Module 2 Practice Exam Summer 2023, Exams of Biology

Download Module 2 Practice Exam Summer 2023 and more Exams Biology in PDF only on Docsity! Module 2 practice exam Summer 2023 Hey everyone! This practice exam was made by me and approved by Dr. Ambivero in reference to important topics that may or may not appear on the exam. This should not be your only study tool going into the exam, but rather serve as extra practice to get you guys exposed to the format, and the type of questions that may appear on the exam. I recommend trying to approach this practice exam as if it were the real exam by timing yourself and not using any PowerPoint slides or notes, in order to test your knowledge on the material. Best of luck! *Anything denoted in red are extra important takeaways 1. What is the function of the Z ring in binary fission? A. It forms a contractile ring at the septum => Made up of FtsZ (tubulin homologues) molecules important for bacterial septation B. It controls the replication of DNA => Replisome contains DNA replication machinery C. It separates the newly synthesized DNA molecules => ParA polymerizes/depolymerizes to attach to ParB which recognizes the DNA Sequence parS which is next to the origin of replication D. Both A and B E. Both B and C 2. Which of the following was the first broad-spectrum antibiotic discovered? A. Salvarsan => First Synthetic antibiotic B. Chloramphenicol => Made by a bacterium C. Penicillin => First True antibiotic D. Oxazolidinone => Considered new “drug of last resort” E. Vancomycin 3. Which of the following is true about biofilms? (select all that apply) A. Only bacteria of similar strains can form biofilms => Composed of many different microorganisms B. Heterogeneity among the bacteria can lead to increased interactions and communication => Microbes with varying diversity communicate heavily in biofilms via quorum sensing C. Microbes that grow attached to the surfaces of these biofilms are planktonic => They are sessile, think plankton are planktonic; they are freely floating D. The most metabolically active cells are located at the base of the biofilm => Slow growers near the base of the biofilm (Ch. 7 slide 35) not as metabolically active but still active E. They often have an EPS which provides structural and functional support => Extracellular polymeric substance makes biofilms tough to remove Ex. Biofilms on surface of teeth can cause damage in the form of cavities and tooth decay; have to scrape it off in a dental procedure. Conventional cleaning agents and antibiotics can’t get past the EPS barrier. 4. Which of the following is true in relation to the central dogma of biology? A. DNA is the template for its own replication => Depends on the holoenzyme DNA polymerase B. The flow of genetic information goes from DNA to RNA to proteins C. mRNA is the template for protein translation D. Both A and C E. All of the above => (Ch. 13 slide 2) 5. In regard to proteins: => Made up of single or multiple polypeptides, contain covalent and non-covalent bonds A. Denaturing results in the loss of secondary structures => Denaturing results in a protein losing all its structures except their primary structure; Ex. increasing temperature or altering pH E. 9 11. Silent mutations are not likely to yield problems in the genomes of cells. Which of the following is an explanation for this? A. Codon degeneracy allows multiple codons to code the same amino acid B. Silent mutations are often caused by point mutations that result in minor frame changes in the genome C. The wobble hypothesis => Explains tRNA anticodon in the 3rd position can “wobble” and bind to multiple codons in the mRNA code which can lead to the same amino acid being coded D. Both A and C E. All of the above 12. Which of the following conditions will not result in a lag phase occurring? (select all that apply) => In lag, bacteria are slowly dividing and getting accustomed to a new environment, in log phase, they are the “healthiest” and “happiest” A. Cells inoculated from a stationary phase into a fresh medium B. Cells in log phase growing in glucose are placed into a fresh lactose medium C. Cells inoculated in a rich medium are placed in a poor medium environment D. Cells in log phase growing in a lactose medium are placed in a medium of only glucose => Biphasic growth, if a cell is using lactose, it can also use glucose which makes up lactose. E. Cells growing exponentially in a glucose medium are placed into a fresh glucose medium 13. A bacterial culture in a test tube is observed to have grown all throughout the medium, however, it is found to be most abundant near the top of the tube. Which of the following is true about this bacterial culture? => Notice strict anaerobes do not express SOD or catalase A. It is a facultative anaerobe => (Ch. 7 slide 30) B. It has SOD but not catalase C. It has both SOD and catalase => (Ch. 7 slide 31) D. It grows best in the absence of oxygen => It can grow with or without oxygen, but prefers to grow in the presence of oxygen E. Both A and C 14. Quorum sensing: A. Is a type of density-independent communication between bacterial cells => Density-dependent B. Is responsible for the symbiosis between a vibrio bacteria and bioluminescence in squids C. Can only be found in bacterial biofilms D. Is