MCB 100 Exam 2 iClicker Questions

During treatment of waste water to make it potable, about 90% of the microbes are removed

A. by preliminary fermentation

B. in the sedimentation step

C. by treatment with alum

D. by treatment with chlorine or ozone

E. in the filtration step

E. in the filtration step

Which statement regarding the quality of drinking water is MOST accurate?

A. Permissible levels of contaminants vary from state to state

B. There are federal laws that dictate standards for drinking water quality

C. Drinking water is safe only if there are no microbes or chemicals present

D. There are no standards for the quality of drinking water

E. Drinking water is potable when there are no pathogens present

A. Permissible levels of contaminants vary from state to state

Which of the following statements is false?

A. The grouping of microorganisms in a phylogenetic scheme that is based on nucleic acid sequence data is not always the same as the grouping of microorganisms in a taxonomic scheme based on morphological traits

B. The cells of prokaryotic organisms are divided into compartments by internal membranes, which is efficient for energy purposes

C. In the most popular current phylogenetic scheme, prokaryotic organisms are divided into two domains called Bacteria and Archaea

D. Most chemoautotrophic organisms on Earth are prokaryotes and can use inorganic energy sources to make organic compounds from carbon dioxide

E. The cells of prokaryotic microorganisms contain 70S ribosomes, and most have circular chromosomes, but some have linear chromosomes.

B. The cells of prokaryotic organisms are divided into compartments by internal membranes, which is efficient for energy purposes

The bacterial arrangement illustrated here is known as

A. Staphylococcus

B. Palisades

C. Pleomorphic

D. Tetrad

E. Streptobacillus

B. Palisades

When Pseudomonas aeruginosa is grown in LB under aerobic conditions and then stained for biofilm formation the results area ring as shown for the left tube. When the bacteria are grown anaerobically in the presence of arginine (Arg), the results on the right are obtained. Which statement best explains the observed results?

A. Arg caused the P . aeruginosa bacteria to lyse under anaerobic conditions and all the polysaccharide slime coated the tube wall

B. Arg stimulated the P . aeruginosa bacteria to make much more polysaccharide slime that coated the tube wall

C. The Arg dissolved the polysaccharide into hydrophobic layers that coated the tube wall

D. The P.aeruginosa bacteria used Arg to grow anaerobically, so that it no longer had to grow at the air-liquid interface, which allowed it to form a biofilm all over the tube wall

E. The hydrophobic Arg in the medium coated the tube wall and was stained with crystal violet dye

D. The P. aeruginosa bacteria used Arg to grow anaerobically, so that it no longer had to grow at the air-liquid interface, which allowed it to form a biofilm all over the tube wall

Why do doctors caution patients who are pregnant to avoid deli meats, cold cuts, and soft cheeses?

A. Fermentation of those foods by Listeria will cause nausea

B. Listeria bacteria can make these foods taste sour

C. The Listeria bacteria can degrade the nutrients of the food

D. These foods are soft and easy for the bacteria to spread throughout

E. The Listeria bacteria can easily grow in the uncooked food stored in the refrigerator

E. The Listeria bacteria can easily grow in the uncooked food stored in the refrigerator

Listeria virulence is directly related to the ability to:

A. produce powerful toxins that lyse eukaryotic cells

B. form resistant endospores that can withstand harsh chemical environments

C. live within cells and thus avoid exposure to the immune system of its host

D. move rapidly through the body using multiple flagella called comet tails

E. resist most antimicrobial agents due to resistant cell walls.

C. live within cells and thus avoid exposure to the immune system of its host

Why do male teenagers typically have more acne than male adults?

A. sebum production is decreased by testosterone, which is more in adult males

B. The P. acnes bacteria overgrow during puberty when sebum is abundant due to high levels of testosterone, particularly in males

C. During puberty, hair follicles increase in number so more zits can happen, particularly in males

D. The aerobic environment of hair follicle enhances P.acnes growth

E. All of the above contribute to more acne in male teenagers

B. The P. acnes bacteria overgrow during puberty when sebum is abundant due to high levels of testosterone, particularly in males

Which of the following is an advantage for a bacterium having the ability to invade and reside inside host cells?

A. The bacteria can bind to antibodies and get transported to lymph nodes

B. The host cytosol is rich in nutrients, if access can be gained by the bacteria

C. The bacteria can colonize and form biofilms

D. Multiple bacteria can use the host cell as a vesicle to exchange metabolites with eachother

B. The host cytosol is rich in nutrients, if access can be gained by the bacteria

Suppose you have two A-B toxins, A-B and A'-B'

A-B binds specifically to neurons and blocks protein synthesis to kill the nerve cells. A'-B' binds specifically to intestinal epithelial cells and blocks Na2+ uptake to cause diarrhea. What would injection of a hybrid toxin, A'-B, into an animal do to its muscle cells?

