FINAL Flashcards
Most bacteria reproduce by _____.
Binary fission
What are the algal blooms that occur in Lake Erie and other bodies of water primarily caused by?
Fertilizer run off from agricultural fields and residential areas
What is the terminal electron acceptor in anaerobic respiration?
an inorganic molecule other than oxygen
What is required for microbial cell growth?
reduced cofactors
anabolic intermediates
energy conserved in chemical bonds
The energy from catabolic reactions is used to produce _____.
ATP
What is oxidative phosphorylation made possible by?
A proton gradient that is formed by an electron transport chain
The growth of almost all bacteria in the environment is limited by ____.
the availability of one or more nutrients
The glycolysis pathway and the tricarboxylic acid pathway (Krebs Cycle) are commonly referred to as central metabolism. Why?
Essentially all carbon sources (amino acids, lipids, aromatic compounds, etc.) are metabolized by first transforming them into intermediates of these two pathways.
Archaea and Bacteria are unified as prokaryotes in lacking _____.
nuclei and membrane enclosed organelles
The cell membrane of bacteria ______.
Is sub-permeable
consists of a lipid bilayer
Proteins are _____.
polymers of amino acids that are connected by peptide bonds
The production of CO2
The complete oxidation of pyruvate
A series of chemical reactions in which produced by the oxidation of pyruvate
TCA Krebs Cycle
What does not occur as part of the TCA (Krebs) cycle?
the oxidation of NADH
When a bacterial culture contains only one type of organism, it is called a _____.
pure culture
What happens during Metabolism?
catabolism and anabolism both occur
energy from catabolism is conserved as ATP and is used in anabolism to make the macromolecules found in cells
There are many similarities and differences between Gram-negative and Gram-positive bacteria. What are some similarities? What are some differences?
Similarities:
the cell membrane of both Gram-negative and Gram-positive bacteria are lipid bilayers
Differences:
There is a second membrane (called the outer membrane) just outside the cell wall of Gram-negative bacteria, but this is absent from Gram-positive bacteria.
The cell wall of Gram-negative cells is composed of only one or two layers of peptidoglycan whereas the cell walls of Gram-positive bacteria have many peptidoglycan layers.
Pasteur used swan-necked flasks to ____.
disprove the theory of spontaneous generation
Bacteria cell walls are made of peptidoglycan that consists of _____.
linear polysaccharides that are cross linked by short polypeptide chains to form a ‘mesh like’ structure that maintains cell integrity
Why do Prokaryotes and Eukaryotes have many things in common?
they share a common ancestor
Regarding early life on Earth, microbial life existed ______.
for hundreds of millions of years before plant and animal life.
In aerobically respiring prokaryotic organisms the tricarboxylic acid (TCA) cycle ______.
provides cells with important anabolic intermediates that are required for growth
provides a means to completely oxidize organic substrates
is coupled to electron transport processes that result in the conservation of energy in the form ATP.
Pasteurization requires ______.
the use of heat to kill most of the microorganisms found in liquids to protect against infectious diseases such as tuberculosis
What happens during fermentation?
NADH is oxidized to form NAD+
the terminal electron acceptor is an inorganic compound
_________ describe steps that should be followed to determine the cause of an infectious disease.
Koch’s Postulates
Bacterial cells reproduce by binary fission, which results in exponential growth of the population. If the size of a bacterial population at time zero (t0) is 20 cells and the generation time is 30 minutes, then how many cells will be in the population after 2 hours of growth?
320 cells
The surface of your kitchen counter has 107 bacterial cells so you clean it with a disinfectant that kills 99% of germs on contact. How many bacteria remain and are viable?
10^5 Bacteria
An operon consists of _____.
a set of genes that encode proteins in the same metabolic pathway
a promotor
an operator site
The process in which bacteria pass their genes to other species of bacteria is known as ______.
horizontal gene transfer
You have one copy of a small gene that you wish to amplify by the polymers chain reaction (PCR). After 7 replication cycles, how many double-stranded DNA molecules do you have?
128
Put the following in the correct order.
Steps in PCR:
(1) Incubate at 94°C to denature DNA strands;
(2) Incubate at 72°C for DNA synthesis;
(3) Incubate at 60°C for primer hybridization.
1,3,2
Generation time is best defined as _____.
the time it takes for a bacterial cell to divide
Required for strictly aerobic bacteria
can be toxic or lethal to some organisms
toxicity mostly due to the production of superoxide radicals that are powerful oxidizing agents
aerobic bacteria can protect themselves but strict anaerobes can not
Oxygen
We wished to determine the abundance of bacteria in a sample of milk. To do this ten-fold serial dilutions of a one milliliter milk sample were prepared. One milliliter of the fourth dilution was plated in a pour plate. After incubation, the plate had 35 colonies. How many bacteria were in the original milk sample?
350,000 cells per ml
_____ have a bacteriostatic effect on most bacteria.
Low temperatures
Which process converts one parent double-stranded DNA molecule to two identical offspring molecules?
replication
What molecule carries information that is used by ribosomes to make specific proteins?
mRNA
An experiment began with 2 cells and ended with 256 cells. How many generations did the cells go through?
7
_____ is determined by the order of nitrogen-containing bases in DNA
Genetic code
______ is a sequence of nucleotides in DNA that codes for a functional product
a gene
A strand of messenger RNA is made that is complimentary to one of the two DNA strands happens during what?
Transcription
Encodes all the information needed for the inheritance of traits.
Encodes the sequences of messenger RNAs
Has two strands of DNA that are bound together by hydrogen bonds
Is comprised of four deoxyribonucleotides
DNA
According to the base pairing rule of nucleic acids
A can pair with U
A can pair with T
C always pairs with G
True or False
Amino acids are linked together by hydrogen bonds to form polypeptides.
