BIOMI PRELIM 1 COMBINATION

Bacteria are typically how many times smaller than humans?

1. Hundred

2. Thousand

3. Hundred thousand

4. Million

5. None of the above

Million

Scientists still debate which of the following are truly alive:

1. Archea

2. Bacteria

3. Eukaryotes

4. Viruses

Viruses

What is the central dogma of life when it comes to molecular biology

1. DNA > RNA > PROTEIN

2. RNA >DNA> PROTEIN

3. PROTEIN > RNA > DNA

4. DNA > PROTEIN > RNA

1. DNA > RNA > PROTEIN

Rank the cellular components from most abundant to least abundant

1. DNA

2. RNA

3. Proteins

4. Lipids

5. Polysaccharides

Proteins: biggest fraction of cell dry mass (~50–60%) → enzymes, cytoskeleton, ribosomes, etc.

RNA: very abundant because ribosomal RNA makes up a huge portion of ribosomes (~20% of mass)

Lipids: membranes and storage (~10%)

Polysaccharides: storage/structural (glycogen, cell wall components) → smaller fraction

DNA: only one genome copy (or a few) → very small mass

Even though DNA tells us more about microbes, why might your doctor do a Gram stain on bacteria cultured from your body?

1. Look for ribosomes that make protein

2. Look for DNA polymerase

3. Looks for RNA polymeras

4. See what kind of cell envelope it has

See what kind of cell envelope it has

Why are gram negative bacteria resistant to many antibiotics?

1. Thick peptidoglycan is insensitive

2. Outer membrane is impermeable to many

3. Their nucleus protects their DNA

4. Their organelles degrade the antibiotic

Outer membrane is impermeable to many

What is the difference between bacteria and fungi?

1. Only bacteria have ribosomes

2. Fungi have peptidoglycan.

3. Bacteria have a nucleus

4. Fungi have organelles and bacteria dont don't.

Fungi have organelles and bacteria don't

If P. Acnes and Malassezia do the same thing, could you use your zit cream to treat your dandruff?

1. Yes, of course

2. No, antibiotics dont work on a fungus

3. Nobody has dandruff and zits at the same time

4. Depends on your skin type

No, antibiotics don't work on fungus

Which of the following is more closely related to fungi:

Archaea,

Bacteria,

Humans

Impossible to tell

Humans

Which of the following bet explains the orgin of eukaryotic cells

1. An archaea engulfed a bacterium

2. A bacterium engulfed an archaea.

3. a bacterium domesticated a virus and kept its genes

4. an archaea domesticates a virus and keeps its genes

1. A bacterium engulfed an archaea.

Which of the following is NOT a biological symbiosis:

1. Two humans living together in a house

2. Bacteria living in cow guts

3. Fungi living on plant roots

4. Coronaviruses and humans

5. Algae living inside corals

1. Two humans living together in a house

Which of the follow are true?

1. Both medinensis and N. fowleri symbioses with humans are obligate

2. Neither is obligate.

3. D. medinensis is obligate and N.fowleri is facultative

4. D. medinensis is facultative and N.fowleri is obligate

5. None of the above

D. medinesis is obligate and N fowleri is facultative

What makes eukaryotes different from bacteria and archaea?

A) Eukaryotes are always larger than bacteria and archaea
B) Eukaryotes can be symbionts, while bacteria and archaea cannot
C) Eukaryotes have organelles
D) Eukaryotes are always multicellular
E) Bacteria and archaea have organelles

Eukaryotes have organelles

Which of the following is true about head lice?

1. They only infect people with poor hygiene.

2. They are facultative mutualists.

3. they are obligate parasites.

4. They cannot transmit (vector) bacterial diseases between humans.

1. they are obligate parasites.

Which of the following are true?

A) Bacteria in head lice are always pathogens of humans

B) Bacteria in head lice are always pathogens of head lice

C) Bacteria in head lice may not grow in head lice, but are always pathogens of humans

D) Bacteria in head lice may be symbionts of head lice and may be pathogens of humans

Bacteria in head lice may be symbionts of head lice and may be pathogens of humans

What types of microorganisms inhabit the human oral cavity?

A) Bacteria
B) Archaea
C) Eukaryotic microorganisms
D) Viruses
E) All of the above

All of the above

Gingipain is an enzyme that is secreted outside P. endodontalis and breaks down host cell proteins into smaller components. Would this be a...

A) Anabolic reaction
B) Catabolic reaction
C) Neither
D) Both
E) None of the above

Catabolic reaction

Organic acids that cause cavities mostly come from

1. Anerobic respiration

2. Aerobic respiration

3. Fermentation

4. Anabolism

5. None of the above

1. Fermentation

Which of the following might be reasons that Koch's postulates are not always satisfied for microbial diseases?

