Practice Exam 2   BIO 108

 



1)Salts and sugars work to preserve foods by creating a
A)Depletion of nutrients.
B)Lower pH.
C)Lower osmotic pressure.
D)Hypotonic environment.
E)Hypertonic environment.

2)Which of the following is an advantage of the standard plate count?
A)Requires incubation time
B)Determines the number of viable cells
C)Chemical and physical requirements are determined by media and incubation.
D)Cannot be used to count bacteria in food
E)Can readily count cells that form aggregates

3)Which of the following is an advantage of the direct microscopic count?
A)Can readily count organisms that are motile
B)Requires a large number of cells
C)Enumerates dead cells
D)Sample volume is unknown.
E)Requires no incubation time

4)Which of the following is NOT used to determine metabolic activity?
A)NO2- produced from the electron transport chain
B)Decreased dissolved oxygen
C)Turbidity
D)CO2 produced from the Krebs cycle
E)Acid production from fermentation

5)Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample?
A)9 B) 72 C) 36 D) 4 E) 18

 

Figure 6.2

 



6)In Figure 6.2, which section shows a growth phase where the number of cells dying equals the number of cells dividing?
A)a B) b C) c D) d E) a and c

7)A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a(n)
A)Differential medium.
B)Selective medium.
C)Enrichment culture.
D)A and B
E)B and C

8)During which growth phase will gram-positive bacteria be most susceptible to penicillin?
A)Stationary phase
B)Lag phase
C)Log phase
D)Death phase
E)The culture is equally susceptible during all phases.

9)Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt?
A)Thermophiles
B)Facultative halophiles
C)Hyperthermophiles
D)Anaerobes
E)Psychrophiles

10)An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through?
A)32 B) 4 C) 6 D) 5 E) 64

11)Which of the following is the best method to sterilize heat-labile solutions?
A)Pasteurization
B)Autoclave
C)Dry heat
D)Membrane filtration
E)Freezing

12)Which of the following substances can sterilize?
A)Phenolics
B)Chlorine
C)Alcohol
D)Soap
E)Ethylene oxide

13)Place the following surfactants in order from the most effective to the least effective antimicrobial activity:
1-Soap; 2-Acid-anionic detergent; 3-Quats.
A)2, 1, 3 B) 3, 2, 1 C) 1, 3, 2 D) 1, 2, 3 E) 3, 1, 2

14)Iodophors differ from iodine (I2) in that iodophors
A)Are combined with a nonionic detergent.
B)Don't stain.
C)Are less irritating.
D)Are longer lasting.
E)All of the above.

15)Which of the following is a limitation of the autoclave?
A)Cannot inactivate viruses
B)Cannot be used with glassware
C)Cannot be used with heat-labile materials
D)Cannot kill endospores
E)Requires a long time to achieve sterilization

16)Which of the following substances is NOT an oxidizing agent?
A)Glutaraldehyde
B)Hydrogen peroxide
C)Chlorine
D)Iodine
E)Ozone

17)Which of the following substances is NOT effective against nonenveloped viruses?
A)Ozone
B)Alcohol
C)Chlorine
D)Ethylene oxide
E)All are equally effective.

18)Which of the following will NOT destroy prions?
A)Proteases
B)Incineration
C)NaOH + autoclaving at 134°C
D)Boiling
E)All of the above destroy prions.

19)Which of the following pairs is mismatched?
A)DNA gyrase  coils and twists DNA
B)DNA ligase  joins segments of DNA
C)Transposase  insertion of DNA segments into DNA
D)RNA polymerase  makes a molecule of RNA from an RNA template
E)DNA polymerase  makes a molecule of DNA from a DNA template

20)DNA is constructed of
A)Two strands of nucleotides running antiparallel.
B)Nucleotides bonded AC and GT.
C)A single strand of nucleotides with internal hydrogen bonding.
D)Two strands of identical nucleotides with hydrogen bonds between them.
E)None of the above.

