Final Bio Exam

Which of the following forms of metabolism produces the MOST ATP per molecule of glucose?

aerobic respiration

In a population where some individuals are immune to SARS-CoV-2, every new case of the virus will directly lead to 3.5 new cases.

false

Pathogenic microbes and normal microbiota both activate an immune response.

false

Pathogenic microbes and normal microbiota both release toxins.

false

Which molecule holds the least amount of energy?

CO2

The antibodies found in mucus, saliva, and tears are

- IgG - IgM - IgA - IgE

The presence of which antibody would indicate that a patient has a current infection rather than a past infection or vaccination?

- IgM - IgA - IgG - IgD - IgE

Streptococcal infections are extracellular. What adaptive immune cells are important in protecting against strep?

- T-helper cells - Cytotoxic T-cells - B-cells - T-helper cells and B-cells - T-helper cells and cytotoxic T-cells

Which of the graphs in the figure best depict the effect of placing a culture of bacteria in an autoclave at time x?

- a - b - c - d - e

In the figure, which diagram of a cell wall possesses lipopolysaccharide molecules responsible for symptoms associated with infection?

- a - the answer cannot be determined from the information provided - b - both a and b - neither a or b

Select all of the following that are shared characteristics between pathogenic microbes and normal microbiota.

- adherence to host tissues - release of toxins - entering the host by a portal of entry - activates an immune response - disrupts the normal functioning of the host

Which organisms can tolerate oxygen but CANNOT perform aerobic respiration?

- b, d, and e - d - a - b - b and d

How does having a capsule increase the virulence of a bacterial cell?

- bacteria with a capsule cannot be phagocytized by immune cells - the capsule speeds up asexual reproduction of the bacteria - a capsule gives bacteria antibiotic resistance - the capsule increases bacteria motility

All of the following are physical barriers to pathogens, except _____.

- hairs - T-cells - unbroken skin - mucous - tears

Newborn immunity resulting from the transfer of antibodies across the placenta is

- innate immunity - naturally acquired, active immunity - naturally acquired, passive immunity - artificially acquired, active immunity

Which type of RNA genome is NOT possible in viruses?

- linear double stranded - linear single stranded - circular single stranded - circular double stranded

Select characteristics of bacteria from the list below.

- potentially pathogenic - some are germs - cell wall with peptidoglycan - multicellular - eukaryotic

_______ is the preservation of beef jerky from microbial growth by removal of water and is a _______ form of microbial control

- radiation, bactericidal - filtration, bacteriostatic - desiccation, bactericidal - desiccation, bacteriostatic - radiation, desiccation

What does an antigen bound to MHC I on the surface of a cell indicate about that cell?

- the cell is a plasma cell and is making antibodies - the cell has encountered an exogenous antigen - the cell is displaying the antigen for a helper T cell to recognize - the cell is infected with an endogenous antigen

What can happen if the ciliary defense of the respiratory tract is inhibited?

- the mucous membrane would dry out - mucous and microbes will enter the lungs - microbes and mucus will be swallowed - all first line defenses are shut down

A house fly transmits tularemia by carrying tularensis on its feet. This is an example of

- vehicle contact transmission - indirect contact transmission - mechanical transmission - biological transmission - droplet transmission

Which of the cells listed below can present exogenous antigens on Class II MHC proteins?

- virus-infected epithelial cells - healthy epithelial cells - B cells - macrophages - B cells or macrophages

Which of the cells listed below can present exogenous antigens on Class II MHC proteins?

- virus-infected epithelial cells - healthy epithelial cells - B-cells - macrophages - B cells or macrophages

Put these steps in order: 1. B cell receptor on surface of B cells binds antigen. 2. Antigen breakdown products bind major histocompatibility complex protein and are "displayed" on B cell surface. 3. Antigen-antibody complex is internalized and processed. 4. B cell is activated to divide and differentiate into plasma cells and memory cells.

1, 3, 2, 4

In the table, the zone of inhibition is a measure of

the diameter of the area where E. coli growth is prevented

The doubling time of a bacterium was measured at two different temperatures. Which results would be expected of a thermophile?

- 20 minutes at 42°C; 220 minutes at 62°C - 220 minutes at 42°C; 20 minutes at 62°C - 220 minutes at 10°C; 20 minutes at 37°C - no growth at 10°C; 20 minutes at 37°C - 20 minutes at 10°C; 220 minutes at 37°C

During a six month period, 239 cases of pneumonia occurred in a town of 300 people as a result of Coxiella burnetii infections. Before the outbreak, 2000 sheep were kept 30 miles northwest of the town, 95% of sheep tested positive for C. burnetii. Wind blew from the northwest, and rainfall was 0.5cm compared with 7 to 10cm during each of the previous three years. In situation 14.1 what is the incidence of pneumonia in humans for the six-month period?

- 300 - 239/300 = 77% - 95% - 95% of 2000 = 1900 - 239/539 = 44%

In the 1832 cholera outbreak in New York City 4,000 people were sick with cholera by July 1st and in the month of July another 1,000 people got sick. If the total population of NYC was 250,000, what was the incidence of cholera for the month of July?

- 4,000/250,000 or 1.6% - 1,000/250,000 or 0.4% - 5,000/250,000 or 2% - 3,000/250,000 or 1.2%

Cattle feed mixed with 10^6 coli was subject to heating at 55°C, 60°C, and 65°C. The number of E. coli remaining in the feed after heating for 120 seconds is shown below. Estimate the thermal death time for the E. coli in cattle feed at 65°C.