used by bacterial cells mainly to determine the availability of nutrients => Bacteria also use quorum sensing to determine density of the bacterial population E. Is used by Rhizobium in order to increase their virulence upon legumes => Nitrogen fixation for legumes, mutualistic relationship 15. Which of the following is true? A. The MIC measures the lowest concentration needed to kill a pathogen => MIC for Inhibition and MLC for Lethal concentration. Drugs have to exceed this level in order to be effective B. The larger the therapeutic index, the safer the antimicrobial drug is to prescribe => Index = toxic/therapeutic dosage. C. Vancomycin is a broad-spectrum antibiotic that is effective against VRE=> Narrow spectrum that only works on Gram-positive bacteria D. SecA is an ATP hydrolyzing enzyme responsible for recognizing and cleaving the signal peptide at the C-terminus => Cleavage occurs at the N-terminus E. 23s rRNA is a ribozyme that is a part of the small subunit of the ribosome => Part of the large subunit (50s) 16. Most human pathogens are likely to be: A. Mesophiles => Body temperature in humans, most are going to be mesophiles B. Psychrophiles => Some can be pathogenic Ex. Salmonella, Listeria C. Halophiles => Salt loving, Ex. Staphylococcus aureus D. Both A and C E. All of the above 17. Molecular chaperones: => Can also re-fold denatured proteins A. Are proteins that prevent other proteins from misfolding B. Can aid in the transport of proteins across membranes C. Can protect cells from thermal damage via HSPs => Heat-shock proteins D. Both A and B E. All of the above 18. Bacteria growing in a hypotonic solution are likely to have ______________, while bacteria in a hypertonic solution are likely to have ______________. A. Contractile vacuoles; mechanosensitive channels B. Compatible solutes; mechanosensitive channels C. Mechanosensitive channels; compatible solutes D. Mechanosensitive channels; contractile vacuoles 19. VBNC and PCD are both alternate hypotheses that are associated with what phase of microbial growth? => VBNC not another name for sporulation A. Death phase => Viable but not culturable still a major medical issue, no specific reason for why cells undergo this B. Long-term stationary phase C. Stationary phase D. Log phase E. Lag phase E. Both A and C 26. Atypical bacteria: => Review question (Ch. 3 slide 31) also includes Rickettsia A. Include bacteria like Mycoplasma which do not have cell walls B. Include Chlamydia which has a waxy cell wall => Mycobacteria have mycolic acid/ waxy cell wall C. Include many obligate intracellular pathogens D. Both A and C E. All of the above 27. Which of the following is a true statement? A. Deinococcus radiodurans is considered the world’s toughest bacterium because it has multiple backup copies of DNA, and it is able to withstand extreme temperatures => (Ch. 7 slide 33) Carotenoids can absorb radiation and protect the cell from UV damage B. Halotolerant microbes are found to grow best in the presence of high salt content => This would be Halophiles C. T4SS is a one-step system that is only found in Gram-positives => Found in both Gram + and Gram - D. Both A and B E. Both A and C 28. What was the first true antibiotic discovered? A. Chloramphenicol => First broad spectrum antibiotic B. Kanamycin C. Vancomycin D. Penicillin => Cell wall inhibitors are the best class to fight off bacteria, while nucleic acid synthesis inhibitors are the worst class E. Salvarsan => Anti-virals are difficult to identify due to them requiring our cellular machinery to replicate; anti-virals can affect our cells as well 29. Which of the following is false regarding bacterial growth? A. Bacterial populations are the most uniform and healthiest during log phase B. GASP phenotype is often seen during long-term stationary phase => Growth advantage in stationary phase, associated with natural selection of these bacteria C. Viable but not culturable bacteria are not able to replicate in a medium due to their inability to metabolize => They can still metabolize/replicate they just choose not to on a dish/culture (VBNC) D. The total number of viable cells remains constant during stationary phase E. All of the above are true 30. A bacterial population is observed to increase rapidly from 10 cells to 100,000,000 cells in the span of 5 hours. What is g? A. 0.22 minutes B. 13 minutes C. 25 minutes D. 35 minutes E. 0.13 hours 31. DNA polymerase synthesizes from ________ and mRNA is read from ________ A. 5’ to 3’ and 5’ to 3’ B. 5’ to 3’ and 3’ to 5’ C. 3’ to 5’ and 5’ to 3’ D. 3’ to 5’ and 3’ to 5’ 32. A newly synthesized synthetic drug has been made that is effective against many resistant bacteria including MRSA and VRE, is only used in hospitals and is now considered to be the new “drug of last resort”. What is this antibiotic? => Bacteria can develop resistance via efflux pumps, enzymes (ß-lactamase), and developing mutations. We combat drug resistance by giving two or more at the same time, giving appropriate concentrations, and using only when necessary A. Fluoroquinolone B. Azithromycin C. Oxytetracycline D. Gentamycin E. Oxazolidinone => Synthetic, only used in hospitals to prevent overuse and resistance. Very few side effects, and can be used on VRE, MRSA (highly resistant S. aureus) and other nosocomial infections. Bacteriostatic and inhibits peptide bond formation. 