MCB 2610 Exam 2 UConn Maty

Bacteria and Archaea are similar in that they both share the following characteristics:

A. Small, Prokaryotic, single celled, Nuclear membrane, Cell walls, cause human disease

B. Large, Prokaryotic, Multi-celled, Nuclear membrane, Cell walls (made of peptidoglycan), not known to cause human disease

C. Small, Prokaryotic, single celled, No Nuclear membrane, Cell walls (made of Pseudopeptidoglycan), are always beneficial

D. Small, Prokaryotic, single celled, No Nuclear membrane, Cell walls (made up of sugars)

E. Small, Prokaryotic, single celled, No Nuclear membrane, Cell walls (made up of sugars), not known to cause human disease

D. Small, Prokaryotic, single celled, No Nuclear membrane, Cell walls (made up of sugars)

Which of the following statements about the bacterial glycocalyx is TRUE?

• Capsules are loosely attached and primarily help bacteria retain moisture.

• Slime layers are highly organized and allow bacteria to evade the immune system.

• The glycocaly is composed only of glycoproteins and is found inside the cell wall.

• Capsules are firmly attached, highly organized, and help bacteria evade immune responses.

• Slime layers are tightly bound to the cell wall and found only in
  Streptococcus species.

• Capsules are firmly attached, highly organized, and help bacteria evade immune responses.

What is the likely consequence of mutating all D-form amino acids in the peptidoglycan peptide side chains of a bacterial cell to L-form amino acids?

• Nothing, there is no difference between the L and D forms of amino acids

• You have made the cell wall weaker and susceptible to degradation by enzymes

• You prevent it from being flipped from the cytoplasm across the plasma membrane

• You prevent NAM and NAG from linking together

• You prevent lysozyme from being able to work

You have made the cell wall weaker and susceptible to degradation by enzymes

Which of these would be included in the Gram-negative cell envelope?

• outer membrane, cell wall, peptidoglycan, LPS

• outer membrane, peptidoglycan, teichoic acid, capsule

• Peptidoglycan, slime-layer, cytosol, teichoic acid

• Plasma membrane, peptidoglycan, teichoic acid, capsule

• Cytosol, cell wall, teichoic acid, LPS

outer membrane, cell wall, peptidoglycan, LPS

Why is it often difficult to treat a Mycoplasma infection?

• Mycoplasma have a thick peptidoglycan layer that blocks antibiotics.

• Mycoplasma lack a cell wall, making many common antibiotics ineffective.

• Mycoplasma can easily mutate, leading to antibiotic resistance.

• Mycoplasma bacteria have teichoic acids and are easily destroyed by the immune system.

• Mycoplasma have an LPS in the cell walls blocking antibiotics.

Mycoplasma lack a cell wall, making many common antibiotics ineffective.

Which term describes bacteria with flagella distributed all over the cell surface?

• Monotrichous

• Lophotrichous

• Amphitrichous

• Peritrichous

• Polar

Peritrichous

Based on the image, are periplasmic flagella in Gram-positive or Gram-negative bacteria?

Gram-negative

Why do Gram negative bacteria need specialized secretory systems?

• Because they need additional mechanisms to move molecules across their outer membrane

• Because they need additional mechanisms to move molecules across their plasma membrane

• Because they need specific pathways for the cell excrete polysaccharides

• Because they need specific pathways for the cell to release oxygen gas

• Because they need additional mechanisms for the cell generate ATP

Because they need additional mechanisms to move molecules across their outer membrane

Why are bacterial endospores a major concern in healthcare environments?

• They are easily destroyed by routine disinfectants

• They multiply rapidly on dry surfaces making them difficult to eliminate.

• They can survive for long periods on surfaces, making them difficult to eliminate

• They can only survive inside the human body

• They are inactivated by exposure to air

They can survive for long periods on surfaces, making them difficult to eliminate

Which of the following correctly describes a key difference between bacterial and eukaryotic flagella?

• A. Bacterial flagella are composed of microtubules while Eukaryotic flagella are composed of flagellin.

• B. Eukaryotic flagella rotate in a counterclockwise direction, while bacterial flagella slide back and forth.

• C. Bacterial flagella are powered by a proton motive force, while eukaryotic flagella use ATP.

• D. Both bacterial and eukaryotic flagella are enclosed by the plasma membrane.

C. Bacterial flagella are powered by a proton motive force, while eukaryotic flagella use ATP.

Which of the following correctly describes a difference in cell wall composition between eukaryotes and bacteria?