- >120 seconds - <120 seconds - >65C - <65C - between 55-65C

A patient has recently developed a bacterial infection in the tissues surrounding their cardiac pacemaker. The patient's medical team is working fast to treat the infection before the bacteria can establish a biofilm on the surface of the pacemaker. Why will it be more difficult to treat the infection with antibiotics if the bacteria form a biofilm? Select all that apply.

- Bacteria in a biofilm may have abilities that counteract the action of antibiotics. - cells are more metabolically active at the base of a biofilm - Bacteria in a biofilm readily exchange antibiotic resistance genes. - The extrapolymeric substance allows faster diffusion of antibiotics in the biofilm - Cells are metabolically inactive in a biofilm - Biofilms are comprised of a gram negative bacteria that have a natural resistance to antibiotics

How is a B-cell receptor similar to an antibody?

- Both coat the surface of a pathogen to enhance phagocytosis - B-cell receptors and antibodies are bound to the surface of cells - Antibodies and B-cell receptors can both bind to antigen - Antibodies and B-cell receptors both bind to "self" or human cells - B-cell receptors and antibodies are bound to the surface of cells AND antibodies and B-cell receptors can both bind to antigen

B cells, macrophages, and dendritic cells differ from other human cells in that they express _____ on their surface.

- CD8 receptors - MHC-II receptors - MHC-I receptors - interleukin-2 - CD4 receptors

How does the ciliary escalator function to eliminate microbes from the host organism?

- Cilia use digestive enzymes to kill microbes - The escalator recruits inflammatory cells to the respiratory tissues - Microbes are trapped in mucus secretions and moved towards the throat by cilia - Peristalsis sends microbes to the lung alveoli where they are killed

Which of the following describe a virus outside of a host cell?

- DNA or RNA genome - using the host cell to reproduce and form new viruses - part of the domain eukarya in the phylogenetic tree of life - inactive - DNA or RNA genome AND inactive

Why do bacteria grow at less than their optimum doubling time during the lag phase?

- During lag phase, bacteria are synthesizing molecules to prepare for rapid cell growth. - Bacterial DNA replication is inhibited during the lag phase so bacteria are not able to divide. - Bacteria are overwhelmed by waste products that prevents their growth during the lag phase. - Bacteria are not metabolically active during the lag phase. - Many bacteria are dying during the lag phase.

Which of the following is an example of an opportunistic infection?

- E. coli lives in the human intestine and obtain nutrients from the host while producing vitamins used by the host - Virus particles enter through droplet transmission and invade a host cell in order to replicate and eventually kill the host cell - S. typhimurium is spread through contaminated food and damages host tissues in the gastrointestinal tract - S. pyogenes present in the mouth of a healthy person spreads to the throat and causes an infection of these tissue and very sore throat in the host - Gonorrhea is spread by having unprotected sex with a person infected with the bacteria Neisseria gonorrhoeae

The electron carrier flavin adenine dinucleotide exists in three forms; FAD, FADH, and FADH2. Which form of the electron carrier is the most oxidized?

- FADH2 - FADH - FAD

Which of the organisms in the figure has the LONGEST doubling time?

- Geobacillus stearothermophilus - Neisseria meningitidis - more information is required to determine doubling time - Escherichia coli

Yeast is important in the food industry. To take advantage of this fact, Ricky has added yeast to three different types of grapes to try to make wine. Grape 1 has high sugar, Grape 2 has medium sugar, and Grape 3 has low sugar. Predict the outcome of this experiment.

- Grape 1 produced the highest level of alcohol, while Grape 3 produced the lowest - Grape 3 produced the highest level of alcohol, while Grape 1 produces the lowest - All three grapes produced high levels of alcohol - All three grapes produced low levels of alcohol

Herpes simplex virus type 2 (HSV-2) uses epithelial cells in the cervix as a host cell. HSV-2 does not normally infect epithelial cells in other areas of the body. Which characteristics of HSV-2 explains this tissue tropism?

- HSV-2 has spikes that specifically connect to the surface of cervical epithelial cells - HSV-2 has a DNA genome - HSV-2 is small in size - HSV-2 is inactive outside its host cell - HSV-2 is an enveloped virus

Select all of the TRUE statements about antigen presentation of intracellular and extracellular antigens.

- Intracellular antigens are presented on MHC I proteins but extracellular antigens are presented on MHC II proteins - Intracellular antigens are inside a host cell but extracellular antigens are outside and must be brought into the cell - A small portion of intracellular antigen is displayed on the cell surface but the entire extracellular antigen is displayed on the cell surface - Cytotoxic T cells recognize intracellular antigens but helper T cells recognize extracellular antigens

A man develops a respiratory infection caused by a virus. He is not given antibiotics and subsequently recovers after about two weeks. Which best explains why his body destroyed some of his own cells during the viral infection?

- Most viruses transform normal cells into cancer cells that use up available nutrients, causing cell death. - Certain types of phagocytes in the body are able to penetrate virus-infected cells in order to seek out and engulf viruses. - Viral proteins are intracellular antigens that are bound to MHCI molecules and presented to cytotoxic T-lymphocytes that lead to destruction of the infected cell. - Antibodies are able to coat the viruses before they are able to absorb to host cells, resulting in the death of host cells. - The complement cascade is initiated by viral proteins in the host and ultimately results in the death of host cells.

