Bacteria & Enzyme Inhibitor – Microbiology
This capter covers bacteria and enzyme inhibitor of microbiology.
What is microbiology?
Microbiology is the study of:
living things that are too small to see without a microscope – correct
microscopes
bacteria
germs
What kind of organism would a microbiologist NOT study?
none of these – correct
protists
bacteria
viruses
What is the standard metric unit for 10-3m ?
millimeter (mm) – correct
micrometer (um)
nanometer (nm)
centimeter (cm)
About what size are most bacteria?
1 um (micrometer) – correct
0.5 nanometer (nm)
1.5 millimeter (mm)
2 Angstrom
To whom do we attribute the invention of the microscope?
Anton van Leeuwenhoek – correct
Louis Pasteur
John Snow
Fransesco Redi
The theory of spontaneous generations holds that
life can arise from non-living material – correct
life can only arise from living things
viruses are not alive
bacteria are not alive
What is objective of Koch’s postulates?
Identify the specific bacterium that causes a specific disease – correct
isolate bacteria
refute spontaneous generation
aseptic surgery
Which of these are contributions of Louis Pasteur to the field of microbiology?
all of these – correct
rabies vaccine
refutation of spontaneous generation
invention of the autoclave
What was John Snow’s major contribution to microbiology?
he was the first epidemiologist – correct
Snow invented the microscope
he invented Pasteurization
invented the autoclave
What concept did Ignaz Semmelweis contribute to health care?
sanitation; washing hands – correct
he discovered penicillin
father of epidemiology
he founded the red cross
Which of these structures is NOT present in both prokaryotes and eukaryotes?
ribosomes
plasma membrane
nucleus – correct
nucleic acids
What is taxonomy?
evolutionary descent
the science of classification – correct
the study of taxes
making stuffed animals
What is phylogeny?
evolutionary descent – correct
the study of phyla
binomial nomenclature
classification
What is a heterotroph?
a unicellular organism
a eukaryote
a sexually reproducing organism
an organism that requires organic carbon for energy and as a source of carbon – correct
What species is Pseudomonas aeriginosa?
Pseudomonas
prokaryote
bacteria
aeriginosa – correct
Why are bacteria hard to classify?
all of these – correct
most cannot be cultured in the laboratory
they lack morphological diversity
there is a high degree of lateral gene transfer among bacteria
How can DNA be used to classify bacteria?
hybridization
DNA sequencing
determine G+C ratio
all of these – correct
Classifying a bacterium is different than identifying a bacterium.
True
False
What range of number of colonies on a standard Petri plate is considered countable?
30 to 300 – correct
20 to 200
1 to 500
up to 1000
If I took 1 ml of a culture containing 7,000 cells per ml and added it to a tube containing 9 ml of sterile water, the concentration of cells in the second tube would be about
700 cells per ml – correct
7,000 cells
7,000 cells per ml
70 cells per ml
If I took 2 ml of a culture containing 4000 cells/ml and added that to a tube containing 2 ml of sterile water, the concentration of cells in the second tube would be
4000 cells/ml – correct
8000 cells
2000 cells/ml
none of these
should be 2000 cells/ml
I collect a volume of 0.1 ml of a culture. What volume of sterile water should I add to achieve a 1:10 dilution?
0.9 ml – correct
1 ml
0.1 ml
10 ml
I have a culture estimated to contain 106 colony forming units (CFU)/ml. How many 1:10 dilutions do I need to reduce the concentration to about 102 CFU/ml?
4 – correct
6
5
3
If I plate 0.1 ml of a culture is counts as a 1:10 dilution.
True – correct
False
What do we call the set of lenses nearest our eyes?
Oculars – correct
eyepieces
objectives
iris diaphragm
If I am looking through a 10X ocular and 10X objective, what is the total magnification?
100X – correct
10X
20X
1000X
What is contrast?
differences in light intensity – correct
increase in apparent size
resolution
depth of field
What is resolution?
ability to distinguish two closely spaced points – correct
increase in apparent size
differences in light intensity
magnification
Which of these types of microscope can increase the contrast of a specimen without staining it?
all of these – correct
dark field
phase contrast
DIC
Which of these types of microscopes will give me the best resolution of a thick specimen?
con focal – correct
phase contrast
epifluorescence
transmission electron
The limit of useful magnification of a microscope using white light to iluminate the specimen is about
1000X – correct
10,000X
100x
there is no limt
Which of these is an advantage of epifluorescence microscopy?
multiple staining – correct
resolution of thick specimens
do not need to stain specimen
very inexpensive
The principle advantage of electron microscopes over light microscopes is
Much higher useful magnification – correct
ease of sample preparation
better resolution of thick specimens
specimens do not have to be stained
What is the standard metric unit for 1 x 10-9m?
