Micro Exam 1

Term
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single-celled
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Terms in this set (36)
single-celled
bacteria, archaea, yeasts, protozoa
multicellular
molds, helminths
smallest microbes incapable of metabolism or replication on their own
viruses
What is the difference between the lytic and lysogenic cycles of bacteriophages? (Level 2 -
Understanding)
A. The lytic cycle is a viral reproduction mechanism, while the lysogenic cycle is how
archaea
reproduce.
B. The lytic cycle results in the lysis of the infected cell, while the lysogenic cycle is
when the viral DNA is integrated into the host genome.
C. During the lytic cycle the phage DNA injects its DNA, while in the lysogenic cycle the
DNA is not
injected at all.
D. The lytic cycle results in the lysis of the infected cell, while the lysogenic cycle
releases its DNA through exocytosis.
E. The lytic cycle happens over time, while the lysogenic cycle happens very quickly.
B - TRUE because the lytic cycle is when viral DNA is injected, and then new DNA is synthesized
into phages. The cell then lyses which releases the new phages. The lysogenic cycle is when the
injected DNA integrates into the DNA of its host so that when the daughter cells are made, each
copy contains the DNA with the section of the viral DNA.
Yeasts reproduce asexually via: (Level 1 - Remembering)
A. Sporulation where mycelia grow into a fruiting body which makes spores
B. Budding where a small bud forms on cell membrane of parent cell and splits off
C. Sporulation where two different mating types come together and form spores
D. Binary fission where the parent cell splits in two after copying the DNA
E. Meiosis where one parent cell creates four daughter cells each with half the
initial DNA
b. TRUE. Yeasts use the process of budding to reproduce.
Why is the electron transport chain the last step in aerobic respiration? (Level 2 -
Understanding)
a. Oxygen was not available until the last step
b. It relies on the products from the other steps of respiration
c. The protein complexes were not fully formed until the last step
d. ATP was not available until the last step
e. It forms CO2 which is the final waste product
B - true because it uses NADH and FADH2 from the previous steps as electron donors to
kickstart the ETC process
The cell wall of Gram-negative bacterial cells has an added layer of protection against
certain toxic chemicals due to the: (Level 2 - Understanding)
a. Mycolic acids
b. Thick layer of peptidoglycan
c. Outer membrane
d. LPS
e. Core polysaccharide
C - True because Gram-negative cells have an outer membrane that can filter out certain
harmful chemicals such as some (but not all) antibiotics
A disease has broken out among lab mice. The lead scientist is a microbiologist and wants to
determine what is causing the illness. They initially isolated the sick mice from the healthy
ones to contain the pathogen. They did not change anything else in the mice's environment.
From one of the sick mice, a sample was taken and grown in a pure culture. The microbe
was then injected into one of the mice in the healthy population. How will the
microbiologist know whether or not that microbe was the pathogen or not? (Level 2 -
Understanding)
A. If the pathogen is present in the injected mouse
B. If the pathogen is present in the mice's food/environment
C. If the injected mouse is showing the same symptoms as the ill mice.
D. If there is a bump at the injection site
E. If the first culture matches the one taken from the injected mouse.
C - Yes: This follows Koch's postulate. If the microbe caused the disease, then it should cause
the same symptoms in the new injected mice because the germ theory says that each microbe
that causes disease causes a specific disease, meaning a specific set of symptoms.
What is the function of spike proteins on a virus? (Level 2 - Understanding)
A.) allows virus to recognize and bind to host receptors
B.) make the virus harder to detect
C.) virus protection
D.) act as a motility structure similar to flagella
E.) aids in viral reproduction
A- TRUE: spike proteins are what allow viruses to bind to host cells
What cell appendage is most likely causing a bacterial to adhere to the host? (Level 2 -
Understanding)
A-Flagella
B- Cell receptors
C-Fimbriae
D-Cilia
E-Spike proteins
C- Fimbriae is the answer as they are thick, short spikes that help bacteria adhere to surfaces
and other bacteria. The strong holds that they have with surfaces of other cells prevents it from
easily being removed...especially when a person urinates with a UTI.
