Microbiology 240 - Exam 1 Multiple Choice
A
An enzyme produced in response to the presence of a substrate is called a(n) A) inducible enzyme. B) repressible enzyme. C) restriction enzyme. D) operator. E) promoter
A
Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of A) osmotic lysis. B) inhibition of molecular transport. C) decreased synthesis of peptidoglycan. D) plasmolysis. E) cell shrinkage.
True
Antibiotics that target the cell wall are an effective treatment against many pathogenic bacteria.
C
Each of the following statements concerning the gram-positive cell wall is true EXCEPT A) it maintains the shape of the cell. B) it is sensitive to lysozyme. C) it protects the cell in a hypertonic environment. D) it contains teichoic acids. E) it is sensitive to penicillin
False
Endospores are a reproductive structure.
False
Many enzymes in both prokaryotic and eukaryotic cells are compartmentalized within organelles.
B
The antibiotic amphotericin B disrupts plasma membranes by combining with sterols; it will affect all of the following cells except: A) animal cells B) gram-negative bacteria cells C) fungal cells D) mycoplasma cells E) plant cells
B
When glucose is high, cAMP is _____ : CAP _____ bind the lac operator, and RNA polymerase _____ bind the lac promoter. A) high; does; does B) low; does not; does not C) high; does not; does D) low; does not; does E) None of the answers is correct.
E
Where are phospholipids most likely found in a eukaryotic cell? A) surrounding flagella B) around organelles C) the plasma membrane D) ribosomes E) the plasma membrane, around organelles, and surrounding flagella
C
Where are phospholipids most likely found in a prokaryotic cell? A) flagella B) around organelles C) the plasma membrane D) ribosomes E) the plasma membrane and around organelles
B
Which drawing in the figure is a tetrad? A) a B) b C) c D) d E) e
D
Which drawing in the figure is streptococci? A) a B) b C) c D) d E) e
A
Which drawing in the figure possesses an axial filament? A) a B) b C) c D) d E) e
A
Which of the following are NOT energy reserves? A) carboxysomes B) polysaccharide granules C) lipid inclusions D) sulfur granules E) metachromatic granules
B
Which of the following organelles most closely resembles a prokaryotic cell? A) nucleus B) mitochondrion C) Golgi complex D) vacuole E) cell wall
B
Which of the following pair is mismatched? A) glycocalyx - adherence B) pili - reproduction C) cell wall - toxin D) cell wall - protection E) plasma membrane - transport
E
Which of the following pair is mismatched? A) metachromatic granules - stored phosphates B) polysaccharide granules - stored starch C) lipid inclusions - poly-B-hydroxybutric acid D) sulfur granules - energy reserve E) ribosomes - protein storage
B
Which of the following pairs is mismatched? A) DNA polymerase — makes a molecule of DNA from a DNA template B) RNA polymerase — makes a molecule of RNA from an RNA template C) DNA ligase — joins segments of DNA D) transposase — insertion of DNA segments into DNA E) DNA gyrase — coils and twists DNA
D
Which of the following pairs is mismatched? A) endoplasmic reticulum - internal transport B) Golgi complex - secretion C) mitochondria - ATP production D) centrosome - food storage E) lysosome - digestive enzymes
B
Which of the following statements about bacteriocins is FALSE? A) The genes coding for them are on plasmids. B) They cause food-poisoning symptoms. C) Nisin is a bacteriocin used as a food preservative. D) They can be used to identify certain bacteria. E) Bacteriocins kill bacteria.
D
Which of the following statements about gram-negative cell walls is FALSE? A) They protect the cell in a hypotonic environment. B) They have an extra outer layer composed of lipoproteins, lipopolysaccharides, and phospholipids. C) They are toxic to humans. D) They are sensitive to penicillin. E) Their Gram reaction is due to the outer membrane.
D
Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids? A) In an isotonic solution, nothing will happen. B) In a hypotonic solution, the cell will lyse. C) Water will move into the cell. D) Intracellular contents will leak from the cell. E) Any of the above might happen.
