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