In which of the following environments would you expect neutrophiles to grow best in? (Level 2 - Understanding) a) A human stomach (1.5-3.5 pH) b) Hydrothermal vents (371°C) c) The dead sea (34% salinity) d) A water droplet on a leaf (7 pH) e) Inside a frozen glacier (0°C)D - correct because water has a PH of 7, and that's the optimal PH for a neutrophile to grow in.Which of the following microbes would not care whether oxygen is present? (Level 2 - Understanding) a. Obligate aerobes b. Facultative aerobes c. Facultative anaerobes d. Aerotolerants e. MicroaerophilesD - true: Aerotolerants do not use oxygen, but are not harmed by itThe electron transport chain is not required for: (Level 2 - Understanding) a.) Aerobic respiration b.) Anaerobic respiration c.) Fermentation d.) The Krebs cycle e.) Pyruvate oxidationc.) Fermentation: true because fermentation only produces ATP through glycolysis, and not through the Krebs cycle or electron transport chain.Once a bacteria colony is at the stationary stage during its stage, the exponential curve plateaus. Why does this plateau occur? (Level 2 - Understanding) a. The bacteria are not growing anymore so the curve plateaus. b. The bacteria colony is equally multiplying and dying causing the plateau due to natural changes in their environment. c. The bacteria are dying faster than it is growing. d. The bacteria have accumulated too many mutations. e. The bacteria colonies hit a plateau to allow the bacteria to grow exponentially again.b. True; bacteria are dying and growing at the same rate due to environmental changes such as increase in waste products and lack of remaining nutrients.Which of the following structures in prokaryotes allows for selective permeability? (Level 2 - Understanding) A. Peptidoglycan B. Ribosomes C. The Cell Wall D. The Plasma Membrane E. CytoplasmD. True b/c the plasma membrane contains a phospholipid bilayer with hydrophobic tails and hydrophilic heads that allow non-polar molecules such as carbon and polar, uncharged ones like water (selective permeability)The cell wall of prokaryotic cells differs from eukaryotic cells in that: (Level 2 - Understanding) a. Prokaryotic cells do not have a cell wall b. Prokaryotic cell walls contain peptidoglycan c. Prokaryotic cell walls contain chitin or cellulose d. Prokaryotic cell walls contain large ribosomes e. Prokaryotic cell walls are thickerb. True - Peptidoglycan is ONLY found in prokaryotic cell walls; Eukaryotic cell walls do not require peptidoglycan because of their membrane bound organelles and well-organized structureHow does uncoating contribute to the multiplication cycle of virus? (Level 2 - Understanding) a. Protein capsid opens to release genetic material in host b. The production of proteins in the genetic material c. The production of the new copies of the virus d. The construction of the new virus forms e. Involves endocytosisA - correct b/c this allows the virus genetic material to be copied to reproduce new virusesA nematode is classified as what kind of helminth? (Level 1 - Remembering) A) Cestodes B) Flukes C) Roundworms D) Trematodes E) TapewormsThe correct one is c, roundworms. The other answers are all other classifications of helminths and they are all distinctly different from the roundworms (nematodes).In which environment would you most likely encounter a mesophile? (Level 2 - Understanding) a) Hot springs b) The human body c) Glaciers d) Hydrothermal vents e) Deep ocean watersB- true b/c the human body is 37 degrees Celsius, and mesophiles live in 10-50 degrees CelsiusWhich answer most accurately describes the peptidoglycan of Gram-positive, Gram- negative and acid-fast bacteria? (Level 2 - Understanding) a. Gram-positive cell wall is thin. Gram-negative cell wall is thick. Acid-fast is thin. b. Gram-positive cell wall is thick. Gram-negative cell wall is thin. Acid-fast is thick. c. Gram-positive cell wall is thick. Gram-negative cell wall is thin. Acid-fast has no cell wall. d. Gram-positive cell wall is thin. Gram-negative cell wall is thick. Acid-fast is thick. e. Gram-positive cell wall is thick. Gram-negative has no cell wall. Acid-fast has no cell wall.b. True. Gram-positive cells have thick peptidoglycan layers, gram-negative have thin peptidoglycan, and acid-fast are thick due to thin peptidoglycan plus mycolic acids that make it thick.Protozoan cyst would be most similar to: (Level 3 - Analyzing) a. slime layer b. spores c. egg d. endospore e. capsulesD. TRUE: both are dormant structures however it is not as good as endosporesWhy does the lytic cycle take less time to complete the DNA replication compared to the lysogenic cycle? (Level 2 - Understanding) A. Less viral DNA is injected in the lytic cycle compared to the lysogenic cycle B. The lytic cycle occurs at warmer temps, so it occurs quicker C. The lytic DNA replication occurs immediately and results in many copies while the lysogenic cycle has to make daughter cells before the DNA is replicated D. The lytic cycle does not produce as many copies as the lysogenic cycle so it can replicate a lot faster E. The lytic cycles DNA is shorter than the DNA in the lysogenic cycle so it is able to reproduce a lot faster as it has less to copy.C - TRUE because the production of the