D) Icosohedral E) Pleiomorphic F) DNA genome G) RNA genome H) Single-stranded genome I) Double-stranded genome J) (+) stranded genome K) (-) stranded genome
B) Enveloped E) Pleiomorphic G) RNA genome H) Single-stranded genome J) (+) stranded genome
Which nucleobases can bind to remedisivir? A) A B) G C) C D) U
B) G C) C D) U
Yersinia species are members of the (multiple correct answers) A) Alphaproteobacteria B) Gammaproteobacteria C) Vibrionales D) Enterobacteriales E) Firmicutes
B) Gammaproteobacteria D) Enterobacteriales
Rhinovirus (multiple correct answers) A) Is Enveloped B) Is Naked C) Has (+) stranded nucleic acid D) Has (-) stranded nucleic acid E) Virion contains RNA. F) Virus infection cycle closely resembles that of Poliovirus G) Virus infection cycle closely resembles that of Ebolavirus H) Has one nucleic acid strand per virion I) Has multiple nucleic acids strands per virion
B) Is Naked C) Has (+) stranded nucleic acid E) Virion contains RNA. F) Virus infection cycle closely resembles that of Poliovirus H) Has one nucleic acid strand per virion
Staphylokinase (multiple correct answers) A) Is made early in infection B) Is made late in infection C) Stimulates blood clotting D) Stimulates fibrinolysis E) Binds to Prothrombin and converts it to an active form F) Binds to Plasminogen and converts it to an active form G) Directly converts fibrinogen into fibrin
B) Is made late in infection D) Stimulates fibrinolysis F) Binds to Plasminogen and converts it to an active form
All Influenza viruses (multiple correct answers) A) Packages DNA in its virion B) Packages RNA in its virion C) Packages (+) stranded nucleic acid in its virion D) Packages (-) stranded nucleic acid in its virion E) Packages double-stranded nucleic acid in its virion.
B) Packages RNA in its virion D) Packages (-) stranded nucleic acid in its virion
When influenza viruses enter endosomes of host cells, the acidic pH causes (multiple correct answers) A) Proteolysis of hemagglutinin B) Release of the sialic acid binding domain of hemagglutinin C) The conversion of two shorter alpha helices into one long alpha helix D) Exposure a previously buried fusion peptide to the endosomal membrane E) The conversion of monomers of hemagglutinin into trimers.
B) Release of the sialic acid binding domain of hemagglutinin C) The conversion of two shorter alpha helices into one long alpha helix D) Exposure a previously buried fusion peptide to the endosomal membrane
Reverse transcriptase of HIV (multiple correct answers) A) Synthesizes RNA B) Synthesizes DNA C) Synthesizes single-stranded and double-stranded nucleic acid D) Requires a tRNA primer E) Requires an rRNA primer F) Can degrade RNA in an RNA-DNA duplex G) Can degrade DNA in an RNA-DNA duplex
B) Synthesizes DNA C) Synthesizes single-stranded and double-stranded nucleic acid D) Requires a tRNA primer F) Can degrade RNA in an RNA-DNA duplex
Which of the following statements about measles virus proteins are accurate (multiple correct answers) A) All proteins are synthesized in equimolar ratios by proteolysis of a polyprotein B) The N protein is abundant due to a greater abundance of N protein mRNA C) The L protein is made a low levels due to a low abundance of the L protein mRNA D) The P, M, F, and H proteins have intermediate abundances and intermediate levels of mRNA E) The different abundances of the various mRNA is due to different rates of destruction.
B) The N protein is abundant due to a greater abundance of N protein mRNA C) The L protein is made a low levels due to a low abundance of the L protein mRNA D) The P, M, F, and H proteins have intermediate abundances and intermediate levels of mRNA
Which of the following statements about the Spike protein are accurate? (multiple correct answers) A) Four Spike submits bind together to form a tetramer. B) When first synthesized Spike has an "SP" sequence that initiates protein secretion. This SP sequence is removed during or after protein secretion. C) Spike has a "TM" sequence that stops secretion so that mature Spike spans the viral envelope. D) Approximately 40 amino acids of spike remain in the inside of the virus particle, while the rest lies in the membrane or outside the virus
B) When first synthesized Spike has an "SP" sequence that initiates protein secretion. This SP sequence is removed during or after protein secretion. C) Spike has a "TM" sequence that stops secretion so that mature Spike spans the viral envelope. D) Approximately 40 amino acids of spike remain in the inside of the virus particle, while the rest lies in the membrane or outside the virus
Interferons (multiple correct answers) A) are antibacterial agents produced by skin, GI-tract, and lung cells B) are secreted by eukaryotic cells in response to intracellular infection C) are only produced by activated phagocytes D) are host-specific and virus-specific E) can block bacterial replication F) warn nearby cells of a viral infection G) cause nearby cells to produce a double-strand RNase H) cause nearby cells to temporarily stop protein synthesis. I) Cause nearby infected cells to undergo apoptosis.
B) are secreted by eukaryotic cells in response to intracellular infection F) warn nearby cells of a viral infection G) cause nearby cells to produce a double-strand RNase H) cause nearby cells to temporarily stop protein synthesis. I) Cause nearby infected cells to undergo apoptosis.
Nucleoside Analog DNA synthesis inhibitors (multiple correct answers) A. Must have an OH group at the 3' position of the deoxyribose B. Could have an H group at the 3' position of the deoxyribose C. Could have an N3 (azide) group at the 3' position of the deoxyribose D. Could have a double bond between the 2' and 3' positions of the deoxyribose E. Could lack the 2' and 3' carbons of the deoxyribose
B. Could have an H group at the 3' position of the deoxyribose C. Could have an N3 (azide) group at the 3' position of the deoxyribose D. Could have a double bond between the 2' and 3' positions of the deoxyribose E. Could lack the 2' and 3' carbons of the deoxyribose
RegII-alpha is released from intestinal epithelial cells and kills bacteria that penetrate into the mucus layer that separates intestinal villi from bacteria. Bacteria are killed by a mechanism that resembles that of (multiple correct answers) A. Vancomycin B. Defensins C. Membrane Attack Complex D. Gramicidin E. Lysozyme
B. Defensins C. Membrane Attack Complex D. Gramicidin
The mucociliary escalator (or elevator) (multiple correct answers) A. Function to trap and sweep pathogens into the urine B. Has a moving conveyor belt of mucus that contains defensins and lysozyme C. Harbor normal microbiota that inhibit pathogens from colonizing D. Produce fatty acids with a low pH that kills microbes E. Trap and sweep microbes from the bronchi back up to the throat to be swallowed
B. Has a moving conveyor belt of mucus that contains defensins and lysozyme E. Trap and sweep microbes from the bronchi back up to the throat to be swallowed
Formation of an endospore by member of the firmicutes (multiple correct answers) A. Is characterized by symmetric cell division B. Is initiated by nutrient limitation and high population densities C. Requires that the mother cell engulf the forespore D. Is characterized by the disintegration of the mother cell chromosome E. Causes the lysis of the mother cell
B. Is initiated by nutrient limitation and high population densities C. Requires that the mother cell engulf the forespore D. Is characterized by the disintegration of the mother cell chromosome E. Causes the lysis of the mother cell
What sorts of genetic elements would you characterize as contributing to the "flexible gene pool" (multiple correct answers) A. The portions of chromosomes that direct fundamental and essential processes such as protein synthesis B. Lysogenic bacteriophages that integrate into the chromosomes C. Lysogenic bacteriophages that lysogenize by forming plasmids D. Conjugative plasmids E. Integrative conjugative elements F. Mobilizable genomic islands G. Transposons H. Lytic bacteriophages
B. Lysogenic bacteriophages that integrate into the chromosomes C. Lysogenic bacteriophages that lysogenize by forming plasmids D. Conjugative plasmids E. Integrative conjugative elements F. Mobilizable genomic islands G. Transposons
Which statements about Hfr strains are accurate? (multiple correct answers) A. They are formed by site-specific recombination between two copies of IS3 B. They have an entire plasmid integrated into the host chromosome C. They can initiate conjugative DNA transfer D. They transfer very large fragments of host chromosomal DNA, in principle all of it E. The chromosomal DNA that is transferred to the recipient becomes a new plasmid
B. They have an entire plasmid integrated into the host chromosome C. They can initiate conjugative DNA transfer D. They transfer very large fragments of host chromosomal DNA, in principle all of it
Robert Koch first applied Koch's postulates to which pathogen? A. Mycobacterium tuberculosis B. Bacillus anthracis C. Salmonella enterica D. Staphylococcus aureus E. Vibrio cholerae F. None of the above
Bacillus anthracis
At least one isolate of the 1918 influenza virus was able to bind both alpha2-3 and alpha2-6 sialic acids. Binding alpha2-3 sialic acids may have caused _ resulting in _, while binding alpha2-6 sialic acids may have caused _, resulting in __ Binding to cells deep in the lung/ life-threatening infections/ binding to cells in the upper respiratory tract/ high levels of contagion. Binding to cells in the upper respiratory tract/ life-threatening infections/ binding to cells deep in the lung/ high levels of contagion. Binding to cells deep in the lung/ high levels of contagion/ binding to cells in the upper respiratory tract/ life-threatening infections. Binding to binding to cells in the upper respiratory tract/ high levels of contagion/ cells deep in the lung/ life-threatening infections.
Binding to cells deep in the lung/ life-threatening infections/ binding to cells in the upper respiratory tract/ high levels of contagion.
Septicemic plague is caused by an infection of the Blood stream Lymph nodes Lungs Meninges Gastrointestinal tract
Blood stream
Salmonella species are least closely related to Escherichia coli Yersinia pestis Vibrio cholerae Pseudomonas aeruginosa Bordetella pertussis.
Bordetella pertussis
How does YopE block endocytosis of Yersinia by macrophages? By converting the GTP-bound form of several G proteins to their GDP-bound forms By cutting off the C-terminus of several G proteins, liberating them from the host membrane By converting the GDP-bound form of several G proteins to their GTP-bound forms By removing phosphate groups from phosphotyrosine-proteins By cleaving complement protein C3b
By converting the GTP-bound form of several G proteins to their GDP-bound forms
How does YopT block endocytosis of Yersinia by macrophages? By converting the GTP-bound form of several G proteins to their GDP-bound forms By cutting off the C-terminus of several G proteins, liberating them from the host membrane By converting the GDP-bound form of several G proteins to their GTP-bound forms By removing phosphate groups from phosphotyrosine-proteins By cleaving complement protein C3b
By cutting off the C-terminus of several G proteins, liberating them from the host membrane
M. tuberculosis (multiple correct answers) A) Resists phagocytosis by alveolar macrophages B) Is efficiently engulfed by intestinal macrophages C) Blocks fusion between phagosomes and lysosomes. D) Is efficiently engulfed by lung epithelial cells E) Blocks the acidification of the phagosome.
C) Blocks fusion between phagosomes and lysosomes. E) Blocks the acidification of the phagosome.
How are the nine or so proteins of HIV expressed? (multiple correct answers) A) Each is encoded by a separate RNA, as found in influenza virus B) Each is synthesized as a separate mRNA, as found in ebola and measles viruses C) Each is synthesized by alternative splicing of an RNA D) In some cases, mature proteins are made by proteolysis of a polyprotein by HIV protease E) In one case, two mature proteins are made by proteolysis of a polyprotein by the host protease furin
C) Each is synthesized by alternative splicing of an RNA D) In some cases, mature proteins are made by proteolysis of a polyprotein by HIV protease E) In one case, two mature proteins are made by proteolysis of a polyprotein by the host protease furin
Influenza virus (multiple correct answers) A) Is icosahedral B) Is filamentous C) Is sometimes referred to as pleomorphic D) Has an RNA genome E) Has a double-stranded genome F) Has a positive-stranded genome G) Has a lipid envelope H) Has Neuraminidase and Hemagglutinin proteins on its surface
C) Is sometimes referred to as pleomorphic D) Has an RNA genome G) Has a lipid envelope H) Has Neuraminidase and Hemagglutinin proteins on its surface
The 4th generation test for HIV can detect (multiple correct answers). A) HIV RNA B) HIV proviral DNA C) P24 antigen D) Anti-IgM antibodies E) Anti-IgG antibodies F) Abundance of CD4 cells. G) Anti-HIV antibodies.
C) P24 antigen G) Anti-HIV antibodies.