A. Nothing

B. Cause cell lysis

C. Kill the cells

D. Cause the tissue swelling

E. Cause paralysis

A. Nothing

Although the proteins they transfer may be different, the type 3 secretion systems of E. coli, Salmonella, Shigella, and Yersinia function similarly in that they

A. transfer nutrient proteins from the host cell into the bacteria

B. transfer bacterial proteins from one bacterium cell to another

C. secrete bacterial protein toxins into the medium to act on the host

D. uptake nutrient proteins from the medium into the bacteria

E. transfer bacterial proteins from the bacterium into the host cell

E. transfer bacterial proteins from the bacterium into the host cell

Suppose you have two A-B toxins, A-B and A'-B'. A-B binds specifically to muscle cells and blocks protein synthesis to kill the muscle cells. A'-B' binds specifically to intestinal cells and blocks Na2+ uptake to cause diarrhea. What would injection of a hybrid toxin, A'-B, into an animal do to muscles at the site of injection?

A. Nothing

B. Cause cell lysis

C. Kill the cells

D. Cause tissue swelling

E. Cause paralysis

D. Cause tissue swelling

How do archaeal ribosomes differ the most from bacterial ribosomes?

A. Archaeal ribosomes are 80S while bacterial ribosomes are 70S

B. Unlike bacteria, archaea don't have ribosomes

C. Ribosomal DNA content

D. Ribosomal RNA content

E. Archaeal ribosomes have 1 subunit, while bacterial ribosomes have 2

D. Ribosomal RNA content

Which of the following statements about archaea is true?

A. Archaea lack true peptidoglycan in their cell walls

B. The initial amino acid in the peptides of archaea is N-formylmethionine

C. Archaeal cytoplasmic membranes' lipids contain unbranched, linear hydrocarbon chains

D. Archaea are all extremophiles

E. Archaea are important human pathogens

A. Archaea lack true peptidoglycan walls

Which of the following is not a reason archaea thrive in extreme environments?

A. Cytoplasmic enzyme composition

B. Cell membrane composition

C. Amino acid composition

D. Nuclear composition

E. DNA composition

D. Nuclear composition

How many of these images were acquired with a TEM?

A. 1

B. 2

C. 3

D. 4

E. 5

Refer to lecture 14 notes

A. 1

Which of the following microbes is an archaea?

A.

B.

C.

Refer to lecture 14 notes

B

How many of these images were acquired with a TEM?

A. 1

B. 2

C. 3

D. 4

E. 5

Refer to lecture 14 notes

D. 4

Why don't archaea appear to cause pathogenesis in humans?

A. We haven't found one yet

B. They do cause pathogenesis, we just don't know which disease yet

C. Antibiotics that kill bacteria also kill archaea

D. Archaea live in extreme environments that humans can't survive

A. We haven't found one yet

Simple eukaryotes that carry out photosynthesis are known as:

A. fungi

B. mushrooms

C. euglenids

D. lichens

E. algae

E. algae

Which of the following are not eukaryotic microbes?

A. Mushrooms

B. Archaea

C. Water molds

D. Protozoa

E. Brown Algae

B. Archaea

A unicellular fungus is a _______, while masses of long, intertwined fungal ________ are called ____________.

A. mold/yeast/haustoria

B. hypha/mold/slime mold

C. yeast/hyphae/slime mold

D. yeast/hyphae/mycelia

E. mold/mycelia/hyphae

D. yeast/hyphae/mycelia

Fungal hyphae that lack cross walls are called

A. mycelial hyphae

B. sexual mycelia

C. asexual mycelia

D. septate hyphae

E. aseptate hyphae

E. aseptate hyphae

Which of the following do not have hyphae associated with them?

A. molds

B. mushrooms

C. yeast

D. lichens

E. molds and mushrooms

C. yeast

All truly pathogenic fungi exist in the environment as molds but grow in the body as spherical yeasts. This trait is known as ________

A. morphogenesis

B. mushrooming

C. morphotype shift

D. dimorphism

E. anamorphism

D. dimorphism

Which of the following statements about Candida is FALSE?

