Portage Learning Microbiology Final Exam Rated A+ (100% Correct Questions & Answers)2023, Exams of Microbiology

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Portage Learning Microbiology Final Exam Rated A+

(100% Correct Questions & Answers)Latest 2023/

Microbiology is the study of what? - Answer Microbiology is the study of microbes (microorganisms and viruses) and their biological processes. What is the smallest biological unit of life? - Answer A cell What is a macromolecule? - Answer A macromolecule is classified as a complex molecule that is composed from smaller subunits. What are the four main types of macromolecules? - Answer Proteins, nucleic acids, lipids and carbohydrates What various functions do proteins have in a cell? - Answer Proteins may facilitate the movement of materials in or out of a cell. Some can act as enzymes that catalyze, or speed up, biochemical processes. Others play a structural role while other proteins, such as filaments, enable movement. What are the two major types of nucleic acids and their roles? - Answer There are two major types of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleic acids are chemical molecules that carry genetic information within the cell. DNA contains a vast amount of hereditary information and is responsible for the inheritable characteristics of living organisms. RNA is responsible for deciphering the hereditary information in DNA and using it to synthesize proteins. What is the plasma membrane, and what is it made up of? - Answer The plasma membrane serves the cell as a surrounding barrier that separates the inside of the cell from the outside surrounding environment. The plasma membrane also restricts the movement of materials (water, nutrients, etc) either in or out of the cell, thus allowing a cells to absorb and keep what is needed (influx) while also preventing the escape (out flux) of essential nutrients. The plasma membrane is composed of lipids (hydrophobic hydrocarbons). What are the three main components of polysaccharides? - Answer Polysaccharides are composed of carbon, hydrogen and oxygen atoms. Examples would include, C6H12O6 (glucose) C12H22O11 (sucrose) and C6H10O5 (cellulose). What is the primary difference between prokaryotic and eukaryotic cells? - Answer Eukaryotic cells contain a nucleus, a membrane enclosed region within the cell that contains the genetic material. Prokaryotic cells do not have a nucleus and can be further classified as either Bacteria or Archaea. What are the main morphologies of bacteria? - Answer Bacteria can be described as coccus (round/spherical), bacillus (rod), vibrio (curved rod) or spirillum (spiral/corkscrew). Which group (classification) of microbes is noted for its ability to survive under harsh conditions? - Answer Archaea. They are able to survive in extremely harsh

environmental conditions such as high salt levels, acid conditions, high temperatures and oxygen-poor conditions. What are the four main classifications of Eukarya? - Answer Eukaryotic microorganisms are classified as either belonging to Animalia, Plantae, Fungi or Protista. Can viruses be classified as either prokaryotic or eukaryotic? - Answer No. Viruses are considered neither prokaryotic nor eukaryotic. Viruses are not considered living and do not replicate on their own, meaning they must replicate within a host. The lipid bilayer of the plasma membrane is composed of what? - Answer The cell membrane is a bilayer composed primarily of amphipathic phospholipids, meaning they contain a polar hydrophilic (water loving) head group and a non-polar hydrophobic (water fearing) tail region. The lipid bilayer is situated in such a way where the non-polar tail groups face inward thus orienting the polar head groups to interact with water both outside and inside of the cell. What are the primary cellular organelles described in this module? Be sure to know the roles of each. - Answer Ribosomes (protein synthesis), ER (site of protein synthesis), Golgi (protein modification and distribution), lysosomes (waste disposal), mitochondria (ATP generation) and chloroplasts (plants only; site of photosynthesis). Be able to identify the primary organelles within a cell as shown in Figures 1.4 - Answer Prokaryotic Cell Be able to identify the primary organelles within a cell as shown in Figures 1.5 - Answer Eukaryotic Cell Be able to identify the primary organelles within a cell as shown in Figures 1.6. - Answer EC magnified True/False. A virus is considered a microorganism. - Answer False. Viruses are not living and as such are not considered microorganisms. Viruses can, however, be classified as microbes, a more general term that includes microorganisms and viruses. What is the smallest biological unit of life? - Answer A cell At a generalized level, all cells are comprised of what? - Answer Macromolecules* *A student may also answer: Proteins, Lipids, Nucleic acids and Carbohydrates, but they must answer with all four to be fully correct. How many different types of amino acids are available from which to make proteins?

• Answer 20 How many amino acids are classified as being essential amino acids? - Answer 9

What are the two major types of nucleic acids and their roles? - Answer There are two major types of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleic acids are chemical molecules that carry genetic information within the cell. DNA contains a vast amount of hereditary information and is responsible for the inheritable characteristics of living organisms. RNA is responsible for deciphering the hereditary information in DNA and using it to synthesize proteins. Complete the following DNA strand, and indicate how many bonds are formed for each complementary pair: 3' GGTCATCG 5'5' CC AGC 3' - Answer 3' GGTCATCG 5'5' CCAGTAGC 3'There are 2 bonds formed between A and T, and 3 bonds between G and C. The plasma membrane (select all that are true): A) Only restricts movement of materials into the cell. B) Is often a bilyaer comprised of lipids C) Cannot prevent essential nutrients from escaping D)Contains hydrophobic tails pointing inward. - Answer B & D How many carbon atoms are present in glucose? - Answer 6, The molecular formula of Glucose is C6H12O True of False: Eukaryotic cells do not have a nucleus. - Answer False, Eukaryotic cells do have a nucleus (prokaryotic cells do not). True or False: Prokaryotic cells can be subdivided into Bacteria and Archaea. - Answer True True or False: Archaea is noted for its ability to survive under harsh conditions. - Answer True, Archaea can often be found in harsh conditions such as high salt levels, high acid conditions, high temperatures and even oxygen-poor conditions. Which of the following microorganisms are considered to be Eukarya? Select all that apply. - Answer Animalia Plantae Fungi Protista Microorganisms classified as _________ obtain most of their energy by converting light energy into chemical energy. - Answer Plantae Which of the following are considered Protista? Select all that apply. - Answer Algae, Amoeba True or False: A defining characteristic of Protista is the inability of colonies to form tissue layers. - Answer True The function of the lysosome is (select all that apply): - Answer Waste disposal via hydrolytic enzymes, Lysosomes are membrane-enclosed organelles capable of degrading unwanted cellular debris

Identify the following cellular components by matching the number with the description. A. Cell wallB. LysosomeC. CentrioleD. Rough endoplasmic reticulumE. Plasma membraneF. NucleusG. Golgi apparatus - Answer 1: F 2: B 3: E 4: G 5: D The combination of the cell membrane and the outer membrane is referred to as the (select all that apply): - Answer Cell envelope, The cell wall is also known as the 'outer membrane' and does not apply. A capsid is relative to a virus. The outer leaflet is only a partial description of the cell membrane. The function of the mitochondria is (select all that apply): - Answer To produce energy (ATP), Mitochondria are considered the power plant of the cell, as it produces ATP. True or False. All multicellular microorganisms classified as Animalia are autotropic.