• A. Plant cell walls are made of chitin, while bacterial cell walls are made of cellulose.

• B. Fungal cell walls contain chitin made of N-acetylmuramic acid, while bacterial cell walls contain glucan and mannan.

• C. Yeast cell walls contain glucan and mannan, while bacterial cell walls contain peptidoglycan made of N-acetylglucosamine and N-acetylmuramic acid.

• D. Both bacterial and fungal cell walls are composed of identical polysaccharides.

• E. Bacterial cell walls are simpler than eukaryotic cell walls and lack any peptide components

C. Yeast cell walls contain glucan and mannan, while bacterial cell walls contain peptidoglycan made of N-acetylglucosamine and N-acetylmuramic acid.

Which of the following transport mechanisms is found only in eukaryotic cells and not in Bacterial cells?

• A. Simple diffusion

• B. Facilitated diffusion

• C. Active transport

• D. Osmosis

• E. Endocytosis

E. Endocytosis

Which of the following statements correctly compares bacterial and eukaryotic ribosomes?

• A. Bacterial ribosomes are larger than eukaryotic ribosomes and contain more RNA.

• B. Eukaryotic ribosomes are 70S, while bacterial ribosomes are 80S.

• C. Bacterial ribosomes are found only in the nucleus, while eukaryotic ribosomes are found in the cytoplasm.

• D. Bacterial ribosomes are 70S and eukaryotic ribosomes are 80S, with differences in subunit composition and sensitivity to antibiotics.

• E. Both bacterial and eukaryotic ribosomes are identical in structure and function.

D. Bacterial ribosomes are 70S and eukaryotic ribosomes are 80S, with differences in subunit composition and sensitivity to antibiotics.

Which of the following statements correctly compares bacterial and eukaryotic genomes?

• A. Bacterial genomes are linear and located in the nucleus, while eukaryotic genomes are circular and found in the cytoplasm.

• B. Eukaryotic genomes are typically smaller and contain fewer genes than bacterial genomes.

• C. Bacterial genomes are usually a single circular DNA molecule, while eukaryotic genomes consist of multiple linear chromosomes housed in a nucleus.

• D. Both bacterial and eukaryotic genomes are organized into chromosomes with histone proteins.

• E. none of the above

C. Bacterial genomes are usually a single circular DNA molecule, while eukaryotic genomes consist of multiple linear chromosomes housed in a nucleus.

Which of the following best supports the endosymbiosis theory explaining the origin of mitochondria and chloroplasts in eukaryotic cells?

• A. Mitochondria and chloroplasts have double membranes, circular DNA, and 70S ribosomes, and can grow and divide independently within the cell.

• B. Tsetse flies host bacteria that have lost genes necessary for survival outside the host, showing a modern example of symbiotic dependency.

• C. Paramecium ingests algae that continue to perform photosynthesis inside the host, mimicking early organelle function.

• D. Mitochondria and chloroplasts are believed to have originated from free-living prokaryotes engulfed by ancestral eukaryotic cells.

• E. All of the answers are correct.

E. All of the answers are correct.

Which of the following correctly matches a group of protozoa with its method of locomotion?

• A. Amoebae - move using cilia

• B. Ciliates - move using pseudopodia

• C. Amoebae - move using flagella

• D. Flagellates - move using whiplike flagella

• E. Ciliates - pili

D. Flagellates - move using whiplike flagella

Which of the following statements about fungal infections (mycoses) is TRUE?

• A Mycoses are more common in individuals who are immunocompromised or on long-term antibiotics.

• B. Fungi grow rapidly and are easily treated with standard antibiotics.

• C. Fungal infections are typically acute and resolve quickly without treatment.

• D. All fungi infect only immunocompromised individuals and never healthy hosts.

• E. Fungal pathogens do not change form and remain in a single growth phase.

A. Mycoses are more common in individuals who are immunocompromised or on long-term antibiotics.

Which of the following statements correctly compares membrane characteristics between bacteria and eukarya?

• A. Both bacteria and eukarya have phospholipid bilayers, but only eukarya use ester linkages in their lipid structures.

• B. Bacterial membranes contain a high abundance of structural proteins, while eukaryotic membranes contain fewer.

• C. Sterols are present in bacterial membranes for stability, but absent in eukaryotic membranes.

• D. Eukaryotic membranes contain branched fatty acid chains with ether linkages, while bacterial membranes contain straight chains with ester linkages.

