Module 9
Which statement about bacteria is TRUE?
Bacteria are cellular and are sometimes classified as life forms.
Trypanosomes and parabasalids
Excavates
Bacteriophages decrease food safety.
False
Which eukaryotic organelles likely arose from symbiotic relationships between larger cells and bacteria?
Mitochondria and chloroplasts
Most protists are:
aquatic
Forams and actinopods
Rhizarians
Actinopods are mostly marine plankton rhizarians with long, filamentous cytoplasmic projections called __________.
axopods
Prokaryotes divide using a process called________.
binary fission
Botox is the marketed version of the botulism exotoxin, used to treat muscle spasms and for cosmetic purposes.
True
The dense cytoplasm of the prokaryote contains ribosomes and storage granules.
True
The Archaea plasma membranes are made up of branched-chain hydrocarbons bounded to glycerol by:
ether linkages.
Crenarchaeota are also called:
sulfur bacteria.
Ancestors of ____ may have possessed mitochondria, which were lost or reduced during evolutionary history.
Giardia
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
Herpesviruses
dsDNA: large complex enveloped virus; replicates in host nucleus
When a virus penetrates the host plasma membrane and moves into the cytoplasm it is called:
penetration
What is the translation of "pseudopodia," a characteristic of the amoebas?
False feet
Streptococci, the bacteria responsible for strep throat infections, is classified within which group of bacteria?
Gram-negative bacteria
Viral proteins can damage host cells by which process?
Overwhelming the host cell with a large number of viruses
Which protist group are characterized by a multinucleate amoeboid-like feeding form?
Plasmodial slime molds
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
Which statement about euglenoids is FALSE?
They have a pellicle.
Members of the alveolates are characterized by the presence of:
flattened vesicles under the plasma membrane.
According to the progressive hypothesis, viruses may have originated as mobile genetic elements such as:
plasmids
Which of the following are rod-shaped bacteria?
Bacilli
Which algal group contains individuals that are typically unicellular and form siliceous shells?
Diatoms
Plasmids of bacteria often have genes involved in:
antibiotic resistance.
Conjugation is the process by which one bacterium transfers genetic material to another through direct contact.
True
Papovaviruses
dsDNA: nonenveloped virus
Cells that have a single flagellum or are amoebas with no flagella are _________.
unikonts
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
Lactic-acid bacteria are used for:
producing sauerkraut.
Who is credited with the discovery of prions as a new biological principle of infection?
Stanley Prusiner
What is vertical gene transfer?
The transmission of genetic material from parents to offspring during reproduction
What is the purpose of sex pili?
To transmit DNA between bacteria
Fimbriae are only visible with the use of an electron microscope.
True
Foraminiferans are Rhizarians.
True
Retroviruses have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.
True
Red algae, green algae, and land plants are collectively called _______________.
archaeplastids
The genome of most plant viruses consists of what kind of RNA?
ssRNA
Dinoflagellates and water molds
Chromalveolates
What is a prophage?
It is phage DNA that is integrated into bacterial DNA.
Which statement about biofilms is FALSE?
Biofilms are usually less than 2 μm thick.
A virus is a very small infective agent that consists of a core of nucleic acid and is dependent on a living host.
True
The archaeplastids include the red algae and the green algae.
True
Which characteristic defines a virus?
Viruses cannot metabolize.
Togaviruses
ssRNA that can serve as mRNA ; enveloped viruses
Bacterial conjugation is related to____________.
horizontal gene transfer
Viroids cause a variety of plant diseases and are composed only of:
strands of RNA.
What commercial product is derived from the processing of red algae?
Carrageenan
Which of the following is the most common structure of a virus?
Icosahedron
Some protists consist of a single cell with multiple nuclei. This condition is known as:
coenocytic
Which type of protist is responsible for malaria in humans, parasitic to both humans and mosquitoes?
Apicomplexans
What is the protein coat of a virus called?
Capsid
Alveolates and stramenopiles
Chromalveolates
Mycobacteria
Contain waxy cell wall
Where would you likely find Euryarchaeota bacteria?
Cow digestive tracts
You find a unicellular organism that forms lobe-like pseudopodia. When you expose the cells to cAMP, they aggregate into a slug like structure. Based on this information, you correctly conclude that this organism is known as:
Dictyostelium discoideum.
Which protist groups consists of individuals who often have intracellular shells of interlocking plates?
Dinoflagellates
Which protist group possess a crystalline rod in their flagella?
Euglenoids
Diplomonads and euglenoids
Excavates
Diplomonads belong to which of the following group of eukaryotes?
Excavates
_________ secrete many-chambered tests with pores through which cytoplasmic projections extend to move and obtain food.
Forams
Of the following, which group exhibits a diverse morphology, forming unicells, filaments, and sheets?
Green algae
At what stage of the lysogenic cycle would a prophage appear?
Integration
Mycoplasma
Lack cell walls
Which is an anaerobic excavate that is an endosymbiont of animals?
Parabasilid
_______________ are those that have been almost eradicated and then suddenly recur, causing an epidemic.
Re-emerging viruses
What does ssDNA stand for?
Single stranded DNA
Which statement about radiolarians is FALSE?
They lack silica shells.
The most common mode of reproduction in bacteria is:
binary fission.
