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BMSC 210 Midterm 1 Questions | 100% Correct
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The person who described the "wee animalcules" was? - ✔✔Antoni van Leeuwenhoek In what/which domain(s) of life is/are microorganisms represented? - ✔✔Archaea, Bacteria, Eukarya Which of the following statements is correct? A. Microorganisms represent a much smaller amount of Earth's biomass than animals B. Microorganisms are significant in number, but not in overall biomass C. Microorganisms represent a much smaller amount of Earth's biomass than plants D. Microorganisms are significant contributors to the total biomass on Earth - ✔✔D Robert Koch contributed to the field of microbiology by being the first person to... A. develop the tuberculin test only B. use agar as a solidifying agent in growth media only. C. develop the tuberculin test, formulate four postulates for definitively linking a specific microorganism to a specific disease, and use agar as a solidifying agent in growth media. D. formulate four postulates for definitively linking a specific microorganism to a specific disease only - ✔✔C Regarding early life on Earth, which statement is true? A. Microbial life, plant life, and animal life all appeared at about the same time B. It is impossible to determine which type of life first appeared. C. Microbial life existed long before animals but has been around for about the same amount of time as plants.
D. Microbial life existed for billions of years before plant and animal life. - ✔✔D Electron microscopy has greater ________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons. A. Resolution B. Penetration C. Magnification D. Contrast - ✔✔A You have discovered a new microorganism and would like to classify it as a eukaryote or a prokaryote. To investigate this question, you prepare a slide with a simple stain and view it with a light microscope with a 40X objective lens and 10X ocular lens. You also prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote). You can see the cells on your control slide, but you don't see cells when you look at your unknown microorganism. What can you conclude from this experiment? A. The experiment failed to visualize the organism because the stain killed it. B. The new unknown microorganism is probably an archaeon. C. The cells of the new unknown microorganism may be too small to see with the objective and ocular lenses you used. D. Your new unknown microorganism is probably a virus - ✔✔C The use of the Gram stain in microbiology is important because it differentiates A. bacterial cells with different types of cell walls. B. Bacteria from Archaea. C. archaeal cells with different types of metabolism. D. prokaryotic from eukaryotic cells - ✔✔A Viewing the shape of a bacterial or archaeal cell using a microscope gives a great deal of information about the metabolism and lifestyle of the organism. (True or False) - ✔✔False
D. 20-carbon side chains. - ✔✔A True or False: Cells can move both toward a gradient and away from a gradient. - ✔✔True Which of the following statements is FALSE? A. Flagellar rotation generates ATP. B. In flagellar motion, the basal body acts as a motor. C. The hook is the wider region at the base of the flagellum. D. A flagellar protein subunit is flagellin. - ✔✔A Type IV pili are involved in A. twitching motility. B. attachment to surfaces, twitching motility, and pathogenesis. C. attachment of cells to surfaces. D. pathogenesis. - ✔✔B Chemotaxis is a sensory response affecting the rotational direction of the flagellar motor. (True or False) - ✔✔True Using phase contrast microscopy on a wet mount of live cells, you observe motile bacilli moving rapidly and randomly through the field of view, changing directions after a brief tumble and taking off in a different direction. These cells are exhibiting ________ motility. - ✔✔Swimming Which of the following statements is TRUE concerning mRNA? A. mRNA has complex secondary structure. B. mRNA is the product of translation.
C. mRNA has a very short half-life. D. mRNA is catalytic. - ✔✔C Unlike Eukarya, Archaea and Bacteria do not have a nucleus, so they can A. use polysomes to make multiple copies of a protein. B. perform coupled transcription and translation. C. supercoil their chromosomes. D. use RNA polymerase for transcription. - ✔✔B Which feature is true for RNA polymerase activity but NOT true for DNA polymerase activity? A. Nucleotide primer is unnecessary. B. Newly synthesized strands are antiparallel to its template strand. C. Growth of nucleotide sequence is only in the 5′→3′ direction. D. Precursor nucleotides can contain adenine, guanine, or cytosine. - ✔✔A In Bacteria and Archaea, most proteins that are transported across membranes begin with a 15- 20 residue amino acid sequence called a A. - 35 sequence. B. signal sequence. C. sec sequence. D. tat sequence. - ✔✔B Regulatory proteins A. are influenced by small molecules. B. regulate transcription.
B. addition of short sections of new amino acid sequence. C. degradation of the enzyme. D. feedback inhibition. - ✔✔B When the nontemplate strand of a gene is transcribed into RNA, what is likely to result? A. A complementary sRNA will bind to it and form a functional ribozyme with secondary structure. B. It will complementarily bind to the gene sequence, form a hairpin loop, and transcriptionally repress the gene. C. The complementary mRNA transcribed from the template strand will bind to it and halt its translation. D. A global regulator will identify this as a stress, respond by inducing ribonuclease production, and it will be degraded. - ✔✔C How is the activity of a riboswitch controlled? A. Small RNA complementary binding disrupts its function. B. Metabolite binding can change its structure. C. Sigma factor binding alters its structure. D. By other riboswitches - ✔✔A Regulation of enzyme activity occurs A. at any point on the enzymatic production pathway. B. at the start of translation. C. posttranslationally. D. at the start of transcription - ✔✔A? To allow cell wall extension with new peptidoglycan during cell division, preexisting peptidoglycan is severed using ____________ to cleave the β-1, 4 glycosidic bonds.
