Antibiotics, bacteria anatomy and antibiotic reistance

Exponential growth

Source of energy: chemical sources for chemotrophs and light for phototrophs

No net change, with the number of living cells equal to the number of dead cells

<p>To monitor the growing population of bacteria</p> Signup and view all the answers

<p>Chemostatic bacterial growth</p> Signup and view all the answers

<p>Heterotrophs</p> Signup and view all the answers

<p>pH has an ideal range for optimum activity</p> Signup and view all the answers

<p>Death phase</p> Signup and view all the answers

<p>The slime layer provides protection and allows attachment to surfaces, and it also masks markers on the cell wall that trigger an immune response.</p> Signup and view all the answers

<p>Peptidoglycan is a complex, semi-rigid structure composed of a carbohydrate backbone with peptide cross-bridges and tetrapeptide side chains, and it prevents osmotic rupture.</p> Signup and view all the answers

<p>Gram-negative bacteria have a thin layer of peptidoglycan and an outer membrane made up of lipopolysaccharide, giving them a rough appearance under the microscope, whereas Gram-positive bacteria have a thick layer of peptidoglycan and a smoother appearance.</p> Signup and view all the answers

<p>The cytoplasmic membrane acts as a permeability barrier, allowing certain molecules to pass through while keeping others out, and is also the site of many proteins involved in transport, communication, and energy conservation.</p> Signup and view all the answers

<p>Flagella are important for motility and come in different arrangements, including monotrichous, lophotrichous, amphitrichous, and peritrichous, and are composed of multiple rings, including the L ring, P ring, M ring, and C ring.</p> Signup and view all the answers

<p>Gram-negative bacteria have an L ring, P ring, M ring, and C ring, whereas Gram-positive bacteria lack the L ring but have a larger P ring.</p> Signup and view all the answers

<p>The outer membrane is composed of lipopolysaccharide and provides an additional layer of protection and structure to the cell.</p> Signup and view all the answers

<p>Electrochemical gradient between inside and outside of the cytoplasm</p> Signup and view all the answers

<p>Run</p> Signup and view all the answers

<p>To detect nutrients that are beneficial to them</p> Signup and view all the answers

<p>To allow adherence</p> Signup and view all the answers

<p>Prokaryotic ribosomes are 70S, while eukaryotic ribosomes are 80S</p> Signup and view all the answers

<p>Highly soluble in blood, allowing rapid transmission</p> Signup and view all the answers

<p>To store reserve materials such as glycogen, carbohydrates, and lipids</p> Signup and view all the answers

<p>Transformation</p> Signup and view all the answers

<p>Transpeptidase</p> Signup and view all the answers

<p>Ability of bacteria to survive treatment by certain antibiotics</p> Signup and view all the answers

<p>To provide a qualitative assessment of antibiotic effectiveness</p> Signup and view all the answers

<p>To determine the lowest concentration of antibiotic required to inhibit bacterial growth</p> Signup and view all the answers

<p>A cross-bridge between D-Alanine molecules</p> Signup and view all the answers

<p>Bactericidal antibiotics kill bacteria, whereas bacteriostatic antibiotics prevent bacterial cell division. Bactericidal antibiotics target and kill bacterial cells, while bacteriostatic antibiotics prevent bacteria from multiplying, giving the host's immune system a chance to fight the infection.</p> Signup and view all the answers

<p>β-Lactam antibiotics, like penicillin, target the peptidoglycan cell wall of bacteria, weakening it and ultimately leading to the death of the bacterial cell. The ring structure of β-Lactam antibiotics is crucial for their antibacterial activity.</p> Signup and view all the answers

<p>Natural antibiotics are produced naturally by fungi or bacteria, semi-synthetic antibiotics are chemically modified natural antibiotics, and totally synthetic antibiotics are manufactured. Each type is classified based on its origin and method of production.</p> Signup and view all the answers

<p>Broad-spectrum antibiotics target a wide range of bacteria, whereas narrow-spectrum antibiotics target specific types or groups of bacteria. Broad-spectrum antibiotics are often used empirically, while narrow-spectrum antibiotics are used for specific infections.</p> Signup and view all the answers