Synthesis of the longer gag-pol polyprotein rather than the shorter gag polyprotein (multiple correct answers) A) Requires slippage of reverse transcriptase during a run of U residues B) Requires slippage of RNA polymerase during a run of U residues C) Requires slippage of a ribosome during a run of U residues D) Occurs about 5% of the time, ensuring a ratio of 1 gag-pol polyproteins per 19 gag polyproteins E) Occurs about 5% of the time, ensuring a ratio of 1 gag polyproteins per 19 gag-pol polyproteins
C) Requires slippage of a ribosome during a run of U residues D) Occurs about 5% of the time, ensuring a ratio of 1 gag-pol polyproteins per 19 gag polyproteins
The L protein of measles virus (multiple correct answers) A) Synthesizes (+) stranded RNA from a (+) stranded template B) Synthesizes (-) stranded RNA from a (-) stranded template C) Synthesizes (+) stranded RNA from a (-) stranded template D) Synthesizes (-) stranded RNA from a (+) stranded template E) Adds a Cap to the 5' end of RNA F) Adds methyl groups to the 3' end of the RNA G) Adds a poly-A tail to the 3' ends of the RNA molecules H) Stops polymerization at the end of each gene but 70-80% remain bound, travel to the next transcription start site, and resume synthesizing RNA. I) Synthesizes more GP mRNAs than NP mRNAs (these gene names refer to Ebola virus) J) Is able to transcribe full length (+) stranded antigenomes and (-) stranded genomes that lack Caps and lack poly-A tails.
C) Synthesizes (+) stranded RNA from a (-) stranded template D) Synthesizes (-) stranded RNA from a (+) stranded template E) Adds a Cap to the 5' end of RNA G) Adds a poly-A tail to the 3' ends of the RNA molecules H) Stops polymerization at the end of each gene but 70-80% remain bound, travel to the next transcription start site, and resume synthesizing RNA. J) Is able to transcribe full length (+) stranded antigenomes and (-) stranded genomes that lack Caps and lack poly-A tails.
Pla is (multiple correct answers) A) located in the bacterial cytoplasm B) located in the bacterial periplasm C) located in the bacterial outer membrane D) Released as individual proteins to the extracellular milieu E) Some is released from the cell envelope as outer membrane vesicles.
C) located in the bacterial outer membrane E) Some is released from the cell envelope as outer membrane vesicles.
The Rous sarcoma virus causes cancer of muscle tissue in chickens. This virus (multiple correct answers) A. Contains all three of the genes found in other related viruses, including influenza virus B. Contains an extra gene called C-Src, which is not found in most related viruses C. C-Src contains several introns that are missing in V-Src D. V-Src is truncated at its carboxy terminus, causing it to be hyperactive in stimulating cell division
C-Src contains several introns that are missing in V-Src V-Src is truncated at its carboxy terminus, causing it to hyperactive in stimulating cell division
Which of the following complement proteins is converted from an inactive form to two active proteins by proteolysis? (multiple correct answers) A. C1 B. C3 C. C5 D. C6 E. C7 F. C8 G. C9
C3 C5
Which complement protein plays a role in opsonization of a microbe? A. C1b B. C2b C. C3b D. C3a E. C4b F. C5b G. C5a
C3b
Complement protein C3 is converted to two fragments by proteolysis. What are the names and functions of these fragments?
C3b optimizes the surface of the pathogen, making intensities to engulf by phagocytic cells C3a makes capillaries leak out cells and molecules needed for immunity
Acyclovir Is a protease inhibitor Can be taken orally Can be taken by injection Eradicates herpes virus Has a nitrogenous base that resembles thymine.
Can be taken orally
lipopolysaccharide (multiple correct answers) A. is found only in members of the firmicutes B. contains two fatty acids C. contains a glycerol backbone D. can be toxic, causing disseminated intravascular coagulation E. is hugely variable from strain to strain
Can be toxic, causing disseminated intravascular coagulation is hugely variable from strain to strain
Bacterial flagella A. Function in a whip-like motion, hence the name "flagellum", which is Latin for "little whip" B. Can spin like a propeller in a clockwise and counterclockwise directions C. A powered by a gradient of sodium ions across the inner membrane D. Can help pathogenic bacteria to adhere to the surface of a host cell E. Cause self-flagellation F. None of the above
Can spin like a propeller in a clockwise and counterclockwise directions
The Salmonella pathogenicity island 1 (SPI-1) Causes Salmonella to bind to the cell surface, forming a pedestal. Causes Salmonella to invade host cells by a process called membrane ruffling Prevents fusion of the Salmonella-containing vacuole with lysosomes Blocks endocytosis. Injects typhoid toxin.
Causes Salmonella to invade host cells by a process called membrane ruffling
Two revolutionary treatments for sickle cell disease are in stage III trials. One of these treatments Causes knockout mutations in the gene that causes the disease Causes knockout mutations in the gene for fetal hemoglobin Causes knockout mutations in the gene that encodes a repressor of the gene for fetal hemoglobin Introduces an altered version of the fetal hemoglobin gene None of the above
Causes knockout mutations in the gene that encodes a repressor of the gene for fetal hemoglobin
Proton transport across the cytoplasmic membrane (multiple correct answers) A. Causes the outside of the cell to become more alkaline than the inside B. Causes the outside of the cell to become more acidic than the inside C. Causes the outside of the cell to have a positive charge relative to the inside D. Causes the outside of the cell to have a negative charge relative to the inside E. Can be harness to power the rotation of flagella F. Can be harnessed to synthesize ATP
Causes the outside of the cell to become more acidic than the inside Causes the outside of the cell to have a positive charge relative to the inside Can be harnessed to power the rotation of flagella Can be harnessed to synthesize ATP
The conversion of DNA from a closed complex to an open complex by RNA A. Causes the separation of approximately 10 to 15 bases from their complementary bases on the opposite strand B. Is mediated by ribosomes C. Is necessary for the initiation of translation D. Is facilitated by the underwinding of RNA E. None of the above.
Causes the separation of approximately 10 to 15 bases from their complementary bases on the opposite strand
Capping of B-cell receptors on the surface of an antigen-exposed B cell immediately causes what to occur? VDJ gene switching, recombination, and hypermutation Neutrophil phagocytosis of the antigen Complement cascade signaling and antigen destruction Cell-signaling cascade, inducing cell proliferation and differentiation into plasma cells and memory cells. Helper T-cell proliferation and regulatory T-cell differentiation
Cell-signaling cascade, inducing cell proliferation and differentiation into plasma cells and memory cells.
Describe the stimulus that causes a cell to enter the antiviral state, and what changes occur in these cells' physiology
Cells enter an antiviral state when they detect extracellular type I interferon. This causes them to inhibit protein synthesis, and to destroy mRNA, both of which would block synthesis of viral proteins if the cell is later infected. Both inhibitions are stimulated by double-stranded RNA, a microbe-associated molecular pattern
Which type of cells display antigens complexed with MHC Class I? A. B cells B. Helper T cells C. Cytotoxic T cells D. Macrophages E. Dendritic cells F. Natural Killer Cells G. Cells that have been infected by a virus
Cells that have been infected by a virus
Enterotoxigenic E) coli causes travelers diarrhea by releasing two toxins called Heat Labile toxin (LT) and Heat Stable Toxin (ST). LT resembles _, while ST resembles a host-released peptide called __ Shiga toxin, bradykinin Diphtheria toxin, IL-2 Cholera toxin, antimicrobial peptides TSST, signal peptide. Cholera toxin, guanylin
Cholera toxin, guanylin
Autoinducing peptides (AIP) from heterologous strains of Staphylococcus inhibit expression of RNA III by Competing for binding to the AgrC kinase Dephoshorylating the AgrA response regulator Blocking the processing of the strain's AIP Breaking the thiolactone bond in the AIP Creating a pore in the cell membrane
Competing for binding to the AgrC kinase
How much the genomic (or pathogenicity) island of Listeria monocytogenes be transferred to Bacillus subtilis (multiple correct answers) A. Lysogenic conversion B. Plasmid conjugation C. Conjugation of a plasmid that has integrated into the host genome D. Generalized transduction E. Genetic transformation
Conjugation of a plasmid that has integrated into the host genome Generalized transduction Genetic transformation
Describe briefly how the mRNA that encodes the spike protein is synthesized. (50 words maximum)
Construct the spike gene as double-stranded DNA into a bacterial plasmid to be introduced to bacteria for propagation. Purify the plasmid DNA and add RNA polymerase and rNTPs. Use psuedouracil instead of uracil and then purify mRNA.
In the Rapid Diagnostic Test, which antibodies are derived from goats? Detecting antibody Capture antibody Control antibody All of the above None of the above
Control antibody
Biotin can be synthesized by many types of bacteria. As might be expected, high levels of biotin cause decreased expression of the proteins that are needed to synthesize it. This is one of countless negative feedback loops. Biotin achieves this by binding to a biotin binding protein, which in turn regulates transcription of the biotin biosynthetic operon. The biotin binding protein, in principle (multiple correct answers) A. Could be a repressor that is converted to a functional form by biotin B. Could be a repressor that is converted to a non functional form by biotin C. Could be an activator that is converted to a functional form by biotin D. Could be an activator that is converted to a nonfunctional form by biotin E. Could be a membrane-spanning protein that detects extracellular biotin and in the presence of biotin phosphorylates a cytoplasmic response regulator
Could be a repressor that is converted to a functional form by biotin Could be an activator that is converted to a nonfunctional form by biotin Could be a membrane spanning-protein that detects extracellular biotin and in the presence of biotin phosphorylates a cytoplasmic response regulator
Galactose is a nutrient that causes increased expression of the proteins that are needed to consume it. Galactose functions by binding to a galactose binding protein, which in turn regulates transcription of the galactose catabolic operon. The galactose binding protein, in principle (multiple correct answers) A. Could be a repressor that is converted to a functional form by galactose B. Could be a repressor that is converted to a nonfunctional form by galactose C. Could be an activator that is converted to a functional form by galactose D. Could be an activator that is converted to a nonfunctional form by galactose E. Could be a membrane-spanning protein that detects extracellular galactose and methylates a cytoplasmic response regulator
Could be a repressor that is converted to a nonfunctional form by galactose Could be an activator that is converted to a functional form by galactose
The Daptacel vaccine consists of six different antigens. Antibodies against which of them might actually target the bacteria themselves (multiple correct answers)? A) Diphtheria toxoid B) Tetanus toxoid C) Pertussis toxoid D) Filamentous hemagglutinin E) Pertactin F) Fimbriae.
D) Filamentous hemagglutinin E) Pertactin F) Fimbriae.
Synthesis of rhinovirus proteins requires mRNA that (multiple correct answers) A) Has a Cap made by the viral L protein B) Has a Cap that is made by host capping enzymes C) Has a Cap that is snatched from host mRNA's D) Has an IRES and no cap. E) Has a long poly-A tail
D) Has an IRES and no cap. E) Has a long poly-A tail
Which of the following statements about Mosquirix is accurate? (multiple correct answers) A) It contains live attenuated parasites B) It contains whole parasites that have been inactivated using formaldehyde C) It contains the entire circumsporozoite protein D) It contains a portion of the circumsporozoite protein E) It contains the native surface protein of the hepatitis B virus F) It contains proteins that are fusions between a portion of CSP and hepatitis B surface protein G) It contains virus-like particles containing nucleic acids H) In principle, it may likely confer immunity to Hepatitis B virus.
D) It contains a portion of the circumsporozoite protein E) It contains the native surface protein of the hepatitis B virus F) It contains proteins that are fusions between a portion of CSP and hepatitis B surface protein H) In principle, it may likely confer immunity to Hepatitis B virus.
The Gardasil 9 vaccine protects against Human Papilloma virus. Which of the following is true? (Multiple correct answers) A) It consists of nine attenuated live viruses B) It consists of the L1 and L2 capsid proteins of nine strains C) It protects against all strains of Human papilloma virus D) It protects against the nine strains that are mostly closely implicated in cervical cancer E) It elicits neutralizing antibodies against the virus F) It is effective against a strain of HPV even if administered after infection by that strain. G) If administered after infection by a strain of HPV, it is still effective against the eight other strains of HPV.
D) It protects against the nine strains that are mostly closely implicated in cervical cancer E) It elicits neutralizing antibodies against the virus G) If administered after infection by a strain of HPV, it is still effective against the eight other strains of HPV.