• E. Both bacteria and eukarya lack sterols and rely solely on proteins for membrane fluidity.

B. Bacterial membranes contain a high abundance of structural proteins, while eukaryotic membranes contain fewer.

Through which three processes can bacteria transfer genes and acquire antibiotic resistance?

A. Transformation, conjugation, transduction

B. Mutation, efflux pumps, biofilm formation

C. Transduction, sporulation, conjugation

D. Horizontal gene transfer, mutation, cell wall

E. Binary fission, mutation, conjugation

Vancomycin and B-lactam antibiotics are similar in what way?

• They both contain beta lactam ring structures

• They both prevent peptide side chain cross-linking in peptidoglycan O

• They both upregulate transpeptidase expression

• They both prevent NAM-NAG glycosdic bond formation in peptidoglycan

• They both cleave NAM-NAG glycosdic bonds in peptidoglycan

• They both prevent peptide side chain cross-linking in peptidoglycan O

Which of the following statements most accurately reflects current understanding of Archaea and their classification based on ribosomal RNA analysis?

A. Archaea possess unique rRNA sequences that place them in a distinct domain of life, as first demonstrated by Carl Woese using small subunit (SSU) rRNA phylogenetics.

B. The 16S rRNA gene is exclusive to Archaea and serves as a unique molecular marker distinguishing them from other domains.

C. The 80S ribosome, composed of 60S and 40S subunits, is a defining feature of Archaea, distinguishing them from both bacteria and eukaryotic cells.

D. The 70S ribosome, composed of 50S and 30S subunits, is characteristic of eukaryotic cells and was a key factor in differentiating Archaea from Bacteria. As first demonstrated by Carl Woese using small subunit (SSU) rRNA phylogenetics.

E. Due to high conservation of rRNA sequences, these genes are unsuitable for resolving evolutionary relationships among microbial domains.

A) Archaea possess unique rRNA sequences that place them in a distinct domain of life, as first demonstrated by Carl Woese using small subunit (SSU) rRNA phylogenetics.

Which of the following statements is true about archaeal flagella (archaella) compared to bacterial flagella?

A) Archaeal flagella are thicker than bacterial flagella.

B) Archaeal flagella are composed of a single type of flagellin protein.

C) Archaeal flagella likely grow from the base rather than the tip, similar to Type IV pili.

D) Archaeal flagella use proton motor force for energy instead of ATP.

E) Archaeal flagella are hollow structures like bacterial flagella.

C) Archaeal flagella likely grow from the base rather than the tip, similar to Type IV pili.

Which of the following statements is true regarding pseudomurein in archaeal cell walls?

A) Pseudomurein contains N-acetylmuramic acid (NAM) and B-1,4-glycosidic bonds.

B) Pseudomurein contains N-acetyltalosaminuronic acid (NAT) and ß-1,3-glycosidic bonds.

C) Pseudomurein is found in bacterial cell walls and contains D-amino acids.

D) Pseudomurein provides no physical or osmotic protection to the cell wall.

E) Pseudomurein is identical in structure to bacterial peptidoglycan.

B) Pseudomurein contains N-acetyltalosaminuronic acid (NAT) and ß-1,3-glycosidic bonds.

Which of the following statements is true regarding the plasma membranes of Bacteria, Archaea, and Eukarya?

A) All three domains have phospholipid bilayers with ester linkages.

B) Only Archaea can have a monolayer plasma membrane with ether linkages.

C) Eukarya have the highest abundance of structural proteins in their plasma membranes.

D) Bacteria contain sterols for membrane stability similar to Eukarya.

E) Archaea use straight-chain fatty acids linked by ester bonds in their membranes.

B) Only Archaea can have a monolayer plasma membrane with ether linkages.

Which of the following is true about the genetic material in Archaea?

A) Circular DNA with histone-like proteins

B) Circular DNA without histones

C) Linear DNA with histones

D) Linear DNA without histones

E) Circular and linear DNA with histones

A) Circular DNA with histone-like proteins

Rectangle or triangle shaped?

ARCHAEA

Vancomycin

Attacks peptidoglycan directly. Resistance is due to a replacement so vancomycin cant bond.

Beta lactams

Targets transpeptidase, beta lactamase inactivates the beta lactam ring

Who can secrete?

Gram negative becuase it has an outer membrane

Siderophores

Iron-binding molecules that are secreted when iron levels are low, uses ABC transport, involves ATP

S-layer

Most abundant in archaea, found above the cell envelope

Which kind of bacteria produce LPS?

Gram negative