C
Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5 percent NaCl? A) Sucrose will move into the cell from a higher to a lower concentration. B) The cell will undergo osmotic lysis. C) Water will move out of the cell. D) Water will move into the cell. E) No change will result; the solution is isotonic.
C
A gene is best defined as A) a segment of DNA. B) three nucleotides that code for an amino acid. C) a sequence of nucleotides in DNA that codes for a functional product. D) a sequence of nucleotides in RNA that codes for a functional product. E) a transcribed unit of DNA.
A
A gram-positive bacteria suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to A) conjugation. B) binary fission. C) meisosis. D) transformation. E) transduction.
C
According to the operon model, for the synthesis of an inducible enzyme to occur, the A) end-product must not be in excess. B) substrate must bind to the enzyme. C) substrate must bind to the repressor. D) repressor must bind to the operator. E) repressor must not be synthesized.
A
Bacteria are a commonly used organism for studies of genetic material in the research laboratory. The nucleic acids must first be isolated from the cells for these studies. Which of the following would most likely be used to lyse the bacterial cells for nucleic acid isolation? A) lysozyme B) polymixins C) alcohol D) water E) mycolic acid
D
Based on the information in the table, prostate cancer is probably the result of which kind of mutation? A) analog B) frameshift C) missense D) nonsense E) None of the answers is correct.
C
By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration? A) simple diffusion B) facilitated diffusion C) active transport D) extracellular enzymes E) aquaporins
False
Cells placed in a hypotonic solution tend to lose water due to osmotic pressure.
C
Conjugation differs from reproduction because conjugation A) replicates DNA. B) transfers DNA vertically, to new cells. C) transfers DNA horizontally, to cells in the same generation. D) transcribes DNA to RNA. E) copies RNA to make DNA.
A
Culture 1: F+, leucine+, histidine+ Culture 2: F-, leucine-, histidine- Looking at the cultures above, if culture 1 mutates to Her, what will be the result of conjugation between the two cultures? A) They will both remain the same. B) 1 will become F+, leu+, his+; 2 will become F+, leu+, his+ C) 1 will remain the same; recombination will occur in 2 D) 1 will become F-, leu+, his+; 2 will become Hfr, leu+, his+ E) The answer cannot be determined based on the information provided.
A
Culture 1: F+, leucine+, histidine+ Culture 2: F-, leucine-, histidine- Looking at the cultures above, what will be the result of conjugation between cultures 1 and 2? A) 1 will remain the same; 2 will become F+, leucine-, histidine- B) 1 will become F-, leu+, his+; 2 will become F+, leu-, his- C) 1 will become F-, leu-, his-; 2 will remain the same D) 1 will remain the same; 2 will become F+, leu+, his+ E) 1 will remain the same; 2 will become F+ and recombination may occur
C
DNA is constructed of A) a single strand of nucleotides with internal hydrogen bonding. B) two complementary strands of nucleotides bonded A—C and G—T. C) two strands of nucleotides running antiparallel. D) two strands of identical nucleotides with hydrogen bonds between them. E) None of the answers is correct.
D
Fimbriae and pili differ in that A) there are only one or two pili per cell. B) pili are used for motility. C) pili are used to transfer DNA. D) pili are used for transfer of DNA and motility. E) pili are used for attachment to surfaces.
E
Functions of the glycocalyx include all of the following EXCEPT A) biofilm formation. B) increased virulence. C) source of nutrition. D) protection against dehydration. E) binary fission.
E
Genetic change in bacteria can be brought about by A) mutation. B) conjugation. C) transduction. D) transformation. E) All of the answers are correct.
C
How do spirochetes and spirilla differ? A) Spirochetes do not have a cell wall but spirilla do. B) Spirilla are found in chains of cells whereas spirochetes exist as individual cells. C) Spirilla have an external flagella but spirochetes have axial filaments. D) Spirochetes have a rigid, corkscrew shape while spirilla are helical and more flexible. E) Spirochetes and spirilla are basically the same organisms and the terms can be used interchangeably.