Which of the following proteins are synthesized on ribosomes that are associated with the endoplasmic reticulum? (multiple correct answers) A) PB1 (RNA polymerase basic 1) B) PB2 (RNA polymerase basic 2) C) PA (RNA polymerase acidic) D) NA (Neuraminidase) E) HA (Hemagglutinin) F) M1 (Matrix protein 1) G) M2 (Matrix protein 2) H) NP (Nucleocapsid protein) I) NS1 (Nonstructural protein 1) J) NS2 (Nonstructural protein 2)
D) NA (Neuraminidase) E) HA (Hemagglutinin) G) M2 (Matrix protein 2)
Clinicians can determine the nucleic acid sequence of a patient's HIV to help them prescribe the optimal antiviral medications. When doing so, which two genes are sequenced? (multiple correct answers) A) MA B) CA C) NC D) Protease E) Reverse Transcriptase F) Integrase G) Surface (component of the spike) H) Transmembrane (component of the spike) I) Tat J) Nef K) Vif L) Vpr M) Vpu
D) Protease E) Reverse Transcriptase
Cycloserine is a mimic of A. Glycine B. N-acetylglucosamine C. D-alanine D. L-alanine E. Diaminopimelic acid
D-alanine
The beta-lactam ring of penicillin(s) is a mimic of A. Glycine B. N-acetylglucosamine C. D-alanine D. L-alanine E. Diaminopimelic acid
D-alanine
Toll-like receptors (TLRs) are eukaryotic membrane proteins that (multiple correct answers) A. form channels through which bacterial proteins can enter the eukaryotic cell B. cause the cell to phagocytize the bacteria C. cause the release of antibiotics to kill the bacteria D. cause the release of cytokines that trigger host defenses against the bacteria E. activate the complement cascade F. bind bacterial and viral macromolecules G. resemble a protein found in fruit flies called "toll"
D. cause the release of cytokines that trigger host defenses against the bacteria F. bind bacterial and viral macromolecules G. resemble a protein found in fruit flies called "toll"
Which of the following antimicrobials might plausibly be present in the mucus of the mucociliary elevator of healthy individuals? Defensins Vancomycin Penicillin Bacitracin Cycloserine
Definsins
B cells expressed a membrane-bound form of IgM. How can these cells differentiate into plasma cells that express soluble (not membrane-bound) IgG molecules? (multiple correct answers) A. Random fusion of V, D, and J regions of DNA B. Random assortment of heavy and light chains C. Deletion of DNA encoding the stop-secretion portion of the B cell receptor D. Deletion of the RNA encoding the stop-secretion portion of the B cell receptor E. Deletion of the DNA encoding the IgM constant region F. Deletion of the RNA encoding the IgM constant region G. Somatic Hypermutation
Deletion of the RNA encoding the stop-secretion portion of the B cell receptor Deletion of the DNA encoding the IgM constant region
The Sortase enzyme, which is found in many members of the Firmicutes (multiple correct answers A. Functions as a signal peptidase and removes the signal sequence of secreted proteins B. Detects the sequence LPXTG that is found near the C-terminus of some proteins C. Forms a transient covalent bond between itself and the T residue of the LPXTG sequence D. Transfers the recently secreted protein to the pentaglycine that is attached to the pentapeptide of Lipid II E. Is required for two dozen proteins of Staphylococcus aureus to bind to peptidoglycan, many of which play essential roles in pathogenesis
Detects the sequence LPXTG that is found near the C-terminus of some proteins Forms a transient covalent bond between itself and the T residue of the LPXTG sequence Transfer the recently secreted protein to the pentaglycine that is attached to the pentapeptide of Lipid II Is required for two dozen proteins of Staphylococcus aureus to bind to peptidoglycan, many of which play essential roles in pathogenesis
Describe the properties of a dichroic mirror that are useful in fluorescence microscopy.
Dichroic mirrors reflect one wavelength of light, but ransmit another wavelength, generally a longer wavelength. For example, such a mirror could reflect flue light downward onto a sample but transmit fluorescent light upward to the eyepiece or camera
The 2' carbon of the deoxyribose portion of DNA Is linked to a phosphate group distinguishes it from RNA in that It lacks an OH group Provides an oxygen atom that makes the deoxyribose cyclic Is linked to the nitrogenous base
Distinguishes it from RNA in that it lacks an OH group
Which MAMP might the virus release during infection? Peptidoglycan Lipopolysaccharide Flagellin Double-stranded DNA Double-stranded RNA Formyl-Met-peptides
Double-stranded RNA
Human papillomavirus A) Is an RNA virus B) Packages double-stranded RNA into its virion C) Has a genome 152 kilobases long D) Has a lipid envelope E) Is icosahedral F) Must integrate into the host genome in order to complete its life cycle G) Must integrate into the host genome in order to cause cervical cancer
E) Is icosahedral G) Must integrate into the host genome in order to cause cervical cancer
A new strain of E) coli that sickened 4000 Europeans in 2011 evolved from _ by acquisition of _____ toxin genes and a drug resistance plasmid EHEC, shiga EAEC, heat-labile Commensal E. coli, shiga EAEC, cholera EAEC, shiga
EAEC, shiga
Briefly describe in your own words how sera from persons receiving the Moderna vaccine were evaluated.
ELISA shows antibody activity by changing color depending on concentration of protein present ELISA was performed on individuals' sera to evaluate their antibody production
In the figure that you saw of one Bordetella pertussis cell, which feature is dreadfully incorrect? Fimbriae Pertactin Pertussis toxin Filamentous Hemagglutinin Endotoxins
Endotoxins
Which component made the whole-cell vaccine "reactogenic"? Fimbriae Pertactin Pertussis toxin Filamentous Hemagglutinin Endotoxins
Endotoxins
Which of the following properties are SHARED by BOTH SARS viruses and influenza viruses? (circle all correct answers) A. Spherical B. Filamentous C. Enveloped D. Naked E. Genome RNA F. Genomic DNA G. Genome double-stranded H. Genome single-stranded I. Genome (+) stranded J. Genome (-) stranded
Enveloped Genome RNA Genome single-stranded
The length of a merozoite is comparable to that of Thiomargarita spp Escherichia coli A parvovirus A prion A Sporozoite
Escherichia coli
What are the functions of the excitation filter and the barrier (or emission) filter that are used in fluorescence microscopes?
Excitation measures all wavelengths except the one that can excite the specimen barrier measures all wavelengths except that at which specimen fluoresces
Which of the following describes Type 6 secretion? (multiple correct answers) A. Exports proteins to the extracellular milieu B. Exports proteins directly into bacterial recipient cells C. Exported proteins require a signal sequence and general export machinery are temporarily located in the periplasmic space D. Exported proteins are covalently attached to the bacterial peptidoglycan E. Export system evolved from the flagellar basal body F. Export system evolved from conjugative DNA transfer G. Exported proteins are generally toxic to the recipient cell
Exports proteins directly into bacterial recipient cells Exported proteins are generally toxic to the recipient cell
Which of the following are being tested as a possible vaccine for COVID? (multiple correct answers) A) Whole viable SARS-CoV-2 B) The SARS virus from 2003 C) MERS virus D) Coronaviruses that cause common colds E) Adenoviruses F) Adenoviruses that have a copy of the gene encoding Spike G) SARS Lipopolysaccharide You Answered H) SARS-CoV-2 ribosomal RNA I) mRNA encoding Spike, encapsulated within a lipid nanoparticle
F) Adenoviruses that have a copy of the gene encoding Spike I) mRNA encoding Spike, encapsulated within a lipid nanoparticle
Complement molecule, C1 complex, will bind to an IgG antibody at the: VL portion Fc portion F(ab')2 portion J-chain region CL portion
Fc portion
If a sickled red blood cell were to lyse, it would necessarily release Sporozoites Merozoites Gametocytes Fibers of crystalline hemoglobin Hemozoin Ookinetes
Fibers of crystalline hemoglobin
In testing E) coli for serotype, the H-antigen refers to the type of Hemagglutinin Flagella Hemolysin Lipopolysaccharide Pilus
Flagella
When the kinase activity of BvgS is inactive which proteins are expressed? Flagella Flagella plus fhaB Flagella plus fhaB plus pertussis toxin fhaB plus pertussis toxin
Flagella
Type III secretion system evolved from __ while Type IV systems (like the one that secretes pertussis toxin) evolved from _____ Conjugation systems, flagellar basal body Filamentous hemagluttinin, flagellar basal body Bacteriophage stalks, general protein export machinery Flagellar basal body, conjugation systems Both evolved from the flagellar basal body
Flagellar basal body, conjugation systems
Type III secretion system evolved from __ while Type IV systems (like the one that secretes the pertussis toxin of Bordetella pertussis) evolved from _____ Conjugation systems, flagellar basal body Filamentous hemagglutinin, flagellar basal body Bacteriophage stalks, general protein export machinery Flagellar basal body, conjugation systems Both evolved from the flagellar basal body
Flagellar basal body, conjugation systems
Describe the roles of the "fluorophore" and the "quencher" of the peptide fragment that is used to assay for inhibitors of the SARS-CoV2 protease. How do we know when we have an effective protease inhibitor? Can you name such a protease inhibitor?
Fluorophore is excited by a wavelength of fluorescence, emitting light at a longer wavelength. The quench absorbs the fluorescent light, only at invisible
The cell type of Plasmodium falciparum that forms gametes after being ingested by a mosquito is called a Sporozoite Merozoite Gametocyte Ookinete None of the above
Gametocyte
Yersinia pseudotuberculosis causes infections primarily of the Lung Gastrointestinal tract Skin Urinary tract Conjunctiva
Gastrointestinal tract
Describe the major reagents used to identify various serotypes of influenza
H and N are the major reagent types used to identify serotypes H refers to hemagglutinin and the number refers to the type N refers to neuraminidase and the number refers to the type
The 1918 Spanish Flu and the 2009 Swine flu both were of the ______ serotype. H1N1 H2N2 H3N2 H5N1 H7N7
H1N1
People who were 88 years old in 1918 had been exposed to the __ as children and were ______ protected against the Spanish Flu pandemic. H1N1, strongly H1N8, partially H3N8, poorly H1N1, partially H1N8, poorly None of the above
H1N1, strongly
People who were 68 years old in 1918 had been exposed to the __ as children and were ______ protected against the Spanish Flu pandemic H1N1, strongly H1N8, partially H3N8, poorly H1N1, partially H1N8, poorly
H1N8, partially
Which was the second country in the western hemisphere to establish its sovereignty from a European country (excluding First Nations peoples)? United States Canada Haiti Argentina Brazil
Haiti
Synthesis of flavivirus proteins requires mRNA that Has a Cap made by the viral NS3 and NS5 proteins Has a Cap that is made by host capping enzymes Has a Cap that is removed from host mRNA's Has an IRES and no Cap. None of the above
Has a Cap made by the viral NS3 and NS5 proteins
Zidovudine (multiple correct answers) A. Has a nitrogenous base identical to thymine B. Has a 2' OH group C. Has a N3 (azide) group at the 3' position D. Has a triphosphate at the 5' position E. Is a substrate for cellular enzymes that can add the triphosphate at the 5' position
Has a nitrogenous base identical to thymine Has a N3 (azide) group at the 3' position Is a substrate for cellular enzymes that can add the triphosphate at the 5' position
Synthesis of hepatitis C virus proteins requires mRNA that Has a Cap made by the viral N3 and N5 proteins Has a Cap that is made by host capping enzymes Has a Cap that is removed from host mRNA's Has an IRES and no Cap. None of the above.
Has an IRES and no Cap.
N-acetylmuramic acid A. Has three more carbons than N-acetylglucosamine B. Forms a covalent bond with the pentapeptide C. Forms a covalent bond with the pentaglycine that is found in Firmicute cell walls D. Has five more carbon atoms than glucose E. Forms a covalent bond with D-alanine of the pentapeptide
Has three more carbons than N-acetylglucosamine Forms a covalent bond with the pentapeptide Has five more carbon atoms than glucose
Describe how hemoglobin S (HbS) resembles hemoglobin B, and how they differ.
HbS is a tetramer containing 2 normal alpha subunits similar to hemoglobin B HbS also contains 2 mutant beta subunits which converts glutamate at position 6 to valine and causes a sickle shape
How did Antonie van Leewenhoek make microbes visible in his primitive microscope? A. Gram stain B. Natural fluorescence C. Fluorescence using an artificial dye D. Photoactivatable fluorescent protein E. He kept this information secret
He kept this information secret
The antivirals Zanamivir and Oseltamivir resemble sialic acid and bind to the active site of neuraminidase. It should in principle be possible to develop other drugs that resemble sialic acid and bind to Hemagluttinin RNA-dependent RNA polymerase Ion channel (M2) Matrix protein (M1) Nucleoprotein (NP)
Hemagluttinin
Merozoites invades erythrocytes and feeds on hemoglobin. In this process, potentially toxic heme accumulates, and detoxified by conversion to Oligopeptides Hematozoa Hemozoin Myoglobin Hemophila
Hemozoin
The gene encoding HgS protects against malaria and does not cause sickle-cell anemia when Homozygous Heterozygous Hemizygous Haploid Diploid
Heterozygous
The mucus in the mucociliary elevator is loaded with antimicrobial macromolecules. From what you know about antibodies, which of the following would you surmise to be present in this mucus? IgA IgD IgE IgG IgM
IgA
Laboratory isolation of an anti-Streptococcus antibody was found to bind to ten Streptococcus pyogenes antigens at one time. The antibody isolated was: IgG IgD IgM IgE IgA
IgM
During the course of an intestinal infection with Salmonella enteritidis, the B cells undergo class switching. What switching is most likely to occur? (Antibodies enter the gastrointestinal tract only if they can be secreted). IgD to IgE IgA to IgG IgM to IgA IgD to IgM IgG to IgM
IgM to IgA
In the Rapid Diagnostic Test, the control line contains Immobilized goat antibodies that bind mouse antibodies Immobilized mouse antibodies that bind a Plasmodium protein Soluble mouse antibodies that bind Plasmodium protein Soluble mouse antibodies that bind all goat antibodies Plasmodium proteins that bind antibodies in the serum of human patients
Immobilized goat antibodies that bind mouse antibodies
Contrast a lytic viral infection of a host cell with a latent infection.