• Answer False, They are heterotropic. What is cellular metabolism? - Answer Metabolism is a controlled set of biochemical reactions that occur in living organisms in order to maintain life. What is the primary function of enzymes, and how are they regulated? - Answer Enzymes speed up chemical reactions. Most notably, the enzyme is not consumed during the reaction and can be used repeatedly by the cell. Enzymes can also be regulated by a cofactor such that in the absence of the proper cofactor, enzymes are inactive while in its presence enzymes are active. What is the difference between catabolism and anabolism? - Answer Catabolism is the process of breaking down larger molecules into useful energy sources whereas anabolism is the building up or biosynthesis of macromolecules from smaller molecular units into larger complexes, most often associated with cellular growth and repair. ATP has the energy to________, while ADP has the capacity to _______energy. - Answer Answer 1: Donate Answer 2: Accept Chemotrophs can be subdivided into what two additional subgroups? - Answer Chemotrophs, which acquire energy from preformed chemicals found in the environment, can be divided into either organotrophs (removing electrons from organic molecules such as glucose) or lithotrophs, which remove electrons from inorganic molecules. Chemotrophs utilize which form of phosphorylation? - Answer Chemotrophs use oxidative phosphorylation (as opposed to photo or substrate-level phosphorylation).

Oxidative phosphorylation utilizes the energy released by the chemical oxidation of nutrients to reform ATP. What are the three distinct stages in the catabolism of glucose? - Answer Glycolysis is the first step of this process and yields 2 molecules of ATP. Next, by either fermentation (or respiration) 2 additional molecules of ATP can be produced. Last, the electron transport chain (ETC) produces 34 ATP via an oxidative phosphorylation event at the plasma membrane. What are the reactants of glycolysis? - Answer Reactants are defined as any molecules present and involved at the beginning of a specific chemical reaction (ie) glycolysis. In terms of writing out a chemical reaction, the reactants are everything located to the left of the arrow. The reactants of glycolysis are glucose, the co- enzyme NAD+ and ATP. What are the two main strategies for replenishing cellular concentrations of NAD+, and when these strategies be utilized? - Answer Fermentation and Respiration are the two strategies used by the cell to convert NADH (end product of glycolysis) back to NAD+. Fermentation occurs in the absence of oxygen (anaerobic conditions) while respiration occurs under aerobic (presence of oxygen) conditions. Notably, respiration is more efficient that fermentation. How are the TCA and ETC related? - Answer The end products of the Kreb's (TCA) cycle are used to fuel the electron transport chain. In other words, as the Kreb's cycle (TCA) produces an abundance of reduced electron carriers (NADH and FADH2), it fuels the ETC. As the electrons are transferred from NADH/FADH2 to terminal electron acceptors a proton motor force is generated, ATP synthase is activated and up to 34 molecules of ATP can be produced. In the absence of sugars, are entirely different metabolic pathways used to process alternative sugar sources (fructose or lactose)? - Answer No. Additional enzymatic steps are simply required at the beginning of catabolism to convert complex sugars into the usable forms of either glucose or a glucose intermediate (glucose- 6 - phosphate). Excluding sugars, what are the other sources of energy? Which is highest in energy?

• Answer Polysaccharides, proteins and lipids can all serve as potential energy sources in the absence of sugar. Lipids are rich in energy, often having several reduced carbon molecules (high in hydrogen content) that can be used in both the TCA and ETC cycles. In what organelle does photosynthesis take place? - Answer Photosynthesis, the process of capturing sunlight and converting it into usable energy source, occurs in the chloroplasts. Chloroplasts are double-membrane enclosed organelles. Each chloroplast contains the green photosynthetic pigment chlorophyll. In phosphorylation, the light reactions always occur where? - Answer In phosphorylation, the light reactions always occur where?

What are the byproducts of light reactions used for in dark reactions? - Answer The ATP and NADPH produced via light reactions are used in dark reactions to convert carbon dioxide and water into organic carbon compounds as well as useful carbohydrates (a process called carbon fixation). Complete the following chemical reaction by placing the appropriate number in the blanks: CO2 + ATP + NADPH + H20 →C6H12O6 + ADP + NADP+ - Answer 6CO2 +18 ATP

• 12NADPH + 12H20 →C6H12O6 +18 ADP + 12NADP+ Identify the enzyme associated with the following enzymatic reactions: A-B → B-A Ab + C → A + Cb - Answer 1: Isomerases 2: Transferases What determines the specificity of an enzyme? - Answer The specificity of an enzyme is heavily influenced by its active site—a unique chemical structure bound only by select target molecules. The structure is influenced by the amino acid composition of the protein as this in turn influences the fold, shape and 'appearance' of the enzyme. The active site (and it's target protein) can be thought of as a lock- and-key relationship. The active site provides a specificity (like a lock) that only specific target proteins can bind—much like how only a specific key will fit into, unlock and 'activate' a lock. True or False: As movement requires energy, metabolism can be defined as a controlled set of biochemical reactions that occur in only motile organisms in order to maintain life. - Answer False, Metabolism occurs in all living organisms, not just those that move. True or False: Enzymes are polysaccharides that catalyze chemical reactions. - Answer False, Enzymes are proteins that catalyze chemical reactions. What are the usually metal ions known to assists enzymes during the catalysis reaction? - Answer Cofactors are usually metal ions and assist enzymes during the catalysis reaction. Define catabolism. - Answer Catabolism is the process of breaking down larger molecules into useful energy sources. Upon cellular injury, which metabolic process is involved during the growth and repair phases of the cell? - Answer The anabolic process would be active as it (by definition) is involved in the building up of small complexes into larger complexes. Describe the energy transfer process relative to both ATP and ADP. - Answer ATP has the energy (phosphate group) to donate while ADP can accept energy in the form of a phosphate group. Thus, ATP can be reduced (ATP ⟶⟶ADP + Pi) while ADP can be built into ATP (ADP + Pi ⟶⟶ATP).