1. Some people can be infected but they dont get sick

2. Some pathogens cannot yet be culutured

3. Some pathogens lose virulence when being cultured

4. All of these

1. All of these

Which of the following is the first line of human immune defense against pathogens

A) White blood cells
B) Skin / Epithelial tissues
C) Inflammatory compounds
D) Red blood cells
E) Hair

B) Skin / Epithelial tissues

Why doesn't Limulus amoebocyte lysate recognize strep pyrogenes?

1. It’s an anerobic

2. Its a cocci

3. It has no LPS

4. It produxes enzymes that deactivate the lysateanaerobic

It has no LPS (lipopolysaccharide)

Which of the following is not a mechanism by which pathogens evade the immune system?

A) They change their surface molecules to look like their host
B) They replicate in immune-related cells
C) They eat immune cells
D) They interfere with host cell signaling immune responses
E) They constantly change their surface molecules

They eat immune cells

Most cases of conjunctivitis should be treated with antibiotics?

True

False

False

Where are molds found on the tree of life

What term best describes mold and mildew removers like the one pictured (Clorox mold/mildew)

A) Antibiotic
B) Antifungal
C) Antiviral
D) Disinfectant

Disinfectant

Rank treatments for black mold

Bleach, , Vinegar,Hydrogen peroxide Soapy water

Bleach, Hydrogen peroxide, Vinegar, Soapy water

Which of the following "opportunities" allows normal harmless bacteria to become pathogenic?

A) Weakened immune system
B) It ends up in the wrong place (wounds, catheters)
C) When our normal microbiome gets disrupted after antibiotics
D) All of these

All of these

What can biofilm matrices (aka EPS) be built from?

A) Proteins
B) Polysaccharides
C) DNA
D) All of these

All of these

Why form a biofilm

A) Stay in place
B) Stay safe
C) Make friends
D) Do things they cant do on their own
E) All of the above

All of the above

Why might bacteria want to regulate density-dependent activities?

A) Efficient resource use
B) Virulence regulation
C) Symbiosis management
D) Any of these

Any of these

Which of the following bacteria is most abundant in the healthy gut microbiome of humans?

A) Bacteroides
B) Clostridium
C) Prevotella
D) Escherichia coli

Prevotella

What goods and services does your gut microbiome provide?

A) Nutrition
B) Immunomodulation
C) Mood regulation
D) Colonization resistance
E) All of these

All of these

What is the main way(s) drinking water is treated to make it safe to drink?
A) Filtration
B) Chlorination
C) Boil
D) A and B
E) B and C

A and B

Why do we test for fecal coliforms in drinking water?

A) All waterborne diseases are caused by E. coli
B) E. coli is a good indicator of overall water quality
C) It tells us how much COVID is present
D) We need some to keep our microbiome healthy
E) None of the above

E. coli is a good indicator of overall water quality

E. coli strains that can make people sick encode special genes in their...
A) Core genome
B) Accessory genome
C) Pan genome
D) None of these

Accessory genome

How many MORE microbial genes are found in the average human gut than in the human genome?

2. 2x (40,000 vs. 20,000)
3. 10x (200,000 vs. 20,000)
4. 150x (3,000,000 vs. 20,000)
5. Impossible to tell

150x (3,000,000 vs. 20,000)

What is the relationship between sugar, lactic acid bacteria and your teeth?

A) They convert sugar into lactic acid, which lowers the pH and dissolves your teeth
B) They don't like sugar! They only like to eat things that are acidic
C) They are probiotics which are good for you, so they help your mouth avoid cavities!
D) They are found deep within a biofilm on your teeth and block sugar from chewing away your enamel

They convert sugar into lactic acid, which lowers the pH and dissolves your teeth

Why is Step mutants a bigger problem in the gut than in the mouth?

A) It only produces a biofilm in the gut

B) It produces kills off good bacteria

C) There is a lot of histidine in the gut that is convert to a proinflammatory product

D) It causes histidine deficiency

There is a lot of histidine in the gut that is convert to a proinflammatory product

Which of the following are true about volatile fatty acids?

A) Fermentation byproducts from microbes eating dietary fiber

B) Produced in the absence of oxygen

C) Small enough to enter the bloodstream as another food and energy source

D) Help regulate our appetite and immune system

E) All of these

All of these

can your gut microbiome affect your mood??

Yes

NO

Perhap

Yes

What is the take-home message of this graphical abstract?

1 Old pooh makes young mice sick

Young pooh make old mic ehealhtier

Gut micrbiome alter the intesines and inflamamtion

All of these

Which part of the body has the greatest fungal diversity?

Large intestine or colom

What is an enzyme?

A type of carbohydrate

 

A protein that can catalyze reactions

 

It is part of DNA

 

Fatty acids that have formed into a micelle

A protein that can catalyze reactions

What is a microbiome?

 

eukaryotic cells found in a habitat

 

community of microorganisms that can usually be found living together in any given habitat.

