Download Fall 2005

BIOLOGY 204
GENERAL MICROBIOLOGY
INSTRUCTOR: Dr A. Hemsley
ANTELOPE VALLEY COLLEGE
FALL 2005
THEORY TEST 2
100 POINTS
STUDENT NAME: ___________________________________
STUDENT I.D. NUMBER: _____________________________
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Perusal time = 10 minutes
Test time = 105 minutes
ANSWER ALL QUESTIONS
Read ALL questions carefully during perusal time, you may write if you wish.
Use the back of each sheet if you do not have enough writing space, but please label each answer.
Question subheadings are NOT of equal points value.
Points allocated for each subheading are shown at the end of the question.
GOOD LUCK!
QUESTION 1 (Total =10 points)
Match entries in the left column with answers from the lettered choices in the right colum n. Write your letter choice to
the far left of each question in the spaces provided. Use each answer only ONCE.
(1 Point per correct pair)
_____ 1. A disinfectant that is an effective degermer
a.
Iodine
_____ 2. Early antiseptic, now considered carcinogenic
b.
Autoclave
_____ 3. Halogen used extensively in municipal water treatment
c.
Bacteriostasis
_____ 4. Halogen used as an antiseptic, very effective as a tincture
d.
Virucide
_____ 5 Enzyme denaturants, some toxicity
e.
Sanitization
_____ 6. Prevention of bacterial growth without killing the bacteria present
f.
Triclocarban
_____ 7. Instrument using pressurized steam to sterilize
g.
Ethanol
_____8.
h.
Chlorine
Agent capable of killing viruses
i
Heavy metals
_____ 10. Surface active agent capable of assisting in mechanical
j.
Phenol
_____ 9.
(e.g. mercurochrome)
Reduction of pathogen counts on eating and drinking utensils
to safe public health levels
degerming
page 1
QUESTION 2 (Total =10 points)
Flask A contains Clostridium tetani cells in glucose minimal salts medium, incubated at 37oC with aeration. Flask B
contains Clostridium tetani cells in glucose minimal salts medium, incubated at 37oC in an anaerobic jar. The cultures are
both grown for twenty-four hours.
a.
Which culture produced more ATP?
b.
Which culture had the shorter generation time? Why?
c.
Which culture had the greater cell mass? Why?
d.
Referring back to your answer to Part C., what are the cells in the other culture likely to be doing?
page 2
QUESTION 3 (Total =20 points)
A. As a hospital administrator, you have been asked to purchase the disinfectants and antiseptics for a new hospital.
Briefly discuss four factors that might influence your choices of purchase. Remember, a well-organized answer will gain
more points!
(16)
B.
Provide four purposes of culturing microbes
(4)
Page 3
QUESTION 4 (Total =20 points)
A.
Describe the phenomenon of multiple replication forks as it has been observed in bacterial DNA replication
(5)
B.
What advantage do bacteria gain from the process you described in Part A.?
C. List three other strategies bacteria can use to gain the same advantage you have outlined in Part B.
(5)
(5)
D. The enzyme DNA Ligase requires an ATP molecule to provide energy when it joins DNA fragments together, but
DNA Polymerase does not require ATP. Explain why this is so.
page 4
QUESTION 5 (Total =20 points)
Fill in the blanks in the following sentences. (1 point per correct sentence)
1.
The nucleotide that pairs with C in RNA is____________________________.
2.
The first amino acid in all protein molecules is____________________________.
3.
The codon sequence that signals protein synthesis initiation is
4.
A microbial test commonly performed to detect carcinogens is the ____________________________.
5.
One physical agent capable of causing mutations is ____________________________.
6.
A DNA mutation where a base change does not affect the protein sequence of the gene product is
____________________________.
called a ____________________________ mutation.
7.
A DNA mutation where a base change affects one amino acid in the protein sequence of the gene
product is called a ____________________________ mutation.
8.
A DNA mutation where a base change introduces a STOP codon in the protein sequence of the gene
product is called a ____________________________ mutation.
9.
One target area of a microbe that disinfectants may injure is the____________________________.
10.
____________________________is a mechanism introduces new genetic material into a bacterium as naked
DNA.
11.
____________________________ is a mechanism introduces new genetic material into a bacterium by way of
a bacteriophage vector.
12.
____________________________ is a mechanism introduces new genetic material into a bacterium due to a
mating event initiated by the F plasmid.
13.
Plasmids confer a survival advantage, such as____________________________ to bacteria possessing them.
14.
____________________________ is an enzyme that catalyses the formation of a DNA chain.
15.
The ____________________________ is an enzyme used to cut DNA at specific sequences.
16.
One important recombinant gene product expressed in bacteria is____________________________.
17.
A method of artificially introducing genes into cells is
____________________________ .
18.
A recombinant vaccine produced in yeast cells is the
____________________________.
19.
A vaccine that consists of proteins alone is known as a
____________________________.
20.
One agricultural application of genetic engineering is _____________________________ (give a specific
example).
page 5
QUESTION 6 (Total = 20 points)
You are planning to clone a gene from a frost-resistant weed into an alfalfa plant. You have located the gene for frost
resistance and have 4 restriction enzymes available that would remove a piece of DNA containing this gene from one of the
plant chromosomes. The restriction enzymes you could use are shown here, with small arrows indicating the sites of the
nicks introduced into the sugar phosphate backbone.
Pci I
…ACATGT…3’
3’
… TGTACA…5’
5’
Bsr G I
5’
…TGTACA…3’
3’
…ACATGT…5’
Cvi A II
5’
Nsp I
5’…RCATGY…3’
3’
…YGTACR…5’
…CATG…3’
3’
…GTAC…5’
R = any purine
Y = any pyrimidine
A. Which 2 enzymes would generate compatible ends on DNA fragments cut from the weed and a
plasmid polylinker? Explain your answer
(10)
B. Which enzyme would generate ends that were the most difficult to rejoin?
(5)
C. Explain your answer to part B.
(5)
page 6