21)Which of the following statements about bacteriocins is false?
A)They can be used to identify certain bacteria.
B)Bacteriocins kill baceria.
C)The genes coding for them are on plasmids.
D)They cause food-poisoning symptoms.
E)Nisin is a bacteriocin used as a food preservative.

22)When glucose is high, cAMP is ________ : CAP ________ bind the lac operator, and RNA polymerase ________ bind the lac promoter.
A) low, doesn’t, doesn’t
B) high, doesn’t, does
C) low, doesn’t, doesn’t
D) low, does, does
E) high, does, does

23)Genetic change in bacteria can be brought about by
A)Conjugation.
B)Transduction.
C)Transformation.
D)Mutation.
E)All of the above.

24)The initial effect of ionizing radiation on a cell is that it causes
A)Base substitutions.
B)The formation of highly reactive ions.
C)Bonding between adjacent thymines.
D)DNA to break.
E)The cells to get hot.

25)Synthesis of a repressible enzyme is stopped by
A)The substrate binding to the repressor.
B)The end-product binding to the promoter.
C)The allosteric transition.
D)The corepressor binding to the operator.
E)The corepressor-repressor binding to the operator.

26)The mechanism by which the presence of glucose inhibits the arabinose operon is
A)Translation.
B)DNA polymerase.
C)Induction.
D)Repression.
E)Catabolite repression.

27)An enzyme that makes covalent bonds between nucleotide sequences in DNA is
A)RNA polymerase.
B)Transposase.
C)Restriction enzyme.
D)DNA ligase.
E)DNA polymerase.

28)An enzyme that cuts double-stranded DNA at specific nucleotide sequences.
A)DNA ligase
B)DNA polymerase
C)Transposase
D)Restriction enzyme
E)RNA polymerase

29)Repair of damaged DNA might be viewed as a race between an endonuclease and
A)DNA ligase.
B)Helicase.
C)Primase.
D)DNA polymerase.
E)Methylase.

30)Assume the two E.coli strains shown below are allowed to conjugate.
Hfr: pro+, arg+, his+, lys+, met+, ampicillin-sensitive
F: pro-, arg-, his-, lys-, met-, ampicillin-resistant
What supplements would you add to glucose minimal salts agar to select for a recombinant cell that is lys+, arg+, amp-resistant?
A)Proline, histidine, methionine
B)Ampicillin, lysine, arginine
C)Ampicillin, prolein, histidine, lysine
D)Lysine arginine
E)Ampicillin, proline, histidine, methionine

Figure 9.2

 



31)In Figure 9.2, the enzyme in step 2 is
A)DNA polymerase.
B)Spliceosome.
C)Reverse transcriptase.
D)DNA ligase.
E)RNA polymerase.

32)Which of the following is NOT an agricultural product made by DNA techniques?
A)Glyphosate-resistant crops
B)Frost retardant
C)Pectinase
D)Bacillus thuringiensis insecticide
E)Nitrogenase (nitrogen fixation)

33)If you have inserted a gene in the Ti plasmid, the next step in genetic engineering is
A)Splicing T DNA into a plasmid.
B)Inserting the Ti plasmid into Agrobacterium.
C)Transformation of E. coli with Ti plasmid.
D)Inserting the Ti plasmid into a plant cell.
E)Transformation of an animal cell.

34)Which of the following methods of making rDNA could be described as "hit or miss"?
A)Protoplast fusion
B)Gene gun
C)Transformation
D)Cloning
E)Viral transduction

35)E. coli makes insulin because
A)It's an ancient gene that now has no function.
B)The insulin gene was inserted into it.
C)It picked up the insulin gene from another cell.
D)It needs to regulate its cell-glucose level.
E)No reason; it doesn't make insulin.