In a lytic infection progeny viruses are rapidly produced and the host cell is generally lysed shortly afterward. In a latent infection, viruses do not replicate, but reside quiescently within the host cell, thought they may at some future point in time enter a lytic pathway.
Collectively the Yop proteins that are translocated from the Yersinia cytoplasm to the host cytoplasm Inhibit phagocytosis, stimulate cytokine release, and stimulate apoptosis. Inhibit phagocytosis, inhibit cytokine release, and stimulate apoptosis. Inhibit phagocytosis, inhibit cytokine release, and inhibit apoptosis. Stimulate phagocytosis, inhibit cytokine release, and stimulate apoptosis. Stimulate phagocytosis, stimulate cytokine release, and stimulate apoptosis.
Inhibit phagocytosis, inhibit cytokine release, and stimulate apoptosis.
The mecA gene of MRSA strains encodes a protein that Hydrolyzes penicillin-type antibiotics Alters the penta-peptide to L-ala-D-glu-L-Lys-D-ala-D-ala to L-ala-D-glu-L-Lys-D-ala-D-lactate Is resistant to clavulanic acid Correct! Is a penicillin-resistant transpeptidase Detects vancomycin
Is a penicillin-resistant transpeptidase
Vegetative growth of a member of the Firmicutes A. Is characterized by symmetric cell division B. Is initiated by nutrient limitation and high population densities C. Requires that the mother cell engulf the forespore D. Is characterized by the disintegration of the mother cell chromosome E. Involves the lysis of the mother cell
Is characterized by symmetric cell division
The 3' carbon of the deoxyribose portion of DNA Is linked to a phosphate group Distinguishes it from RNA in that it lacks and OH group Provides an oxygen atom that makes the deoxyribose cyclic Is linked to the nitrogenous base
Is linked to a phosphate group
The 5' carbon of the deoxyribose portion of DNA Is linked to a phosphate group Distinguishes it from RNa in that it lacks an OH group Provides an oxygen atom that makes the deoxyribose cyclic Is linked to the nitrogenous base
Is linked to a phosphate group
Which is true of Shiga toxin (circle all correct answers) The toxin has 5 B subunits, each of which has two binding sites for Gb3 It has 1 A1 subunit and 1 A2 subunit The A1 and A2 subunits are created by cleavage of the A subunit by signal peptidase The A1 and A2 subunits are covalently joined between two serines. The A2 subunit is an N-glycosylase that removes one adenine residue from the 18S subunit of bacterial ribosomes. The A2 subunit ADP-ribosylates a diphthamide residue of Elongation Factor 2.
It has 1 A1 subunit and 1 A2 subunit
Negative DNA supercoiling is useful because (multiple correct answers) A. It helps particular regions of DNA to "melt" ie. to become single-stranded, especially those regions that are rich in A:T base pairs B. it holds together the antiparallel strands of DNA in the double helix C. it provides energy for transcription D. it prevents RNA from pairing with DNA in the double helix E. It helps to make a chromosome more compact
It helps particular regions of DNA to "melt" ie. to become single-stranded, especially those regions that are rich in A:T base pairs It helps to make a chromosome more compact
What happens to the virus protein coat when a bacterial cell is infected? It enters the host cell with the viral genome It remains on the outside of the host cell It enters the host cell separately from the viral genome It is released to attach to and inject another host cell It becomes part of the host cell membrane
It remains on the outside of the host cell
Imagine a host cell was infected by a virus, and that fragments of viral protein were presented in a complex with MHC Class I on the surface of the cell. That host cell would be Killed by Complement Killed by cytotoxic T cells but not killed by Natural Killer cells Not killed by cytotoxic T cells and not killed by Natural Killer cells Killed by cytotoxic T cells and by Natural Killer cells Not killed by cytotoxic T cells but killed by Natural Killer cells
Killed by cytotoxic T cells but not killed by Natural Killer cells
In bacteria whose peptidoglycan contains pentaglycines, where on Lipid II is the pentaglycine attached? N-acetyl muramic acid N-acetyl glucosamine Glucosamine L-Lysine D-alanine L-alanine
L-Lysine
Adenylate cyclase toxin is inactive in bacteria because bacteria Lack calmodulin Have calmodulin Modify the toxin by ADP ribosylation Lack G proteins Cannot synthesize this protein
Lack calmodulin
Which two ways are used by natural killer cells to detect virus-infected host cells? (only one correct answer) Expression of MHC-I with self-peptide OR antibodies bound to cell surface Expression of MHC-I with foreign peptide OR complement bound to cell surface Lack of MHC-I OR antibodies bound to cell surface Lack of MHC-I OR complement bound to cell surface Lack of MHC-I OR membrane glycoproteins lacking sialic acid
Lack of MHC-I OR antibodies bound to cell surface
In testing E) coli for serotype, the O-antigen refers to the type of Hemagglutinin Flagella Hemolysin Lipopolysaccharide Pilus
Lipopolysaccharide
Pla is covalently bound to Phospholipid Lipid II Lipopolysaccharide Peptidoglycan Sortase
Lipopolysaccharide
What sorts of molecules would you expect to find in an outer membrane vesicle (OMV)? (multiple correct answers) A. lipopolysaccharide B. endotoxin C. phospholipids D. RNA E. DNA F. Enzymes found in the cytoplasm G. Enzymes found in the periplasm H. Porins I. Proteins that are found in the inner membrane
Lipopolysaccharide Endotoxin Phospholipids Enzymes found in the periplasm Porins
The BCG vaccine, which protects against tuberculosis consists of A Mycobacterium exotoxin Mycobacterium envelope glycolipids Killed whole cells DNA that expresses mycobacterium antigens after incorporation into human nuclear DNA) Live attenuated Mycobacterium bovis cells.
Live attenuated Mycobacterium bovis cells.
Staphylococcus aureus adhesins tend to be expressed at _ phase while their secreted toxins tend to be expressed at _ phase Log, log Log, stationary Stationary, log Stationary, stationary.
Log, stationary
In the question above, the toxin genes were acquired by _ while the drug resistance plasmid was acquired by _ Lysogenic conversion, conjugative transfer Conjugative transfer, lysogenic conversion Natural Transformation, conjugative transfer Lytic infection, lysogenic conversion Lytic infection, an integrative conjugative element
Lysogenic conversion, conjugative transfer
During an infection, some pathogens have an enzyme that alters the chemical structure of their peptidoglycan. These enzymes remove the acetate group from N-acetyl glucosamine and from N-acetylmuramic acid. This deacetylation provides a defense against the innate immune system and would most likely protect these cells from A. Defensins B. Reactive oxygen species C. Lysozyme D. Iron sequestration E. Complement F. NETosis
Lysozyme
If a hepatocyte (liver cell) is infected with a hepatitis virus, and wanted to present the antigen to cytotoxic T cells, which receptor would it use? MHC II CD4 Either MHC I or MHC II CD8 MHC I
MHC I
A cell that has been infected by a virus might display virus-derived antigens complexed with ____ and killed by _____ A. MHC class I; CD8 cells B. MHC class I; CD4 cells C. MHC class II; CD8 cells D. MHC class II; CD4 cells E. HMC class I; natural killer cells F. MHC class II; natural killer cells G. B cell receptors; CD8 cells H. B cell receptors; CD4 cells I. B cell receptors; natural killer cells J. T cell receptors; CD8 cells K. T cell receptors; CD4 cells L. T cell receptors; natural killer cells M. None of the above
MHC class I; CD8 cells
What are the two types of cells that present antigens bound to MHC II? (multiple correct answers) A) Macrophages B) Neutrophils C) B cells D) T cells E) Natural killer cells
Macrophages B cells
"CRE" is a catchall abbreviation used by epidemiologists. What are these people referring to? A single genus that is resistant to a single antibiotic Many members of a family of bacteria that are resistant to a single antibiotic A single genus that is resistant to many (in some cases all) antibiotics Many members of a family of bacteria that are resistant to many antibiotics and can transfer the resistance genes to antibiotic-sensitive bacteria by conjugative transfer
Many members of a family of bacteria that are resistant to many antibiotics and can transfer the resistance genes to antibiotic-sensitive bacteria by conjugative transfer
The cell type of Plasmodium falciparum that emerges from an infected liver cell is called a Sporozoite Merozoite Gametocyte Ookinete None of the above
Merozoite
Which two companies are currently testing influenza vaccines that consist of lipid-encapsulated mRNA? (two correct answers) A. Astra-Zeneca B. Moderna C. Johnson and Johnson D. Pfizer-BioNtech E. Novavax F. Sinovac G. Inovio
Moderna Pfizer-BioNtech
Why are myeloma cells necessary for the creation of monoclonal antibodies?
Monoclonal antibodies require the culturing of cells that express antibodies. B cells express antibodies but cannot be propagated in vitro. The fusion of B cells with myeloma cell lines results in hybridomas, which still express the same antibodies as their parent B cell, but which now can be propagated in vitro
The pentapeptide that is part of Lipid II is attached to N-acetyl muramic acid N-acetyl glucosamine glucosamine diaminopimelic acid lipopolysaccharide
N-acetyl muramic acid
To reverse the activity of pertussis toxin in vitro one could try adding high amounts of NADH Nicotinamide Nicotine NAD+ ADP-ribose
Nicotinamide
The stxA and stxB genes are located in an operon that also includes the R and S genes. R and S are expressed during lytic virus replication and direct the lysis of the host cell so that phage can be released. With this information, what sort of export system might be required to export shiga toxin across the outer membrane? A type I secretion system A type III injectisome A type IV injectisome A type V autotransporter. A chaperone usher system None
None
Anophelin is delivered from mosquito salivary glands during a blood meal. This protein Stimulates thrombin activity Stimulates factor XIII activity Stimulates factor X activity Stimulates Factor V activity Stimulates Plasmin activity None of the above
None of the above
Bacterial flagella A. function in a whip-like motion, hence the name flagellum, which is Latin for "little whip" B. Can spin like a propeller in only a clockwise direction C. Powered by a gradient of sodium ions across the inner membrane D. Can help pathogenic bacteria to adhere to the surface of a host cell E. None of the above
None of the above
Beta-lactamase destroys penicillin by hydrolysis. This enzyme has a signal sequence and is exported from the bacterial cytoplasm. This is achieved by a ____ secretion (or translocation) system. A. Type 1 B. Type 2 C. Type 3 D. Type 4 E. Type 5 F. Type 6 G. None of the above
None of the above
Beta-lactamase destroys penicillin by hydrolysis. This enzyme has a signal sequence and is exported from the bacterial cytoplasm. This is achieved by a ______ secretion (or translocation) system A. Type 1 B. Type 2 C. Type 3 D. Type 4 E. Type 5 F. Type 6 G. None of the above
None of the above
Hepatitis C virus is spread primarily Via contaminated water or food By inhalation Sexually By mosquitos or ticks None of the above
None of the above
How many strains of coronavirus are recognized as human pathogens? How many were known to be deadly prior to the year 2000? 5, 1 6, 0 7, 1 8, 0 9, 1 None of the above
None of the above
Influenza virus contains _ RNA particles and encodes ___ proteins 1, 6 2, 7 3, 8 5, 9 7, 10 9, 10 None of the above
None of the above
The conversion of DNA from a closed complex to an open complex A. Causes the separation of two or three bases from their complementary bases on the opposite strand B. Is mediated by Ribosomes C. Is necessary for the initiation of translation D. Is facilitated by the underwinding of RNA E. None of the above
None of the above
The vaccine used to protect against measles Is a trivalent vaccine that also protects against influenza and polio Contains purified measles proteins such as the viral adhesin Contains viruses that have been inactivated using formaldehyde Contains DNA that encodes several measles proteins Contains a harmless virus that resembles measles virus None of the above
None of the above
There is a small literature that suggests that infections with herpes viruses may be beneficial to the host. Which of the following is the true about the paper in Nature 477:326? The study used macaque monkeys It used viruses closely related to human varicella zoster (chickenpox) virus and Herpes simplex virus Infection conferred resistance to Salmonella and Staphylococcus Resistance was due to specific antigens encoded by these viruses The authors enthusiastically recommended that all people be infected with genital herpes viruses. None of the above
None of the above
Variola virus is the causative agent of smallpox. "Variolation" refers to the practice of immunizing patients against smallpox using Variola virus that had been rendered safe by Treatment with formaldehyde Treatment with carbolic acid Treatment with high temperature Attenuation by growth in culture for many generations None of the above
None of the above
Which of the following could serve as an initiation point for DNA synthesis? A. A 2' OH group of RNA B. A 3' OH group of RNA that has a bound phosphate group C. A 5' OH group of RNA that has a bound phosphate group D. A 5' OH group of RNA E. A 5' OH group of DNA F. None of the above.
