Unit 4 Quesitons Flashcards
What is most infectious microbe?
Wolfbachia
What bacteria has gliding ability for predation?
Myxococcus Xanthus
What is most dangerous animal?
Mosquitoes (has ability to pass on diseases)
What if all prokaryote suddenly vanished from Earth suddenly?
No organism would be abl;e to live since nutrient cycling and biogeochemical cycling will be shut down as most prokaryotes responsible
Which process provide greatest amount of free energy?
Aerobic respiration
Which processes provide least amount of free energy?
Methanogenesis by archaea
What elements contain intermediate oxidationt state forms?
Carbon, nitrogen, sulfur
What elements contain no intermediate oxidation state forms?
Iron, phosphate, maganase
Approximately how much of the total carbon on Earth is fixed by microbes such as diatoms and cyanobacteria?
a) 10%
b) 20%
c) 30%
e) 50%
e) 90%
d) 50%
Archaea and reducing bacteria work together to oxidize methane using sulfate as the terminal electron acceptor in the process of ___ methanogenesis
Reverse
Which gas is most abudant greenhouse gase in the atmosphere?
Methan (CH4)
____ is group of low molecular weight organic molecules that can bind Fe3+ and facilitate its uptake by cells
Siderophores
What is regarded as major CO2 sinks?
forest
The human body has roughly 22,000 protein-encoding genes, but the number of genes present in the microbiome is over ______.
a) 1 million
b) 3,000
c) 8 million
d) 50,000
a) 1 million
Which three of the following are produced by Staphylococcus epidermis to interfere with the growth of other bacteria on the skin, such as S. aureus?
a) Bacteriocins
b) Antibodies
c) Hormones
d) Molecules that interfere with quorum sensing
e) Proteases that degrade adhesins
a) Bacteriocins
d) Molecules that interfere with quorum sensing
e) Proteases that degrade adhesins
A group of microbes that provides activities and metabolites required for health and homeostasis of the host is called ___________
functional core microbiome
Bacteriocins are toxic peptides produced by Gram-positive bacteria that target ______.
a) closely related strains or species
b) endospores
c) most Gram-positive bacteria
d) Gram-negative bacteria
a) closely related strains or species
A bacteriophage that infects a bacterial cell and becomes lysogenic may be beneficial for the host bacterium when ______.
a) the bacteriophage becomes defective and cannot excise from the chromosome
b) its genes are not already present in the host CRISPR repeats
c) nutrients are limited
d) the bacteriophage carries genes that expand the cell’s metabolism
d) the bacteriophage carries genes that expand the cell’s metabolism
Termites are dependent on their endosymbionts to carry out which two processes?
a) degrade chitin as a carbon source
b) generate methane gas
c) complete the digestion of cellulose
d) fix CO2 using electrons from H2S
e) convert (fix) nitrogen to a usable form
c) complete the digestion of cellulose
e) convert (fix) nitrogen to a usable form
Hydrothermal vent fluids are ______. [Choose three.]
a) high in hydrogen sulfide
b) oxygen-rich
c) high in fixed nitrogen
d) devoid of oxygen
e) up to 350°C
f) around 2°C
a) high in hydrogen sulfide
d) devoid of oxygen
e) up to 350°C
Microbial autotrophs, organisms who use carbon dioxide as their carbon source, fuel the reactions to fix CO2 by either _____ or ______.
a) phototrophy
b) lithotrophy
c) auxotrophy
d) heterotrophy
a) phototrophy
b) lithotrophy
The unique hemoglobin of giant red tube worms (Riftia spp) transports which two gases to the animal’s trophosome?
oxygen and hydrogen sulfide
In a facultative symbiotic interaction between two species of bacteria, Blank______.
a) each individual species requires the other for all aspects of growth and metabolism
b) each individual species is capable of growth in the absence of the other
b) each individual species is capable of growth in the absence of the other
Identify the common characteristic of cooperation and mutualism.
a) Both harm one partner
b) Both are symbiotic relationships
c) Both involve a modification of the environment
b) Both are symbiotic relationships
If an aphid is treated with an antibiotic, it dies. Which is the best explanation for this observation?
a) Aphid cells convert antibiotics to toxins.
b) Aphids harbor obligate mutualistic bacteria.
c) Aphid cells are susceptible to antibiotics.
d) Bacteria living in aphids become pathogenic upon exposure to antibiotics.
b) Aphids harbor obligate mutualistic bacteria.
