exam 3 Flashcards
Bacteria living in salt marshes are most likely which of the following?
halotolerant
Bacteria isolated from a hot tub at 39 °C are probably which of the following
mesophile
In which environment are you most likely to encounter a hyperthermophile?
hydrothermal vent at the bottom of the ocean
When two organisms benefit from one another?
mutualism
Bacteria that grow in mine drainage at pH 1–2 are probably which of the following?
acidophiles
A bacterium is grown at 30°C, but its minimum growth temperature is 34 °C, at this
temperature the bacteria?
will not grow
In which environment are you most likely to encounter an acidophile?
a hot vent at pH 1.5
A microbiologist isolates a bacterial species from the surface of a kitchen sponge left at
room temperature. Lab results show it grows best around 25 °C. How would this organism
be classified based on its temperature preference?
mesophile
Staphylococcus Aureus is a common pathogen that can cause a wide variety of different
disease states because it is highly pathogenic due to its vast amount of ____________.
What the correct term? And the correct definition for the term?
virulence factors - the factors that encode for toxins that aid bacteria in causing disease
Growth phase in growth curve: number of dying cell is higher than the number of cells dividing
death phase
Growth phase in growth curve: number of new cells equal to number of dying cells
stationary phase
Growth phase in growth curve: new enzymes to use available nutrients are induced
lag phase
Growth phase in growth curve: binary fission is occurring at maximum rate
log phase
Cells are producing secondary metabolites during which phase of the growth curve?
stationary and/or late log phase
Which of the following serve as a terminal electron acceptor for a type of respiration?
Oxygen gas, nitrate, sulfate, carbon dioxide gas
Which of these individual processes gives a cell the potential to produce the most ATP per
glucose molecule?
aerobic respiration (electron transport chains/oxidative phosphorylation)
. Which of the following is a major (very abundant) atom in most living cells?
phosphorus
Which of the following is not a nitrogenous base found as a component of nucleic acids?
benzene
When does ATP release a large amount of usable energy which can be used to do work?
When it loses one of its three phosphate group to become ADP
The organelles of eukaryotic cells which are involved in ATP production and cellular
respiration are called…
mitochondria
Electron Transport Chains are involved in..
oxidative phosphorylation
Some microorganisms are able to use CO2 as a carbon source, transforming it into C6H12O6.
During this process, the CO2 which has accepted hydrogens has become…
reduced
Two Pyruvic Acid…
is an end-product of glycolysis from one glucose, and may then enter either respiration or fermentation, depending on the cell’s capacities
The homolactic and alcoholic fermentations are similar in that…
both re-oxidative NADH to NAD+
During aerobic respiration, certain enzymes actively pump protons (H+) across a membrane,
creating a buildup of positive charge and lower pH on one side. What is the biological
purpose of this gradient?
to store energy in the form of a proton motive force that drives ATP synthesis
The net yield of ATPs per glucose molecule metabolized by a prokaryotic cell which carries
out glycolysis, the Krebs cycle, and oxidative phosphorylation is approximately
38 ATP
How does oxygenic photosynthesis differ from anoxygenic photosynthesis?
H2O is split apart to yield the products of oxygenic photosynthesis; H2S is split
apart to yield the products of anoxygenic photosynthesis
codons are found on
mRNA
In the total oxidation of one glucose molecule by a living cell, how much glucose bond
energy is actually trapped in the form of ATP?
39%
According to the definition used in the course, a food differs from a nutrient in that
A food requires digestion into smaller subunits before a cell can assimilate it; a
nutrient is small enough to be assimilated
In the process of oxidative phosphorylation, the energy of a proton motor force is used to
generate
ATP
A patient is treated with an antibiotic that targets actively dividing bacterial cells. After
treatment, a few bacteria survive despite not having genetic resistance. What best explains
the survival of these cells?
They are persister cells that temporarily shut down activity, making them less
affected by antibiotics
A microbiologist is comparing two spherical bacterial cells: one is twice the size of the other. Which cell is expected to grow more quickly due to more efficient nutrient exchange?
The smaller cell, because it has a higher surface area-to-volume ratio
Which type of organism cannot survive in the presence of oxygen, even at low levels?
obligate anaerobe
Generation time that is measured during the logarithmic (exponential) phase of the
population growth curve…
Is the time it takes for a population of microorganisms to double in number
In the stationary phase of a microbial population growth curve…
the number of cell deaths equals the number of new cells
Members of the prokaryotic, endospore-forming genus Clostridium are classified as
obligate anaerobes
A bacterial colony is exposed to hydrogen peroxide. It produces bubbles, indicating the
breakdown of a toxic compound. What substance is being neutralized by the enzyme
catalase?
hydrogen peroxide
Which of the processes involving DNA which were discussed in the course is best described
as being semi-conservative?