From what source do chemotrophs acquire energy? - Answer Chemotrophs acquire energy from preformed chemicals found in the environment. An organism that obtains its source of carbon from inorganic molecules such as carbon dioxide is referred to as a ____________? - Answer Autotroph A reactive intermediate would be present in which phosphorylation process? A) Photophosphorylation B) Substrate-level phosphorylation C) Oxidative phosphorylation - Answer Substrate-level phosphorylation, The chemical compound losing the phosphate group is referred to as the phosphorylated reactive intermediate. The catabolism of a single molecule of glucose goes through what 3 distinct transitions? - Answer The breakdown of glucose goes through (1) Glycolysis then (2) Fermentation or Respiration and finally through (3) the electron transport chain (ETC). What is the most energetic transition in the catabolism of glucose? - Answer The electron transport chain yields 34 ATP while both glycolysis and fermentation (or respiration) each yield only 2 ATP. Identify the reactants of the following chemical equation: Glucose + 2NAD+ →→ 2 NADH + 2 Pyruvate + 2 ATP - Answer The reactants are to the left of the arrow: Glucose and 2NAD+ The presence of what molecule 'signals' to the cell that glycolysis is about to start? - Answer Glucose- 6 - phosphate (G6P) True or False: During fermentation one means of eliminating pyruvate is by converting it into lactic acid. - Answer True, Pyruvate can be converted into either lactic acid or ethanol and then eliminated from the cell. How many ATP does the tricarboxylic acid (TCA) cycle produce per pyruvate? - Answer 2 ATP True or False. The reactants of the TCA cycle directly enter and fuel the electron transport system. - Answer True In the absence of glucose, which of the following can be used as alternative energy sources? Select all that apply. - Answer Carbohydrates, Lipids, Lactose For the catabolism of proteins and lipids, which of the following enzymes are used? Select all that apply. - Answer Proteases, Lipases Proteases breakdown proteins while lipases breakdown lipids. True or False. The β-oxidation pathway is responsible for the anabolism of fatty acid chains. - Answer True

Describe the relationship between chloroplasts and chlorophyll. - Answer Both chloroplasts and chlorophyll are associated with photosynthesis. Chloroplasts are the double membrane-enclosed organelles that contain the photosynthetic pigment chlorophyll. True or False: Chloroplasts are specific to algae and plants. - Answer True The process of photophosphorylation produces which of the following: select all that apply. - Answer NADPH, ATP What is one of the main functions of light reactions? - Answer Similar to the electron transport chain, one of its main functions is to generate a proton concentration gradient to generate ATP. True or False: The Calvin cycle must occur in the absence of light. - Answer False, The term 'dark reactions' (also known as the Calvin Cycle) simply denotes the second stage in photosynthesis—dark reactions do not actually require darkness in order to occur. How many turns (or repititions) of the Calvin Cycle are required to generate one molecule of glucose? - Answer six Complete the following equation by placing the appropriate numbers where indicated. [answer1]CO2 + [answer2]ATP + [answer3]NADPH + [answer4] H20 → C6H12O6 + [answer5]ADP + [answer6] NADP+ - Answer 1. 6

2. 18
3. 12
4. 12
5. 18
6. 12 Match the following reactions to its corresponding enzyme: 1.A−B+H2O→A−OH+B−H1.A−B+H2O→A−OH+B−H 2.A−B→B−A2.A−B→B−A 3.A+B→A−B3.A+B→A−B 4.A−B→A+B4.A−B→A+B A: Lyases B: Transferases C: Oxidoreductases D: Hydrolases E: Ligases: F: Isomerases - Answer 1) D

2. F
3. E
4. A

Define the measurements micrometer and nanometer. - Answer A micrometer (μm) is defined as being one-millionth of a meter and is commonly designated at 10- 6 meters. A nanometer (nm) equals 10-9 m or one-billionth of a meter. What are the two critical factors that influence your ability to see an object? - Answer Resolution and contrast. Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one. The contrast is the difference in light absorbance between two objects. Poor contrast gives a high background and makes the visualization of multiple objects difficult. For instance, trying to identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against 2 dark objects = high contrast). If you wish to increase the amount of light going into a microscope, what part would you adjust? - Answer The iris diaphragm controls the amount of light that passes through the sample and into the objective lens. Thus, as you open the iris more light is permitted to pass through to illuminate the sample. As light passes through a microscope, what is the last piece that light passes before reaching your eyes? - Answer Once light passes through the sample and the objective lens it is directed through the ocular lens, or eyepiece, directly into your eye. How is the total magnification of an object calculated? - Answer Total magnification is calculated by multiplying the power of the objective and the power of the eyepiece. For instance, a 40x objective with a 10x eyepiece would make an object appear ( x 10) 400 times larger (400x). What is one limitation of fixing your sample? - Answer Fixation requires you to irreversibly kill your sample. Thus, determining the motility (cell movement) of a sample is impossible. Fixation also runs the risk of distorting the specimen shape and arrangement. Phase-contrast microscopy provided what benefits to imaging? - Answer Phase contrast microscope can provide detailed images of live cells without staining. By using specialized condensers and objectives, a phase contrast microscope amplifies the slight differences between cells and the surrounding medium (background) to make the cells highly distinguishable. What is the distinguishing feature of dark field microscopy? - Answer Unlike bright field or phase contrast microscopy where light passes directly through the sample, dark field microscopy reflects light off of the specimen at an angle. The resulting image is an exceptionally dark background and a vibrant specimen. Unlike brightfield microscope, fluorescence microscopes illuminate samples through what spectrum? - Answer The energy of the incoming light is in the form of the ultraviolet (UV) spectrum.

What is the primary difference between TEM and SEM? - Answer During transmission electron microscopy the electron passes through the sample whereas during scanning electron microscopy the electron is reflected off the sample creating a three dimensional 'shell' model of the specimen. Gram staining is based on what basic principle? - Answer Gram staining, developed by Hans Christian Gram in 1884, began with the basic observation that different types of bacteria react differently to various dyes. Some bacteria readily take up a specific dye while others do not. What is a key determinant in a bacteria being Gram-positive? - Answer Gram- positive bacteria have a thick peptidoglycan layer. The Gram stain exploits this characteristic by using the dye combinations of Crystal violet and Iodine. Crystal violet is retained by the thick peptidoglycan cell wall and forms a stable complex with iodine (upon its addition) effectively trapping the dyes in the cell. The resulting mixture is a purple coloration of the cell. What is the purpose of heat fixing a sample? - Answer Heat fixing ensures the samples tightly adhere to the glass slide prior to staining (and washing) procedures. What is the primary purpose of a wet mount? - Answer Wet mounts are most often performed to visualize live cells as well as the motility and behavior of an organism. The acid-fast stain is most often used to identify what specific microorganism? - Answer Acid-fast stains are used to identify bacterial stains showing a high degree of resistance to decolorization. Mycobacterium tuberculosis is the most common use for an acid-fast stain. True or False: A nanometer (10-9) is longer than a micrometer (10-6). - Answer False, A nanometer is 1,000 times smaller than a micrometer. Resolution and contrast are two critical factors that influence your ability to see an object. Explain each. - Answer Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one. Contrast is the difference in light absorbance between two objects. Poor contrast gives a high background and makes the visualization of multiple objects difficult. For instance, trying to identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against 2 dark objects = high contrast). Assuming a constant (non-adjustable) light source power, identify the part of the microscope you would adjust to limit the amount of light entering the microscope. Select all that apply. - Answer Iris diaphragm The iris controls the amount of light that passes through the sample and into the objective lens. Thus, it can be adjusted (opened or closed) to alter the amount of light.

