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Test 2

You scored 63.5833333333334 out of 109

Question 1

Your answer is CORRECT.

Which of the following is false regarding prokaryotic genes and genomes?

A) Most prokaryotic genomes are comprised of a single circular chromosome; in addition, some may also

have genes contained on plasmids and linear chromosomes.

B) Genes and operons that are functionally part of the same process (e.g., nitrogen metabolism) are

controlled together as part of a regulon.

C) Structural genes contain information that specifies for a protein or a type of RNA molecule.

D) Control sequences in DNA do not code for proteins, rather they serve to regulate gene function.

E) None of the above are false; A-D are all true statements.

Question 2

Your answer is CORRECT.

Which of the following does not apply to replication of the circular prokaryotic chromosome?

A) It utilizes only one replisome which contains 2 DNA polymerase molecules, a DNA primase, & a DNA

helicase.

B) The primer in DNA replication is an RNA starter sequence with a free 3' OH group.

C) The lagging strand is synthesized 5' to 3', and the leading strand is also synthesized 5' to 3'.

D) Its completion requires the activity of RNase H, replacement with DNA, and DNA ligase activity.

E) It is initiated at the oriC sequence where DNA strand separation occurs forming a replication bubble

containing two replication forks.

Question 3

Your answer is CORRECT.

Which of the following is false regarding DNA and RNA structure?

A) Phosphodiester bonds form the sugar phosphate backbone of DNA.

B) Purines and pyrimidines of both DNA strands hydrogen bond to each other via complimentary base

pairing.

C) The 5' phosphate at the end of one strand will be directly opposite to the 5' phosphate end of the

complimentary strand.

D) RNA exists as a single strand that may complimentary base pair with itself to form different structures.

E) The stability of DNA is much greater than that of RNA.

Question 4

Your answer is INCORRECT.

Which statement is not applicable to plasmids?

A) Plasmids copied via rolling circle replication do not undergo bidirectional replication.

B) They replicate independent of the chromosome.

C) Plasmids of high copy number are more likely to be passed on to daughter cells following cell division.

D) Plasmids may be lost by a cell if selective pressure is not maintained.

E) All the above are applicable to plasmids.

Question 5

Your answer is CORRECT.

Without __________, the core RNA polymerase binds and releases DNA at random.

A) sigma factor

B) initiation factor

C) Shine-Dalgarno sequence

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Test 2

You scored 63.5833333333334 out of 109 Question 1 Your answer is CORRECT. Which of the following is false regarding prokaryotic genes and genomes? A) Most prokaryotic genomes are comprised of a single circular chromosome; in addition, some may also have genes contained on plasmids and linear chromosomes. B) Genes and operons that are functionally part of the same process (e.g., nitrogen metabolism) are controlled together as part of a regulon. C) Structural genes contain information that specifies for a protein or a type of RNA molecule. D) Control sequences in DNA do not code for proteins, rather they serve to regulate gene function. E) None of the above are false; A-D are all true statements. Question 2 Your answer is CORRECT. Which of the following does not apply to replication of the circular prokaryotic chromosome? A) It utilizes only one replisome which contains 2 DNA polymerase molecules, a DNA primase, & a DNA helicase. B) The primer in DNA replication is an RNA starter sequence with a free 3' OH group. C) The lagging strand is synthesized 5' to 3', and the leading strand is also synthesized 5' to 3'. D) Its completion requires the activity of RNase H, replacement with DNA, and DNA ligase activity. E) It is initiated at the oriC sequence where DNA strand separation occurs forming a replication bubble containing two replication forks. Question 3 Your answer is CORRECT. Which of the following is false regarding DNA and RNA structure? A) Phosphodiester bonds form the sugar phosphate backbone of DNA. B) Purines and pyrimidines of both DNA strands hydrogen bond to each other via complimentary base pairing. C) The 5' phosphate at the end of one strand will be directly opposite to the 5' phosphate end of the complimentary strand. D) RNA exists as a single strand that may complimentary base pair with itself to form different structures. E) The stability of DNA is much greater than that of RNA. Question 4 Your answer is INCORRECT. Which statement is not applicable to plasmids? A) Plasmids copied via rolling circle replication do not undergo bidirectional replication. B) They replicate independent of the chromosome. C) Plasmids of high copy number are more likely to be passed on to daughter cells following cell division. D) Plasmids may be lost by a cell if selective pressure is not maintained. E) All the above are applicable to plasmids. Question 5 Your answer is CORRECT. Without __________, the core RNA polymerase binds and releases DNA at random. A) sigma factor B) initiation factor C) Shine-Dalgarno sequence