Outbreaks of impetigo have occurred at two local preschools. To determine if the two outbreaks are being caused by the same microbe, cotton swabs are used to take a sample of microbes from the blisters of children at each preschool. Samples are subjected to Grain stain and additional tests. Gram stain results indicate that samples from both preschools are Gram positive coccus bacteria. Based on these results alone, why can't you conclude that the microbe causing the two outbreaks isn't the same?

- One of the microbes may have mutated to become Gram positive between the time of sampling and the time of staining. - Gram positive microbes don't cause impetigo so the samples must be contaminated. - The microbes that cause impetigo are resistant to many antibiotics and therefore can't be Gram stained - There are two possible Gram positive microbes that can cause impetigo.

How do the cell walls of fungi and bacteria differ?

- Only bacteria cell walls contain cellulose - Only bacteria cell walls contain peptidoglycan. - Only fungi cell walls contain phospholipids. - Fungi don't have cell walls because they are not cellular.

Select all of the conclusions that can be drawn from Pasteur's experiments with the S-shaped flasks?

- Pasteur's observations support the theory of spontaneous generation - Microbial life can be destroyed by heat - beef broth is an unsuitable environment for growing microorganisms - microbial life can arise from nonliving matter - microbes can be blocked from accessing favorable growth conditions - microorganisms can be present in nonliving matter, such as air, liquids, and solids

Which of the following is incorrect about temperate phages?

- Phage DNA is present in the host cell when the virus is in lysogeny. - Cause viral DNA to be incorporated into the bacterial chromosome. - Viral DNA is replicated with host DNA and passed on to host cell progeny. - Cause lysis of host cells - Viral DNA enters host cell and becomes latent as a prophage

An enzyme that makes covalent bonds between the sugar of one nucleotide and the phosphate groups in another nucleotide to form the sugar phosphate backbone in DNA is

- RNA polymerase - DNA ligase - DNA helicase - transposase - DNA polymerase

What is happening inside a comedone? Select all that apply.

- Sebum and shed skin cells clog the hair follicle - P. acnes consumes sebum - pH is altered - exoenzyme are released by P. acnes and kill white blood cells

In an experiment to establish the median infectious dose (ID50) for two strains of Streptococcus pneumoniae, populations of lab mice are exposed to increasing doses of each strain and the percentage of mice infected is measured. Select all correct conclusions from the experimental data shown below.

- Strain A is more virulent than Strain B - Mice exposed to the same number of cells will more likely be infected by Strain A - Strain B has a higher ID50 than Strain A

Tamiflu is a common medication given for influenza treatment. It works by protecting and blocking sialic acid molecules on the surfaces of host cells and influenza virus envelopes as they leave the cell. Which statement reflects the mechanism of Tamiflu's action?

- Tamiflu interferes with the metabolic properties of the virus - Tamiflu interferes with the replication of the RNA genome of the flu virus - Tamiflu interferes with the release of the budding viruses from the infected host cells - Tamiflu blocks protein synthesis of the viral genome

Once inside the phagocyte, how are microbes killed?

- The membrane attack complex causes lysis of the microbe. - Inhibition of bacteria cell wall construction - Lysozyme and digestive enzymes break apart the microbe in the phagolysosome - An increase in salt concentration leads to plasmolysis of the microbe

How does a phagocyte "know" it is in contact with a pathogen instead of another body cell?

- The phagocyte detects enzymes released by the pathogen and follows them by chemotaxis - The pathogen is packaged in the phagosome by immune cells so the phagocyte can bind to it and engulf it. - Pathogens have capsules coated in Toll-like Receptors (TLRs) that phagocytes can adhere to. - Phagocytes recognize Pathogen-Associated Molecular Patterns (PAMPs) on the surface of pathogens. - Phagocytes are not able to distinguish body cells (self) from pathogens (non-self) and destruction happens at random

A patient returns to the doctor 2 weeks after cutting their leg while hiking because the wound is red, sore, and contains pus. It appears to be infected with MRSA but the doctor takes a swab of the wound for testing to be sure. Which test result would be consistent with a MRSA infection in the wound?

- The swab is spread over a Mannitol Salt Agar plate. There is growth but the microbe does not ferment mannitol to turn the agar yellow. - A rapid diagnostic test indicates the presence of DNA from S. epidermidis - Plasma does not clot after being incubated with microbes from the swab - When the swab is spread over blood agar, there is an area of clearing around microbe growth.

What is the purpose of NADH and FADH2 in cellular metabolism?

- They catalyze chemical reactions essential for metabolism. - They are enzymes that make ATP. - They carry electrons to the electron transport system. - They accept electrons at the end of the electron transport system. - They pump H+ against the concentration gradient.

A short list of Covid-19 "facts" is being circulated on Facebook. Find the statements that are not correct from this "fact" list.

- You cannot give another person Covid-19 if you are not experiencing symptoms - Covid-19 is the first coronavirus to infect humans. - Some individuals have Covid-19 but are asymptomatic - The genes of the virus that causes Covid-19 are made of DNA - Covid-19 spreads by droplets released when a person speaks, coughs, sings, or sneezes are inhaled by another person

Which of the following would alter a B cell's ability to bind to an antigen?