True
If you observe rod-shaped red cells after the Gram stain, you can assume their cell walls contain endotoxin.
D
In a hypertonic solution, a bacterial cell will typically A) lyse. B) burst. C) stay the same. D) plasmolyze. E) osmolyze.
C
In bacteria, photosynthetic pigments are found in A) chloroplasts. B) cytoplasm. C) chromatophores. D) mesosomes. E) ribosomes.
C
In the figure, base 2 is attached to A) ribose. B) phosphate. C) deoxyribose. D) thymine. E) The answer cannot be determined based on the information provided.
B
In the figure, if base 4 is thymine, what is base 11'? A) adenine B) thymine C) cytosine D) guanine E) uracil
A
In the figure, if base 4 is thymine, what is base 4'? A) adenine B) thymine C) cytosine D) guanine E) uracil
C
In the figure, if compound C reacts with the allosteric site of enzyme A, this would exemplify A) a mutation. B) repression. C) feedback inhibition. D) competitive inhibition. E) transcription.
C
In the figure, if enzyme A is a repressible enzyme, compound C would A) always be in excess. B) bind to the enzyme. C) bind to the corepressor. D) bind to RNA polymerase. E) bind to gene a.
B
In the figure, if enzyme A is an inducible enzyme, A) compound C would bind to the repressor. B) compound A would bind to the repressor. C) compound B would bind to enzyme A. D) compound A would react with enzyme B. E) compound C would react with gene a.
D
In the figure, the antibiotic chloramphenicol binds the 50S ribosome as shown. From this information you can conclude that chloramphenicol A) prevents transcription in eukaryotes. B) prevents translation in eukaryotes. C) prevents transcription in prokaryotes. D) prevents translation in prokaryotes. E) prevents mRNA-ribosome binding.
D
In the figure, which colonies are streptomycin-resistant and leucine-requiring? A) 1, 2, 3, and 9 B) 3 and 9 C) 4, 6, and 8 D) 4 and 8 E) 5 and 6
A
In the figure, which diagram of a cell wall contains porins? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
A
In the figure, which diagram of a cell wall contains teichoic acids? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
C
In the figure, which diagram of a cell wall has a structure that protects against osmotic lysis? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided
B
In the figure, which diagram of a cell wall is a gram-negative cell wall? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
B
In the figure, which diagram of a cell wall is decolorized by alcohol? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
B
In the figure, which diagram of a cell wall is resistant to many antibiotics (e.g., penicillin)? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
B
In the figure, which diagram of a cell wall possesses molecules responsible for symptoms associated with infection? A) a B) b C) both a and b D) neither a nor b E) The answer cannot be determined based on the information provided.
B
Oxygen crosses a plasma membrane A) by osmosis. B) through simple diffusion. C) with the help of a nonspecific transporter. D) through facilitated diffusion. E) through porins.
E
Refer to the table. If a frameshift mutation occurred in the sequence of bases shown below, what would be the sequence of amino acids coded for? 3' ATTACGCTTTGC A) leucine-arginine-lysine-alanine B) asparagine-arginine-lysine-alanine C) asparagine-cysteine-valine-serine D) Translation would stop at the first codon. E) The answer cannot be determined based on the information provided.
B
Refer to the table. If the sequence of amino acids encoded by a strand of DNA is serine-alanine-lysine-leucine, the coding for the antisense strand of DNA is A) 5' ACAGTTTCAAT. B) 5' TCTGCAAAGTTA. C) 3' UGUGCAAAGUUA. D) 3' UCUCGAAAGUUA. E) 3' TCACGUUUCAAU.
B
Refer to the table. If the sequence of amino acids encoded by a strand of DNA is serine-alanine-lysine-leucine, what is the order of bases in the sense strand of DNA? A) 3' UGUGCAAAGUUA B) 3' AGACGTTTCAAT C) 3' TCTCGTTTGTTA D) 5' TGTGCTTTCTTA E) 5' AGAGCTTTGAAT
D
Refer to the table. The anticodon for valine is A) GUU. B) CUU. C) CTT. D) CAA. E) GTA.