What is the total magnification (relative to your eye) of a sample imaged with a 20x objective and a 15x eyepiece? Show your math. - Answer 20 x 15 = 300x magnification True or False: A cell that is adherent, flat (thin), and unstained is easily identified using bright field microscopy. - Answer True Which of the following could NOT be seen clearly by the unaided eye? Select all that apply. - Answer Virus with a diameter of 0.2 μm Bacteria with diameter of 24 μm A and C. The unaided eye can, on average, clearly resolve objects > 100 μm Label the following unmarked microscope components (numbered arrows) by matching it with the components provided (letters). A. StageB. Fine Adjustment KnobC. Iris DiaphragmD. NeckE. Condenser LensF. EyepieceG. ObjectiveH. BaseI. Coaxial Controls - Answer 1) F 2)D 3 )B 4)G 5)A 6)H This type of microscope utilizes ultraviolet (UV) light to illuminate stained objects. - Answer Fluorescence This type of microscope can provide detailed images of live cells without staining. - Answer Phase-Contrast This type of microscope enhances contrast between specimen and background but does not permit the visualization of intracellular structures. - Answer Dark Field This type of microscope is capable of capturing images in multiple focal planes, rendering a specimen in 3-D. - Answer Confocal Identify what type of electron microscope was used to capture the following image and explain your choice. - Answer The image was captured using a Scanning Electron Microscope (SEM). The above image shows the trademark 'shell' image (no subcellular organelles are visible) reminiscent of SEM. Only TEM is capable of visualizing subcellular substrucutres. Gram-Positive cells appear [answer1] in color due to a [answer2] peptidoglycan layer in the cell wall. - Answer 1. Purple

2. Thick Gram-Negative cells appear [answer1] in color due to a [answer2] peptidoglycan layer in the cell wall. - Answer 1. Pink
3. Thin

True or False: The distinguishing characteristic of Gram-Negative bacteria is the presence of LPS in the outer membrane. - Answer True True or False: If you wish to study the motility of an organism you cannot heat fix, but you can chemically fix the specimen. - Answer False, Both heat and chemical fixation strategies will kill the cell, making motility observations impossible. You want to observe the size and shape of a cell. What is the easiest staining technique that you could perform? Name at least one dye you would use during this process. - Answer Simple stain. You could use any of the following: methylene blue, crystal violet, safranin or fuschin. You suspect a patient may have TB. Once a sample has been obtained, it is sent off to the lab for an acid-fast stain. If the patient were infected with TB, describe what you would expect to see on the stained slide. - Answer You would expect to see red cells (TB+) on a blue background (TB negative). True or False: A Giemsa stain can be used to determine the presence of pathogenic bacteria. - Answer False Identify what type of electron microscope was used to capture the following image and explain your choice. - Answer The above image is captured via a Transmission Electron Microscope (TEM). Even at 20nm resolution (inset image), subcellular substructures are still visible. The image lacks the outside 'shell' only appearance of SEM. What is another name for a liquid growth media, and what are the basic components? - Answer Growth media in a liquid form is often referred to as nutrient broth. As the name implies its composition consists primarily of essential 'ingredients' such as a rich source of sugars, amino acids and vitamins. Together, a nutrient broth provides the microbe with a source of carbon/energy, which, in turn, encourages its expansion. What is selective media? - Answer Selective media allows for only the growth of certain microbes while restricting the growth of all others. What is differential media? - Answer Differential media is used to distinguish between two (or more) related microbes. What are the requirements of a fastidious microbe? - Answer A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. What is agar? - Answer In its simplest form agar is liquid growth media that has had a hardening agent added to it. Agar is created when a polysaccharide derived from seaweed (algae) extract is added to growth media. Agar is used to create a solid, smooth surface on which microbes can grow.

True or False: LB agar is classified as a non-selective, differential media. - Answer False, LB agar is both a non-selective and non-differential media. LB agar is often used to expand unknown microbial population because it encourages microbial growth due to the presence of universal nutrients (non-differential) and absence of restrictive factors (non-selective). What are the three forms of hemolysis found on blood agar plates? - Answer Alpha (green), Beta (clear zones) and Gamma (white/tan). Microbes capable of alpha hemolysis present with greenish-brown color colonies due to the incomplete (partial) lysis of red blood cells. Beta hemolysis is classified as the capacity of a microbe to completely lyse red blood cells. The resulting lysis presents as a distinct zone of clearing around the growing colony. Gamma hemolysis designates the absence or lack of hemolytic activity and the resulting colonies are often white/tan in color growing on the red background color of the unaffected blood agar plate. What is the primary purpose of Columbia CNA agar? - Answer As it suppresses the growth of Gram-negative bacteria CNA agar is, therefore, used for isolation of Gram- positive microbes. Name the type of plate derived from BAP that contains lysed red blood cells. - Answer Lysed red blood cells (RBCs) are a primary component in the formulation of Chocolate agar. Define the selective and differential abilities of a MacConkey agar plate. - Answer MacConkey agar is selective in that only Gram-negative microbes will grow on the agar—Gram-positive microbes simply do not grow. MacConkey agar is also considered a differential media as it distinguishes between microbes capable of fermenting lactose (red colonies) and those that are non-fermenters (white/tan colonies). What colors would you expect to see on an EMB plate containing E. coli? - Answer The EMB plate itself is red in color while in the presence of E coli, the growing colonies will take on a distinctive metallic green sheen. Note: You are responsible for knowing the color and general properties (selective vs differential) of all of the agar plates described within this module, with a special emphasis on how a particular agar plate aids in identifying select microbes. What is the name of the process of spreading a bacterial culture onto a petri dish? - Answer Plating. Plating microbes can be done using a sterile loop, a sterile swab, or a sterilized wire loop. Each device is simply a means of spreading the bacteria, most commonly in a simple back-and-forth motion, across the plate. What is the primary advantage of plating a bacterial culture as opposed to having it grow in solution? - Answer The primary advantage of plating a bacterial sample onto agar is that cells are held in place. Unlike in a nutrient broth where bacterial cells can multiply but are free to move around in solution, bacteria plated onto agar are fixed in such a way as to support the formation and visualization of colonies.