- a reduction in the number of MHCI molecules on the B cell surface - damage to the B cell's Toll-Like Receptors - a DNA mutation that causes an alteration in the B cell receptor - coating the B cell in antibody - inhibition of the B cell's ability to present antigen on MHCII

Activation of the complement cascade may result in which of the following? (Select all that are correct)

- acute inflammation - reduced blood vessel permeability - antibody production - apoptosis of infected cells - lysis of the pathogen

Which of the following statements regarding metabolic reactions is FAlSE?

- anabolic reactions build large molecules from smaller ones - energy is released in catabolic reactions - ATP holds more energy than ADP in its molecular structure - The formation of ADP requires an input of energy

Syphilis is a sexually-transmitted infection caused by the bacteria Treponema pallidum. Syphilis was once treated by infecting the patient with the protozoa that causes malaria, Plasmodium falciparum. Malaria is a disease spread by an insect vector that is characterized by repeated cycles of fever, shaking, and chills. Why would this treatment control syphilis? Select all correct answers.

- antibodies produced against falciparum would also bind to T. pallidum so both microbes would be targeted for destruction. - Malaria will raise the host's body above the optimal growth temperature of T. pallidum - Both P. falciparum and T. pallidum will be trapped in the mucus secretions of the mucous membrane. - Fever can lead to the production of iron-binding proteins so this essential nutrient is not available to T. pallidum or P. falciparum

The histocompatibility complex proteins (MHC) function in

- antigen presentation - recognition of self - B cell maturation - antigen presentation AND recognition of self - antigen presentation, recognition of self, AND B cell maturation

Which of the following substances or processes kills microorganisms on laboratory surfaces?

- antisepsis - disinfectants - degermers - pasteurization

Which organisms can produce ATP by fermentation or anaerobic respiration?

- b, c, d and e - a, b, c and e - a and b - a, b and c - b, c, and d

The Valley of the Drums is a site in Bullitt County, Ky that is contaminated with a toxic waste called PCB (polychlorinated biphenyl). This site may be a good candidate for a microbial

- biome - nutrient recycling and decomposition - bioremediation - genetic engineering - infectious disease

How is a B-cell receptor similar to an antibody?

- both coat the surface of a pathogen to enhance phagocytosis - B-cell receptors and antibodies are bound to the surface of cells - antibodies and B-cell receptors can both bind to antigen - antibodies and B-cell receptors both bind to "self" or human cells - B-cell receptors and antibodies are bound to the surface of cells AND antibodies and B-cell receptors can both bind to antigen

What is plasmolysis?

- bursting of the cell due to a damaged cell wall - change in cell size as a result of cold temperatures - shrinkage of the cell's cytoplasm caused by high osmotic pressure - a pause in cellular metabolism and ATP production caused by the presence of sugar - oxidative damage in the cell because of the presence of oxygen

Which of the statements below are true for aerobic respiration? Select all that apply.

- can only be performed by human cells - can occur in anaerobic environments - produces more ATP per molecule of glucose than other forms of metabolism - uses only inorganic molecules as a final electron acceptor - uses oxygen as a final electron acceptor - uses an Electron Transport System - produces byproducts like acetone, lactic acid, and ethanol

An interaction between two immune cells and an antigen is shown in the figure. MHCI and the T cell receptor are sticking out from the surface of cell 1 and cell 2 respectively and interacting with each other as shown. Identify the immune cells.

- cell 1; APC, cell 2; phagocyte - cell 1; APC, cell 2; B cell - cell 1; nucleated cell, cell 2; CD8 T cell - cell 1; APC, cell 2; CD4 T cell

A researcher creates an antibiotic that binds only to B. anthracis, lysing the cell from the outside. After a couple of years using this antibiotic, some resistant organisms are found. Which of the following best outlines the mechanism for the development of this resistance?

- cell division of B. anthracis -> altered target -> resistant bacterium - mutation of B. anthracis -> altered target -> resistant bacterium - mutation of B. anthracis -> altered porins -> resistant bacterium - cell division of B. anthracis -> altered porins -> resistant bacterium

How does viral replication differ from cellular replication?

- cells must first get into the virus's genome before cellular replication can occur - they use their own machinery to copy DNA - the cellular genome hijacks the virus's machinery forcing it to replicate - they use the machinery and metabolism of a host cell to produce multiple copies of themselves

Which virulence factor causes MRSA wounds to be filled with a lot of pus?

- coagulase - leukocidins - catalase - methicillin-resistance - Protein A

Pathogenic Staphylococcus produce coagulase and testing for production of this enzyme can help to diagnose Staphylococcal diseases like MRSA. How does coagulase aid Staphylococcus in infecting host tissues?

- coagulase destroys the structure of skin so the bacteria can invade - coagulase is an adherence factor that allows bacteria to attach to skin cells and gain entry into the host. - coagulase lyses blood cells so the bacteria can use their nutrients to divide and increase in number - coagulase destroys immunoglobulin proteins so the adaptive immune system is unable to locate and target the bacteria - coagulase causes the blood to clot, which provides a place for the bacteria to hide from immune cells

Which of the following regarding antimicrobial control agents is FALSE?

- contaminating organic debris such as blood or sputum decreases effectiveness - some agents kill by denaturing microbial cell proteins - soap and detergent are good at degerming because they are surface-active agents - phenols are no longer used in surgery because they cause skin irritation - alcohol is most effective at 100% concentration

Viruses exhibit all of the following except ______.