Chlamydia
lack peptidoglycan walls
Which of the following is true for exotoxins?
The effect on the host is similar for all.
Which statement describes a virulent phage?
A virulent phage destroys bacteria.
Unikonts also have a ____________ that has major evolutionary significance.
triple-gene fusion
What is the correct unit of measurement for the size of most viruses?
Nanometers
Actinomycetes
Resemble fungi
An example of an excavate that has a pellicle is Euglena.
True
Lytic reproductive cycles destroy host cells.
True
The immunodeficiency virus that causes acquired immunodeficiency syndrome is an enveloped virus.
True
Small hairlike structures made up of protein on the surface of bacteria are called:
fimbriae
Humans have __________ pairs of chromosomes.
23
What are Koch's postulates?
A set of guidelines to demonstrate that a specific pathogen causes specific disease symptoms
Which of the following statements is correct in the context of golden algae?
Are mostly unicellular, biflagellate freshwater and marine stramenopiles
Which structure acts like a motor for the bacterial flagellum?
Basal body
_____________ are collared flagellates in the opisthokont clade, which also includes fungi and animals.
Choanoflagellates
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
Bacteriophages attach to the cell walls of bacteria by envelope proteins.
False
The nucleic acid core of the virus is not surrounded by a protein coat called a capsid.
False
Members of which protist group is one of the fossilized deposits in the unique geological formation of the White Cliffs of Dover?
Foraminiferans
Which statement about an F factor is FALSE?
It is found in recipient cells, not donor cells.
A bacterial cell wall is made up of ______________.
N-acetyl glucosamine, N-acetyl muramic acid, and amino acids
____________ are the largest and most complex of all algae.
brown algae
Orthomyxoviruses
ssRNA that serves as template for mRNA synthesis; medium sized enveloped that often exhibit projecting spikes
What is commensalism?
A relationship between individuals of two species in which one benefits and the other derives neither benefit nor harm
Red algae and green algae
Archaeplastids
Which is the only prokaryote to carry on photosynthesis that generates oxygen?
Cyanobacteria
Which of the following are responsible for some very serious diseases, including Ebola hemorrhagic fever?
Pathogens
Which protist is responsible for late blight of potatoes, the cause of the Irish potato famine in the mid-19th century?
Phytophthora
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.
Which protist group does not have flagellated cells?
Red algae
What is a chain of round bacteria called?
Streptococci
Protists have various means of locomotion; they move by all of the following means EXCEPT:
by mycelium.
The DNA molecule is packaged into thread-like structures called ____________.
chromosomes
Cyanobacteria
contain chlorophyll
Which statement describes a temperate virus?
A temperate virus does not always destroy its host.
How are viruses classified by the ICTV?
By their host range and other characteristics
Parabasilids are excavates that lack functional mitochondria and lack a Golgi complex.
False
Red tides are caused by red algae.
False
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
Genomic deoxyribonucleic acid is chromosomal DNA.
True
Horizontal gene transfer greatly contributes to the rapid evolution that takes place in prokaryotes.
True
Some elongated fimbria are important in transferring DNA between bacteria.
True
Amoebozoans and opisthokonts
Unikonts
Cellular slime molds and choanoflagellates
Unikonts
What is a very small infective agent that consists of a core of nucleic acid and is dependent on a living host?
Virus
Which of the following cause disease and often death?:
Viruses that have only a lytic cycle
Retroviruses
ssRNA enveloped viruses; contains reverse transcriptase for transcription of RNA into DNA; two identical molecules ssRNA
I am characterized by having a test and axopods. Who am I?
Actinopods
_________ are parasites that produce sporozoites and are nonmotile.
Apicomplexans
Which of the following is NOT part of the Chromalveolates group of eukaryotes?
Euglenoids
Which protist clade (supergroup) is characterized by their greatly modified mitochondria?
Excavates
Which protist group contains the organism Trypanosoma, a colorless parasite that can cause African sleeping sickness?
Excavates
Which Archaea have the ability to carry out a form of the Calvin cycle, capturing sunlight with bacteriorhodopsin?
Extreme halophiles
After an endospore forms, the cell membrane of the original cell lyses, releasing the endospore.
False
Amoebozoans move by means of flagella.
False
An emerging virus is one that is not new to a population or that is rapidly increasing in incidence.
False
Bacterial chemoautotrophs use organic chemicals as an energy source.
False
Gram-negative cell walls have an outer membrane that contains lipids and peptidoglycans.
False
Which hypothesis asserts that viruses are remnants of cellular organisms and evolved from small cells that were parasites in larger cells?
Regressive hypothesis
_______________ are RNA viruses that have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.
Retroviruses
How do retroviruses differ from other RNA viruses?
Retroviruses have reverse transcriptase instead of RNA-dependent RNA polymerase.
Which protist group typically consists of amoeboid cells surrounded by a hard outer shell through which cytoplasmic projections extend?
Rhizarians
Most bacterial cells can keep from bursting in a hypotonic environment because of:
a rigid cell wall.
Before an animal cell's membrane fuses with a virus, the virus must first:
attach to a specific receptor on the plasma membrane of the host cell.
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.
Many green algae produce spores asexually by mitosis; if these spores have flagella and are motile, they are called __________.
zoopores