The loss of photosynthetic pigments from the endosymbiotic photosynthetic dinoflagellates of coral, or the complete expulsion of dinoflagellates from the coral, is called coral ______
bleaching
An antagonistic interaction in which one partner obtains biochemical precursors and energy from a living victim is termed ______.
a) predation
b) competition
c) parasitism
c) parasitism
Which three statements describe a host-parasite relationship?
a) The host must eventually eliminate the parasite.
b) The parasite can kill the host immediately.
c) The host must be harmed.
d) The parasite must benefit.
e) The parasite must coexist with the host, at least temporarily.
c) The host must be harmed.
d) The parasite must benefit.
e) The parasite must coexist with the host, at least temporarily.
The uniquely microbial process that fuels autotrophy in some microbial primary producers is ______.
a) prototrophy
b) auxotrophy
c) phototrophy
d) lithotrophy
d) lithotrophy
An antagonistic interaction in which one partner obtains biochemical precursors and energy after killing a victim is termed ______.
a) predation
b) competition
c) parasitism
a) predation
An endosymbiotic relationship where one partner benefits and one is harmed, but also involves at least a temporary state of coexistence is called ______.
a. parasitism
b. mutualism
c. predation
d. facultative cooperation
a. parasitism
Which statement regarding the interaction of a temperate bacteriophage and its host bacteria is false?
a. The decision of whether an infection will be lytic or lysogenic is determined by environmental factors.
b. The outcome of a lytic infection is always negative for the host bacterial cell.
c. The outcome of a lytic infection is always negative for the temperate bacteriophage.
c. The outcome of a lytic infection is always negative for the temperate bacteriophage.
Termites are aided in the digestion of wood by ______ that complete lignocellulose degradation and by ______that fix atmospheric nitrogen.
a. protists / bacteria
b. archaea / bacteria
c. bacteria / archaea
d. protists / archaea
a. protists / bacteria
An example of an obligatory symbiotic interaction is Blank______.
a. Vibrio species and the bobtail squid because the Vibrio colonizes the squid every day
b. “cheater” bacteria and antibiotic producers because they get the benefit but do not contribute
c. a virus because it absolutely requires a host cell for replication
a. Vibrio species and the bobtail squid because the Vibrio colonizes the squid every day
Aphids and Buchnera aphidicola bacteria are obligate mutualistic symbionts. Therefore, if the bacterial partner is separated from the insect and placed in a culture medium, the expected result would be that the bacteria would Blank______.
a. grow more quickly than usual
b. grow more slowly than usual
c. die
d. be unaffected
c. die
If an aphid is treated with an antibiotic, it dies. Which is the best explanation for this observation?
a. Aphids harbor obligate mutualistic bacteria.
b. Aphid cells convert antibiotics to toxins.
c. Bacteria living in aphids become pathogenic upon exposure to antibiotics.
d. Aphid cells are susceptible to antibiotics.
a. Aphids harbor obligate mutualistic bacteria.
the bright red color of the gill plumes of giant red tube worms (Riftia spp.) is due to a unique type of ______.
a. siderophore
b. hemoglobin
c. myoglobin
d. transferrin
b. hemoglobin
In coral bleaching, which microbial component of the coral holobiont is affected?
a. Ammonia oxidizing archaea in the coral skeleton
b. The endosymbiotic photosynthetic dinoflagellates
c, Nitrogen fixing bacteria in the mucus layer
d. Chitin degrading bacteria in the mucus layer
b. The endosymbiotic photosynthetic dinoflagellates
Most human diseases are transmitted by the ___ system through any other system
a. respiratory
b. digestive
c. nervous
a. respiratory
Which of the following is a fomite?
a. droplets from sneeze
b. pus
c. contaminated needle
d. insects
c. contaminated needle
In one experiment, relationship between numbers and a specific infection is measured quantitatively with experimental animals. For a computation of LD ____ of 500 animals die from disease
a. 100
b. 250
c. 500
d. 800
b. 250
Intoxication vs. infection
Intoxication: disease from entry of toxin and organism does not have to enter body
Infection: organism needs to enter body and go to target to attach to receptor
Exotoxins
AB toxin (2 subunit protein)
gram + and gram -
heat susceptible (not resistant)
more toxic
Endotoxins
Lipid A
Onlyn gram -
Heat stable and resistant
less toxic
A measure of the tendency of a system to accept or donate electrons is known as the _________ _________
redox potential
Sulfate, the fully oxidized species, is reduced by plants and microbes for use in amino acid and protein biosynthesis; this is described as ______
assimilary sulfate reduction
Methane is a greenhouse gas of increasing concern because it has about 25 times the global warming potential of _________ _________.