A. Candida is present in the digestive tract of 40-80% of all healthy individuals

B. Candida can be transmitted between adults during sexual contact

C. Candida causes thrush in children

D. Candida can be passed on to babies during childbirth

E. Candida can be easily treated with topical antifungals in immunocompromised individuals

E. Candida can be easily treated with topical antifungals in immunocompromised individuals

Ringworm is cause by __________

A. sexual reproduction of worms inside the body

B. spread of mycelia deep into the living body tissues

C. dermatophytes growing in the outer dead tissue layers of the skin

D. a strong allergic response to the presence of dermatophytes

E. toxins produced and released at the infection site by dermatophytes

C. dermatophytes growing in the outer dead tissue layers of the skin

The most common source of tinea cruris (jock itch) is ___________

A. sexual contact

B. spread from feet

C. contact with soil

D. sharing clothing

E. bath tubs or showers

B. spread from feet

Most mycoses are difficult to treat because ____________

A. many fungi have developed resistance to antifungal drugs

B. funglicides that kill fungi are rapidly metabolized by the liver

C. treatment causes major disruption of the microbiota

D. fungal drugs are extremely expensive

E. fungi are biochemically similar to humans

E. fungi are biochemically similar to humans

The deadliest mushroom toxin is produced by __________________

A. Psilocybe cubensis

B. Trichophyton rubrum

C. Blastomyces dermatidis

D. Amanita phalloides

E. Aspergillus fumingatus

D. Amanita phalloides

Which of the following is not true of aflatoxins?

A. The can be carcinogenic

B. They can cause liver damage

C. They are derived form polyketides

D. They are fatal to many animals

E. They are produced by Penicillium

E. They are produced by Penicillium

_______ are the environmental reservoir for infection with Cryptococcus neoformans

A. Mice

B. Cats

C. Birds

D. Deer

E. Fleas

C. Birds

Opportunistic fungi that can be pathogens in some people __________

A. always have two physiological and structural forms

B. are part of the normal microbiota for many individuals

C. have special adhesion proteins for colonizing the body

D. have the same geographical distribution as over pathogenic fungi

E. are difficult to diagnose because they are so prevalent

B. are part of the normal microbiota for many individuals

Healthy humans typically become infected with Toxoplasma gondii by ____________

A. petting a contaminated cat

B. cleaning a contaminated cat's litter box

C. ingesting undercooked meat containing T. gondii

D. working in the garden

E. swimming in contaminated lakes

C. ingesting undercooked meat containing T. gondii

The fever that is associated with malaria is primarily the result of ________

A. lysis of hepatocytes

B. reproduction of Plasmodium inside erythrocytes

C. lysis of leukocytes

D. lysis of Plasmodium trophozoites

E. release of a toxin from Plasmodium

B. reproduction of Plasmodium inside erythrocytes

Are viruses good or bad?

A. Good

B. Bad

Depends

What are the minimal components of a virus?

A. DNA

B. Protein

C. DNA or RNA and Protein

D. RNA

E. The central dogma- DNA to RNA to Protein

C. DNA or RNA and Protein

Are viruses alive?

A. Yes

B. No

Depends

Which type of nucleic acid is NOT found in the genome of viruses?

A. Single-stranded DNA

B. Circular, single stranded RNA

C. Linear, double stranded RNA

D. Circular, double stranded DNA

E. Linear, single stranded RNA

B. Circular, single stranded RNA

Which statement MOST accurately describes lytic viral replication?

A. Viruses can reproduce only under certain environmental conditions

B. Viruses reproduce by binary fission

C. Viruses reproduce rapidly in the environment

D. Virus replication usually results in the death and lysis of the host cell

D. Virus replication usually results in the death and lysis of the host cell

The period of time required to complete the lytic cycle is called?

A. The lytogenic time

B. The burst time

C. Lytic accumulation

D. Lysogeny

E. Doubling time

B. The burst time

Which of the following is NOT part of the lysogenic cycle of bacteriophages?

A. Prophage

B. Lysogeny

C. Prophage replication

D. Host-cell lysis

E. Induction

D. Host-cell lysis

Are bacteriophages part of our microbiome?

A. True

B. False

A. True

During the synthesis phase of a double-stranded DNA animal virus depicted below, correctly name the host-cell processes that are hijacked by the virus

A. 1= transcription 2= replication 3= translation

B. 1= transcription 2= translation 3= replication

C. 1= translation 2= replication 3= transcription

D. 1= replication 2= translation 3= transcription

E. 1= translation 2= transmutation 3= transcription

D. 1= replication 2= translation 3= trasncription

What is NOT a reason an animal virus would want to have a host cell envelope around its capsid?

A. To avoid the host cell cytoplasm

B. To provide extra protection from the environment

C. To avoid killing its host

D. To hide from the immune system

E. To incorporate a more complex array of surface receptors onto the virus

A. To avoid the host cell cytoplasm

What led to polio being eradicated in the Americas?

A. Americans developed resistance to the poliovirus

B. A phage that infects polio spread throughout the Americas

C. A widely available cost-effective vaccine

D. An expensive vaccine that the US government provided to US citizens

E. Implementation of modern hygiene approaches prevented further spread of polio throughout the Americas

D. An expensive vaccine that the US government provided to US citizens