What is the purpose of the quadrant streak approach? - Answer The purpose of this method is to generate an individual colony so that a single (pure) bacterial sample can be picked from the plate. In a three-phase dilution gradient, which phase most likely contains individual colonies: phase 1 (P1) or phase 3 (P3)? - Answer Individual colonies are most likely going to appear within the phase 3 streaks. You begin with P1 (highest concentration), dilute during P2 and then further dilute the sample in P3. However, it is possible to see individual colonies in P2 if only a small portion of P1 was carried over into P2. True or False: Differential media is best suited for distinguishing between two similar species of bacteria. - Answer True Growth media does not contain restrictive factors, while selective media is best used to encourage the growth of one microbe while simultaneously discouraging the growth of the other. Since two similar species of microbes are being studied they must be differentiated under similar but just slightly different conditions (differential media). A researcher is asked to determine if a sample contains Neisseria meningitides. Knowing Neisseria meningitides is slow growing and other foreign microbes may also be present in the culture, which type of media would be best suited? - Answer Selective media What are the requirements of a fastidious microbe? - Answer A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. True or False: LB agar is classified as a selective, non-differential media. - Answer False What is agar used for in microbiology? - Answer Agar is used to create a solid, smooth surface on which microbes can grow. Blood agar is which type of medium? Select all that apply. - Answer Enriched, Differential (Blood agar can be used to differential between species based on its hemolytic activity.) Match the following hemolytic class with its description of the activity.

1. Alpha Hemolyses A. No change
2. Beta hemolysis B. Greenish-brown color
3. Gamma hemolysis C. Distinct zone of clearing - Answer 1) B

2. C
3. A

Columbia CNA agar is most closely related to which media: - Answer Blood agar, CNA agar is similar to BAP as it is also enriched with blood and allows for differentiation based on hemolytic patterns. True or False: Chocolate (cocoa) is not a component of Chocolate agar plates. - Answer True, The name is derived simply based on the color that actually comes from the presence of 'cooked' (lysed) red blood cells in the media. A researcher is studying a strain of E. coli currently growing on a MacConkey plate. However, the researcher can't remember if E. coli is Gram-positive or Gram- negative. Would a Gram stain be necessary to confirm? Why or why not? - Answer No. A Gram stain would not be necessary, as only Gram-Negative microbes will grow on MacConkey agar. Thus, E. coli is a Gram-Negative microbe. In an attempt to detect the presence of the pathogenic strain of E. coli O157:H7, a researcher spread a culture onto a MacConkey agar with failed results. What type of agar should they (correctly) try next? Why? - Answer The microbe should be plated on SMAC (Sorbitol-MacConkey agar) as it is specifically formulated to detect O157:H7. Pathogenic E. coli (O157:H7) cannot ferment sorbitol while non- pathogenic E. coli can ferment both soribitol and lactose. Therefore, colonies that ferment (acidic conditions; non-pathogenic) can be differentiated from non- fermenters (neutral to basic conditions; pathogenic). What is the Gram status (positive or negative) of microbes growing on Eosin Methylene Blue (EMB) agar plates? - Answer Gram-Negative. EMB plates specifically restrict the growth of Gram-Positive bacteria. Mannitol salt agar will turn what color in the presence of the pathogenic strain Staphylococcus aureus? - Answer Yellow Pathogenic Staph aureus will turn the agar from red to yellow. What is the process of spreading a bacterial culture onto a petri dish called? - Answer Plating In order to visual individual colonies of bacteria would you culture your sample in a liquid media or on a solid (agar) media? Why? - Answer Solid (agar) media. The primary advantage is that cells are held into place. When grown in a nutrient broth, bacterial cells can multiply but are free to move around in solution. When grown on agar within a petri dish the fixed in such as way as to form colonies. True or False: The visualization of colonies on a petri dish represents bacterial cells that have often multiplied a million times over. - Answer True, To form a bacterial colony the initial cell must have multiplied many times over, often greater than a million, in order for the naked eye to resolve it. True or False. The purpose of a quadrant streak is to expand a bacterial population.

• Answer False, The purpose of the quadrant streak is to generate individual colonies such that a single (pure) bacterial sample can be isolated.

To be considered a pure culture, the sample (1) can be traced back to a single cell and (2)__________? - Answer The culture must also be free from external contaminants. Simply put, a pure sample would never contain multiple bacterial species (ie) Strep and Staph. A dilution gradient is formed when carrying out what generalize plating strategy? - Answer A quadrant streak. The resulting gradient should always contain within it the growth of individual colonies. In what phase of a dilution streak would you expect to find the lowest concentration of bacteria, P2 or P4? - Answer P4 (Phase 4) would contain the lowest concentration of bacteria. The phases rank (from highest to lowest), P1 > P2 > P3 > P4. True or False. When performing a dilution streak a new (or sterilized) loop is not required for each phase as long as the bacterial culture is pure. - Answer False, A new or sterilized loop is absolutely required for each phase. Failure to do so would prevent the establishment of a dilution gradient, as the same bacterial concentration would be spread across both phase regions, regardless of whether or not the culture is pure. In order to encourage growth of a slow growing microbe what might a researcher do during a phase dilution streak? - Answer A researcher may either (1) opt to perform only a 3-phase dilution streak or (2) pass the loop through the previous phase multiple times (as opposed to only once). True or False. Pathogenic strains of bacteria tend to grow slower than normal non- pathogenic bacterial strains. - Answer False, Pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37°C, which is why researchers may set incubators at 25°C to restrict its growth. When given an unknown bacterial sample the first step is to expand the current bacterial population. Which form of media best suites this need? Why? MSA agar LB media containing ampicillin and neomycin MacConkey agar Blood agar - Answer Blood agar. All other options (A, B and C) are all forms of selective media, meaning they may potentially inhibit the growth of the unknown sample. Although blood agar is considered a differential media, it is, most importantly, a non-selective media. Given the alternatives, this is the best option. Define the concept of universal precautions. - Answer Universal precautions means any and all samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials. What would a researcher be certain to note while analyzing a microbial sample? - Answer A lab researcher would be certain to note1. Size and shape2. Any observable motility3. Gram status (positive or negative)4. The presence of any chemical reactions5. Changes in color localized to the organism or the surrounding media6. Capture (or draw) images of any of the characteristics described above

