bio test 9
Which statement about bacteria is TRUE?
Bacteria are cellular and are sometimes classified as life forms.
How do some bacteria respond to adverse environmental conditions?
Bacteria form endospores.
Which statement about biofilms is FALSE?
Biofilms are usually less than 2 μm thick.
Diplomonads belong to which of the following group of eukaryotes?
Excavates
Most protists are:
aquatic
How do retroviruses differ from other RNA viruses?
Retroviruses have reverse transcriptase instead of RNA-dependent RNA polymerase.
Prokaryotes divide using a process called________.
binary fission
____________ are the largest and most complex of all algae.
brown algae
Botox is the marketed version of the botulism exotoxin, used to treat muscle spasms and for cosmetic purposes.
True
Conjugation is the process by which one bacterium transfers genetic material to another through direct contact.
True
The dense cytoplasm of the prokaryote contains ribosomes and storage granules.
True
The immunodeficiency virus that causes acquired immunodeficiency syndrome is an enveloped virus.
True
What is the outcome of the process illustrated in the accompanying figure?
Two new genetically identical cells that differ genetically from what they were before
The most significant difference between archaea and bacteria is the:
absence of peptidoglycans in the cell walls of archaea.
Pseudopodia are used by Amoeba for ingesting food as well as for:
locomotion.
Peptidoglycan consists of:
sugars crosslinked with proteins.
Crenarchaeota are also called:
sulfur bacteria.
The bacterium that causes botulism disease is harmless until it:
contains a certain prophage DNA.
Polydnaviruses are particles that consist of multiple circles of _______________ encased in capsid proteins and an envelope
dsDNA
Members of the alveolates are characterized by the presence of:
flattened vesicles under the plasma membrane.
Transformation, conjugation, and transduction are forms of vertical gene transfer for prokaryotes.
False
Which protist group are characterized by a multinucleate amoeboid-like feeding form?
Plasmodial slime molds
The body of a water mold is called a mycelium.
True
Mycoplasma
lack cell wall
Actinomycetes
resemble fungi
You find a protist that has a single flagellum surrounded by a collar of microvilli. You correctly conclude that this organism is a(n):
cellular slime mold.
Unikonts also have a ____________ that has major evolutionary significance.
triple-gene fusion
Land plants are thought to have arisen most directly from a red algal ancestor.
False
When brown algae divide asexually, each new cell retains half of the original cell.
False
Streptococci, the bacteria responsible for strep throat infections, is classified within which group of bacteria?
Gram-negative bacteria
Which of the following typically occurs all at once and results in rapid cell lysis?
Phage release
Which statement best describes the composition of cell walls found in water molds?
Some individuals have cell walls of chitin, and others have cell walls of cellulose.
Who is credited with the discovery of prions as a new biological principle of infection?
Stanley Prusiner
An example of an excavate that has a pellicle is Euglena.
True
Which statement describes a virulent phage?
A virulent phage destroys bacteria.
______ are unicellular amoebozoa found in soil, fresh water, the ocean, and other organisms.
Amoebas
_________ are parasites that produce sporozoites and are nonmotile.
Apicomplexans
Which of the following statements is correct in the context of golden algae?
Are mostly unicellular, biflagellate freshwater and marine stramenopiles
Which protist groups consists of individuals who often have intracellular shells of interlocking plates?
Dinoflagellates
Which Archaea have the ability to carry out a form of the Calvin cycle, capturing sunlight with bacteriorhodopsin?
Extreme halophiles
Bacteriophages attach to the cell walls of bacteria by envelope proteins.
False
Actinopods are mostly marine plankton rhizarians with long, filamentous cytoplasmic projections called __________.
axopods
Chlamydia
Lack peptidoglycan cell walls
Which eukaryotic organelles likely arose from symbiotic relationships between larger cells and bacteria?
Mitochondria and chloroplasts
Most bacterial cells can keep from bursting in a hypotonic environment because of:
a rigid cell wall.
Many green algae produce spores asexually by mitosis; if these spores have flagella and are motile, they are called __________.
zoopores
Bacterial conjugation is related to____________.
horizontal gene transfer
The Archaea plasma membranes are made up of branched-chain hydrocarbons bounded to glycerol by:
ether linkages.
Bacterial chemoautotrophs use organic chemicals as an energy source.
False
What type of conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics?
Lysogenic
Plasmids of bacteria often have genes involved in:
antibiotic resistance
Which structure acts like a motor for the bacterial flagellum?
Basal body
What is the protein coat of a virus called?
Capsid
Which are the symbiotic dinoflagellates, which live in the bodies of marine invertebrates such as corals?
Zooxanthellae
Which characteristic defines a virus?
Viruses cannot metabolize.
Which algal group contains individuals that are typically unicellular and form siliceous shells?
Diatoms
Which protist is responsible for late blight of potatoes, the cause of the Irish potato famine in the mid-19th century?
Phytophthora
What is the purpose of sex pili?
To transmit DNA between bacteria
Fimbriae are only visible with the use of an electron microscope.
True
Lytic reproductive cycles destroy host cells.