DNA replication
Which of the following enzymes is most likely to be encoded for on genes of a bacterial
plasmid?
enzymes which give the cell resistance to specific antibiotics
All of the following are examples of negative symbiotic relationships except
commensalism
Electron transport chains are used in aerobic respiration, and in anaerobic respiration
t/f
true - ETCs can be used by other organisms that do not use O2
A bacterial plasmid carries genes for enzymes which can degrade the pesticide DDT. How
can you best assure the plasmid will be maintained by this bacterial population?
Grow the bacteria with DDT in the growth medium
Probably sites for the location of an episome in a prokaryotic cell include..
the bacterial chromosome
A eukaryotic fungus has a measurable rate of metabolism and enzymatic activity at 58 C.
What will happen to the fungus after the temperature is decreased to 10 C?
The fungus will not grow
Generally, every 10 C increase in temperature will affect enzyme activity, by
increasing it by 2 times
Some bacteria can detect when their population reaches a certain size and change gene expression in response. Which molecule is commonly used by Gram-negative bacteria to coordinate this group behavior?
Acyl homoserine lactones (AHLs)
What is the correctly listed mechanisms of antibiotic action that you have to know for this
class?
Inhibition of microbial cell wall synthesis, nucleic acid, protein synthesis, and cell
membrane function
What is the removal of waste products from the cell?
Excretion
Microorganisms living in close proximity can never use each other’s waste products for
growth or energy.
t/f
False
An experiment began with 4 cells and ended with 128 cells. How many generations did the
cells go through?
5
You come down with a sickness, but you realize that the symptoms you are experiencing are
from one of the six pathogen focus you have learned in MICR 231. You are food poisoning
from consuming hand prepared food, caused by an enterotoxin. What are bacteria is causing
your intoxication?
staphylococcus aureus
Archaea usually grow in a few restricted or specialized habitats, such as
anaerobic, hypersaline, extremely cold or hot
What type of microorganism would you find living on dead organic matter?
saprophyte
What ORGANIC compound is being reduced (electron acceptor) in this reaction?
pyruvate
Which of the following would use carbon dioxide gas as its major carbon source?
photoautotroph
What organism is a major concern in health care, that is due to antibiotic resistance?
Methicillin-resistant Staphylococcus aureus (MRSA)
Which is involved in translation?
tRNA, rRNA, mRNA, and ribosomes
For penicillin to be active against eubacteria, the eubacterial cells must
be actively growing
ATP is required to do
chemical, transport, and mechanical work
Which process is responsible for making ATP during glycolysis and fermentation?
substrate-level phosphorylation
For each pair of electrons passing from NADH located inside the mitochondrial to oxygen,
how many ATP molecules can be generated?
3
Which of the following is not a total population count method?
plate count using media containing agar
Which of the following groups of microorganisms are photoautotrophs?
eucaryotic algae
When does ATP release a large amount of usable energy which can be used to do work?
when it loses its terminal phosphate group to become ADP
Which of the following associations is characterized by some degree of coexistence whereby one organism benefits at the expense of the other?
parasitism
Organisms can synthesize ATP by oxidative phosphorylation
when they pass electrons to oxygen through an electron transport system
containing cytochromes
How many oxygen molecules are required in the fermentation of one molecule of glucose to
ethanol and CO2?
0
Before most molecules can enter the TCA cycle, they must be converted to this and loses
one of its carbons in the transition step? Resulting in a two carbon fragment, which joins to a coenzyme.
acetly-CoA
What are the small segments of DNA that can move from region of a DNA molecule to
another, as part of a plasmid or chromosome, and carry genes for Antibiotic resistance?
transposons
Giant tube worms near hydrothermal vents survive by hosting bacteria in their
trophosomes. These bacteria use inorganic compounds to make organic molecules. What
type of metabolism do they use?
chemoautotrophs
When a bacterial cell fully breaks down glucose using aerobic respiration, the atoms from
glucose are primarily released as:
small inorganic molecules expelled as waste (CO2 & H2O)
A researcher is studying a microbe that must infect a host cell to grow and reproduce.
Attempts to culture it on standard lab media have failed. How would this organism be
classified?
obligate parasite