Nanometer – correct
micrometer
millimeter
Angstrom
The hydrolysis of starch into glucose and maltose molecules is an example of;
dehydration synthesis
catabolism – correct
cheap starch
anabolism
What is an enzyme?
a catalyst – correct
a substrate
a lipid
none of these
How do enzymes speed up reactions?
Enzymes increase the temperature of the solution
Enzymes add protons to the system
They lower the energy of activation – correct
Enzymes add energy to the reaction
What is an enzyme’s substrate?
the produt of the reaction
the molecule upon which it acts – correct
the amino acid composition of the enzyme
all of these
What is an enzyme’s active site
the area where it moves atoms up a concentration gradient
its substrate
none of these
the place on the enzyme where it interacts with its substrate – correct
I am measuring the rate at which the product of an enzyme catalyzed reaction accumulates in a solution. When I add an inhibitor, the rate goes down, and adding more substrate does not change the rate. What kind of inhibitor is this?
competitive
non-competitive – correct
temperature sensitive
protein denaturant
You are studying a biosynthetic pathway and you discover that the final product of the pathway is a non-competitive inhibitor of the first enzyme in the pathway. This phenomenon is called
product cycling
protein denaturation
all of these
feed back inhibition – correct
What do we know about the enzymes produced by bacteria living in 95oC water?
they are stable and active at 95o – correct
these will be denatured
these must be constructed of novel amino acids
nothing can live at 95o
What are the energy and carbon sources of a photoheterotroph?
light, inorganic carbon
light, organic carbon – correct
organic carbon
reduced inorganic molecules, inorganic carbon
What is a psychrophile?
organism that lives in high salt environments
organism that lives at low pH
people that love horror movies
organism that lives at low temperatures – correct
Quiz Score: 6 out of 10
Score for this quiz: 6 out of 10
Submitted Sep 27 at 10:19pm
This attempt took 11 minutes.
Which of these catabolic ‘styles’ is most efficient at extracting energy from organic carbon compounds?
aerobic respiration – correct
anaerobiosis and fermentation
anaerobic respiration
they are all the same
What is the objective of cellular respiration?
convert energy stored in carbon -carbon bonds into ATP – correct
acquiring oxygen
making water
glycolysis
Two ATPs per glucose are generated in fermentation
True
False – correct
Humans are obligate aerobes. Therefore our cells never do fermentation.
True
False – correct
Which of these is a product of the transition reaction?
all of these – correct
acetyl
CO2
NADH
Some ATP’s are generated directly in the Krebs cycle.
True – correct
False
In cellular respiration, when carbon-carbon bonds are broken, hydrogens are released and these are stored on co-enzymes like NAD.
True – correct
False
what is chemiosmosis?
using energy to establis a proton gradient across a membrane – correct
the osmosis of chemicals
the movement of water across a membrane
none of these
What is the role of oxygen in aerobic cellular respiration?
it is the terminal electron acceptor – correct
it is to burn carbon
to make water
oxidize NAD
Some bacteria use a molecule other than oxygen at the terminal electron acceptor.
True – correct
False
In what phase of the bacteria growth curve does the number of cells increase exponentially?
none of these
log phase – correct
stationary phase
lag phase
What factor is likely to cause a broth culture to transition from log phase to stationary phase?
running out of physical room
running out of water
all of these
running out of a particular nutrient – correct
What factor is likely to cause a broth culture to transition from stationary phase to death phase?
the accumulation of toxic wastes – correct
to run out of room
running out of energy
to run out of a particular nutrient
What are complex media?
growth media that contain ingredients that are not fully characterized – correct
media whose exact composition is know
media that repress the growth of certain types of bacteria
none of these
What are differential media?
differential media suppress the growth of some bacteria
contain ingredients to encourage the growth of certain types of bacteria
they allow us to distinguish types of bacteria based on an observable biochemical reaction – correct
all of these
What is the objective of streaking for isolation?
determining the concentration of bacteria in a broth culture
identifying a bacterium
preventing contamination
obtaining pure cultures – correct
What is the purpose of a chemostat?
maintain cultures in log phase – correct
maintain cultures in stationary phase
prevent contamination
determine the concentration of cells in a broth culture
Which of these is a techniques for determining the concentration of cells in a broth cuture?
serial dilution and plating
all of these – correct
most probable number
optical density
I counte 67 colonies on a plate made by spreading 100ul of a 10-7 dilution of a culture. What was the original cell denisty of the culture?