D
Refer to the table. What is the sequence of amino acids encoded by the following sequence of bases in a strand of DNA? 3' ATTACGCTTTGC A) leucine-arginine-lysine-alanine B) asparagine-arginine-lysine-alanine C) asparagine-cysteine-valine-serine D) Translation would stop at the first codon. E) The answer cannot be determined based on the information provided.
True
Small, hydrophobic molecules pass through a cell membrane most easily by diffusion.
True
Spheroplasts, protoplasts, and mycoplasms are bacterial cells without cell walls.
D
Synthesis of a repressible enzyme is stopped by the A) allosteric transition. B) substrate binding to the repressor. C) corepressor binding to the operator. D) corepressor-repressor complex binding to the operator. E) end product binding to the promoter.
C
The DNA found in most bacterial cells A) is surrounded by a nuclear membrane. B) utilizes histones for chromosomal packaging. C) is circular in structure. D) is linear in structure. E) is found in multiple copies.
True
The cell walls of bacteria are responsible for the shape of the bacteria and the difference in the Gram stain reaction.
D
The damage caused by ultraviolet radiation is A) never repaired. B) repaired during transcription. C) repaired during translation. D) cut out and replaced. E) repaired by DNA replication.
D
The difference between simple diffusion and facilitated diffusion is that facilitated diffusion A) moves materials from a higher to a lower concentration. B) moves materials from a lower to a higher concentration. C) requires ATP. D) requires transporter proteins. E) does not require ATP.
D
The initial effect of ionizing radiation on a cell is that it causes A) DNA to break. B) bonding between adjacent thymines. C) base substitutions. D) the formation of highly reactive ions. E) the cells to get hot.
True
The internal structure of eukaryotic cilia and flagella are the same.
E
The mechanism by which the presence of arabinose controls the arabinose operon is A) catabolite repression. B) translation. C) DNA polymerase. D) repression. E) induction.
A
The mechanism by which the presence of glucose inhibits the arabinose operon is A) catabolite repression. B) translation. C) DNA polymerase. D) repression. E) induction.
A
The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar to A) human DNA. B) T. aquaticus DNA. C) a mixture of human and T. aquaticus DNA. D) human RNA. E) T. aquaticus RNA.
False
The number of organelles such as chloroplasts, mitochondria, and rough endoplasmic reticulum is the same in all eukaryotic cells.
B
The terms "run" and "tumble" are generally associated with A) cell wall fluidity. B) taxic movements of the cell. C) clustering properties of certain rod-shaped bacteria. D) cell membrane synthesis.
B
Transformation is the transfer of DNA from a donor to a recipient cell A) by a bacteriophage. B) as naked DNA in solution. C) by cell-to-cell contact. D) by crossing over. E) by sexual reproduction
B
What will happen if a bacterial cell is placed in distilled water with lysozyme? A) The cell will plasmolyze. B) The cell will undergo osmotic lysis. C) Water will leave the cell. D) Lysozyme will diffuse into the cell. E) No change will result; the solution is isotonic.
B
Which of the following have a cell wall? A) protoplasts B) fungi C) L forms D) mycoplasmas E) animal cells
D
Which of the following is NOT a functionally analogous pair? A) nucleus -nucleiod region B) mitochondria - prokaryotic plasma membrane C) chloroplasts - thylakoids D) cilia - pili E) 9+2 flagella - bacterial flagella
A
Which of the following is NOT a product of transcription? A) a new strand of DNA B) rRNA C) tRNA D) mRNA E) None of the answers are correct; all of these are products of transcription.