None of the above
Which of the following describes the coronavirus SAR-CoV2? A. Icosahedral B. Filamentous C. DNA genome D. Genome has approximately 10,000 nucleotides E. Genome contains double stranded nucleic acids F. Virus particle is naked G. Virus replicates through a DNA intermediate H. None of the above
None of the above
Bubonic Plague is caused by __ while pneumonic plague is caused by _ and septicemic plague is caused by______: Yersinia pestis; Yersinia enterocolitica; Yersinia pseudotuberculosis Yersinia enterocolitica; Yersinia pseudotuberculosis; Yersinia enterocolitica Yersinia pseudotuberculosis, Yersinia pestis; Yersina enterocolitica Mycobacterium tuberculosis, Pseudomonas aeruginosa; Staphylococcus aereus None of the above.
None of the above.
How many carbon atoms are found on sialic acid? 6 7 8 9 10 None of the above.
None of the above.
Yersinia pestis accesses the body via_ or while its close relative Y. pseudotuberculosis accesses the body via __ Ingestion, flea bite, inhalation Inhalation, ingestion, flea bite Rodent bites, inhalation, ingestion, Inhalation, mosquito bite, ingestion None of the above.
None of the above.
Imagine a host cell was infected by a virus that caused the cell to synthesize a viral protein on the cell surface. Imagine that the host had produced antibodies directed against the viral protein. That host cell would be Killed by Complement Killed by cytotoxic T cells but not killed by Natural Killer cells Not killed by cytotoxic T cells and not killed by Natural Killer cells Killed by cytotoxic T cells and killed by Natural Killer cells Not killed by cytotoxic T cells but killed by Natural Killer cells
Not killed by cytotoxic T cells but killed by Natural Killer cells
Imagine a host cell was infected by a virus that could block all HMC class I from the cell surfacE) That host cell would be Killed by Complement Killed by cytotoxic T cells but not killed by Natural Killer cells Not killed by cytotoxic T cells and not killed by Natural Killer cells Killed by cytotoxic T cells and by Natural Killer cells Not killed by cytotoxic T cells but killed by Natural Killer cells
Not killed by cytotoxic T cells but killed by Natural Killer cells
Which class of HIV antivirals is sold under the name Truvada for the prevention of HIV infection in high-risk populations? Nucleoside Analog RT inhibitors Non-nucleoside analog RT inhibitors Protease Inhibitors Integrase Inhibitors CCR5 inhibitors TM inhibitors
Nucleoside Analog RT inhibitors
The net difference in mass between an active form of a G protein and an inactive form of the same G protein is equivalent to the mass of: One phosphate group One GDP One GTP One ADP-ribose One cAMP
One phosphate group
The cell type of Plasmodium falciparum that results from the fusion of a micro- and microgametocyte is called a Sporozoite Merozoite Gametocyte Ookinete (or Zygote) None of the above
Ookinete (or Zygote)
Why is "PBP2a" an odd choice of names for methicillin-resistant transpeptidase of MRSA strains? What is the rationale for this name?
PBP2a stands for penicillin binding protein but it's odd since the protein doesn't bind to penicillin, its just in the gene family of penicillin binding proteins
Which of the following antimicrobials function by mimicking the substrates of various enzymes? (multiple correct answers) A. Gramicidin B. Polymyxins C. Defensins D. Membrane attack complex E. Penicillins F. Carbapenems G. Cephalosporins H. Vancomycin I. Moenomycin J. Bacitracin K. Cycloserine L. Lysozyme
Penicillins Carbapenems Cephalosporins Cycloserine
During the synthesis of a type I pilus, the __ chaperone transiently provides a _ to complete the Ig fold of each pilin subunit. Ultimately, the chaperone is displaced by the _____ of the adjacent pilin subunit. Periplasmic, beta strand, beta helix Cytoplasmic, beta helix, beta strand Periplasmic, beta strand, beta strand Cytoplasmic, alpha helix, alpha helix Periplasmic, alpha helix, beta helix.
Periplasmic, beta strand, beta strand
In a stable lysogen, which category of prophage genes are express? Lysis genes Phage head genes Phage tail genes Integration/Excision genes Phage repressor genes RecA genes
Phage repressor genes
The rapid diagnostic test (or "point of care" test) for malaria detects Antibodies against Plasmodium proteins Plasmodium proteins Plasmodium-infected red blood cells Plasmodium carbohydrates Toxoplasma gondii proteins
Plasmodium proteins
Why is Yersinia pestis, the causative agent of bubonic plague, considered a potential biowarfare agent? The bacteria is readily available in Europe. There is no effective antibiotic against it. It is readily introduced into the human population by mosquitoes. Pneumonic plague is highly communicable with a high mortality rate. The bacterium forms long-lasting endospores.
Pneumonic plague is highly communicable with a high mortality rate.
Outbreaks of plague in the middle ages started in _ of Europe about 15 years after a weather fluctuation in central or eastern Asia. Port cities Inland cities Hilltop cities Villages surrounded by forest
Port cities
Staphylococcus aureus are generally _ for coagulase activity and __ for catalase activity Positive, positive Positive, negative Negative, positive Negative, negative
Positive, positive
Which classes of biomolecules did we discuss in class that are altered by reactive oxygen species? (multiple correct answers) A. Proteins B. Carbohydrates C. Lipids D. RNA E. DNA
Proteins Lipids RNA DNA
The 4' carbon of the deoxyribose portion of DNA Is linked to a phosphate group Distinguishes it from RNA in that it lacks an OH group Provides an oxygen atom that makes the deoxyribose cyclic Is linked to the nitrogenous base
Provides an oxygen atom that makes the deoxyribose cyclic
The Coronavirus infection cycle requires a DNA-dependent DNA polymerase DNA-dependent RNA polymerase RNA-dependent DNA polymerase RNA-dependent RNA polymerase
RNA-dependent RNA polymerase
TIR protein causes the formation of a pedestal on the apical membrane of intestinal epithelial cells by Directly polymerizes actin Directly polymerizing microtubules Recruiting host proteins that polymerize actin Recruiting host proteins that polymerize microtubules Directly polymerizing a fibronectic net.
Recruiting host proteins that polymerize actin
Integration of the DNA of bacteriophage lambda Occurs adjacent to a tRNA gene Requires a protein called integrase Is irreversible, so excision is impossible Occurs at many different sites on the bacterial chromosome Stops when the integrase is cut into fragments by activated RecA
Requires a protein called integrase
The spike protein of SARS-CoV2 (multiple correct answers) A. Requires proteolysis by a virally encoded protease B. Requires proteolysis by a host encoded protease C. Is translated by using genome-length mRNA D. Is translated using a subgenomic mRNA E. Requires a programmed ribosomal frameshift F. Requires capping of the mRNA that encodes it
Requires proteolysis by a host encoded protease Is translated using a subgenomic mRNA Requires Capping of the mRNA that encodes it
The cell wall synthesizing transpeptidase binds the cell wall pentapeptide __ and penicillin ______ Reversibly, reversibly Reversibly, irreversibly Irreversibly, reversibly Irreversibly, irreversibly
Reversibly, irreversibly
Compare and contrast SARS viruses with influenza viruses in terms of how they ensure that their mRNA's are capped
SARS viruses build 5' caps on their mRNAs. They encode at least 3 and probably all 4 proteins needed to synthesize a cap. Influenza does not encode capping enzymes, and instead does "cap-snatching," which entails the removal of the 5' ends of capped host mRNA's which are then used as primers for viral mRNA synthesis
How does the cleavage site of SARS-CoV2 resemble that of the BAT-RaTG13 virus? How does it resemble the cleavage site of the MERS virus?
SARS-CoV2 resembles MERS virus because they both have monobasic cleavage sites. The cleavage site resembles BAT-RaTG13's cleavage site because they are both furin cleavage sites.
All of the following are true of HIV except? It jumped from apes and monkeys to humans at least six different times SIV sequences from gorillas most closely resemble HIV 1/M, which is the pandemic lineage. The jump to humans is most likely through butchering or consumption of wild game. It probably originated in or near what is now the Democratic Republic of the Congo HIV viral load slowly increases inside infected humans
SIV sequences from gorillas most closely resemble HIV 1/M, which is the pandemic lineage.
Transgenic mice that express a human defensin were more resistant than wild type to A. Vibrio cholerae B. Helicobacter pylori C. Salmonella enterica D. Escherichia coli E. Yersinia pestis F. None of the above
Salmonella enterica
Transgenic mice were made resistant to __ by introduction of a human defensin gene Cholera Plague Salmonella typhi Salmonella enterica E coli
Salmonella enterica
Describe the target of the SapM protein of Mycobacterium tuberculosis. How does this protein enhance the viability of the bacteria inside a macrophage?
SapM protein targets PI3P it dephosphorylates it inhibiting fusion of the phagosome with lysosomes to increase survivability of bacteria
The chemical on the right is sodium dodecyl sulfate, a strong detergent that is used in domestic and industrial cleaners. In aqueous conditions, the sodium (Na+) cation dissociates from the dodecyl sulfate anion. The latter most closely resembles a(n) A. lipopolysaccharide B. Lipid A C. Lipid I D. Lipid II E. saturated fatty acid F. unsaturated fatty acid G. phospholipid
Saturated fatty acid
The A subunit of Ricin resembles the A subunit of Shiga toxin pertussis toxin Pseudomonas exotoxin A Diphtheria toxin Cholera toxin.
Shiga toxin
Which of the following lists begins with the organism most closely related to E. coli and ends with the organism least closely related? Vibrio, Shigella, Salmonella, Pseudomonas, Listeria. Shigella, Salmonella, Vibrio, Pseudomonas, Listeria. Salmonella, Pseudomonas, Vibrio, Listeria, Shigella. Shigella, Salmonella, Pseudomonas, Listeria, Vibrio.
Shigella, Salmonella, Vibrio, Pseudomonas, Listeria.
What evidence is NOT cited as evidence that Abraham Lincoln was suffering from smallpox as he gave the Gettysburg Address? Lincoln reported weakness on the morning that he gave the address A red rash appeared on the fourth day of symptoms that developed into scatter blisters Lincoln's son Tad was earlier diagnosed with a fever and rash Lincoln's physician made a diagnosis of smallpox. Lincoln was bedridden for approximately 2 weeks after symptoms appeared. Full recovery required approximately 7 weeks. Lincoln's personal valet died of smallpox a few weeks after Lincoln's illness appeared Smallpox scars are visible on photographs of Lincoln.
Smallpox scars are visible on photographs of Lincoln.
The signal peptidase cleaves Some signal sequences and some stop-transfer sequences All signal sequences and all stop-transfer sequences Some signal sequences and no stop-transfer sequences All signal sequences and no stop-transfer sequences Some signal sequences and all stop-transfer sequences
Some signal sequences and no stop-transfer sequences
SopE and SptP have opposing functions in host cell invasion. How does Salmonella use these proteins to orchestrate transient engulfment? SopE is injected by SPI1 while SptP is injected later by SPI2 SopE and SptP are injected simultaneously. SopE temporarily "wins" but is rapidly inactivated by proteolysis SopE and SptP are injected simultaneously. SptP temporarily "wins" but is rapidly inactivated by proteolysis. SopE and SptP are injected simultaneously. SopE temporarily "wins" but SptP is converted to an active form by proteolysis SopE and SptP are injected simultaneously. SopE temporarily "wins" but is rapidly inactivated by glycosylation.
SopE and SptP are injected simultaneously. SopE temporarily "wins" but is rapidly inactivated by proteolysis
Which of the following statements about the Spike protein is correct? The N-terminal half of the protein contains a "fusion peptide" (FP) that is embedded in the endosome membrane, leading to fusion of the viral envelope with the endosomE) Spike is cleaved by host proteases at residue 679 Spike is cleaved by viral proteases at residue 679 You Answered The C-terminal half of the protein binds the ACE2 host receptor.