6.7 x 107 CFU/ml
67 x 107 CFU/ml
6.7 x 109 CFU/ml – correct
unable to determine from the information supplied
What does CFU stand for when expressing the concentration of bacteria in a broth culture?
colony forming units – correct
none of these
cell forming units
citizens for unity
DNA replication is semi-conservative. That means that daughter molecules
both daughter molecules contain a mixture of old and new DNA in both strands
are iddferent in that one caontains the old strands and one contains the newly synthesized strands
contains one oreiginal and one newly synthesized strand – correct
none of these
DNA polymerase will synthesize a new strand of DNA in one direction only; 5′ to 3′.
True – correct
False
At each replication fork, one new strand gets synthesized faster than the other.
True – correct
False
What is the function of DNA?
deliver amino acids to the ribosome
carry information from the nucleus to the ribosom
to carry information, usually recipes for the primary structure of proteins – correct
none of these
How do DNA and RNA molecules differ?
number of strands; 1 or 2
base pairing
pentose
all of these – correct
What is the function of the promoter region of a gene or operon?
the start of translation
the start of transcription
site where RNA polymerase can bind to the DNA – correct
regulates rate of transcription
What is an intron?
transposons
the coding regions within a gene
a none coding region within a gene – correct
mutations
What is the function of tRNA?
to deliver amino acids to the ribosome – correct
transfer information from the nucleus to the ribosome
part of the ribosome structure
store the recipes for proteins
What kind of molecule carries anticodons?
rRNA
tRNA – correct
mRNA
DNA
What is the function of RNA polymerase?
synthesize a strand of DNA following an RNA template
synthesize a molecule of RNA using DNA template – correct
make a protein
replicate RNA molecules
What is an operon?
a cluster of gene with related function that are co-regulated – correct
site of protein synthesis
non-coding regions in genes
site where RNA polymerase can bind to the DNA
Gene that are normally ‘on’ but can be turned ‘off’ are
constitutive
none of these
inducible
repressible – correct
How does the presence of lactose induce expression of the Lac operon?
allolactose binds to and inactivates Lac I, the inhibitor protein – correct
lactose blocks transport of tryptophan
lactose binds to the Lac operator region
it binds to the Lac promoter region
If both glucose and lactose are present in the growth medium, transcription of the Lac operon will not be induced. This is called
cheap lactose
mutation
catabolite repression – correct
catabolite induction
Why is it to the cell’s advantage for tryptophan to suppress transcription of the Trp operon?
so that it can utilize lactose
to stimulate the synthesis of other amino acids
so the cell won’t waste energy overproducing the amino acid – correct
all of these
A gene suffers a single base substitution mutation, and the resulting protein has the same length but a different primary structure than the original protein. What kind of mutation was it?
frame shift
nonsense
missense – correct
silent
What is a mutation?
an inversion
an alteration in the mRNA
an alteration of the primary structure of a protein
a random change in DNA base sequence – correct
In prokaryotes, which are haploid, all phenotypic variation is due to mutation.
True
False – correct
Genes that are always expressed are called
Constitutive – correct
repressible
inducible
indestructable
What do restriction endonucleases do?
repair DNA
copy DNA
cut DNA – correct
prime DNA replication
What does agarose gel electrophoresis do?
separates DNA fragments by sequence
cuts DNA
transfers DNA to another bacterium
separates DNA fragments by size – correct
Why do some cloning vectors (plasmids) contain antibiotic resistance genes?
to select for successful clones – correct
prevent contamination
make the clones stronger
all of these
What is biotechnology?
genetically modified organisms
cutting DNA
genetic recombination
using living things to make a product – correct
What is transduction?
horizontal DNA transfer via phage – correct
taking up DNA from the environment
when bacteriophage infect a bacterium
horizontal DNA transfer via pili
What is vertical transfer of genetic information?
transfer of genetic information between cells of the same generation
transfer of DNA via pili
When offspring receive genetic information from their parents – correct
transfer of DNA via phage
What is conjugation?
slecting plasmids that contain the gene of interest
transfer of DNA via phage
abosorbing DNA from the environment
the horizontal transfer of DNA via a pillus – correct
What is reverse transcriptase?
RNA polymerase
an enzyme that uses an RNA template to make DNA – correct
DNA polymerase
ligase
What is polymerase chain reaction (PCR) used for?
PCR seal nicks in the DNA backbone
make a strand of DNA using an RNA template
PCR transfer DNA into eukaryotic cells
to make many copies of a specific portion of a DNA template – correct