Bacterial Peptidoglycan & Gram Stains

Which component of the gram-negative bacterial cell wall is responsible for the endotoxic activity in humans?

Mycoplasma are classified as gram-positive because they lack a cell wall.

What is the primary structural difference that allows Mycoplasma to defy Gram staining classification?

The release of membrane fragments containing __________ into the circulation can lead to endotoxic shock after bacterial lysis.

Match the following reactive oxygen species with their potential sources or consequences in bacterial cells:

Why are some antibiotics, like penicillin, ineffective against Gram-negative bacteria?

The periplasmic space in Gram-negative bacteria is located between the cell's cytoplasmic membrane and the thick peptidoglycan layer.

What is the primary function of spores produced by certain Gram-positive bacteria?

Gram-negative bacteria maintain a negative surface charge, which is important for cellular processes, through _______.

Match the following bacteria with their typical arrangement:

How does the variation in the O-specific side chain of Lipopolysaccharide (LPS) contribute to bacterial pathogenicity?

Which characteristic differentiates Corynebacterium and Listeria from Bacillus and Clostridium?

What is the clinical significance of the structural differences in the O-specific side chain (O-antigen) of LPS among Gram-negative bacteria?

Why might infections caused by Treponema pallidum be difficult to diagnose using traditional Gram staining techniques?

Considering the function of LPS, what would be the most likely consequence of a mutation that significantly reduces the length of the O-specific side chain in a Gram-negative bacterium?

How does the unique cell wall structure of Mycobacteria contribute to their acid-fast staining property?

Which of the following explains why Mycobacteria are only weakly Gram-positive?

How does the diplococci arrangement of Neisseria species contribute to their virulence or pathogenesis?

Considering the metabolic limitations of intracellular bacteria, which strategy would least likely support their survival within a host cell?

Given that certain bacteria rely on fermentation due to their intracellular lifestyle, what is the most likely evolutionary pressure that led to this metabolic adaptation?

If a bacterium is found to produce a variety of mixed acids as fermentation end-products, what is the most reasonable conclusion regarding its metabolic capabilities and potential ecological impact?

How does the unique ATP acquisition strategy of energy-parasitic bacteria most directly impact their host cells?

Which characteristic would be least expected in a bacterium classified as an energy parasite?

In chemoheterotrophic bacteria, what is the primary role of the Krebs cycle?

How do obligate intracellular bacteria, such as Chlamydia and Rickettsia, obtain ATP?

Which metabolic strategy would a bacterium most likely employ if it thrives in an anaerobic environment and uses organic compounds as both a carbon and energy source?

During glycolysis via the Embden-Meyerhof pathway, what is the net ATP production resulting from the direct breakdown of glucose to pyruvic acid?

How does the metabolism of medically important bacteria differ fundamentally from that of chemoautotrophic bacteria?

What is the limiting factor that classifies Chlamydia and Rickettsia as obligate intracellular organisms regarding ATP production?

Which of the following is a key distinction between respiration and fermentation in bacteria?

How does the Embden-Meyerhof pathway contribute to ATP production in bacterial cells?

Why are microaerophilic bacteria able to tolerate low amounts of oxygen despite not possessing catalase?

How do periplasmic flagella contribute to the unique motility of spirochetes?

How does the metabolic flexibility of facultative anaerobes enhance their survival in changing environments?

Why is it crucial to use an anaerobic growth media when culturing blood samples for potential obligate anaerobes?

What metabolic adaptation enables facultative anaerobes to thrive in both aerobic and anaerobic conditions?

How does the lack of catalase impact the survival and growth of microaerophilic bacteria?

Which of the following factors would be MOST detrimental to the survival of an obligate anaerobe?

Compared to obligate aerobes and facultative anaerobes, how does the ATP production of obligate anaerobes growing via fermentation typically differ?

How does the unique periplasmic flagella arrangement benefit spirochetes in their infectious cycle?

If a new antibiotic is designed to inhibit bacterial protein synthesis by targeting a specific ribosomal subunit essential for translation initiation, which subunit would provide a broader spectrum of activity against both Gram-positive and Gram-negative bacteria?

Which of the following enzymatic reactions is crucial for detoxifying superoxide radicals ($O_2^−$) within bacterial cells, thus preventing oxidative damage?

How would you classify a bacterial species that thrives equally well in both the presence and absence of oxygen, without deriving any additional benefit from its presence?

Which characteristic of spirochetes is most directly related to their ability to cause persistent infections, such as Lyme disease or syphilis?

A bacterial pathogen has evolved a novel mechanism to suppress the host's oxidative burst during phagocytosis. Which enzyme would be the most strategic target for this pathogen to inhibit in order to enhance its survival?

Which of the following explains why visualizing spirochetes requires dark-field microscopy rather than standard bright-field microscopy?

Considering the mechanisms of action of erythromycin and tetracycline, which statement best describes a potential strategy for overcoming bacterial resistance that targets both Gram-positive and Gram-negative bacteria?

Which molecular modification to Lipid A would MOST likely reduce the risk of endotoxic shock in a human infected with a Gram-negative bacterium?

Why do Mycoplasma's lack of a cell wall make them resistant to certain classes of antibiotics.

How does the release of Lipid A during bacterial lysis initiate a systemic inflammatory response in humans?

A researcher is investigating a new Gram-negative bacterium. They discover that its Lipid A has a modified structure that reduces its ability to stimulate an immune response. Which modification would MOST likely explain this?

If a bacterium lacked the enzymes to break down reactive oxygen species, what would be the MOST likely consequence?

A bacterium is genetically engineered to produce an altered form of Lipid A with increased hydrophobicity. What is the MOST likely consequence of this modification?

Why do Mycoplasma species often require sterols in their growth medium?

Why are bacteria with mutations that impair the production or regulation of enzymes to detoxify reactive oxygen species (ROS) often less virulent?

Periplasmic Space

Charge regulation

Cell division

Antigenicity

Gram-negative Bacteria

Core Polysaccharide

Lipid A

Endotoxic (Septic) Shock

Mycoplasma

Reactive Oxygen Species (ROS)

Bacillus & Clostridium

Corynebacterium & Listeria

Neisseria

Spirochetes

Main Spirochete

O-Specific Side Chain (O-Antigen)

Acid-Fast Stain

Mycobacteria

Septic Shock

Reactive Oxygen species

Oxygen Detoxifying Enzymes

Endotoxic Shock Symptoms

Endotoxic Shock

Erythromycin target

Tetracycline target

Catalase function

Peroxidase function

Superoxide dismutase function

Spirochete cell wall

Spirochete motility

Axial flagella location

Energy Parasites

Fermentation End-Products

ATP Transport System

ATP Source for Energy Parasites

Energy parasites dependance on their host

Phototrophs

Chemotrophs

Respiration

Autotrophs

Heterotrophs

Chemoheterotrophs

Fermentation

Embden-Meyerhof Pathway

Microaerophilic Bacteria

Superoxide Dismutase

Facultative Anaerobes

Catalase

Obligate Anaerobes

Periplasmic Flagella