- definite shape - genes - ability to infect host cells - smallest size among all microbe groups - metabolism

A disease transmitted by a needlestick is an example of

- direct contact - droplet transmission - indirect contact transmission by fomite - direct biological transmission by vector - vehicle transmission

The figure shows the Electron Transport System (ETS) embedded in the plasma membrane of a bacteria cell. Use what you know about ETS structure and function to identify where ATP is produced in the figure.

- e - a - b - d - c

The core of every virus particle always contains _______.

- either DNA or RNA - capsomeres - DNA - enzymes - DNA and RNA

Autoimmune disorders are characterized by immune destruction of self tissues. The underlying basis of these disorders is

- failure to delete B and T cells that are reactive to self antigen - an overproduction of complement - an oversecretion of antibodies from memory B cells - failure to produce memory cells

Autoimmune disorders are characterized by immune destruction of self tissues. The underlying basis of these disorders is

- failure to delete B and T cells that are reactive to self antigens - an overproduction of complement - an oversecretion of antibodies from memory B cells - failure to produce memory cells

Staphylococcus aureus in a non-motile, a facultative anaerobe, and a mesophile. You place the S. aureus in a culture tube with all essential nutrients. How should you incubate the tube to produce the highest cell mass of S. aureus within two hours?

- flask with aeration and shaking at 37°C - flask left on the lab bench at 20°C - flask grown in an anaerobic chamber that removes oxygen from the air around the flask at 37°C - flask without aeration at 50°C - flask in a water bath with shaking at 90°C

If the bacteria cell plasma membrane was damaged, what step of metabolism would be affected?

- formation of NADH and FADH2 in glycolysis and the Krebs cycle - Establishment of the hydrogen ion gradient in the Electron Transport System - Formation of ATP in the Krebs Cycle - Breakdown of glucose to pyruvic acid during glycolysis - Formation of ATP in glycolysis

Which of the following statements describes the process of horizontal gene transfer?

- gaining a single new gene sequence from outside of the cell - replication of genomic DNA to be passed on the daughter cells - a DNA mutation that is passed onto offspring by the process of DNA replication and cell division - DNA transferred to the next generation of bacteria from a related cell

What kind of growth pattern is seen in a thioglycolate broth culture of aerotolerant anaerobes and why?

- growth is seen primarily at the surface of the broth as these microbes only use aerobic metabolism - heavy growth is seen at the surface of the broth as well as throughout the tube as these microbes thrive in the presence of oxygen but are able to use fermentation or anaerobic respiration in conditions where the oxygen concentration may be low or absent - growth is seen consistently throughout the tube as these microbes voluntarily choose what type of metabolism they want to use at the time - growth is seen consistently throughout the tube as these microbes mainly rely on fermentation but are able to grow in the presence of oxygen

A virus's ability to infect a host cell depends primarily upon the

- host cell's ability to phagocytize viral particles - presence of receptor sites on the host cell membrane - presence of pili on the host cell wall - type of viral nucleic acid - enzymatic activity of a host cell

You use a germicide to destroy various types of microbes on surfaces in your house. You have to leave the germicide on the kitchen counter for 1 minute to kill all of the enveloped viruses contaminating it from the chicken you prepared for dinner. If you want to use the same chemical in the bathroom to kill the sporulating Clostridium bacteria in the toilet, you should ____ the incubation time with the same chemical.

- increase - decrease - not change

The circulating substances that affect the hypothalamus and initiate fever are ___.

- interferons - lysozymes - complement - histamine - pyrogens

Select all phases of the bacterial growth curve where the number of cells is NOT increasing (either staying the same or decreasing).

- lag phase - log phase - stationary phase - death phase

A bacteria culture was grown in a glucose medium without O2. O2 was added to the medium at the time marked X. The rates of glucose and oxygen (O2) consumption and number of cells are shown in the Figure. Addition of O2 to the medium at time X resulted in

- less production of ATP - the bacteria performing fermentation - less efficient metabolism - a slower growth rate of the bacteria - the bacteria switching to aerobic metabolism

Match the virulence factor with its effect on a microbe's ability to invade and infect a host

- lipopolysaccharide: endotoxin produced by Gram negative bacteria that elicits a strong immune response in the host - urease produced by H. pylori: exoenzyme produced to neutralize pH and enable the microbe to penetrate host tissues - hyaluronidase produced by streptococci and staphylococci: exoenzyme produced to degrade connections between host cells - botulinum toxin: disrupts the functioning of muscle cells to prevent contraction

Jo, a technician in a microbiology lab, is measuring the number of bacteria cells in a culture in the morning and again in the afternoon using serial dilutions and viable plate counts. Jo counted more colonies from the morning test than the afternoon test. What was the culture's growth phase that afternoon?

- log - lag - stationary - death

Which of the following is correct and supports the argument that most microbes do not cause harm to humans.

- microbes are capable of infecting humans and causing diseases - overuse of antibiotics has led to microbe resistance to these drugs - microbes can perform photosynthesis, decomposition, and be used in food production - virulent microbes cause severe disease - a healthy human does not have microorganisms growing in their body normally

Your friend meets you after a long run and is sweating so much that they have soaked through their shirt. What prevents pathogenic microbes from overgrowing in their sweaty armpits?