Spike is cleaved by host proteases at residue 679
The cell type of Plasmodium falciparum that transits from the site of infection to the liver is called a Sporozoite Merozoite Gametocyte Ookinete None of the above
Sporozoite
Helicobacter pylori colonizes the __ because it __. Stomach; survives only in people suffering from achlorhydria Gallbladder; feeds on bile Gallbladder; escapes alveolar macrophages Stomach; is lysozyme-resistant Stomach; tolerates acid
Stomach; tolerates acid
Based on the previous question, you might predict that people who survived the 1918 epidemic as young children would likely be ______ protected against the 2009 swine flu epidemiC) (The correct answer has been confirmed). Strongly Partially Poorly Not
Strongly
The poly-A tails of influenza mRNA are Obtained by tail-snatching Obtained by Cap-snatching Synthesized by viral RNA polymerase from an equivalent number of U residues on the (-) strands Synthesized by slippage of viral RNA polymerase during the transcription of a short run of U residues on the (-) strands.
Synthesized by slippage of viral RNA polymerase during the transcription of a short run of U residues on the (-) strands.
Terminal deoxynucleotide transferase Finds regions of microhomology between the DNA fragments Trims off non-complementary nucleotides Synthesizes DNA in a template-independent fashion during somatic recombination of antibody genes. Synthesizes DNA in a template-dependent fashion to fill the gaps in the DNA at the site of recombination Cuts DNA at the function between V regions and flanking DNA
Synthesizes DNA in a template-independent fashion during somatic recombination of antibody genes.
The Quantiferon TB test is a test for the presence of Anti-TB antibodies Viable tuberculosis bacteria Two mycobacterial proteins ESAT-6 and CFP-10 Circulating IFN-gamma T cells that recognize mycobacterial antigens.
T cells that recognize mycobacterial antigens.
Which of the following are effective ways to inactivate endospores? (multiple correct answers) A. Temperatures above 121 C B. Concentrated bleach C. Desiccation D. Temperatures above 100C E. Detergents, alcohols
Temperatures above 121 C Concentrated bleach
Protein synthesis can be directly inhibited by (multiple correct answers) A. Zidovudine B. Tetracycline C. Rifampin D. Streptomycin E. Chloramphenicol F. Erythromycin G. Ciprofloxacin H. Carbapenem
Tetracycline Streptomycin Chloramphenicol Erythromycin
Which of the following are TRUE about the two strands of DNA in a double helix? (multiple correct answers) A. The bases of one strand interact with the bases of the other B. They are antiparallel C. They are complementary D. They have equal amounts of adenine and guanine E. They have base-stacking interactions
The bases of one strand interact with the bases of the other They are antiparallel They are complementary They have base-stacking interactions
Gram-positive bacteria should stain a dark purple with Gram stain. What is the best explanation for a Gram-positive bacterium appearing pink after performing a Gram stain? The crystal violet was left on for too long The iodine was left on for too long The decolorizer was left on for too long The safranin was left on for too long The stain was properly performed
The decolorizer was left on for too long
Imagine that you have just used Gram's stain to stain a proteobacterium such as Escherichia coli. The bacteria stained a dark purple. What is the most likely explanation? A. The crystal violet step was omitted B. The iodine solution step was omitted C. The ethanol step was omitted D. The safranin was omitted E. none of the above
The ethanol step was omitted
Which of the following steps is NOT part of the life cycle of a LYTIC phage? Phage DNA is injected into the bacterial cell The phage DNA integrates into the bacterial chromosome Many copies of phage DNA are made The phage DNA is transcribed, and the resulting mRNA is translated to make capsid proteins None of the above, all of the above steps are part of the life cycle of a lytic phage
The phage DNA integrates into the bacterial chromosome
How is it possible for a B cell to synthesize a membrane-associated antibody and then differentiate into a plasma cell that secretes virtually the same antibody? The primary transcript encoding the heavy chain can be spliced in two different ways The primary transcript encoding the light chain can be spliced in two different ways The gene can be undergo a programmed DNA deletion. The membrane-spanning portion of the antibody can be removed by a proteasE) The 3' end of the mRNA can be degradeD)
The primary transcript encoding the heavy chain can be spliced in two different ways
Despite the fact that M. tuberculosis is a member of the "gram positive" group, it stains very poorly with Gram's stain because It has a thin layer of peptidoglycan The stain is hypersensitive to ethanol The safranin counterstain displaces crystal violet The waxy capsule protects the peptidoglycan from crystal violet None of the above; it stains well with Gram's stain.
The waxy capsule protects the peptidoglycan from crystal violet
Why are proteobacteria more resistant to lysozyme (molecular weight 14307 daltons, approximately 140 amino acids in length) and vancomycin (MW 1449) than are members of the firmicutes? this outer membrane blocks access to the target proteobacteria have a thinner cell wall than Firmicutes the porins of Firmicutes are too small to allow lysozyme or vancomycin to enter proteobacteria do not have the target molecule to which lysozyme or vancomycin binds none of the above; proteobacteria are just as sensitive as members of the Firmicutes
Their outer membrane blocks access to the target
Describe the roles of the "fluorophore" and the "quencher" of the DNA fragment that is used to test for SARS-CoV2 RNA.
These are found on Tac-man probes. The fluorophore is normally able to absorb a particular wavelength of light and fluoresce at a longer wavelength. However, the proximity of the quencher absorbs the fluorescence and makes it undetectable. PCR amplification requires the use of a DNA polymerase that has a 5'-3' exonuclease activity that destroys DNA that lies in the path of the enzyme. This activity destroys Tac-man probes, feeing their fluorophores, whos fluorescence can then be detected
Which of the following accurately describes proteins that are exported from the cell by a Type 1 mechanism? (multiple correct answers) A. These proteins are synthesized on cytoplasmic ribosomes B. They have signal sequences that are removed by the signal peptidase C. They accumulate transiently in the periplasm D. They have a domain that forms a pore (or "beta barrel") in the outer membrane E. They cross the outer membrane via a complex of proteins that act by a piston-like mechanism that requires polymerization and depolymerization F. The "linker" and "passenger" exits from the periplasm through the pore G. Some "passengers" are released by proteolysis, while some members of this family are not released and reside stably on the outer face of the outer membrane H. They cross both inner and outer membranes by a single channel
These proteins are synthesized on cytoplasmic ribosomes They cross both inner and outer membranes by a single channel
Which of the following accurately describes proteins that are exported from the cell by a Type 5 mechanism? (multiple correct answers) A. These proteins are synthesized on cytoplasmic ribosomes B. They have signal sequences that are removed by the signal peptidase C. They accumulate transiently in the periplasm D. They have a domain that forms a pore (or "beta barrel") in the outer membrane E. They cross the outer membrane via a complex of proteins that act by a piston-like mechanism that requires polymerization and depolymerization F. The "linker" and "passenger" exits from the periplasm through the pore G. Some "passengers" are released by proteolysis, while some members of this family are not released and reside stably on the outer face of the outer membrane
These proteins are synthesized on cytoplasmic ribosomes They have signal sequences that are removed by the signal peptidase They accumulate transiently in the periplasm They have a domain that forms a pore (or "beta barrel") in the outer membrane The "linker" and "passenger" exits from the periplasm through the pore Some "passengers" are released by proteolysis, while some members of this family are not released and reside stably on the outer face of the outer membrane
Which of the following are CORRECT about endospores? (multiple correct answers) A. They are each produced within a mother cell, which lyses at the end of endospore formation B. They are resistant to brief boiling but killed by 121 degrees C C. They can be killed with sufficiently high levels of bleach D. They are viable for at the very least 1000's of years, and possibly millions of years E. They rapidly resume binary fission in appropriate growth medium F. They are made by members of the Actinobacteria G. They are made by members of the Proteobacteria H. They are made by members of the Firmicutes
They are each produced within a mother cell, which lyses at the end of endospore formation They are resistant to brief boiling but killed by 121 degrees C They can be killed with sufficiently high levels of bleach They are viable for at the very least 1000's of years, and possibly millions of years They rapidly resume binary fission in appropriate growth medium They are made by members of the Firmicutes
How is it that some humans are naturally resistant to HIV? They are heterozygous for CCR5 loss of function mutations They are homozygous for CCR5 They are homozygous for CCR5 loss of function mutations They are heterozygous for CXCR4 loss of function mutations They are homozygous for CXCR4 They are homozygous for CXCR4 loss of function mutations Both A and B Both A and C
They are homozygous for CCR5 loss of function mutations
Why are viruses absent from Woese's phylogeny of all organisms? They are obligate parasites They do not encode rRNA They do not encode tRNA They do not encode mRNA
They do not encode rRNA
In the blood clotting cascade _ converts Fibrinogen into __ by proteolysis. The resulting proteins form a polymer that is crosslinked by ______ Thrombinogen, Fibrin, XIII Thrombin, Fibrin, XIIIa Plasmin, Fibrin, XIIa Thrombin, XIIIa, Fibrin XIIIa, Fibrin, Thrombin
Thrombin, Fibrin, XIIa
Ciprofloxacin targets Ribosomes DNA polymerases Topoisomerases RNA polymerases Transglycosylases
Topoisomerases
One of the most effective treatments for sickle cell disease requires a bone marrow transplant. However, only one third of patients can find a suitable donor, and even then, there is a risk of transplant rejection. To minimize this risk, immunosuppressive drugs are used, which can cause the patient to become immune compromised. True False
True
Genes for heavy-chain antibody production consist of _ segments, whereas genes for light-chain antibody production consist of _ segments. VJ; VDJ VDJ; VJ VDJ; VDJ VDJ; VD VJ; VJ
VDJ; VJ
The term "herd immunity," when used to describe an influenza epidemic, refers to: the fact that this pandemic started on bird farms in Asia a swine flu epidemic that originated from a bovine population nasal immunizations working better than shot inoculations Vaccination or natural immunity of the majority of a population can provide some protection nonimmune individuals children living in rural areas having stronger immune systems than urban children
Vaccination or natural immunity of the majority of a population can provide some protection nonimmune individuals
Amantadine blocks the acidification of the ___, preventing __ Endosome, hemagglutinin-mediated membrane fusion Endosome, viral uncoating Virion interior, hemagglutinin-mediated membrane fusion Virion interior, viral uncoating Removal of sialic acid by neuraminidase
Virion interior, viral uncoating
How does HIV manage to synthesize 20-fold more MA, CA, and NP proteins than PR, RT, and IN proteins? When converting RNA to DNA, 5% of reverse transcriptase molecules slip 1 nucleotide at a run of U residues, creating in a new reading frame that encodes the MA, CA, NP, PR, RT, and IN proteins. When converting RNA to DNA, 5% of reverse transcriptase molecules fail to synthesize the DNA that encodes the PR, RT, and IN proteins. When translating the MA, CA, and NP polyprotein, 5% of the ribosomes slip 1 nucleotide at a run of U residues, and continue in a new reading frame to synthesize the PR, RT, and IN proteins. When transcribing HIV proviral DNA, 5% of host RNA polymerase molecules slip 1 nucleotide at a run of U residues, creating in a new reading frame that encodes the MA, CA, NP, PR, RT, and IN proteins. 5% of mRNAs are unspliced and synthesize MA, CA, NP, PR, RT, and IN, while 95% are spliced in such a way that PR, RT, and IN sequences are removeD)
When translating the MA, CA, and NP polyprotein, 5% of the ribosomes slip 1 nucleotide at a run of U residues, and continue in a new reading frame to synthesize the PR, RT, and IN proteins.
Would it be possible to use fluorescence in situ hybridization (FISH) to detect viruses? If so, how would the procedure have to be modified compared to the procedure presented in class?
Yes, it would be possible. The FISH probes described in class hybridize to rRNA. This would not work with viruses, which have no rRNA. Instead, probes can be designed to some other viral DNA or RNA sequence
In modern times, plague in the United States can best be described as a __ disease Nosocomial Anthroponotic Opportunistic Zoonotic Commensal
Zoonotic
Which of the following cell types is diploid? Sporozoite Trophozoite Merozoite Gametocyte Microgametocyte Macrogametocyte Zygote
Zygote
An example of an antigen that could stimulate naïve B-cell proliferation and differentiation without the help of a T cell would be a(n): a highly repetitive lipopolysaccharide molecule from Proteus vulgaris plasmid DNA molecule from Yersinia pestis anthrax toxin molecule from Bacillus anthracis porin protein molecule from Escherichia coli
a highly repetitive lipopolysaccharide molecule from Proteus vulgaris
Superantigens bore holes on eukaryotic cell membranes inhibit phagocytosis prevent degranulation of macrophages are antipyrogenic activate a large fraction of either B cells or T cells.
activate a large fraction of either B cells or T cells.