Carbon dioxide
Which of these results in increased numbers of beneficial bifidobacteria in a child’s intestinal tract?
a. Adding solid food to the diet
b. Bottle feeding instead of breastfeeding
c. Breastfeeding
d. Switching from breast milk to cow’s milk
c. Breastfeeding
This figure shows the availability of alternative terminal electron acceptors as O2 concentration declines with depth in water and soil. Based on your analysis of the figure, which of the following best explains why sulfate reducing bacteria and methanogens are not evenly distributed in the same sediment ecosystem?
Sulfate reduction has a more negative standard free energy change (ΔG0’) than methanogenesis
The term that describes the unity of the human host and its associated microbes is ______.
a. holobiont
b. metagenome
c. microbiome
a. holobiont
The normal community of microbiota that humans host begins developing ______ and becomes a stable community of microbes by age _____.
a. before birth; one
b. at birth; three
c. at birth; ten
d. before birth; three
b. at birth; three
Which of the following events is most likely to result in a long-term change in the adult microbiome?
a. Receiving a vaccination against shingles
b. Maintaining a gluten-free diet for a year
c. Contracting influenza
d. Switching to organic skin moisturizer
b. Maintaining a gluten-free diet for a year
Though a process called bacterial interference, Staphylococcus epidermis produces substances that ______.
a. increase inflammation
b. inhibit the growth of other bacterial species on the skin
c. prevent bacterial cell entry through an open wound
d. interfere with wound healing
b. inhibit the growth of other bacterial species on the skin
The idea that a healthy gut microbiome is protective against the establishment of pathogens in the gut is termed ______.
a. immune surveillance
b. probiotic tolerance
c. mucosal tolerance
d. colonization resistance
d. colonization resistance
If bacterial interference by Lactobacillus acidophilus in the vagina is reduced as a result of antibiotic treatment or hormonal fluctuations, an overgrowth of Gram-negative anaerobes can cause a condition called bacterial _______
vaginosis
True or false: The anatomy and physiology of human skin do not vary, therefore the normal microbiota of the skin is consistent throughout the body surface.
False
In the duodenum, the low number of bacteria present are mostly ______.
Gram negative or Gram positive
Gram positive
Colonization resistance refers to the idea that Blank______.
a. once the gut microbiome is established in an infant, it cannot be changed substantively
b. pathogens cannot establish themselves in the gut in the presence of antibiotics
c. the microbiota in the gut is protected from disease by the presence of a healthy community
c. the microbiota in the gut is protected from disease by the presence of a healthy community
A yeast infection is most commonly caused by an overgrowth of which normal inhabitant of the vagina?
a. Aspergillus
b. Saccharomyces
c. Candida
d. Penicillium
c. Candida
Fecal microbiome transplant from obese mice to germ-free mice results in the germ-free mice Blank______.
a. maintaining their weight, when dietary fat is cut in half
b. maintaining their weight, regardless of their diet
c. becoming obese, regardless of their diet
d. becoming obese, correlated with eating a diet of 40% fat
e. becoming obese, despite running mazes for 6 hours/day
c. becoming obese, regardless of their diet
Through chemical modification, gut microbes convert a liver product to Blank______ which impact the growth of other gut microbes and modulate lipid, glucose, and energy metabolism in the liver, kidney, and heart.
a. bacteriocins
b. coprostanols
c. secondary bile acids
d. proteases
c. secondary bile acids
In a healthy human, which of the following tissues is normally free of microorganisms?
a. Muscles
b. Skin
c. Mucous membranes
d. Gut
a. Muscles
In a healthy human, which of the following tissues is normally colonized by microorganisms?
Multiple choice question.
Mucous membranes
Muscles
incorrect
Cerebrospinal fluid
Blood
