Flashcards in Test 2 Deck (64):
A bacterium that can grow at temperatures of 55*C and has a minimum temperature growth temperature of 45*C is referred to as a
A bacterium with an optimum growth temperature of 20-40*C is referred to as a
A bacterium with an optimum growth temperature of 15*C or less and can grow at 0*C is referred to as a
A bacterium that requires high levels of sodium chloride for growth is referred to as a
A bacterium that can grow at pH values of 1 to 5 is referred to as an
Most human pathogens are classified as
Lysozyme attacks the peptidoglycan cell wall of bacteria, converting the cells into protoplasts. These "cells wall-less" protoplasts will grow normally if they are maintained in a/an ________ environment but will burst when in a/an __________ environment
A(n) ___________ can survive in water up to pH of 11.5
A(n) ____________ is capable of causing spoilage in refrigerated foods.
Infection with the microorganism Pneumocystic carinii produces pneumonia in many indicviduals infected with AIDS. Some scientists consider P. carinii to be a protozoan and others consider it to be a fungus. Which of the following characteristics would P. carinii need to have to support both viewpoints?
prokaryotic and contain rigid cell walls, eukaryotic and non-photosynthetic, single-celled and animal like, multicellular and ingest particulate food, spore forming and contain one circular chromosome
Eukaryotic and non-photosynthetic
Fungi that grow as a yeast at one temperature but grow as mold at another temperature are called
Each of the following statements concerning fungi is correct EXCEPT:
Yeasts are fungi that reproduce by budding, Molds are fungi that have elongated filaments called hyphae, Thermall dimorphic fungi exist as yeasts at 37 degrees C and as molds at 25 degrees C, both yeasts and molds have a cell wall made of peptidoglycan, or all of these are correct.
Both yeasts and molds have a cell wall made of peptidoglycan.
Each of the following statements concerning fungi and protozoa is correct EXCEPT:
Both fungi and protozoa are eukaryotic organisms, Fungi possess a cell wall whereas protozoa do not, Both fungi and protozoa use flagella as their organ of motility, Both fungi and protozoa generate energy in mitochondrion, or none of these.
Both fungi and protozoa use flagella as their organ of motility
In microbiology lab, you make three different culture plates: one general purpose plate, one selective media plate, and one differential media plate. Unfortunately you forget to label the different plates so you do not know which is which. To determine the identity of each plate you inoculate it with two different strains of laboratory bacteria. After inoculation, you see that a particular plate has allowed both organisms to grow, but one has changed color. Which plate do you think this is?
differential media plate
A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is a
differential and selective media.
A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, how long will it be before the culture contains more than 10,000 cells/ml?
If a student accidentally inoculates a bacterial culture into a hypertonic solution instead of a balanced nutrient broth which of the following would describe the inoculated culture?
Water will leave the cells
A microbiology student noticed that a Fluid Thioglycollate culture broth tube was very turbid at the surface and turbid throughout the rest of the tube. She can conclude that the
organisms are facultative anaerobes
An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through?
Why is oxygen a beneficial molecule for obligate aerobes but a deadly one for obligate anaerobes?
Obligate anaerobes usually lack protective enzymes such as catalase.
Mad Cow disease
All of these
Viruses that can remain latent (usually in neurons) for many years are most likely
Viruses that can infect bacteria are called
Viruses are limited in their host range because
they can only absorb to cells with proper receptors
All of the following descriptions concerning viral multiplication and nucleic acids are true EXCEPT that:
Viruses contain DNA or RNA, not both.
Viruses replicate only in living cells.
Viruses use the cell's biosynthetic machinery to synthesize copies of themselves.
The nucleic acid of a virus is surrounded by a protein coat.
All of the above.
All of the above
Which of the following enzymes is most likely involved in the following reaction? 2O^2 + 2H+ --> H2O2 + O2
which of the following enzymes is most likely involved in the following reaction? 2H2O2 --> 2H2O + O2
One of the bacteria isolated from a foul-smelling discharge taken from an abscess is missing superoxide dismutase, catalase, and peroxidase. Which statement best describes this microorganism?
This bacterium is an anaerobe
A lambda DNA stand is labeled with radioactive 32P and packaged into a viral capsid. The newly made virus is allowed to infect an E. coli cell. The cell does not lyse, but instead begins normal mitosis. At this stage, radioactivity would most likely be detected:
in the cytoplasm of the E. coli host cell
The lambda phage is largely incapable of infecting bacterial species other than E. coli. This is most likely because:
Other bacterial species lack the specific cell surface proteins that lambda normally binds.
Lambda phages entering the lytic or lysogenic infection pathways do NOT differ from each other in their:
Mode of viral DNA injection
The virus attaches itself to the glycoproteins outside the host cell
the virus enters the cell by fusion and is enveloped in a lysosome as it enters the cell membrane
The enzymes of the lysosome react with the capsid causing the nucleic acids to be released into the cell.
The virus embeds its genetic information into the host cell causing it to begin production of viral parts
The virus the spontaneously begins assembling that viral parts into new virions
The virions release from the host cell by budding or lysis, causing harm to the host cell.
The beginning phase of bacterial growth when the bacteria have just been introduced to the new environment. No substantial growth takes place during this period.
The phase where the bacteria begin to replicate exponentially. The bacteria are most active during this phase due to rapid replication.
The bacteria are now in a stable period where the growth and death rates are equal. Bacteria reach this phase when nutrients become sparse and when bacterial waste causes problems with cell growth.
The death of bacteria greatly surpasses the growth of new bacteria. This phase can last until enough bacteria have died out that others can live, or until all the bacteria are destroyed.
Which of the phases would most likely be missing detectable growth and therefore be resistant to penicillin?
The Lag phase.
On which of the growth phases would treatment with gentimicin (which inhibits protein synthesis) have a maximal effect?
The Log phase.
Cervical cancer (family)
Measles virus (family)
Hepatitis B (family)
Influenza viruses (family)
Rabies virus (family)
A microbiologist describes an organism as a chemoheterotrophic, aerotolerant, mesophilic, facultatively halophilic bacillus. Describe the organism's metabolic an structural features in plain English.
The organism is a rod shaped bacterium that likes in environment that has a high salt content. This bacterium needs to feed off of other organisms as its source of carbon and can grow in an environment containing oxygen, but does not use it metabolically. This bacteria grows best at a temperature close to human body temperature, around 37 degrees C.
A pastry chef accidentally inoculated a cream pie (note: cream pies are not baked) with six S. aureus cells. If S. aureus has a generation time of 60 minutes, how many cells would be in the cream pie after 7 hours? Would the number of bacteria continue to double every 60 minutes? Why or why not?
If the chef inoculated the cream pie with six S. aureus cells, and S. aureus has a generation time of 60 minutes, the cream pie would have 768 cells after 7 hours. The number of bacteria could continue to double for a while, but would eventually stop because the bacteria would run out of nutrients or their waste products would cause them to stop growing.