Several proteins of the complement system are converted to __ forms by __ inactive, proteolysis inactive, phosphorylation active, acylation active, proteolysis active, phosphorylation
active, proteolysis
EHEC strains of E. coli A) Colonize cattle without causing significant disease B) Have the O157 serotype of O antigen C) Have the H7 serotype of H antigen D) Can be ingested by eating undercooked meat, or drinking contaminated water E) Have the genes that synthesize shiga toxin F) Can cause Hemolytic Uremic Syndrome
all of the above
How does the adenylate cyclase toxin protect the bacteria from the innate immune system? Why is the toxin catalytically inactive in bacterial cells? A) It creates pores in the membrane of host cells, including macrophages. B) It overproduces cAMP. C) It can bind to and inactivate the host CR3 protein, thereby blocking its ability to bind C3b, which is required for engulfment. D) It is catalytically inactive in bacterial cells because it requires calmodulin to be active, and bacteria lack this protein.
all of the above
IL-1 (multiple correct answers) A. Is synthesized by cells that detect MAMPS via a Toll-like receptor (TLR) B. Is a somewhat small protein (17.5 KD) C. Is synthesized in a precursor form that is converted to an active form by a type of protease called a caspase D. Is secreted from the cell that made it and binds to an IL-1 receptor on the surface of a capillary endothelial cell E. Stimulates production of receptors for neutrophil adhesins, including selectins, ICAM-1 and VCAM-1
all of the above
In determining whether a person is infected by HIV, one could test for (multiple correct answers) A) HIV RNA in plasma B) HIV proviral DNA in PBMCs (peripheral blood mononuclear cells) C) HIV proteins D) Anti-HIV IgM E) Anti-HIV IgG
all of the above
Membrane-spanning proteins can (multiple correct answers synthesize ATP at the expense of the proton gradient increase the proton gradient at the expense of ATP detect environmental signals and transmit information to the cytoplasm pump nutrients into the cell pump drugs and other toxic compounds out of the cell
all of the above
NETosis (multiple correct answers) A) Is initiated by the binding of a MAMP such as LPS to a TLR. B) Causes the death of the neutrophil C) Causes the production of Neutrophil Extracellular Traps (NETs) composed primarily of DNA, that immobilize bacteria D) Causes the release of proteases that are harmful to microbes E) Traps microbes
all of the above
NETosis (multiple correct answers) A) Releases active Tissue Factor, which stimulates the blood clotting cascade B) Causes the destruction of Tissue Factor Pathway Inhibitor (TFPI), loss of which which stimulates the blood clotting cascade C) Releases a protease that converts inactive XII to active XIIa, which stimulates the blood clotting cascade D) Might in principle be defeated by a pathogen that releases enzymes that either cleave DNA or that stimulate the dissolving of blood clots, or botH)
all of the above
Polymyxins (multiple correct answers) contain a short peptide contain a lipid insert into biomembranes and disrupt their integrity are synthesized by certain microbes presumably to kill other microbes are used as a last line of defense in medicine due to toxic effects on the patient
all of the above
Somatic hypermutation (multiple correct answers) A) Occurs only in B cells B) Occurs only in the DNA that encodes the variable regions of heavy and light chains C) Occurs only when B cells are activated by helper T cells D) Requires "Activation-Induced Cytosine Deaminase" (AID) E) Causes conversion of C residues to U F) Requires an enzyme that excises DNA containing U residues G) Ultimately results in a huge elevation in point mutations in the targeted DNA H) Causes the rapid evolution of B cells whose antibodies have improved affinity for antigen.
all of the above
Staphylococcus aureus can inhibit A) Binding of neutrophils to capillaries and thereby block extravasation B) Detection of Complement C5a by neutrophils C) Detection of formyl-Met peptides D) Binding of Complement C1 to bound antibodies E) Membrane Integrity of neutrophils
all of the above
The killing of infected or cancerous cells by natural killer cells requires the release of granzymes, which (multiple correct answers) A) Are proteases B) Cause the infected or cancerous cell to undergo "apoptosis," a form of programmed cell death C) Degrade ICAD (inhibitor of caspase-activated DNase), causing CAD to migrate to host nuclei and degrade host chromosomal DNA to small fragments. D) Initiate the assembly of the apoptosome, which consists of a battery of "Executioner Caspases" that degrade host proteins. E) Require perforins for entry into infected cells.
all of the above
The processing of cholera toxin into 2 protein fragments that are held together by a disulfide bond is reminiscent of (circle all correct answers) A) Shiga toxin B) Exotoxin A C) Diphtheria toxin D) Ricin
all of the above
The proton motive force drives the following process in bacteria (multiple correct answers) ATP biosynthesis from ADP and Pi flagellar rotation nutrient uptake efflux of toxins such as antibiotics
all of the above
What types of genes were lost as Y. pseudotuberculosis evolved into Y pestis? (multiple correct answers) A) Flagellar genes B) Insecticidal genes C) High affinity permeases for nutrient uptake D) Negative regulators of biofilms E) Adhesins necessary to bind to intestinal epithelium
all of the above
Which of the following can be an outcome of a viral infection of a host cell? (multiple correct answers) Host cell entry with little if any viral gene expression and no harm to the host cell Uncontrolled host cell proliferation, also known as transformation Viral replication and release without host cell lysis Host cell lysis
all of the above
Which of the following factors contributed to the "favorable environment" that caused a single case of HIV infection to spread in the early 20th century in or near Kinshasa, formerly Leopoldville? (multiple correct answers) A) Rapid industrialization B) Forced labor in large labor camps C) Displacement D) Urbanization E) Population increase F) Prostitution G) Disease, malnutrition H) Unsterile injection of vaccines and antibiotics
all of the above
Which of the following molecules can be damaged by Reactive Oxygen Species? (multiple correct answers) A. DNA and RNA bases B. Cysteine C. Iron-sulfur centers D. Lipids E. Proteins
all of the above
Which of the following steps is required for bacteria to become resistant to vancomycin (multiple correct answers) A) They must hydrolyze D-ala-D-ala dipeptide B) They must hydrolyze D-ala from the pentapeptide C) They must overproduce D-lactate, using pyruvate as a substrate D) They must synthesize D-ala-D-lactate E) They must use a "housekeeping" enzyme to join the L-Ala-D-glu-L-Lys tripeptide to the D-ala-D-lactate
all of the above
Which of the following strategies are used by bacteria to resist the lethal effects of various antibiotics? (multiple correct answers) A. Exporting the antibiotic through a dedicated export permease B. Covalently altering the antibiotic by addition of the methyl group, an acetate group, or another modification C. Destroying the antibiotic by hydrolysis D. Replacing the target of the antibiotic with a protein having a similar function but which is resistant to the antibiotic E. Point mutation of a chromosome gene that alters the target or decreases envelope permeability
all of the above
DNA polymerases are not able to initiate synthesis de novo. Instead, they can only extend an existing strand of nucleic acid which acts as a "primer". Which of the following CAN serve as a primer? (Multiple correct answers) A. an RNA primer with a free 3' OH group and a blocked 5' end B. and RNA primer with a free 5' OH group and a blocked 3' end C. a 5' OH group of a DNA molecule that was generated by breaking one DNA strand D. a 3' OH group of a DNA molecule that was generated by breaking one DNA strand E. The 3' OH group of a tRNA F. The 5' OH group of a tRNA G. Lipopolysaccharide
an RNA primer with a free 3' OH group and a blocked 5' end a 3' OH group of a DNA molecule that was generated by breaking on DNA strand The 3' OH group of a tRNA
Which of the following is NOT an integral part of the inflammatory process? dilation of blood vessels release of histamines and prostaglandins chemotaxis of polymorphonuclear leukocytes extravasation antibody synthesis
antibody synthesis
The small segment of antigen that is capable of eliciting an immune response is called a(n): (multiple correct answers) A) hapten B) antigenic determinant C) clonotope D) naïve antigen E) aggretope F) epitope
antigenic determinant epitope
The injection of mRNA that encodes the spike protein of SARS-CoV2 into a patient causes F. natural active immunity G. natural passive immunity H. artificial active immunity I. artificial passive immunity J. none of the above
artificial active immunity
The use of monoclonal antibodies that bind to spike protein causes A. natural active immunity B. natural passive immunity C. artificial active immunity D. artificial passive immunity E. none of the above
artificial passive immunity
AZT, also known as Zidovudine, function A. by blocking the underwinding of viral nucleic acids B. by inhibiting a viral protease C. by inhibiting a host protease D. as a chain-terminating nucleoside analog E. by causing lethal mutagenesis of the viral genome F. by blocking the capping reaction of viral mRNA
as a chain-terminating nucleoside analog
AT-rich DNA will denature (or "melt") at a higher temperature than GC-rich DNA at a lower temperature than GC-rich DNA usually at the same temperature as GC-rich DNA, with some minor variations in accordance with the animal or plant from which it was taken
at a lower temperature than GC-rich DNA
Signal sequences are found: in the 30S ribosomal subunit at the C-terminal end of a mRNA at the 5' end of an mRNA that encodes a secreted protein at the amino terminus of a nascent protein that is destined to reside in the cytoplasm at the amino terminus of a nascent protein that is destined to be secreted at the amino terminus of a mature secreted, extracytoplasmic protein
at the amino terminus of a nascent protein that is destined to be secreted
An activated cytotoxic T cell active against an influenza infection in the lungs would: release pro-inflammatory cytokines throughout the entire lung produce monoclonal anti-influenza antibodies activate B cells to make influenza-specific plasma cells bind to the infected host cells, then release perforin and granzymes travel to the thymus and undergo positive selection
bind to the infected host cells, then release perforin and granzymes
Moenomycin A. Blocks transpeptidation B. Blocks polymerization of the polysaccharide backbone C. blocks recycling of undecanoyl-phosphate D. Blocks synthesis of D-alanine E. Causes lysis of the polysaccharide backbone of the cell wall
blocks polymerization of the polysaccharide backbone
Which of the following molecules can be transported across the cytoplasmic membrane by passive diffusion? Na+ CH3COOH H2O CO2 both C and D
both C and D
In a proper Gram stain, Gram positive cells are stained by: crystal violet only safranin only both crystal violet and safranin (though the safranin stain is masked by the darker crystal violet stain neither crystal violet nor safranin not enough information has been provided to know
both crystal violet and safranin (though the safranin stain is masked by the darker crystal violet stain
Remdesivir and Molnupiravir function A. by inhibiting a viral protease B. by inhibiting a host protease C. as chain-terminating nucleoside analogs D. by causing lethal mutagenesis of the viral genome E. by blocking the capping reaction of viral mRNA
by causing lethal mutagenesis of the viral genome
Describe briefly how cAMP impacts the activity of protein kinase A. Which protein did we discuss in class that is phosphorylated by this kinase?
cAMP is an enzyme activator for protein kinase A so when it is inhibited, protein kinase is not produced CREB is phosphorylated by this kinase
Which is NOT a component of any bacterial cell wall? peptidoglycan teichoic acids N-acetylmuramic acid L-lysine cellulose
cellulose
Directed movements toward or away from a chemical or physical signal are known as: gliding flagellation chemotaxis locomotion slime layer
chemotaxis
The Rous sarcoma virus causes cancer of muscle tissue in chickens. This virus (multiple correct answers) A. contains all three of the genes found in other related viruses, including the murine leukemia virus B. contains an extra gene called V-Src, which is not found in most related viruses C. V-Src has a sequence that is quite similar to the C-Src gene that is found on the chromosomes of chickens and other vertebrates D. V-Src contains several introns that are missing C-Src E. V-Src is truncated at its amino terminus, causing it to be hyperactive in stimulating cell division
contains all three of the genes found in other related viruses, including the murine leukemia virus contains an extra gene called V-Src, which is not found in most related viruses V-Src has a sequence that is quite similar to the C-Src gene that is found on the chromosomes of chickens and other vertebrates (credit given for either answer here, as C-Src ahs introns that are lacking in V-Src)
Which two components of the Gram stain form a complex that is retained by Gram-positive cells? crystal violet and iodine alcohol and safranin safranin and iodine alcohol and iodine crystal violet and safranin
crystal violet and iodine
Which of these arranges the steps of the Gram stain into the correct order? iodine then crystal violet then decolorizer then safranin safranin then decolorizer then crystal violet then iodine crystal violet then decolorizer then iodine then safranin crystal violet then decolorizer then safranin then iodine crystal violet then iodine then decolorizer then safranin
crystal violet then iodine then decolorizer then safranin
Of all the SARS-CoV2 variants circulating in the US, which one is most rapidly displacing all others? alpha beta gamma delta epsilon lambda other
delta
The precursor of each new nucleotide in a strand of DNA is a deoxynucleoside 5'-diphosphate deoxynucleoside 3'-diphosphate deoxynucleoside 5'-triphosphate deoxynucleoside 3'-triphosphate ribonucleoside 5'-diphosphate ribonucleoside 3'-diphosphate ribonucleoside 5'-triphosphate ribonucleoside 3'-triphosphate
deoxynucleoside 5'-triphosphate
Beta-lactamase acts by Modifying penicillin by methylation (addition of a CH3 group) Pumping penicillin out of the cell Replacing the target of penicillin with a functionally similar protein Destroying penicillin by hydrolysis Removing penicillin from the active site of the transpeptidase, restoring the protein to a functional form
destroying penicillin by hydrolysis
The five classes of antibodies (IgG, IgA, IgM, IgE, and IgD) that can be produced during an immune response are based on: differences in CL chain regions differences in VH chain regions differences in CH chain regions differences in VL chain regions differences in all constant and variable chain regions
differences in CH chain regions
Some viruses derive their ____ from the membranes of host cells capsid reverse transcriptase envelope adhesins genome
envelope
When the kinase activity of BvgS is fully active which proteins are expressed? Flagella Flagella plus fhaB Flagella plus fhaB plus pertussis toxin fhaB plus pertussis toxin. none of the abovE)
fhaB plus pertussis toxin
What about the alpha variant? Approximately when was it first detected? What fraction of all new infections in April of 2021 were caused by alpha variants? Approximately what fraction of all infections are caused by alphas currently?