<p>The peptidoglycan cell wall provides structural integrity to bacterial cells. Antibiotics, such as β-Lactam antibiotics, target the peptidoglycan cell wall, weakening it and ultimately leading to bacterial lysis.</p> Signup and view all the answers

<p>In agriculture, antibiotics are used to promote livestock growth and prevent disease. The use of antibiotics in agriculture differs from their medical application, as they are often used prophylactically and at subtherapeutic levels.</p> Signup and view all the answers

<p>To allow for the growth of the organism</p> Signup and view all the answers

<p>Alpha haemolytic: reduction of red blood cells' haemoglobin to methaemoglobin; Beta haemolytic: complete lysis of red blood cells; Gamma haemolytic: lack of haemolysis</p> Signup and view all the answers

<p>Selective agents encourage the growth of desired organisms by making them resistant to the agent, while inhibiting the growth of other organisms</p> Signup and view all the answers

<p>XLD agar is a selective and differential media used to isolate suspected salmonella, appearing black due to the presence of sodium thiosulfate, which prevents the growth of gram-positive bacteria</p> Signup and view all the answers

<p>MacConkey agar is used to isolate gram-negative bacteria and differentiate between lactose fermenting and non-fermenting bacteria, while Mannitol salt agar is used to differentiate between bacteria that can ferment mannitol and those that cannot</p> Signup and view all the answers

<p>Chromogenic media are used to distinguish between specific organisms by producing colourful reactions, making it easier to identify and differentiate between bacteria</p> Signup and view all the answers

<p>Bacteria produce β-lactamases, enzymes that hydrolyse the β-lactam ring, preventing the antibiotic from inhibiting peptidoglycan synthesis.</p> Signup and view all the answers

<p>Clavulanic acid is a suicide inhibitor that binds to β-lactamase, forming a covalent bond and inhibiting its activity.</p> Signup and view all the answers

<p>Bacteria can temporarily change their metabolism to resist antibiotics.</p> Signup and view all the answers

<p>Efflux pumps export antibiotics out of the bacterial cell, reducing their effectiveness.</p> Signup and view all the answers

<p>Bacteria can alter the target site of antibiotic action, reducing antibiotic binding and efficacy.</p> Signup and view all the answers

<p>ESBLs are enzymes that hydrolyse a wide range of β-lactam antibiotics, rendering them ineffective.</p> Signup and view all the answers

<p>Quinolones interfere with changes in DNA supercoiling by binding to DNA gyrase, which is important for controlled unwinding of DNA during replication. This prevents the controlled unwinding of supercoiled DNA, leading to cell death and breaks in the double strand.</p> Signup and view all the answers

<p>Macrolides reversibly bind to the P site on the 50S subunit, disrupting protein synthesis and leading to cell death.</p> Signup and view all the answers

<p>Aminoglycosides bind to the aminoacyl site of 16S rRNA in the 30S subunit of the ribosome, causing mis-incorporation of amino acids into elongating peptides, which leads to cell death.</p> Signup and view all the answers

<p>The Quinoline backbone is a structural feature of Quinolones that allows them to bind to DNA gyrase and inhibit DNA supercoiling.</p> Signup and view all the answers

<p>β-Lactam antibiotics irreversibly bind to transpeptidase (PBP), preventing the formation of cross-bridges in the bacterial cell wall and ultimately leading to cell death.</p> Signup and view all the answers

<p>The lactone ring is a structural feature of Macrolides that allows them to bind to the P site on the 50S subunit and inhibit protein synthesis.</p> Signup and view all the answers

<p>Tetracyclines have a unique structure with four rings, and they inhibit protein synthesis by binding to the 30S subunit of the ribosome.</p> Signup and view all the answers

<p>The amino acid bonded by glycosidic bond is a structural feature of Aminoglycosides that allows them to bind to the 16S rRNA in the 30S subunit of the ribosome.</p> Signup and view all the answers

<p>it is a differential media used to differentiate on ability to ferment sugars and produce hydrogen sulphide produces black precipitate</p> Signup and view all the answers

<p>it is a chromogenic agar used to detect coliform in water and food samples. appears pink on agar,</p> Signup and view all the answers