A. crescentins B. transglycosylases C. autolysins D. both autolysins and transglycosylases - ✔✔C Hemimethylated DNA is found on A. the parental strand of DNA immediately after replication. B. both strands of dsDNA immediately after replication. C. the newly synthesized strand of DNA immediately after replication. D. neither strand of DNA immediately after replication. - ✔✔A FtsZ is related to ________, an important protein involved in cell division. A. actin B. collagen C. myosin D. tubulin - ✔✔D In the process of binary fission in Bacteria, which action occurs first? A. Cytokinesis B. Cell elongation C. Formation of the divisome D. DNA replication - ✔✔D Temperate viruses can enter into either a lytic or lysogenic cycle (True or False) - ✔✔True
C. Fungi D. Bacteria - ✔✔A In contrast to positive ssRNA viruses, such as coronaviruses and polioviruses, the genomes of retroviruses A. lack genes encoding tRNA primers. B. must first integrate into the host's genome before transcription. C. are negative ssRNA. D. lack ribonuclease activity. - ✔✔B Polyproteins made from human viruses, such as poliovirus, must be ________ in order to yield the required functional units of the virus. A. able to interact with VPg proteins B. post-translationally cleaved C. chemically modified with either glycosylation or methylation D. properly folded into secondary and tertiary structures - ✔✔B Blocking polyomavirus SV40's ability to integrate its genome into host cells would A. increase the rate of transformation. B. increase the latent period of SV40. C. avoid cancer development caused by the virus. D. switch SV40 into a lytic life cycle which would be especially harmful to the host cells. - ✔✔C What are Koch's Postulates? - ✔✔1. the microorganism must always be present, in every case of the disease
- the germ must be isolated from a host containing the disease and grow in a lab, in a "culture"
- samples taken from the culture must cause the same disease when introduced into a healthy model animal like a mouse
- the germ must be isolated from the new animal, meaning it is the same organism that causes the disease in the original host Differentiate Gram-positive and Gram-negative (color and cell wall) - ✔✔Gram-positive - purple and thick cell wall Gram-negative - pink and thin cell wall What are the different shapes of bacteria? - ✔✔Coccus - single coccus Diplococcus - pair of two cocci Tetrad - grouping of four cells arranged in a square Streptococcus - chain of cocci Staphylococcus - cluster of cocci Bacillus - single rod Streptobacillus - chain of rods When using a differential interference contrast microscope, what features would differentiate a bacteria from an eukarya? - ✔✔Membrane bound nucleus and size If the pool of ATP is depleted in a cell, what transport system will be affected? A. Antiporter B. ABC transporter C. Symporter D. Group translocation E. Facilitated diffusion - ✔✔B Lysozymes are a defense mechanism in animals. What microbe does it target?
C. the creation of a discontinuous fragment D. the need for two DNA polymerases to be attached to the replisome E. all of the above - ✔✔E Operon vs regulon - ✔✔operon - 1 promoter with many genes (polycistronic) regulon - many promoters (disperse through the chromosome) You are developing a drug that will target a newly identified archaeal pathogen. Your drug targets transcription but exhibits high toxicity towards eukaryotic cells. What is the best explanation? A. the drug targets the RNA polymerase and prevents its activity B. the drug prevents the generation of polycistronic mRNA C. the drug prevents the formation of the stem loop as termination signal D. the drug prevents the activity of the Rho protein - ✔✔A Which scenario would most likely happen if you removed the signal sequence from a secreted protein? A. the protein would only be exported to the periplasm B. the SecA protein would recognize the protein as faulty and degrade it C. the protein would remain in the cytoplasm D. the protein would only be exported to the cytoplasm - ✔✔C You are trying to prevent infections by the spore-producing bacterium Clostridioides difficile. What step of the sporulation cycle should you inhibit? A. Asymmetric cell division B. Engulfment C. Maturation D. Germination - ✔✔D
You work in the food industry and biofilms are a major problem. You must keep surfaces free of bacterial contamination at all times. What step of biofilm formation should you target? A. attachment B. colonization C. maturation D. dispersion - ✔✔A You isolate a virus that contains positive (+) single stranded RNA (ssRNA). Their Baltimore classification group is? - ✔✔IV Why do lytic viruses exhibit a one-step growth curve? - ✔✔Lytic viruses are only released all at once When thinking about the different outcomes of viral infections, what kind of virus is most likely being used as an anti-cancer agent? - ✔✔A virus that causes a lytic infection in cancerous host cells In which of the following stages of the viral infections cycle do enveloped viruses usually acquire their envelopes? A. attachment B. penetration C. biosynthesis D. assembly E. release - ✔✔E