33. A bacterial gene undergoes a mutation that alters the genetic code for an amino acid. A second mutation is then observed within the same gene that alleviates the effects of the first mutation. Which best describes the second mutation? A. A forward mutation B. A nonsense mutation => Produces stop codon UAA, UGA, UAG C. An extragenic suppressor mutation => Two separate genes cancel each other out D. An intragenic suppressor mutation => Happened within the same gene and suppressed the previous mutation E. A missense mutation => Single base pair substitution that changes the amino acid 8 A. 7 – 2 / 0.301(7) B. 0.301(7) / (log 107 – log 102) C. (log 107 – log 102) / 0.301(7) D. (log 107 – log 102) / 0.301 E. 0.301 / (log 107 – log 102) 41. Which of the following is true in regard to adaptations of extremophiles? (select all that apply) => (Ch. 7 slide 29) A. Psychrophiles contain more unsaturated and shorter fatty acids, while hyperthermophile membranes are more saturated B. Psychrophiles often contain more compatible solutes in order to decrease their freezing point C. Hyperthermophiles often include species found in the domain Bacteria => Would be in Archaea D. Hyperthermophiles have more proline and molecular chaperones present within them => Would make sense logically to have more chaperones as they assist proteins from misfolding due to heat/denaturing. Also have more branched amino acids E. Psychrophiles have no secondary structures within their protein structures 42. Streptomyces: A. Is a multicellular fungus => NOT A FUNGUS (When originally discovered, it was thought to resemble filamentous fungi which is why it was appropriately named) B. Is responsible for the majority of antibiotics produced => Majority of antibiotics produced by a bacteria C. Is a Gram-positive soil bacterium D. Both A and B E. Both B and C 43. Which of the following is true regarding DNA and RNA structures? => All living organisms have both DNA and RNA A. RNA lacks a 2’ OH group while it is present in DNA => RNA has that OH group on C2, while DNA lacks it B. DNA is double stranded, while RNA can only be single stranded => RNA can also be seen in a double stranded form in viruses. (Associated with RNAi in living things for my geneticists out there) C. DNA contains a 6-carbon sugar while RNA has a 5-carbon sugar => Both are 5-carbon sugars D. Both A and C E. None of the above 44. Which of the following is a false statement? A. DNA methylation serves to distinguish between new and old DNA in prokaryotes B. Exons are often spliced out during protein maturation => Exons stay in mature mRNA as they can be expressed C. DNA replication is a semi-conservative process => Occurs once per cell cycle, replicates the whole genome, and goes from the oriC to the ter site in bacteria D. Translation of a protein will continue until a nonsense stop codon is reached E. The Tat system contains “twin” arginine residues and are found in both Gram- positive and Gram-negative bacteria 45. Which of the following is true regarding antimicrobial chemotherapy? A. Tamiflu is a neuraminidase inhibitor and is a cure for influenza => NOT a cure for Influenza; H. influenzae does not cause to flu either; Influenza is a ssRNA virus B. Sulfonamides are PABA analogs responsible for inhibiting the production of folic acid in prokaryotes => We do not synthesize folic acid, we get it from our diet C. Tetracycline is a broad-spectrum bacteriostatic antibiotic that binds to the 30S ribosome subunit and is responsible for producing red sweat and urine => Rifamycins are responsible for red sweat and urine. Tetracyclines can produce black teeth, four-ringed structure! D. Both B and C E. Both A and C 46. Which of the following is false regarding the secretory system A. Preproteins signal peptide is recognized by secA => (Ch. 13 slide 27) B. Is a type of macromolecule transport involved with moving folded proteins => Moves proteins that are not folded yet C. SecB prevents proteins from folding D. Chaperones often bind to the signal peptide E. It involves the movement of proteins from the cytoplasm to the external environment => This is secretion (going from inside the cell to outside the cell), while translocation moves from one location in the cell to another location 47. Bacteria can gain new abilities through all of the following except: => Review question A. Conjugation B. Transduction C. Transformation D. Mitosis => No sexual reproduction E. None of the above the cell. If they used a mammalian virus instead, they would not have been able to distinguish DNA vs. protein since they both enter the cell. 5 Math problems on the exam (Examples in the recorded review session): 1) Nt = N0 x 2n (rewrite into this formula) 2) n= logNt−log No 0.301 (rewrite into this formula) 3) 2n (2 x 2 x 2 x 2 etc.) n≤6 4) Calculating Growth rate constant (k = n/t) 5) g= 0.301(t) Nt−No (Flipped for k) Answer Key: 1. A 2. B 3. B E 4. E 5. D 6. C 7. D 8. B 9. B 10. B 11. D 12. D E 13. E 14. B 15. B 16. A 17. E 18. C 19. A 20. E 21. D 22. E 23. C 24. B 25. B 26. D 27. A 28. D 29. C 30. B 31. A 32. E 33. D 34. C 35. C 36. E 37. C 38. D 39. C 40. D 41. A B D 42. E 43. E 44. B 45. B 46. B 47. D 48. A B C D 49. A 50. C 51. B 52. A