first detected 10/30/2020 fraction of all new infections in april 2021: 41% fraction of infections currently: <1%
Pertussis toxin consists of 1 A subunit (called S1) that has the catalytic active site and ____ subunit(s) that constitute the B (binding) domain five identical five completely different five total, two identical copies of one six completely different one
five total, two identical copies of one
Immunization with the childhood DPT (diphtheria, pertussis, and tetanus) vaccine protects against subsequent exposure to tetanus by: stopping isotype switching of B cells from IgM to IgA preloading antigen-presenting cells stimulating quick inflammation upon future exposure producing life-spanning antitetanus IgE antibodies generating tetanus-specific memory B cells
generating tetanus-specific memory B cells
Which of the following are precursors of N-acetylmuramic acid? (multiple correct answers) A. glucose B. glucosamine C. N-acetyl glucosamine D. Diaminopimelic acid E. phospholipid
glucose glucosamine N-acetyl glucosamine
Acyclovir (multiple correct answers) A. has a nitrogenous base identical to guanine B. has a 2' OH group C. has a N3 (azide) group at the 3' position D. has a triphosphate at the 5' position E. is a substrate for cellular enzymes that can add the triphosphate
has a nitrogenous base identical to guanine is a substrate for cellular enzymes that can add the triphosphate
molecules like gramicidin that create toxic pores in bacterial membranes (multiple correct answers) have a hydrophobic exterior that faces the membrane have a hydrophilic interior pore that facilitates cation transport have a hydrophobic interior that faces the membrane have a hydrophilic exterior pore that facilitates cation transport have a hydrophobic pore that facilitates the export of hydrophobic molecules
have a hydrophobic exterior that faces the membrane have a hydrophilic interior pore that facilitates cation transport
In a filamentous virus, the pattern of capsid monomers forms a ____ tube around the genome asymmetrical complex filamentous icosahedral helical
helical
The two strands of the DNA double helix are held together by 5'-3' attraction hydrogen bonds between nucleotide bases codons peptide bonds between nucleotide bases
hydrogen bonds between nucleotide bases
defensins are peptides that have a (multiple correct answers) hydrophobic end that faces out and positively charged end that is buried in the membrane hydrophobic end that is buried in the membrane and a negatively charged end that faces out hydrophobic end that is buried in the membrane and a positively charged end that faces out cationic end that is buried in the membrane and a negatively charged end that faces out disrupt bacterial membranes
hydrophobic end that is buried in the membrane and a positively charged end that faces out disrupt bacterial membranes
Describe why the AXD1222 vaccine (AstraZeneca) strain cannot replicate in humans and how it is propagated in the laboratory.
in the laboratory, the vaccine is a spike gene cloned into a defective adenovirus. This causes the E1A and E1B genes to be deleted and these are necessary for viral replication so the virus doesn't replicate in human cells
Why might the estimate in the previous question require downward revision?
incomplete data
Natural killer cells target: infected cells that have lost MHC class I bacterial cells that have lost MHC class I bacterial cells that are coated with complement bacterial cells that are coated with antibodies infected cells that secrete cytokines
infected cells that have lost MHC class I
In gram-negative bacteria, ATP synthase is partially embedded in cytoplasm peptidoglycan layer cell wall inner membrane outer membrane
inner membrane
The general secretion complex (also known as the SecYEG translocon) is found in the: Nucleus periplasmic space inner or cytoplasmic membrane outer membrane cell wall
inner or cytoplasmic membrane
The 1' carbon of the deoxyribose portion of DNA is linked to a phosphate group distinguishes it from RNA in that it lacks an OH group Provides an oxygen atom that makes the deoxyribose cyclic Is linked to the nitrogenous base
is linked to the nitrogenous base
How does the membrane attack complex, or MAC, kill Gram-negative bacteria? through opsonization it dissolves the cell wall digests the bacterial DNA it creates a pore on the bacterial membranes through antibody-dependent cell cytotoxicity, or ADCC)
it creates a pore on the bacterial membranes
Explain in your own words why the polybasic cleavage site of the SARS-CoV2 virus is considered ominous.
it creates more opportunity for mutations which can be beneficial to the virus's survival
What happens to the virus protein coat when a bacterial cell is infected? it enters the host cell separately from the viral genome it becomes part of the host cell membrane it is released to attach to and infect another host cell it remains on the outside of the host cell it enters the host cell with the viral genome
it remains on the outside of the host cell
All of the following are components of peptidoglycan EXCEPT: N-acetylglucosamine N-acetylmuramic acid lipopolysaccharide amino acids peptide cross-links
lipopolysaccharide
An example of a normal, ordinary antigen (NOT a superantigen) that could stimulate naïve B-cell proliferation and differentiation without the help of a T cell would be a(n): lipopolysaccharide molecule from Proteus vulgaris plasmid DNA molecule from Yersinia pestis protein A molecule from Staphylococcus aureus anthrax toxin molecule from Bacillus anthracis porin protein molecule from Escherichia coli
lipopolysaccharide molecule from Proteus vulgaris
MAC is an abbreviation for multiprotein pore associated with complement microbicidal attack complex membrane attack complex membrane associated cascade mitogen associated comples
membrane attack complex
Imagine that you have just stained the Gram-positive bacterium Staphylococcus aureus. The bacteria stained a dark purple. What is the most likely explanation? A. The crystal violet set was omitted B. The iodine solution step was omitted C. The ethanol step was omitted D. The safranin was omitted E. none of the above
none of the above
Robert Koch first applied Koch's postulates to which pathogen? A. Mycobacterium tuberculosis B. Helicobacter pylori C. Salmonella enterica D. Staphylococcus aureus E. Vibrio cholerae F. None of the above
none of the above
The use of monoclonal antibodies that bind to the soluble IL6 receptor and calm the cytokine storm causes A. natural active immunity B. natural passive immunity C. artificial active immunity D. artificial passive immunity E. None of the above
none of the above
Vibrio cholerae A. colonizes the human stomach B. colonizes 50% of humanity C. can survive at pH=1 D. can cause ulcers and gastric cancer E. is harmless to most people F. is an example of a "commensal pathogen" a microbe that can be harmless or could be harmful, depending on many factors G. none of the above
none of the above
When the kinase activity of BvgS is moderately but not fully active which proteins are expressed? Flagella Flagella plus fhaB Flagella plus fhaB plus pertussis toxin fhaB plus pertussis toxin none of the above.
none of the above.
Transgenic mosquitoes are being developed that express single-chain-fragment-variable antibodies directed against proteins found in _ and _. Flies that are heterozygous for these transgenes are converted to homozygotes using a technology that is based on__. ookinetes, sporozoites, Crispr-Cas9 merozoites, sporozoites, Crispr-Cas9 merozoites, gametocytes, Crispr-Cas9 sporozoites, trophozoites, Crispr-Cas9 Ookinetes, merozoites, Crispr-Cas9
ookinetes, sporozoites, Crispr-Cas9
Where are porins located? cytoplasmic membrane outer membrane peptidoglycan flagellum viral envelope
outer membrane
Which of the following, produced by natural killer cells, is thought of perforate the membranes of infected or cancerous cells? perforins lysins trypsins defensins maganins
perforins
Imagine one person tests positive for anti-Spike IgM while another person tests positive for both anti-spike IgM and anti-spike IgG. What can you conclude about these individuals?
person 1: has gotten vaccine person 2: has been infected with covid
____ can be counted as representing individual infectious virions from a virus suspension. proteomes plaques genomes viruses burst size
plaques
Cytolytic viruses result in the formation of ___, while transforming viruses result in _____. plaques, no proliferation of host cells no proliferation of host cells, plaques proliferation of host cells to a multicellular layer, plaques plaques, plaques plaques, proliferation of host cells to a multicellular layer
plaques, proliferation of host cells to a multicellular layer
The genome of ____ RNA viruses could serve directly as mRNA ambisense double-stranded positive-sense (+) prion negative-sense (-)
positive-sense (+)
The Crispr/Cas9 system is currently being evaluated as an agent in combating HIV. One strategy is to use virus-like particles that resemble HIV and have the same adhesins to deliver the genes encoding Crispr/Cas9 to cells that are targeted by HIV. These virus-like particles would contain nucleic acids that encode Crispr/Cas9 complexes. Such CRISPR-Cas9 complexes could possibly _ infections by targeting _, or might help to __ infections by targeting ______ Manage or cure / HIV integrase enzyme / prevent / reverse transcriptase enzyme prevent / proviral DNA / Manage or cure / HIV protease enzyme prevent / HIV viral RNA / manage or cure / HIV integrase enzyme prevent / CCR5 gene / manage or cure / HIV proviral DNA) Manage or cure / CCR5 gene / prevent / HIV proviral DNA)
prevent / CCR5 gene / manage or cure / HIV proviral DNA)
The bacterial flagellum is a helical protein filament whose ____ motor moves the cell in search of a more favorable environment. shaking vibrating wavelike whiplike propeller-like
propeller-like
The integrated phage genome is called a(n): provirus lytic prion prophage oncogene
prophage
Toxic shock syndrome toxin (TSST) is a T cell superantigen. Intoxication with this causes: stimulation of a large proportion of all T-cells by overriding the normal route of antigen presentation monoclonal B-cell stimulation without T-cell signaling "capping" of several T cell receptors direct overactivation of phagocytic cells, causing autoimmunity dramatic down-regulation in genes that control all cells producing pro-inflammatory cytokines decreased antigen presentation by the antigen-presenting cells, followed by autoantibody formation
stimulation of a large proportion of all T-cells by overriding the normal route of antigen presentation
Describe the "3Q" and "2P" mutations in the spike protein that is used in the Novavax vaccine.
the 2P mutation prevents premature triggering of the fusion peptide the 3Q mutation makes the S1/S2 cleavage site noncleavable
When PCR was first developed, a temperature-labile DNA polymerase was used. What is the advantage of using a thermostable DNA polymerase? With a temperature-labile polymerase, what extra steps were required?
thermostable DNA polymerase is fully functional at higher temperatures necessary to denature DNA during PCR. It was required to reheat the DNA solution before every cycle.
Compare the SARS-CoV2 vaccines made by Pfizer-BioNTech, by AstraZenica-Oxford, and by Novavax. What do they all have in common?
they are all vaccines that use the spike protein or its genes
all of the following statements regarding phospholipids of the cell membrane are true except: they consist of glycerol with ester links to two fatty acids and a phosphoryl group they impart structural rigidity to the membrane they face each other, tail to tail, forming a bilayer the two layers in the bilayer are called leaflets they give the membrane a consistent thickness
they impart structural rigidity to the membrane
In the other of the two revolutionary treatments for sickle cell disease, what is the goal?
to use gene therapy which affects gene expression and little immunosuppression is required
Each adenine-thymine base pair has _ hydrogen bonds, while each guanine-cytosine base pair has_ hydrogen bonds two/one two/three four/three three/two
two/three
How would you use a pseudovirus to test whether the available vaccines protects against SARS-Co2 variants?
you would use a pseudovirus with a luciferase gene to detect infection the pseudovirus expresses SARS-CoV2 wild type spike protein or variants monitor bioluminescence and add antibodies from convalescent patients or vaccinated people to the pseudovirus prior to infection if the vaccine protects against the SARS-CoV2 variants then the antibodies should "neutralize" the pseudovirus, causing a decrease in luminescence