 

the collection of viruses in a habitat

 

pathogenic organisms only

community of microorganisms that can usually be found living together in any given habitat.

Select the statement(s) that are true about anabolism and catabolism? Pick all that apply

Chemical bonds are made during anabolism which usually requires energy

 

Only bacteria can perform anabolism

 

Chemical bonds are broken during catabolism usually releasing energy

 

Only eukaryotes can perform catabolism

Chemical bonds are made during anabolism which usually requires energy

 

 

Chemical bonds are broken during catabolism usually releasing energy

 

What is a virulence factor?

Substances and structures produced by pathogens to help them colonize a host

 

Logical steps used to determine if a microbe causes a disease

 

Essential proteins such as ribosomes

 

Host defense molecules used to prevent infection

Substances and structures produced by pathogens to help them colonize a host

What are Koch's postulates?

Steps in the viral life cycle

 

Steps for avoiding bad breath!

 

A pustule that can form under the eye

 

Criteria used to determine pathogenicity of bacteria

Criteria used to determine pathogenicity of bacteria

What best describes Streptococcus pyogenes?

Gram positive, aerotolerant anaerobe

 

Gram negative, aerobic

 

Gram positive, aerobic

 

Gram negative, anaerobic

Gram positive, aerotolerant anaerobe

What makes Streptococcus pyogenes so infectious?

it expresses virulence factors such as exotoxins, adhesins and secreted enzymes

 

it is exclusively found in the mouth

 

it is not at all infectious!

 

it harbors ribosomal RNA which makes it infectious

it expresses virulence factors such as exotoxins, adhesins and secreted enzymes

What are PAMPS?

 

receptors for different pathogens

 

molecules from pathogens recognized by the immune system

 

a type of cytokine

 

types of molecules that are associated with the host organism (ie us)

molecules from pathogens recognized by the immune system

What is an antibody?

a type of protein found in our adaptive immune response

 

a protein that is part of our innate immune response

 

a type of macrophage

 

complement

a type of protein found in our adaptive immune response

How do pathogens evade the immune system?

some bacteria are enclosed in a capsule which hides them from the immune system

 

All answers are correct

 

invade and replicate in immune cells such as phagocytes

 

interfere with host signaling

All answers are correct

What is the difference between red slime and black mold?

red mold is derived from bacteria, black from fungi

 

red is from archaea, black from fungi

 

No answer is correct

 

red is derived from fungi, black from bacteria

red mold is derived from bacteria, black from fungi

Which of the following are examples of where biofilms may form?

unbrushed teeth

 

medical devices, like urinary catheters

 

All answers are correct

 

water pipes

All answers are correct

Which of the following is false about biofilms?

they make an extra polymeric substance (EPS)

 

they allow for cell to cell communication between bacteria

 

they are made up of only one species of bacteria

 

bacteria within biofilms also have a free-swimming planktonic form

they are made up of only one species of bacteria

What is quorum sensing?

a lineup of bacteria

 

minimum density of individuals needed to control gene expression of the group

 

maximum density of individuals needed to control gene expression of the group

 

only refers to bacteria which glow in the dark

minimum density of individuals needed to control gene expression of the group

Why would you think that antibiotics may be less effective on bacteria who live in a biofilm?

some bacteria may be dormant within the biofilm

 

some swap antibiotic resistance genes with their neighbours

 

All answers are correct

 

difficult for antibiotic to access all bacteria in a biofilm

All answers are correct

What is a fecal transplant?

installation of bacteria from the fecal matter of a healthy individual to one that is ill

 

All of the above

 

The process of converting manure into fertilizer

 

Drinking water contaminated with fecal matter

installation of bacteria from the fecal matter of a healthy individual to one that is ill

Which of the following is TRUE about the role of the healthy microbiome in preventing C difficile super infections

Members of the healthy microbiome degrade the C difficile toxin that makes people sick.

 

Some microbiome bacteria produce primary bile acids that kill C difficile

 

Secondary bile acids produced by beneficial members of the microbiome prevent C difficile spores from germinating

 

C difficile sometimes releases bacteriophage that kill key members of the healthy microbiome

Secondary bile acids produced by beneficial members of the microbiome prevent C difficile spores from germinating

What interventions enabled us to bring down waterborne diseases to a minimum in the last 100 years (multiple correct answers)?

 

chlorination

 

All answers are correct

 

filtration

 

antibiotics added to our drinking water

chlorination

filtration

Which of the following apply to coliform bacteria?

Gram negative

 

a facultative anaerobe

 

All answers are correct

 

found in the gut of warm -blooded mammals

All answers are correct

Which of the following is FALSE about E. coli?

it is only one of many different types of coliform bacteria

 

has a genome that is larger than the human genome

 

some strains cause food poisoning and UTIs

 

is a model organism and tool in molecular biology

has a genome that is larger than the human genome