daughter cells In the lysogenic cycle takes more time than the immediate replication in the lytic cycleHelminths are classified into body types. What is the structure of a flatworm? (Level 1 - Remembering) a. Tubular unsegmented bodies b. Longer segmented bodies c. Ovular unsegmented bodies d. Thin, flat segmented bodies e. Ovular unsegmented bodiesD - True this is the body structure of flatwormsYeasts have mainly glucan in their cell walls whereas molds have: (Level 1 - Memorization) a. Mainly cellulose b. Yeasts do not have a cell wall c. Mainly chitin d. Equal parts chitin and glucan e. Peptidoglycanc. TRUE. Molds tend to have more chitin in their cell walls than yeasts.Mitochondria and chloroplast reproduce through ___________, which is evidence supporting the endosymbiotic theory. (Level 2 - Understanding) a. Spore formation b. Mitosis c. Meiosis d. Binary fission e. FragmentationD. TRUE: mitochondria and chloroplast undergo binary fission; this explains the theory because it is also how prokaryotes divideAcid-fast bacteria and Gram-negative cell walls compare because both contain: (Level 2 - Understanding) a. Mycolic acid b. Thin layer of peptidoglycan c. O-Antigen d. Teichoic acid e. Embedded proteinsB - True; both Gram-negative bacteria and Acid-fast bacteria have thin peptidoglycanWhat is different about doing Koch's Postulates for viruses? (Level 2 - Understanding) A. They can be grown with other microbes since they aren't alive. B. They are grown on a nutrient agar plate C. They are grown with their host cells since they can't survive on their own. D. They are grown in an anaerobic environment since they aren't alive. E. It is not possible to use Koch's postulates for virusesC - TRUE - This is correct because viruses need a host in order to survive therefore the host cell is not counted as if it were the virus and it is still considered a pure culture.Which of the following microbes are characterized by their ability to survive above the boiling point of water (100°C?) (Level 2 - Understanding) a) Psychrophiles b) Extreme halophiles c) Hyperthermophiles d) Thermophiles e) Alkaliphiles.C - correct because hyperthermophiles are the only microbial classification that can survive above the boiling point of water, which is indicated by the prefix hyper before thermophile.Why do prokaryotic cells generally reproduce quicker than eukaryotic cells? (Level 2 - Understanding) a. Prokaryotic and Eukaryotic cells always reproduce at the same rate b. The DNA in the nucleus of prokaryotic cells is circular c. Prokaryotic cells have a simpler structure than eukaryotic cells d. Prokaryotic cells have more DNA than eukaryotic cells e. Eukaryotic cells can only reproduce through binary fissionc. True - Prokaryotic cells reproduce asexually through binary fission and only have a single, circular chromosome and a few other organelles; Eukaryotic cells have a more complex structure (multiple chromosomes in a nucleus, many organelles) forcing the reproduction process to take longerWhat can you infer about the difference between bacteria and archaea? (Level 1 - Remembering) A) Bacteria have ribosomes but archaea do not. B) Archaea have a membrane with branched phospholipid tails while bacteria have a linear phospholipids. C) Archaea live in extreme harsh environments while bacteria live in environments like soil, rock, oceans, and even arctic snow. D) Archaea have survival structures like cysts while bacteria have endospores as survival structures. E) bacteria lack a nucleus but and archaea have a nucleusb) true-Archaea have a membrane with Branched phospholipid tails while bacteria have a phospholipid bilayer.How does absorption work? (Level 1 - Remembering) a. Through three types direct injection, endocytosis, and fusion b. Proteins on the virus (keys) will bind to receptors of the host cell surface (locks). c. They start with producing genetic material d. Produces a protein capsid surrounding the viral genome in order to start the multiplication process e. By injecting DNA into the host cellsBHelminths are classified by the ______ of their egg, larval, and adult stages. (Level 1 - Remembering) A) Agrobiology B) Morphology C) DNA D) Otology E) NephrologyBBacteria growing in the human stomach at pH 1.5 are most likely which of the following? (Level 2 - Understanding) a) Acidophile b) Alkaliphile c) Neutrophile d) Halophile e) HalotolerantA- true b/c the pH 1.5 is acidic and acidophiles thrive in acidic environmentsHow do hyphae contribute to sexual reproduction in fungal cells? (Level 2 - Understanding) a) Budding b) Fusing with another fungal organisms' hyphae c) Produce chitin d) Release enzymes e) Create a dormant cell that is fertilizedBIn the gram staining process, safranin is added. What are its effects on Gram-positive bacteria? (Level 2 - Understanding) A. It stains its purple B. It stains it pink C. It can not stick to gram-positive D. It creates a purple-pink color mix E. It is too light and has no physical effectE. True. The purple stain from Crystal violet will over power the pink color of safranin. Therefore showing no effect.Fungi and protozoa differ in: a. reproductive strategies b. cell wall c. cell membrane d. DNA shape e. ribosome sizeB. TRUE: protozoa lack cell wall