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What is the primary function of antibiotics?
What is the primary function of antibiotics?
Bacteriostatic antibiotics can be used effectively in patients with poor immune systems.
Bacteriostatic antibiotics can be used effectively in patients with poor immune systems.
False
Name one type of bacteria that produces antibiotics.
Name one type of bacteria that produces antibiotics.
Streptomyces
Antibiotics produced by fungi such as Penicillium include __________.
Antibiotics produced by fungi such as Penicillium include __________.
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Match the types of antibiotics with their classification:
Match the types of antibiotics with their classification:
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Which of the following antibiotics is known to act as a bactericidal?
Which of the following antibiotics is known to act as a bactericidal?
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The five main mechanisms of antibacterial action include inhibition of metabolic processes.
The five main mechanisms of antibacterial action include inhibition of metabolic processes.
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What enzyme do penicillins and cephalosporins inhibit to affect bacterial cell wall synthesis?
What enzyme do penicillins and cephalosporins inhibit to affect bacterial cell wall synthesis?
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Which group of antibiotics is considered bactericidal?
Which group of antibiotics is considered bactericidal?
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Tetracyclines inhibit protein synthesis by disrupting codon-anticodon interactions.
Tetracyclines inhibit protein synthesis by disrupting codon-anticodon interactions.
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Name one example of an aminoglycoside antibiotic.
Name one example of an aminoglycoside antibiotic.
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Chloramphenicol is classified as a ____________ antibiotic.
Chloramphenicol is classified as a ____________ antibiotic.
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Match the following antibiotics with their mechanism of action:
Match the following antibiotics with their mechanism of action:
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Which antibiotic binds to the 50S ribosome and is considered narrow spectrum?
Which antibiotic binds to the 50S ribosome and is considered narrow spectrum?
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Macrolides bind irreversibly to the 50S ribosomal subunit.
Macrolides bind irreversibly to the 50S ribosomal subunit.
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What is one of the key actions of aminoglycosides during protein synthesis inhibition?
What is one of the key actions of aminoglycosides during protein synthesis inhibition?
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What is the primary target of Vancomycin in bacteria?
What is the primary target of Vancomycin in bacteria?
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Cycloserine is effective against gram-negative bacteria.
Cycloserine is effective against gram-negative bacteria.
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What class of antibiotics causes disruption in bacterial cell wall synthesis?
What class of antibiotics causes disruption in bacterial cell wall synthesis?
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Polymyxin B and colistin are primarily used as _____ antibiotics.
Polymyxin B and colistin are primarily used as _____ antibiotics.
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Which of the following antibiotics is known to be toxic to kidneys?
Which of the following antibiotics is known to be toxic to kidneys?
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Inhibitors of protein synthesis can lead to the death of bacterial organisms.
Inhibitors of protein synthesis can lead to the death of bacterial organisms.
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What are the two subunits of the bacterial ribosome that are targeted by protein synthesis inhibitors?
What are the two subunits of the bacterial ribosome that are targeted by protein synthesis inhibitors?
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Which of the following antibiotics inhibit protein synthesis at the 50S subunit?
Which of the following antibiotics inhibit protein synthesis at the 50S subunit?
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Nitrofurantoin disrupts codon-anticodon interactions at the 30S subunit of ribosomes.
Nitrofurantoin disrupts codon-anticodon interactions at the 30S subunit of ribosomes.
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What is the primary action of sulfonamides in bacteria?
What is the primary action of sulfonamides in bacteria?
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Rifampin disrupts ______________ synthesis by blocking RNA polymerase.
Rifampin disrupts ______________ synthesis by blocking RNA polymerase.
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Which of these is a common example of a fluoroquinolone?
Which of these is a common example of a fluoroquinolone?
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Match the antibiotic to its mechanism of action:
Match the antibiotic to its mechanism of action:
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Bactericidal effects of sulfonamides require the presence of trimethoprim.
Bactericidal effects of sulfonamides require the presence of trimethoprim.
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Broad-spectrum antimicrobial agents that include furazolidone and nitrofurazone are known as __________.