False
Which of the following are NOT exploited to clone genes?
a) restriction enzymes that ‘cut’ DNA at specific sequences of nucleotides
b) base-pairing of nucleotides to ‘paste’ new DNA into a plasmid vector
c) differences in the sequences of two genes
d) the enzyme DNA ligase that forms covalent bonds between a plasmid vector and a cloned gene
C
Francis Crick and James Waston proposed that DNA was a helix with two strands of DNA that _____.
were bond together by complimentary pairing of nitrogenous bases
were held together by hydrogen bonds that could easily be separated to allow for replication of a chromosome transcription
could be transcribed to produce a complimentary mRNA
Which of the following statements about smooth and rough variants of Streptococcus pneumoniae is true?
a) neither cause disease
b) both cause disease
c) a substance from the ‘rough’ variant transforms ‘smooth’ variants into a form that causes disease
d) they were used by Griffith to show that DNA was responsible for transforming avirulent Streptococcus pneumoniae into virulent Streptococcus pneumoniae
D
_____ complex molecular machines that translate that code of single strands of mRNA into sequences of polypeptides during protein synthesis.
ribosome
This is an example of a ________ mutation (type) that results in a ________ mutation.
point, nonsense
What is the most frequent cause of emerging viral infections?
spread of virus to humans from a zoonotic source
Which of the following was NOT a factor described in the Frontline episode that allowed the most recent Ebola outbreak to spread out of control?
a) Ebola had never been detected in this part of Africa before.
b) The virus spread into large cities that didn’t have adequate health care infrastructure.
c) The virus mutated to spread more efficiently from human to human.
d) The borders between countries were porous, allowing people to move freely back and forth between countries.
e) Contacts of infected people were not being monitored or tracked.
C
Which of the following statements about penicillins and cephalosporins are NOT true:
a) they inhibit bacterial cell wall synthesis.
b) they have largely different chemical structures, but all have ß-lactam rings.
c) they have entirely different chemical structures.
d) they specifically inhibit the growth of prokaryotes.
C
Phylogenetic species concept is the premise for _____.
classifying microorganisms based on evolutionary relationships
classifying microorganisms based on differences in 16S rRNA gene sequences
Name the parts of the Classic Epidemiology “triangle”
Host
Environment
Pathogen
_____ is nonspecific and present at birth.
Innate Immunity
Which of the following statements about macrophages is NOT true?
a) Macrophages have pattern recognition receptors (PRRs) that recognize molecules that are broadly shared by pathogens (PAMPS) but distinguishable from host molecules.
b) The LPS of Gram negative bacteria and teichoic acids of Gram positive bacteria are examples of PAMPs.
c) Macrophages stimulate the production of antibodies that are specific for a particular pathogen
d) Macrophages can ingest, kill and digest invading microorganisms
C
A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?
phagocytosis in the inflammatory responce
Multiple drug resistant bacteria _____.
often have plasmids that encode resistance to multiple antibiotics.
Which of the following statements about the bacterium Rhizobium is NOT true?
a) cells of Rhizobium infect the root hairs of leguminous plants
b) cells of Rhizobium form nodules in leguminous plants
c) cells of Rhizobium protect leguminous plants against ammonia that is applied on crops as fertilizer
d) cells of Rhizobium fix nitrogen in plant nodules
C
Antibiotic resistance in bacteria _____.
develops as a result spontaneous mutations
is readily transferred among various bacterial species by horizontal gene transfer
is often encoded on plasmids
Bacteria can increases the Earth’s temperature by ____.
producing CH4, which is greenhouse gas
A close association between two different organisms that is beneficial to both is _______.
symbiosis
Due to global warming permafrost soils are thawing an releasing what gases into the atmosphere?
methane
carbon dioxide
Which of the following is NOT true about oxygen?
a) It is always used as a terminal electron acceptor in bacterial metabolism
b) It is required for strictly aerobic bacteria
c) It can be toxic or lethal to some organisms
d) Its toxicity mostly due to the production of superoxide radicals that are powerful oxidizing agents
e) Aerobic bacteria can protect themselves from oxygen but strict anaerobes can not
A
Tuberculosis is _____.
second only to HIV/AIDS as the greatest killer worldwide due to a single infectious agent
The “targets” for antibiotics used to treat bacterial infections are:
biochemical processes that are only found in bacteria and not eukaryotic hosts
All of the following can only be done by prokaryotes except for:
a) Methane production
b) Methane oxidation
c) Nitrogen fixation
d) Ammonia metabolism
e) Carbon dioxide fixation without relying on photosynthesis
D
People living with HIV are 20-30 times more likely to develop tuberculosis that people without HIV. Why?
Their immune systems can not function as well as those of healthy individuals
Which of the following statements about the “normal microbiota” of the human body is NOT true?
a) they are diverse species of bacteria that reside in and on the human body
b) they are bacteria that normally cause disease
c) they represent the first line of defense against infectious organisms that might cause disease
d) they often differ between individuals
e) all of the above
B
_____ has only appeared once in history; an outbreak in the southwest United States. Also has repeatedly caused disease in various locations throughout history. Can also be carried and transmitted to humans by deer mice but can also be directly transmitted from human to human.
Hanta Virus
The graph below shows that when an animal host is exposed to the same virus for a second time, the immune system responds immediately and to a higher level. This is an example of:
a) vaccination
b) phagocytosis
c) immunological memory
d) antibiotic effectiveness
C
Early examples of epidemiology include ______.
John Snow collecting cholera surveillance data and shutting down the Broad Street pump in London
Ignaz Semmelweis forcing doctors and interns to wash their hands in his surgical ward to reduce the incidence of puerperal fever