- moisture prevents pathogen growth in the armpits. most microbes prefer to grow in dry places - mucus is antimicrobial and is released by the skin there to prevent pathogen growth - the structure of the hair follicles extends through the epidermis and dermis and prevents pathogen entry past the skin surface - lysozyme is a substance in sweat that breaks apart bacterial cell walls - the armpit contains a lot of propionibacteria normally because of the oily sebum. This protects from pathogenic bacteria growth but also contributes to acne

Figure 1 shows the antibody response in a host following antigen exposure. Based on the figure, you can conclude that the antigen in the initial exposure and in the secondary exposure was _____.

- more concentrated in the secondary exposure - the same antigen - recognized by memory B cells each time - more virulent in the secondary exposure

You have isolated a mutant strain of Serratia marcescens that has an abnormal ribosome that is not functioning well. Which of the following might be affected by this change?

- motility - ability to survive harsh environmental conditions - biofilm formation - production of proteins - three dimensional shape of the cell

Inhibitors that bind away from the enzyme's active site to prevent substrate binding to the enzyme are

- noncompetitive - competitive - coenzymes - dentured - ions

How do the cell walls of bacteria and viruses differ?

- only bacteria cell walls contain cellulose - only viral cell walls contain phospholipids - only viral cell walls contain peptidoglycan - viruses don't have cell walls because they are not cellular

Phagocytes utilize all of the following to help locate and contain microorganisms EXCEPT

- opsonization - chemotaxis - lysozyme - complement - adherence to PAMP on the microbe surface

Antibodies are capable of binding up several antigens at once in order to reduce the number of infectious agents that need to be dealt with. This function of antibodies is known as

- opsonization - neutralization - agglutination - complement fixation

Why does milk eventually spoil despite being pasteurized?

- pasteurization is bacteriostatic and prevents growth of microbes in the milk but doesn't kill them - pasteurization does not kill Gram-negative bacteria - pasteurization reduces the microbe count in the milk and doesn't achieve sterilization - only bacteria that have a capsule are killed by pasteurization and these bacteria will increase in numbers and eventually spoil the milk

Which of the following statements are FALSE?

- pasteurization reduces the presence of microbial life but does not achieve sterility - antisepsis is the removal of microbial life from a living surface - use of an autoclave or dry heat can remove all microbial life - before surgery, the patient's skin must be disinfected - preserving all fruit in sugar is bacteriostatic for microbes in the fruit

In which step of the lytic cycle does the viral DNA enter the host cell?

- penetration - attachment - lysis - biosynthesis - maturation

JayVaugh has a very sore throat. Analysis of a swab from his nose confirmed that the causative organism is Bacillus anthracis, a gram-positive bacteria. Imagine that you are the technician looking at the gram stain from JayVaugh's culture. What would you expect to see as you look through the microscope?

- pink, rod shaped organisms arranged in pairs - purple, spherical shaped organisms arranged in chainlike formations - purple, rod-shaped organisms - pink, spherical-shaped organisms arranged in chainlike formations

In which of the following patterns of disease does the patient experience no signs or symptoms?

- prodromal - invasion - convalescence - incubation - both incubation and invasion

The figure shows the Electron Transport System embedded in the plasma membrane of a bacterial cell. Use what you know about ETS structure and function to identify "2".

- production of ATP - production of ADP - formation of water - the path H+ - FADH2 reduction

The space between the cell membrane and the cell wall is important during aerobic respiration. Why?

- pyruvate is transported into the space to be converted into acetyl CoA to enter the Krebs Cycle - electron carriers are located in this space - oxygen combines with electrons in that space to form water - hydrogen ions are transported into the space to set up a hydrogen gradient

How do phagocytic cells adhere to pathogens?

- receptors on the phagocyte recognize and bind to adhesins on the microbe - PRRs on the phagocyte recognize and bind to TLRs on the microbe - PRRs on the phagocyte recognize and bind to PAMPs on the microbe - Phagocytes are covered in spikes that stick to the pathogen - Phagocytes release exoenzymes that enable them to corner pathogens between host cells and adhere to them

In order to prepare instruments for surgery, it is necessary to sterilize them which is

- removal of all microbial life - using chemicals to temporarily prevent their growth - lowering microbial counts in order to meet public health standards - placing them in a freezer to slow microbial growth

Conjugation differs from reproduction because conjugation

- replicates DNA - transfers DNA vertically to new cells - transfers DNA horizontally to nearby cells without those cells undergoing replication - transcribes DNA to RNA - copies RNA to make DNA

A positive antibody test for HIV infection would be a _____ of infection

- sign - symptom - syndrome - defense - transmission

_______ is very toxic but is commonly used to disinfect hospital equipment and kills microbes by inactivating their proteins.

- soap - formaldehyde - alcohol - bleach - arsenic

In an experiment, an animal was injected with two different antigens. After several days, B lymphocytes were removed from the animal and the individual B cells were placed in separate small containers. Then the original two antigens were placed in the containers with each B cell. What results would you expect to observe?

- some B cells produced an antibody to one of the antigens and not both of them - some of the B cells did not produce antibodies to any of the antigens - each of the B cells produced antibodies to both of the antigens

Your neighbor's child has been diagnosed with a disease that causes the child to make no antibodies. Which of the following functions is this child still able to perform at normal levels?