D
Which of the following is NOT a typical characteristic of most bacterial plasma membranes? A) site of energy production B) composed of a phospholipid bilayer C) contains proteins D) contains cholesterol E) is selectively permeable
C
Which of the following is NOT found in mitochondria and prokaryotes? A) circular chromosome B) 70S ribosomes C) cell wall D) binary fission E) ATP-generating mechanism
C
Which of the following is NOT part of the passive transport process? A) plasma membrane B) transporter proteins C) ATP D) concentration gradient E) aquaporins
E
Which of the following is false about fimbriae? A) They are composed of protein B) They may be used for attachment C) They are found of gram-negative cells. D) They are composed of pilin. E) They may be used for motility.
E
Which of the following is not a distinguishing characteristic of prokaryotic cells? A) They usually have a single, circular chromosome. B) They lack membrane-enclosed organelles. C) They have cell walls containing peptidoglycan D) Their DNA is not associated with histones. E) They lack a plasma membrane.
D
Which of the following statements is FALSE? A) DNA polymerase joins nucleotides in one direction only. B) The leading strand of DNA is made continuously. C) The lagging strand of DNA is started by an RNA primer. D) DNA replication proceeds in one direction around the bacterial chromosome. E) Multiple replication forks are possible on a bacterial chromosome.
E
Which of the following statements is INCORRECT regarding prokaryotic cells? A) Their DNA is not enclosed within a membrane. B) They lack membrane-enclosed organelles. C) They typically have a circular chromosome. D) They reproduce by binary fission. E) They lack a plasma membrane.
B
Which of the following statements is TRUE? A) Endospores are for reproduction. B) Endospores allow a cell to survive environmental changes. C) Endospores are easily stained in a Gram stain. D) A cell produces one endospore and keeps growing. E) A cell can produce many endospores.
E
Which of the following statements is correct about diffusion? A) It requires an expenditure of energy by the cell. B) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. C) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. D) It may require a transport protein. E) It involves movement of molecules down a concentration gradient and may require a transport protein
D
Which of the following statements regarding a bacterium that is R+ is FALSE? A) It possesses a plasmid. B) R+ can be transferred to a cell of the same species. C) It is resistant to certain drugs and heavy metals. D) It is F+. E) R+ can be transferred to a different species
C
Which of the following structures is NOT found in some prokaryotic cells? A) flagellum B) axial filament C) cilium D) pilus E) peritrichous flagella
C
Which of the following terms best describes the cell in the figure? A) peritrichous flagella B) amphitrichous flagella C) lophotrichous flagella D) monotrichous flagella E) axial filament
C
Which one of the following pairs is mismatched? A) metachromatic granules - phosphate storage B) lipid inclusions - energy reserve C) ribosomes - protein storage D) sulfur granules - energy reserve E) gas vacuoles - flotation
B
Which statement best describes what happens when a gram-negative bacterium is placed in distilled water and penicillin? A) No change will result; the solution is isotonic. B) Water will move into the cell. C) Water will move out of the cell. D) The cell will undergo osmotic lysis. E) Sucrose will move into the cell from an area of higher concentration to one of lower concentration.
A
Which statement best describes what happens when a gram-positive bacterium is placed in an aqueous solution of lysozyme and 10% sucrose? A) No change will result; the solution is isotonic. B) Water will move into the cell. C) Water will move out of the cell. D) The cell will undergo osmotic lysis. E) Sucrose will move into the cell from an area of higher concentration to one of lower concentration.
D
Which statement best describes what happens when a gram-positive bacterium is placed in distilled water and penicillin? A) No change will result; the solution is isotonic. B) Water will move into the cell. C) Water will move out of the cell. D) The cell will undergo osmotic lysis. E) Sucrose will move into the cell from an area of higher concentration to one of lower concentration.
C
Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized? A) slime layer B) fimbriae C) capsule D) cell membrane E) cell wall
A
You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has A) ribosomes B) mitochondria C) an endoplasmic reticulum D) a Golgi complex E) all of the above
C
You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell A) has 9 pairs + 2 flagella. B) has a mitochondrion. C) has a cell wall. D) lives in an extreme environment.