Which non-selective yet differential agar plate should be used if a Streptococcus sample is suspected? - Answer A BAP (blood agar plate) would be the quickest way to identify and classify a potential streptococcus microbe based on its hemolytic properties. What disease can result if a patient with streptococcal pharyngitis goes untreated? - Answer Rheumatic fever occurs in approximately 3% of untreated cases of streptococcal pharyngitis, presenting approximately 2-3 weeks post-infection. Streptococcus, E. coli, pseudomonas, and klebsiella are all capable of causing what disease? - Answer All of the above foreign microbes are capable of causing septicemia, also known as blood poisoning. What is a facultative anaerobe? - Answer A facultative anaerobe is capable of growth under both aerobic (with oxygen) and anaerobic (in the absence of oxygen) condition. How can Staphylococcus be differentially tested? - Answer Staphylococcus species are capable of growth in the presence of bile salts. A bacterial swab is taken from a patient with impetigo and streaked across an MSA plate. Following incubation at 37C, what will be the color of the agar? - Answer The causative agent of impetigo is staph aureus, a Gram-positive bacterium capable of fermenting mannitol. Fermentation will lower the pH of the agar and change the dye color from red to yellow. If a patient were suspected to have tuberculosis (TB), which differential stain would you select and why? - Answer To stain for TB, one would utilize an acid-fast stain to best visual the foreign microbe. As a mycobacterium tuberculosis would stain poorly (indeterminate) using the Gram stain. According to the module, which mycobacterium infection will be treated free of charge by the World Health Organization (WHO)? - Answer Leprosy is completely curable using a multiple-drug therapy regimen consisting of various combinations of the drugs dapsone, rifampin and clofazimine—all of which is given free of charge. What are the three main conditions caused by the botulism toxin? - Answer Foodborne, infant and wound. Foodborne botulism is often the result of improperly canned, contaminated, low-acidic foods such as green beans, corn and beats. Infant botulism occurs when children, usually under the age of 6 months consume foods containing the bacteria. A potential source of infant botulism is honey (which is why pediatricians recommend avoiding feeding honey to infants) but can also be found in common places such as soil. Wound botulism occurs when C. botulinum bacteria colonize a deep wound, often a puncture such as those who inject street drugs such as heroine. As contaminated needles are injected through the skin, spores enter the body and, in the absence of oxygen, release the toxin. Why are infants (< 6 months) more susceptible to botulism? - Answer Due to infants still maturing intestinal tract and lack of an adult microbiota, the bacteria are able to

colonize and produce the associated toxin. In adults, only the direct ingestion of the pre-formed toxin causes disease—ingestion of C. botulinum or the associated spores do not cause illness as a mature intestinal microbiota sufficiently prevents bacterial germination and growth. What is the mechanism of action of the toxin produced by clostridium tentani (tetanus)? - Answer The toxin acts on inhibitory neurons causing systemic muscle stiffness and spasms. Muscle stiffness can be observed in the jaw (lock-jaw) or spread systemically (if left untreated) to muscles relating to respiratory function. What Gram-negative bacterium might you come into contact with in a unsanitary hot tub? - Answer Legionella is often associated with unclean water systems such as hot tubs, hot water tanks and AC units. Notably, legionella can only be transmitted through water droplets small enough to be inhaled. What are the three forms of plague, and what regions do they affect? - Answer Bubonic (lymph), pneumonic (lungs) and septicemic (blood). Bubonic plague is best characterized by painfully swollen lymph nodes. Pneumonic plague affects the respiratory system (lungs). The most rare of all three plagues, septicemic plague targets the blood system and, if left untreated, will develop into a life-threatening illness as the blood-borne bacteria can infect all major organs. According to the module, which STD might be best identified via dark-field microscopy? - Answer Syphilis. The causative agent, treponema pallidum, is a thin spirochete, making Gram staining (and visualization) difficult. Treponema is therefore most often best identified via dark-field microscopy. Define the concept of universal precautions. - Answer Universal precautions means any and all samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials. List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample. - Answer A lab researcher would be certain to note: Size and shape Any observable motility Gram status (positive or negative) The presence of any chemical reactions Changes in color localized to the organism or the surrounding media Capture (or draw) images of any of the characteristics described above While observing an unknown sample of limited amounts, a researcher must determine the following observations: (1) the presence of any motility and (2) its Gram status using the same sample—the liquid sample cannot be divided. Which would you determine first and why? - Answer You must determine motility before determining the Gram status. Motility requires a wet mount, while Gram staining requires heat fixing the sample. If one were to begin with the Gram stain the heat fixation process would kill the organism, making any observations regarding motility impossible. The correct approach would be to place the liquid culture on a glass slide and determine its motility status. Next, the same liquid culture can be heat fixed and Gram stained.

A facultative anaerobe is a microorganism capable of growth under what conditions?

• Answer A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen) conditions. As Streptococcus is catalase negative would it thrive or die in the presence of peroxides? Why? - Answer Streptococcus would not survive in the presence of peroxides—it is unable to breakdown peroxides (catalase negative). Left unchecked, peroxides would damage the cellular integrity of Strep causing lysis/cell death. Streptococcus is most often streaked onto: - Answer Blood agar, Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in the classification (and differentiation) process. True or False. The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic Streptococcus. - Answer False, The Lancefield groupings are used to subdivide beta-hemolytic Strep. Greater than 90% of all human streptococcal infections belong to: - Answer Group A, Group A is the causative agent behind > 90% of all Strep infections. Rheumatic fever displays ______ hemolytic activity and occurs when _______ is left untreated. - Answer Beta; Strep. Pharyngitis Strep throat (also known as strep. Pharyngitis) can lead to Rheumatic fever if left untreated and displays beta-hemolytic activity. True or False. Under most circumstances, staphylococcus can be found in ~80% of human population where it remains non-symptomatic. - Answer Staphylococcus in only found (non-symptomatic) in ~30% of the human population. Define commensal bacteria. - Answer The bacterium neither harms nor benefits from the host from which it obtains nutrients. In order to differential screen staphylococcus species, agar plates should contain what additive? - Answer Bile salts. Staphylococcus species are capable of growth in the presence of bile salts. Match the following symptoms with their respective diseases:

1. Childhood Skin Disease near mouth/nsoe
2. infection of thin, transparent scleral tissue.
3. Infection occurs at time of birth
4. Pus-filled lesions on skin or hair
5. Ruptured pustules; treated wtih Penicillin A. Folliculitis B. Scaled-skin syndrome C. Impetigo D. Conjunctivitis

E. Ophthalmia neonatorum - Answer 1.) C 2.) D 3.) E 4.) A 5.) B True or False. The causative agent of conjunctivitis can be either bacterial or viral. - Answer True, There are bacterial (staph) and viral forms of conjunctivitis, both resulting in the inflammation of the conjunctiva and 'pink eye.' True or False. An acid-fast stain is best suited to identify tuberculosis (as opposed to a Gram stain). - Answer True, TB shows a poor Gram stain and should be screened via an acid-fast stain. True or False. When located outside of the lung, TB is usually non-infectious. - Answer True, Although TB can move systemically through the blood and infiltrate other areas (brain, spine and kidney), when located outside of the lung, TB tends to be non-infectious. Identify the disease based on the following (select all that apply): It is a small, acid-fast rod usually remaining asymptomatic for up to 20 years. It affects the skin, nerves, upper respiratory tract, and eyes of infected individuals. - Answer Leprosy, Hansen's disease B and D. Hansen's disease is simply another name for Leprosy. Leprosy is characterized by its ability to remain dormant for up to 20 years as well as the effects observed relative to the patients skin, nerves, lungs and eyes. True or False. Directly ingesting clostridium or its associated spores will not cause illness in adults. - Answer True A 5-month-old child is given honey at breakfast and begins showing symptoms consistent with botulism. Would the child's illness be classified as foodborne, infant, or wound botulism? - Answer Infant. Although food (honey) is consumed, foodborne botulism is derived from improperly canned, low acid foods under anaerobic conditions. Such conditions were not described. No puncture wounds or injuries were described, ruling out wound. The child is suffering from infant botulism, as honey is a potential carrier of clostridium. The intestinal track of young children is still developing and clostridium is able to colonize and produce the associated toxin. True or False. Although there is no cure for tetanus, it can be prevented through vaccination. - Answer True, There is no cure for tetanus. However, tetanus is entirely preventable through vaccination. Identify the medical condition characterized by robust carbohydrate fermentation under anaerobic conditions, swelling of the infected areas and fever. - Answer Gas gangrene. The key identifier here is the robust carbohydrate fermentation, which manifests as intense gas production and swelling—both trademark conditions of gas gangrene.

The alpha-toxin perfringolysin is associated with which medical condition caused by Gram-positive anaerobic bacteria? - Answer Gas gangrene The bacterium that produces the alpha toxin perfringolysin is aptly named Clostridium perfringens. You develop a fever, chills, and pneumonia after recently using a warm midst vaporizer in an attempt to open your sinuses. What bacterial disease would a doctor suspect is causing your symptoms? Would the doctor suspect you contracted it from touching (potentially) contaminated doorknobs? - Answer Legionnaires. No— legionella cannot be spread simply by direct contact between people. Legionella can only be transmitted through droplets small enough to be breathed in. True or False. Bubonic plague is often characterized by painfully swollen lymph nodes. - Answer True Which form of the plague is the rarest? What does it target? - Answer Septicemic plague is the rarest and it targets the blood system. Identify the following disease: - Answer Lyme disease, Lyme disease. The trademark 'bulls-eye' rash is a clear indicator. Gonnorrhea is caused by: - Answer Diplococcic bacteria True or False. Chlamydia trachomatis can be grown on an agar plate alone. - Answer False, Chlyamdia is an obligate parasite and requires a host (viable cells) for its growth. Match the following diseases with their respective symptoms if left untreated: 1.Gonorrhea A. Paralysis, blindness and dementia

2. Syphilis B. Painfully swollen lymph nodes3. Chlamydia C. Cardiac and neurological complications D. Respiratory failure associated with lock-jaw E. Infertility and pelvic inflammatory disease. F. Sore throat, ocular discharge and fever

• Answer 1.) C 2.) A 3.) E Can viruses be classified as either prokaryotic or eukaryotic microorganisms? - Answer No. Viruses are neither prokaryotic nor eukaryotic. What is an obligate intracellular parasite? - Answer As an obligate intracellular parasite, viruses cannot (obligate) replicate unless inside (intracellular) a living host cell. As a parasite, a virus depends on its living host to provide the framework (proteins, etc) to replicate—to make additional copies of itself.

What is a viral capsid? - Answer The capsid is a membrane-like protective structure that contains the genetic material, similar to the nucleus of a eukaryotic cell. What is the viral envelope, and what does the presence (or absence) of it tell you about the type of virus? - Answer The envelope surrounds the viral capsid, is derived from the host cell membrane and serves as an additional barrier to the external environment. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not. What type of microscope would be used to study the shape of a viral capsid? - Answer Due to its size (~30-150 nm) most viral capsids must be visualized via electron microscopy. How does the viral envelope both aid in cell entry as well as hide it from being detected by the immune system? - Answer The viral envelope contains the necessary proteins required for interaction with host cells. As the envelope is derived from the host cell membrane, this camouflages the virus and lowers the likelihood of immune detection by making it appear similar to the normal biological host cell. What must happen before viral replication of its genome can occur? - Answer For all viruses, the genome is replicated following attachment and entry, never before. Describe the basic steps of the viral life cycle. - Answer 1. Attachment: Viral receptors bind to host proteins on the surface of the cell.2. Entry: The virus fuses with the host membrane and enters the cell3. Uncoating: (where applicable) the viral capsid disassembles4. Replication: The viral genome provides the 'blueprint' to make copies of itself5. Exit: New viruses are produced and leave the cell6. New infection: Newly produced viruses leave the host cell and go on to infect new cells. The process outlined above now restarts. What is a bacteriophage? - Answer A bacteriophage is simply a virus (phage) that infects bacteria. What structural aspects make bacteriophages distinct from viruses that infect either animals or plants? - Answer Bacteriophages possess an icosahedral capsid head group and a helical tail. Attached to the tail are fibrous extensions or 'legs' that aid in binding host cells. Notably, this particular structural arrangement has not been observed among viruses that infect either animals or plants. Which viral replicative process results in the destruction of the host cell? - Answer The lytic replication cycle occurs when a bacteriophage replicates within a host until it ruptures, effectively destroying the host bacterial cell. The phrase lytic stems from 'lysis', meaning to rupture or disintegrate (breakdown) a cell. Describe the appearance of a bacterial culture infected with virus at the time of infection versus later once viral replication is occurring at a high rate. - Answer During the initial inoculation of virus and bacteria, the media has a high degree of turbidity (cloudiness). However, as the lytic cycle progresses and more and more bacterial cells are destroyed, the culture media turns from turbid to clear, as turbidity