- stop viruses from binding to cells - stop toxins from damaging host tissues - increase the activity of phagocytic cells - antibody-dependent cell-mediated cytotoxicity - activate cytotoxic T-lymphocytes that kill infected cells

The adaptive immune response differs from the innate response in that

- the adaptive immune response targets specific immunogens and remembers them, mounting an even stronger response on subsequent encounters, whereas the innate response in nonspecific and has no memory - B and T lymphocytes can each target multiple proteins, whereas the innate response targets only a single type of antigen - the adaptive immune response involves physical barriers and nonspecific processes, whereas the innate immune response relies on the actions of B and T lymphocytes - the innate immune response targets microbes that get into host cells, whereas the adaptive response targets only exogenous antigens

Jessica is doing a test in order to determine which type of microbe she is working with. In order to do this test, she uses as thioglycolate broth solution. After letting the bacteria sit in the broth for 24 hours, Jessica returns and observes growth in a band a few centimeters below the surface of the broth, and nowhere else. Based on these results, she can conclude that

- the bacteria are aerobic, and produce enough enzymes to detoxify bacteria in large amounts - the bacteria are aerobic, but only produce enough enzymes to detoxify bacteria in small amounts - the bacteria are aerobic, and can produce enzymes to detoxify oxygen in small amounts - the bacteria are anaerobic, and do not produce enzymes to detoxify oxygen

Neisseria gonorrhoeae is a gram-negative coccus bacteria that causes the sexually-transmitted infection gonorrhea. It has a tendency to form biofilms and can horizontally exchange DNA. Based on this information, what can you conclude about Neisseria gonorrhoeae?

- the cell wall of Neisseria gonorrhoeae contains peptidoglycan - Neisseria gonorrhoeae have flagella that allow taxis in response to a chemical attractant - The scientific name of the bacteria can be abbreviated Neisseria g. - Neisseria gonorrhoeae are oblong in shape and arranged in long chains - Neisseria gonorrhoeae contains several small circular DNA plasmids

Which statement correctly describes the eukaryotic and prokaryotic ribosome?

- the eukaryotic ribosome is located only in the cytoplasm while the prokaryotic ribosome is located in the cytoplasm and in some of the cell's organelles - the eukaryotic ribosome reads A,C,G, and T base pairs while the prokaryotic ribosome reads A,C,G, and U. - The ribosome in the eukaryotic cell cytoplasm is larger than the prokaryotic ribosome. - The eukaryotic ribosome makes mRNA and the prokaryotic ribosome makes DNA.

Select all of the following that would either enhance or reduce a phagocytes ability to bind to a microbe.

- the microbe is an enveloped virus - Initiation of the complement cascade results in the microbe being coated in the complement protein C3b. - A DNA mutation that causes alteration in the phagocytes Toll-Like Receptors - The microbe acquired the ability to make a capsule.

What is the benefit of complementary base pairing in the DNA molecule?

- the replicated DNA molecules have old and new genetic information in them - one strand can serve as a template for construction of a second strand during DNA replication - it enables more codon combinations from the four base pairs - both DNA strands can be synthesized as leading strands

How would a limited food supply affect the bacterial growth curve?

- there would be no lag phase - the log phase would be shortened - the culture would not enter a death phase but would remain stationary indefinitely - the death phase would be shortened - the slope of the log phase growth curve would be steeper

A sample of E. coli has been subjected to heat for 17 minutes and all of the cells in the sample are destroyed. Which of the following terms best describes this event?

- thermal death point - thermal death time - thermal death rate - heat sterilization point - heat pasteurization rate

The rates of O2 and glucose consumption by a bacterial culture are shown in the figure. Assume a bacterial culture was grown in a glucose medium without O2. Then O2 was added at the time marked X. The data indicate that

- these bacteria don't use O2 - these bacteria get more energy anaerobically - aerobic metabolism is more efficient than anaerobic metabolism for these bacteria - these bacteria cannot grow anaerobically - these bacteria use fermentation and not anaerobic respiration

Which of the following statements regarding antibody function is FALSE?

- they can prevent viral attachment to a host cell - they can facilitate phagocyte attack on a bacteria - they can penetrate host cells to bind endogenous antigens - they facilitate cytolysis of cells - they can bind more than one pathogen at a time, forming complexes

Which statement about horizontal gene transfer is associated with conjugation?

- this mechanism may result in the transfer of genes that encode antibiotic resistance - this mechanism requires direct cell-to-cell contact - this mechanism of genetic gene transfer always involves a one-way transfer from a donor cell to a recipient cell - this mechanism is initiated by cells with F plasmids - conjugation can only occur between related cells - conjugation involved a virus transferring DNA from a donor to a recipient cell

What is the purpose of the high concentration of hydrogen ions created by the Electron Transport System on one side of the cell membrane?

- to produce NADH or FADH2 - to power ATP synthase to produce ATP - to produce water for the cell to use - to move electrons along the electron transport system - to produce energy by fermentation

You are in charge of fermentation for Your Favorite Yogurt Company. One day you get a frantic call from your fermentation technologist. It appears that the bacterial cultures in vat one have all lysed due to a bacteriophage infection. You must quickly come up with a solution to keep the yogurt production going.

- treat all bacterial cultures with an antibiotic to kill the bacteriophage - create a mutant bacterial strain to use in your fermentation process that has a deletion of the gene encoding the receptor used by the bacteriophage to bind to the bacterium - add more sugar to the bacterial cultures that promote growth of bacteria and not bacteriophage - create a mutant bacterial strain to use in your fermentation process that overproduces the gene encoding the receptor used by the bacteriophage to bind to the bacterium

Select all of the following that are true reasons why viruses are not living.