36)Which enzyme would cut this strand of DNA: GCATGGATCCCAATGC?
A)Enzyme Recognition
BamHI G↓GATCC
CCCTAG↑G
B)Enzyme Recognition
HaeIII GG↓CC
CC↑GG
C)Enzyme Recognition
EcoRI G↓AATTC
CTTAA↑G
D)Enzyme Recognition
HindIII A↓AGCTT
TTCGA↑A
E)Enzyme Recognition
PstI CTGC↓G
G↑ACGTC

37)A population of cells carrying a desired plasmid is called a
A)PCR.
B)Vector.
C)Clone.
D)Southern blot.
E)Library.

38)The purpose of the Human Genome Project was to
A)Sequence the nucleotides in human DNA.
B)Identify all of the human genes.
C)Translate human DNA.
D)Identify genes of all organisms.
E)None of the above.

39)A colleague has used computer modeling to design an improved enzyme. To produce this enzyme, the next step is to
A)Determine the nucleotide sequence for the improved enzyme.
B)Use siRNA to produce the enzyme.
C)Mutate bacteria until one makes the improved enzyme.
D)Look for a bacterium that makes the improved enzyme.
E)Synthesize the gene for the improved enzyme.

Figure 9.4
 




40)In Figure 9.4, the resulting organism (a) is
A)E. coli.
B)a plant × Pseudomonas hybrid.
C)Bacillus thuringiensis.
D)A tomato plant.
E)Pseudomonas fluorescens.

41)A source of heat-stable DNA polymerase is
A)Saccharomyces cerevisiae.
B)Bacillus thuringiensis.
C)Pseudomonas.
D)Thermus aquaticus.
E)Agrobacterium tumefaciens.

42)The Pap test for cervical cancer involves microscopic examination of cervical cells for cancerous cells. A new, rapid diagnostic test to detect human papilloma virus (HPV) DNA before cancer develops is done without microscopic exam. The steps involved in this FastHPV test are listed. What is the second step?
A)Add an RNA probe for HPV DNA
B)Add enzyme substrate
C)Lyse human cells
D)Add enzyme-linked antibodies against DNA-RNA
E)It doesn’t matter.

43)The use of an antibiotic-resistance gene on a plasmid used in genetic engineering makes
A)Replica plating possible.
B)Direct selection possible.
C)The recombinant cell unable to survive.
D)The recombinant cell dangerous.
E)All of the above.

44)The following steps must be performed to make a bacterium produce human protein X:
1-Translation; 2-Restriction enzyme; 3-Prokaryotic transcription; 4-DNA ligase; 5-Transformation; 6-Eukaryotic transcription; 7-Reverse transcription.
Put the steps in the correct sequence.
A)1, 2, 3, 5, 4, 7, 6
B)6, 7, 2, 3, 4, 5, 1
C)6, 7, 2, 4, 5, 3, 1
D)6, 2, 1, 3, 4, 5, 7
E)5, 2, 3, 4, 7, 6, 1

45)A specific gene can be inserted into a cell by all of the following EXCEPT
A)Protoplast fusion.
B)Agrobacterium.
C)Electroporation.
D)A gene gun.
E)Microinjection.

46)PCR can be used to identify an unknown bacterium because
A)All cells have RNA.
B)DNA polymerase will replicate DNA.
C)All cells have DNA.
D)The RNA primer is specific.
E)DNA can be electrophoresed.

47)PCR can be used to amplify DNA in a clinical sample. The following steps are used in PCR. What is the fourth step?
A)Incubate at 72°C.
B)Collect DNA.
C)Add DNA polymerase.
D)Incubate at 94°C.
E)Incubate at 60°C.

Key:
1)E
2)B
3)E
4)C
5)C
6)C
7)D
8)C
9)B
10)D
11)D
12)E
13)B
14)E
15)C
16)A
17)B
18)D
19)D
20)A
21)D
22)C
23)E
24)B
25)E
26)E
27)D
28)D
29)E
30)E
31)E
32)C
33)B
34)A
35)B
36)A
37)C
38)A
39)A
40)D
41)D
42)A
43)B
44)C
45)A
46)D
47)E