is a function of the number of intact bacterial cells present in the media. Thus, as bacterial cell numbers decrease due to lysis, the media becomes clearer. To what family of viruses does rubella come from and how is it transmitted? - Answer Rubella virus belongs to a family of viruses called Togaviridae. Rubella is transmitted via air-borne particles such as when a person coughs. What is the common name for rubeola, and is it a DNA or RNA virus? - Answer Rubeola is commonly referred to as the measles and belongs to the family of viruses called Paramyxovirus. Rubeola viruses are RNA viruses with a genome ~ 15,000 nucleotides long. What disease state emerges as a viral reactivation of a prior infection with the varicella virus? - Answer Shingles, also known as Herpes zoster, is due to the reactivation of the varicella-zoster virus (VZV). Because VZV lies dormant in inactive nerve cells, its reactivation typically results in painful blisters. However, unlike the initial chickenpox rash, the blisters are localized and limited to small areas. What linear, double-stranded, enveloped DNA virus is the first virus (as of October 26, 1977) to be declared eradicated? - Answer Although once a major cause of death in the world, a smallpox vaccine was developed in 1796 by Edward Jenner. Global vaccination efforts have prevented smallpox from appearing in humans since October 26, 1977, making smallpox the first infectious disease ever to be eradicated. What are the two key glycoproteins found in the influenza virus? - Answer The viral envelope contains two key glycoproteins, hemagglutinins (HA) and neuraminidase (N). Hemagglutinins are heavily involved in the entry of the viral particle into a host cell, while neuraminidase proteins are involved in the budding and release of new viral particles from the host cell. Describe the composition of HIV. - Answer HIV contains two copies of single- stranded, linear RNA that is enclosed by a capsid. The conical capsid surrounds the two RNA strands and is comprised of ~2,000 copies of the viral protein p24. A viral envelope derived from the cell host membrane then surrounds the viral capsid. Within this envelope are two key glycoproteins, gp120 and gp41, which are essential for viral binding and entry into the host cell. True or False. Although viruses may contain their genome within an enclosed space (much like the nucleus of a cell), it is considered neither eukaryotic nor prokaryotic. - Answer True Describe the two basic components of a virus. - Answer A virus has (1) genomic material comprised of either DNA or RNA and (2) a capsid, a membrane-like protective structure that contains the genetic material, similar to the nucleus of a eukaryotic cell. The ________ surrounds the capsid of some viruses. - Answer envelope

True or False. You would expect to see a viral envelope on a virus infecting a bacterial cell. - Answer False. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not. Rank the following viruses based on their size from largest to smallest: Orthomyxovirus Poliovirus Variolavirus - Answer Variolavirus (~200nm) > Orthomyxovirus (100-150nm) > Poliovirus (~30nm) True or False: Viral replication occurs after it attaches and enters the host cell. - Answer True. The viral genome is never replicated before attachment and entry. Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step. Uncoating: Release: Replication: Attachment: Entry: New infection: - Answer 3- Uncoating: the viral capsid disassembles 5 - Release: New virus particles are produced and leave the cell 4 - Replication: the viral genome is the 'blueprint' to make copies of itself 1 - Attachment: viral receptors bind to host proteins on the surface of the cell 2 - Entry: the virus fuses with the host membrane and enters the cell 6 - New infection: newly produced viruses that left the host cell now go on to infect new cells. A virus that infects bacteria is called a [answer1] and contains a [answer2] - sided polygon capsid. - Answer 1. Bacteriophage

2. 20 True or False. Structurally, bacteriophages are similar to viruses that infect animals. - Answer True or False. Structurally, bacteriophages are similar to viruses that infect animals. True Identify the following components of a bacteriophage. - Answer 1-Capsid 2 - Collar 3 - Tail 4 - Base plate 5 - Tail fibers Describe the main differences between lytic and temperate phages. - Answer Lytic bacteriophages replicate within the host bacteria until it ruptures, whereas temporate (or lysogenic) phages primarily exist in a non-replicative state that does not kill the host cell.

Lytic phages replicate all viral proteins needed for the assembly of new virus particles whereas lysogenic phage genomes are integrated into the host genome but production of viral proteins is suppressed. Based on the following image, would you expect the viral titer to be high or low? Why? - Answer Low. As turbidity is a function of the number of intact bacterial cells present in the media, the amount of virus contained within the above tube must be low. As the lytic cycle continues more and more bacterial cells will be destroyed, effectively clearing the media. Which of the following cannot be spread via airborne particles: - Answer None of the above Measles, mumps and rubella can all be spread via airborne particles formed while coughing, sneezing, etc. True or False. A patient infected with rubella is considered infectious one week before and after the appearance of the trademark rash. - Answer True A patient diagnosed with German measles may additionally experience what disease? Select all that apply. - Answer Conjunctivitis, Influenza like symptoms A patient may experience a combination of symptoms such as fever, flu-like symptoms (influenza), cough, conjuctivitis, and a red blotchy skin rash. Which of the following diseases does a linear, double-stranded DNA virus cause? - Answer None of the above Measles, mumps and rubella are all linear, single-stranded RNA viruses. What disease displays as a secondary characteristic swelling of the testes/ovaries and pancreas? - Answer Mumps. A patient infected with mumps (aka epidemic paratitis) has primary swelling in the paratoid (salivary glands) located in the neck but also may have secondary swelling in the testes/ovaries and pancreas. You go to visit a friend who has chickenpox. While visiting what are 2 things you will be sure to avoid so that you don't also become infected? - Answer (1) You would want to be sure to keep a distance especially if your friend is coughing or sneezing as chickenpox can be transmitted through air-borne droplets (sneezing/coughs). (2) You would also be absolutely certain to avoid direct contact with the blisters of an infected individual. True or False. Someone who had chickenpox as a child is likely to develop shingles while in college, where the median age of college students is 18-22 years old. - Answer False. The most common age for VZV reactivation and shingle diagnosis tends to occur in people greater than 60 years of age. True or False. Similar to chickenpox, the blisters that appear with shingles can cover the entire body. - Answer False. Unlike chickenpox blisters, which can form