Broad-spectrum antimicrobial agents that include furazolidone and nitrofurazone are known as __________.
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Study Notes
Antibiotics
- Antibiotics are products produced by microorganisms or similar substances with a molecular weight between 250-5000 Dalton. They inhibit the growth of other microorganisms in low concentrations. Alternatively, they are chemical substances produced by diverse microorganisms, capable of inhibiting the growth of other microorganisms in small concentrations.
- Antimicrobial agents are chemicals that kill or inhibit the growth of microorganisms.
Production of Antibiotics
- The production of antibiotics has been widespread since the pioneering work of Florey and Chain in 1938.
- Actinomycetes and Streptomyces produce about 80% of antibiotics, including streptomycin, tetracycline, and erythromycin.
- Fungi like penicillin and cephalosporium produce ampicillin and cephalothin.
- Bacillus Polymyxa produces polypeptides like polymyxin and colistin.
Actions of Antibiotics
- Bactericidal: Kills bacteria, reducing the bacterial load.
- Bacteriostatic: Inhibits the growth and reproduction of bacteria.
- All antibiotics rely on the immune system to function properly. Bactericidal antibiotics are appropriate for individuals with compromised immunity. Bacteriostatic antibiotics require an intact immune system to effectively function.
Mechanisms of Antibacterial Action
- Antibiotics act through five key mechanisms:
- Inhibition of cell wall synthesis
- Inhibition of the cell membrane
- Inhibition of protein synthesis
- Interference with metabolic processes
- Inhibition of nucleic acid synthesis (DNA & RNA)
Inhibition of Cell Wall Synthesis
- Bacterial cell walls consist of a peptidoglycan layer, which is a polymer of acetylmuramic acid (NAM) and N-acetylglucosamine (NAG).
- Autolysine and transpeptidase (also known as penicillin-binding proteins or PBPs) are important enzymes involved in maintaining the cell wall.
- Penicillins and cephalosporins inhibit transpeptidase, causing bacterial cell death.
- Vancomycin stops peptidoglycan elongation, effective against several resistant infections of Staphylococcus aureus.
- Cycloserine inhibits the formation of basic peptidoglycan subunits.
- Bacitracin disrupts the bacterial cell wall, effective against gram-positive bacteria. Toxic to kidneys.
Inhibition of Cell Membrane
- Cell membranes are essential for regulating the flow of substances into and out of cells.
- Disruption of the cell membrane can lead to leakage of crucial molecules, ultimately leading to cell death.
- Examples of antibiotics targeting the cell membrane include polymyxin B and colistin. Used topically to target bacterial cell membranes.
Inhibition of Protein Synthesis
- Protein synthesis is crucial for bacterial survival. Inhibition of this process disrupts cellular metabolism and growth, leading to bacterial death or growth inhibition.
- Aminoglycosides (gentamicin, neomycin, amikacin, tobramycin, and streptomycin) target the 30S ribosomal subunit.
- Tetracyclines inhibit protein synthesis at the ribosome level by disrupting codon-anticodon interactions.
- Chloramphenicol, Clindamycin, and Macrolides (erythromycin, clarithromycin, azithromycin), act on 50S ribosomal subunit.
Interference with Metabolic Processes
- Sulfonamides inhibit the synthesis of folic acid, a necessary component for the growth of many bacteria
- Most are designed to stay in the GI tract, and some are absorbed systemically to penetrate tissues.
Inhibition of Nucleic Acid Synthesis
- Fluoroquinolones inhibit DNA gyrases. Fluoroquinolones (enrofloxacin, ciprofloxacin, orbifloxacin, difloxacin, marbofloxacin, and sarafloxacin) interfere with DNA supercoiling.
- Rifampin disrupts RNA synthesis.
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Description
This quiz explores the fundamentals of antibiotics, including their production, types, and mechanisms of action. Learn about the key contributors to antibiotic production and how these substances work to inhibit microbial growth. Test your knowledge on significant antibiotics and their classifications.