D) peptidyltransferase E) release factor Question 6 Your answer is INCORRECT. Which of the following can cause transcription to end? A) chaperone protein B) sigma factor C) stop codon D) rho E) more than one of the above Question 7 Your answer is CORRECT. What is the significance of the Shine-Dalgarno sequence? A) It is the site where RNA polymerase binds to begin transcription. B) It is the site where ribosomes bind to begin translation. C) It is the site where DNA polymerase binds to begin chromosome replication. D) It is the site where the tRNA binds to the mRNA in translation. E) It is the site where DNA polymerase begins synthesis of the Okazaki fragments on the lagging strand. Question 8 Your answer is INCORRECT. The __________ of transcription and translation helps microbes rapidly adjust gene expression to changes in their environment. A) coupling B) separation C) processes D) slowing E) pausing Question 9 Your answer is CORRECT. After __________, each polypeptide must be properly folded and placed at the correct cellular or extracellular location. A) replication B) transcription C) translation D) degradation E) conjugation Question 10 Your answer is CORRECT. The DNA that comprises prokaryotic genomes has been acquired solely from prior generations. A) True B) False Question 11 Your answer is INCORRECT. The process of importing free DNA from the environment into cells is called A) transcription. B) transformation. C) conjugation. D) transduction. E) transposition. Question 12 Your answer is CORRECT.

C) Translation D) Constitutive operon E) Derepression Question 19 Your answer is CORRECT. E. coli was inoculated into a culture medium containing both glucose and lactose. The culture begins growing and three hours later, a culture sample was taken and analyzed for lactose; this revealed that the cells had not yet utilized the lactose as its concentration remained unchanged. Which of the following is true regarding the regulation of the lactose operon in these cells during this time interval? A) The lactose repressor was active in these cells. B) The intracellular levels of cyclic AMP (cAMP) very high. C) The lactose permease (lacY gene) was not functioning in these cells. D) The cAMP-CRP complex was increasing transcription of the lacZYA genes in the cells. E) Two of the above statements are correct. Question 20 Your answer is INCORRECT. The absence of tryptophan (trp) in E. coli A) produces an inactive trp repressor B) causes ribosomes to translate the trp leader sequence (trpL) up to the stop codon C) causes tryptophan to act as an inducer of transcription of the trp operon D) prevents transcription of the trp structural genes E) two of the above are correct Question 21 Your answer is CORRECT. An E. coli strain acquires a mutation in its lac repressor gene (lacI); the mutated LacI repressor protein has changed such that it will not bind to the lac operator sequences under any circumstances. As a result, this strain will never be able to grow on lactose. A) True B) False Question 22 Your answer is CORRECT. The stringent response involves all EXCEPT : A) reduction in ribosomal RNA synthesis B) stalled ribosomes and uncharged tRNAs C) nutrient-poor conditions D) ppGpp E) all are involved Question 23 Your answer is INCORRECT. Which of the following explains the regulatory activity of small RNA (sRNA) genes? A) It codes for a sigma factor. B) It prevents CRP interaction with RNA polymerase, thereby blocking its access to the promoter. C) It synthesizes ppGpp. D) It targets mRNAs for degradation or blocks ribosome binding to mRNAs. E) It creates an attenuator stem loop. Question 24 Your answer is CORRECT. Which of the following is not true of phase variation? A) The DNA sequence is not altered or changed. B) It may help the bacteria avoid the immune system. C) It requires recombination.

D) It affects external structures of the bacterium, like the flagellum, capsule, or fimbriae. E) All are true Question 25 Your answer is CORRECT. Which of the following statements is false? A) Constitutive genes are always expressed. B) The activity of a quorum-sensing gene system is highest when the cell number in the population is very low. C) A feature common to all control mechanisms is the ability to sense that something inside or around the cell has changed. D) Binding of attractant changes the intracellular levels of phosphorylated Che-Y to produce smooth runs. E) None are false; all are true statements. Question 26 Your answer is CORRECT. Which of the following are not likely to favor G values that are more negative? A) an increase in reactants over products B) forming products that are simpler and greater in number than the reactants C) formation of products that are more stable and have less energy than the reactants D) forming products that have lower entropy (negative delta S) than the reactants E) all the above favor negative G values. Question 27 Your answer is INCORRECT. Formation of concentration gradients is a common feature among microbes and all cells. Which of the following is false regarding concentration gradients? A) It does not require energy to produce the gradient. B) The gradient can be used to do work. C) Movement of molecules down a gradient releases energy. D) Entropy increases as molecules diffuse down their gradient. E) None are false; all are true. Question 28 Your answer is INCORRECT. Which of the following statements is true regarding the electron donors in bacterial and archaeal metabolism? A) The use of inorganic compounds as electron donors is known as organotrophy. B) Lithotrophy refers to the use of organic molecules as electron sources. C) Organotrophs perform photolysis of small organic molecules.

D) Fe2+, H 2 S, or H 2 would be electron donors for lithotrophs.

E) None are true; all are false statements. Question 29 Your answer is INCORRECT. Which glucose catabolic pathway (A, B, C) is not correctly matched? A. Embden-Meyerhof-Parnas (Glycolysis) Pathwy B. Entner-Doudoroff Pathway C. Pentose-Phosphate Shunt A) Sugar acids catabolized to key intermediate, 6-phosphogluconate, then to pyruvate: B B) Can be used to form building blocks for biosynthesis such purines for DNA or aromatic amino acids: C C) Pathway forms 3 to 7 carbon sugars: A D) The presence of phosphorylated sugars: A, B, and C E) All are matched correctly. Question 30 Your answer is INCORRECT. Which is applicable to fermentation?

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Test 2