True
Some bacteria avoid being phagocytized by a host's immune system by means of:
their capsule or slime layer.
Small hairlike structures made up of protein on the surface of bacteria are called:
fimbriae.
Bacteriophages decrease food safety.
False
Which of the following is the most common structure of a virus?
Icosahedron
A bacterial cell wall is made up of _________
N-acetyl glucosamine, N-acetyl muramic acid, and amino acids
Which statement about viruses is FALSE?
Viruses can manufacture proteins.
Cyanobacteria
contain chlorophyll
What are Koch's postulates?
A set of guidelines to demonstrate that a specific pathogen causes specific disease symptoms
Which statement describes a temperate virus?
A temperate virus does not always destroy its host.
Which type of protist is responsible for malaria in humans, parasitic to both humans and mosquitoes?
Apicomplexans
Which was the first bacterium to be clearly identified as the cause of an infectious disease?
Bacillus anthracis, which causes anthrax
How do bacteria move?
By means of a rotating flagella
Mycobacteria
Contain waxy cell wall
Members of which group are known to form blooms known as red tides?
Dinoflagellates
An emerging virus is one that is not new to a population or that is rapidly increasing in incidence.
False
Which protist group contains the organism Trypanosoma, a colorless parasite that can cause African sleeping sickness?
Excavates
After an endospore forms, the cell membrane of the original cell lyses, releasing the endospore.
False
Amoebozoans move by means of flagella
False
Of the following, which group exhibits a diverse morphology, forming unicells, filaments, and sheets
Green algae
Of the following, which group exhibits a diverse morphology, forming unicells, filaments, and sheets?
Green algae
Which statement about an F factor is FALSE?
It is found in recipient cells, not donor cells.
Which of the following are responsible for some very serious diseases, including Ebola hemorrhagic fever?
Pathogens
_______________ are those that have been almost eradicated and then suddenly recur, causing an epidemic.
Re-emerging viruses
Coralline forms of which group of protists are ecologically important in the formation of coral reefs?
Red algae
Which of the following is true for exotoxins?
The effect on the host is similar for all.
Which statement about radiolarians is FALSE?
They lack silica shells.
The DNA molecule is packaged into thread-like structures called ____________.
chromosomes
Which is the only prokaryote to carry on photosynthesis that generates oxygen?
cyanobacteria
Another name for horizontal gene transfer is____________.
lateral gene transfer
What are subviral agents that depend on co-infection of a host cell with a helper virus?
Satellites
What does ssDNA stand for?
Single stranded DNA
What is the translation of "pseudopodia," a characteristic of the amoebas?
False feet
Ancestors of ____ may have possessed mitochondria, which were lost or reduced during evolutionary history.
Giardia
What are the small circles of DNA that exist within the bacterial cytoplasm in addition to the bacterial chromosome?
Plasmids
Which hypothesis asserts that viruses are remnants of cellular organisms and evolved from small cells that were parasites in larger cells?
Regressive hypothesis
Which statement about euglenoids is FALSE?
They have a pellicle.
The archaeplastids include the red algae and the green algae.
True
The genome of most plant viruses consists of what kind of RNA?
ssRNA
What is a chain of round bacteria called?
streptococci
Horizontal gene transfer greatly contributes to the rapid evolution that takes place in prokaryotes.
True
Retroviruses have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.
True
According to the progressive hypothesis, viruses may have originated as mobile genetic elements such as:
plasmids.
Lactic-acid bacteria are used for:
producing sauerkraut.
What is commensalism
A relationship between individuals of two species in which one benefits and the other derives neither benefit nor harm
At what stage of a lytic infection are phage components put together to make new viruses?
Assembly
How are viruses classified by the ICTV?
By their host range and other characteristics
Where would you likely find Euryarchaeota bacteria?
Cow digestive tracts
Which is the only prokaryote to carry on photosynthesis that generates oxygen?
Cyanobacteria
What is the correct unit of measurement for the size of most viruses?
Nanometers
Although bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on:
the plasma membrane.
Some protists consist of a single cell with multiple nuclei. This condition is known as:
coenocytic.
I am characterized by having a test and axopods. Who am I?
Actinopods
Among the protist groups below, which has organisms that typically move with two or more flagella?
Diplomonads
Bacteria protect themselves from bacteriophage infections by producing restriction enzymes that cut up foreign RNA of the phage.
False
The nucleic acid core of the virus is not surrounded by a protein coat called a capsid
False
What is a prophage?
It is phage DNA that is integrated into bacterial DNA.
Which has an unusual characteristic in that their circular DNA does not have genes for making the proteins needed to replicate and produce new viruses?
Polydnaviruses
_______________ are RNA viruses that have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.
Retroviruses
A bacterium that uses the oxidation of inorganic compounds to provide energy for manufacturing nutritious organic compounds is a:
chemoautotroph.
When a virus penetrates the host plasma membrane and moves into the cytoplasm it is called:
penetration
What are the viruses that attack bacteria?
phages
Dr. Stanley Prusiner concluded that the infective agent of CJD was not a virus because it was not sensitive to radiation, which mutates nucleic acids.
True
