Medical Bacteriology - Exam 2

THIS ISN'T OVER!!!

Which of the following will form a palindromic sequence?

Top Strand: 5’-GAATTC-3’
Bottom Strand: 3’-CTTAAG-5’

A transgenic animal has which of the following characteristics?

Allows targeting specific genes to study

In curve analysis the most accurate point is at the ______ region

50%

An ideal way to compare wild and mutant types is to use a __________

Performing a controlled laboratory experiment with identical conditions for both types

Which of the following statements best describes the difference between immortalized cells and tumor cells?

Immortalized cells are derived from normal cells that have acquired mutations to evade senescence, whereas tumor cells are derived from cancerous cells that proliferate uncontrollably

Lower min MOI's in a gentamycin protection assay suggests ______

High Invasion

Monoclonal antibodies and Fluorescent dyes can reveal changes in cell structures such as _______

Actin

A first virulence factor that reintroduces pathology is likely to satisfy Koch's postulate # _____

3

An avirulent strain which later produces the toxin and is now virulent will satisfy Koch's postulate # ___

4

True or False: Virulence genes can be identified by traditional marked transposon insertion mutagenesis

True

True or False: Microarrays are suitable for multiple gene expressions under different conditions

True 

Which of the following cytokines is primarily responsible for regulating inflammation in the body?

Tumor Necrosis Factor-alpha (TNF-α)

Which of the following is a primary application of bio-photonic imaging in the medical field?

Non-invasive diagnosis of skin cancers (any pathogenesis)

Which of the following is considered an early virulence factor in bacterial pathogenesis?

Adhesins

What is the primary purpose of transposon mutagenesis in genetic research?

To introduce targeted mutations into a genome

What is the primary function of the lacZ gene in the lac operon?

To encode an enzyme that breaks down lactose into glucose and galactose

Mutations at the Promoter will block initiation of which process?

Transcription

In molecular genetic approaches to the identification of bacterial virulence factors, removing genes one by one until the toxin disappears is an example of?

Reverse Genetics 

When a zone (in a Petri dish) of killed cells is caused by invading bacteria, the zone is called a _________

plaque

What is the primary purpose of the SCOTS (Selective Capture of Transcribed Sequences) technique in microbial genetics?

To selectively capture and analyze transcribed sequences during specific biological processes

What is the primary role of the Protospacer Adjacent Motif (PAM) in the CRISPR-Cas9 system?

To provide a recognition site for the Cas9 protein to bind and cleave the DNA

What is one of the primary mechanisms that contributes to the dynamic nature of bacterial genomes? For example, Penicillin resistance

Horizontal gene transfer

Which of the following correctly describes the stages of bacterial infection?

Colonization, Persistence, spread

Endospores are a survival mechanism often seen in which of these conditions?

Dryness

What role does mucin play in the interaction between bacteria and the host’s mucosal surfaces?

Mucin forms a protective barrier that traps and removes bacteria

What is the primary role of the antigen component of lipopolysaccharides (LPS) in Gram-negative bacteria?

The O-ag component serves as a major antigenic determinant,
promoting immune recognition

What is the primary function of siderophores produced by bacteria?

To chelate and transport iron into bacterial cells

Which of the following mechanisms do some bacteria use to limit the effect of the Membrane Attack Complex (MAC) during the host immune response?

Producing capsular polysaccharides composed of sialic acid

Which of the following mechanisms allows bacteriophages, plasmids, or toxins to reduce host defenses?

Plasmids encode antibiotic resistance genes that neutralize host
defenses

Which of the following is a characteristic property of bacterial exotoxins?

They are large secreted proteins that can cause damage to the host by disrupting cellular functions.

Cell signaling attacks are usually caused by this toxin "Type".

Type III

Which of the following mechanisms is involved in the development of endotoxic shock?

Activation of the complement system and Toll-like receptors (TLRs) by
lipopolysaccharides (LPS)

Toxic shock syndrome is associated with?

Superantigens

How do hemolysins contribute to the development of gangrene?

By disrupting lipid membranes of host cells, leading to cell lysis and tissue necrosis

What is a key difference between exotoxins and exoenzymes produced by bacteria?

Exotoxins are secreted proteins that disrupt host cellular functions, while exoenzymes are secreted enzymes that degrade host tissues and facilitate bacterial invasion

Botulism is linked to this genus.

Clostridium

How does botulinum toxin inhibit neurotransmission at the neuromuscular junction?

By cleaving SNARE proteins, preventing the release of acetylcholine