- viruses have DNA or RNA but never both - viruses are acellular - viruses have an organized structure - viruses can adapt to their environments - viruses are obligate intracellular parasites and cannot reproduce without a host - viruses lack essential genes and rely on host genes to perform these functions

Exogenous antigens bound to MHCII on the surface of a B cell

- will be destroyed by a cytotoxic T cell - made it through a portal of entry - are viral - originate in the bone marrow

A graph of a bacterial growth curve is shown below. For this graph, what is the correct y-axis label and scale?

- y-axis label: severity of symptoms, scale: logarithmic - y-axis label: amount of ATP produced, scale: arithmetic - y-axis label: number of bacteria, scale: logarithmic - y- axis label: time, scale: arithmetic

In both scalded skin syndrome and impetigo, Staphylococcus aureus can be the causative agent, exfoliative toxin is released, and the disease is spread by fomite transmission.

1) Staphylococcus aureus 2) exfoliative toxin 3) fomite transmission

Goblet cells secrete mucus that contains substances like IgA that binds to microbes so immune cells can destroy them and lysozyme that breaks down the bacterial cell wall

1) goblet cells 2) mucus 3) IgA 4) lysozyme

The primary immune response to an antigen is slow. The secondary immune response to the same antigen involves memory B and T cells that were not involved in the initial response.

1) is slow 2) memory B and T cells

All nucleated cells express MHC class I molecules on their surface so that they can display intracellular antigens that are infecting them.

1) nucleated cells 2) intracellular 3) are infecting them

The bacterium Escherichia coli is capable of performing aerobic respiration, anaerobic respiration, and fermentation. When would it perform fermentation?

E. coli would perform fermentation if there were no electron acceptor

Each of the following results in drug resistance EXCEPT

a drug being used as a nutrient by the cell

A clinical microbiologist makes serial dilutions of several antimicrobial drugs in broth and then incubates each drug dilution with a standard amount of a patient's isolated pathogen. What is this microbiologist setting up?

a minimum inhibitory concentration test (MIC)

After penetration, animal viruses need to be uncoated but bacteriophage need not be. Why?

bacteriophage inject their DNA into the host during penetration so the capsid doesn't enter the host cell

Which of the following structures are present in all animal viruses?

capsid, spikes, and a genome

Digestion of microorganisms inside phagocytes occurs in the phagosomes.

false

HIV has the ability to attach to and enter almost any host cell it encounters.

false

Some penicillin-resistant bacteria are capable of making β-lactamase enzymes that can ___ penicillin by breaking the bond labeled ____.

inactivate; bond labeled 3 (double bond to O, with nitrogen)

Your child develops an ear infection and the Dr. gives you ten days worth of antibiotics. After three days, you stop giving your child antibiotics. Which of the following is true?

not finishing the antibiotics can select for more antibiotic-resistant bacteria over time

A patient is infected with a bacteria that is producing beta-lactamase. Which of the following antimicrobial drugs or drug combinations could still have an effect on this bacteria?

penicillin prescribed along with a beta-lactamase inhibitor and quinolone

Cells were exposed to varying concentrations of an antibiotic. Which of the following mechanisms of action of this antibiotic could be supported by the data below? Inhibition of

peptidoglycan linkage

Which of the following modes of action would be the most selectively toxic when treating a bacterial infection in a human?

preventing cell wall synthesis

Which of the following statements describes BOTH aerobic respiration and anaerobic respiration?

process involves the ETS and chemiosmosis

Cases of whooping cough, caused by Bordetella pertussis infection, are increasing in Kentucky. Previously successful treatment with erythromycin is now failing. What structure in pertussis is most likely affected by a mutation that is making the organism more resistant to this antibiotic?

ribosome

Competitive inhibition of sulfa drugs on synthesis of folic acid

sulfa drugs mimic the shape of PABA and competitively inhibit its binding to the enzyme active site

A student has obtained a sample of pond water for study. Using the high power lens, he observes several cells with nuclei. He can conclude that the cells are NOT bacteria.

true

An organism that can use only oxygen as the final electron acceptor in its electron transport chain may also have the ability to perform fermentation.

true

Glycolysis is utilized by cells in both respiration and fermentation.

true

In an experiment to establish the median infectious dose (ID50) for two strains of Streptococcus pneumoniae, populations of lab mice are exposed to increasing doses of each strain and the percentage of mice infected is measured. If only one of the strains has the ability to make a capsule, an important virulence factor for infection, it is most likely Strain A.

true

Methicillin-resistant Staphylococcus aureus (MRSA) is harmless on healthy, intact skin but can cause infection if introduced to other parts of the body.

true

Moist heat destroys organisms by denaturing proteins.

true

Pathogenic microbes and normal microbiota both adhere to host tissues.

true

Pathogenic microbes and normal microbiota both enter the host by a portal of entry.

true

The cell walls of bacteria are responsible for the difference in the Gram stain reaction

true

Why do antimicrobial drugs like erythromycin that target protein synthesis in bacteria also harm human cells at high doses?

human cells have a 70S ribosome derived from bacteria in their mitochondria

In what clinical situation is it most appropriate to use a broad spectrum antimicrobial?

in a case of bacterial meningitis; the infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible because we don't have time to determine which drug will work best because the patient would die in the meantime.