Chemistry in Everyday life - Inhibition of cell wall synthesis

Slide 2

• Cell wall plays a crucial role in the structural integrity of bacterial cells
• Inhibition of cell wall synthesis is a key target for antibiotics
• Certain antibiotics can disrupt the process of cell wall synthesis in bacteria
• This disruption leads to the death or inhibition of bacterial growth

Slide 3

• Beta-lactam antibiotics are a class of antibiotics that inhibit cell wall synthesis
• They have a beta-lactam ring in their molecular structure
• Examples of beta-lactam antibiotics include Penicillin and Cephalosporins
• These antibiotics bind to and inhibit enzymes involved in the cross-linking of peptidoglycan, a major component of bacterial cell walls

Slide 4

• Penicillin was the first beta-lactam antibiotic discovered
• It was originally derived from the fungus Penicillium
• Penicillin acts by inhibiting the enzyme called transpeptidase that is involved in cross-linking of peptidoglycan in bacterial cell walls
• Without proper cross-linking, the bacterial cell wall becomes weak and the cell eventually bursts

Slide 5

• Cephalosporins are another class of beta-lactam antibiotics
• They have a similar mechanism of action to penicillin
• Cephalosporins are considered broad-spectrum antibiotics and are used to treat a wide range of bacterial infections
• They are often used as an alternative to penicillin in individuals who are allergic to penicillin

Slide 6

• Inhibition of cell wall synthesis by antibiotics can have various beneficial effects
• It can prevent the growth and spread of bacterial infections
• Antibiotics that target cell wall synthesis are often used to treat bacterial pneumonia, skin infections, and urinary tract infections
• However, it’s important to use antibiotics judiciously to avoid antibiotic resistance and other adverse effects

Slide 7

• Antibiotic resistance is a major concern in the field of medicine
• Overuse and misuse of antibiotics can lead to the development of resistant bacteria
• Bacteria can acquire resistance to antibiotics through various mechanisms such as mutation or horizontal gene transfer
• Antibiotic resistance poses a significant challenge in the treatment of bacterial infections

Slide 8

• To combat antibiotic resistance, it is important to use antibiotics only when necessary
• Antibiotics should be prescribed by healthcare professionals based on proper diagnosis and susceptibility testing
• Patients should follow the prescribed dosage and duration of antibiotic treatment
• Education regarding proper antibiotic use and awareness about antibiotic resistance is vital in reducing its impact

Slide 9

• Along with the benefit of inhibiting bacterial growth, antibiotics can also have side effects
• Common side effects include diarrhea, nausea, and allergic reactions
• It is important to consult a healthcare professional if any side effects occur
• Some individuals may be allergic to certain antibiotics and may experience severe allergic reactions

Slide 10

• In conclusion, the inhibition of cell wall synthesis is a crucial target for antibiotics
• Beta-lactam antibiotics like penicillin and cephalosporins inhibit enzymes involved in cell wall cross-linking
• Proper use of antibiotics and awareness about antibiotic resistance are essential in preserving their effectiveness
• Further research and development of new antibiotics are necessary to combat antibiotic resistance and improve treatment options.

Factors Affecting Reaction Rates

• Concentration of reactants
• Temperature
• Presence of catalysts
• Surface area

Concentration of Reactants

• Higher concentration of reactants leads to more frequent collisions between particles
• Increased collisions result in higher reaction rates
• Rate of reaction is directly proportional to the concentration of reactants
• Example: In the reaction A + B -> C, increasing the concentration of A and B increases the rate of formation of C

Temperature

• Higher temperature increases the kinetic energy of particles
• Increased kinetic energy allows particles to move faster and collide with more energy
• Greater energy of collisions leads to more effective collisions and faster reaction rates
• Rate of reaction generally doubles for every 10-degree Celsius increase in temperature
• Example: The reaction between hydrogen and oxygen to form water proceeds faster at higher temperatures

Presence of Catalysts

• Catalysts are substances that speed up reactions without being consumed in the process
• Catalysts lower the activation energy required for a reaction to occur
• They provide an alternative reaction pathway, allowing the reaction to proceed at a faster rate
• Catalysts remain unchanged after the reaction
• Example: Enzymes in biological systems act as catalysts, facilitating essential biochemical reactions

Surface Area

• Increasing the surface area of solid reactants exposes more particles to the reactants
• More exposed particles allow for more frequent collisions
• Increased collisions enhance the reaction rate
• Pulverizing solids, using powdered reactants, or increasing the surface area of a catalyst can enhance reaction rates
• Example: Burning a large piece of paper takes longer than burning shredded paper due to the difference in surface area

Rate Expression and Rate Constant

• The rate of a chemical reaction is expressed by the rate law or rate equation
• The rate law shows the relationship between the rate of reaction and the concentration of reactants
• The rate constant (k) is specific to a particular reaction and temperature
• Rate = k[A]^m[B]^n, where m and n represent the reaction orders with respect to reactants A and B

Zero Order Reaction

• The rate of a zero-order reaction is independent of the concentration of reactants
• Rate = k[A]^0[B]^0 = k
• The rate constant (k) remains constant throughout the reaction
• Example: The decomposition of hydrogen peroxide with the presence of a catalyst follows the zero-order reaction kinetics

First Order Reaction

• The rate of a first-order reaction is directly proportional to the concentration of a single reactant
• Rate = k[A]^1 or Rate = k[B]^1
• The reaction order is 1
• The rate constant (k) is specific to the reaction and temperature
• Example: Radioactive decay follows first-order kinetics

Second Order Reaction

• The rate of a second-order reaction is directly proportional to either the square of the concentration of a single reactant or the product of the concentrations of two reactants
• Rate = k[A]^2 or Rate = k[A][B]
• The reaction order can be 2 or 1+1
• The rate constant (k) is specific to the reaction and temperature
• Example: The reaction between iodine and bromine in the presence of a catalyst follows second-order kinetics

Reaction Rate and Collision Theory

• The collision theory explains how chemical reactions occur and the factors that influence reaction rates
• According to the collision theory, for a reaction to occur, particles must collide with sufficient energy (activation energy) and in proper orientation
• Increasing the concentration, temperature, or surface area of reactants increases the frequency of collisions, enhancing reaction rates
• Catalysts provide an alternate pathway with lower activation energy, facilitating more successful collisions.

Applications of Inhibition of Cell Wall Synthesis

• Treatment of bacterial infections
• Prevention of bacterial growth and spread
• Use in combination therapy for more effective treatment
• Targeting specific bacterial strains or infections
• Development of new antibiotics with increased efficacy and reduced resistance

Limitations of Inhibition of Cell Wall Synthesis

• Ineffectiveness against certain types of bacteria
• Potential side effects and allergies
• Development of antibiotic resistance
• Interference with the natural balance of microbial communities
• Overuse and misuse leading to reduced efficacy

Antibiotic Resistance and Mechanisms

• Inherent resistance due to differences in cell wall composition among different bacteria
• Acquisition of resistance genes through horizontal gene transfer
• Mutation in target enzymes or receptors
• Increased efflux of antibiotics from bacterial cells
• Production of antibiotic-degrading enzymes

Prevention of Antibiotic Resistance

• Rational use of antibiotics
• Compliance with prescribed dosage and treatment duration
• Avoidance of unnecessary antibiotic use
• Proper hygiene practices to prevent infection
• Development of new antibiotics and alternative treatments

Introduction to Electrochemistry

• Electrochemistry is the study of the interaction between electricity and chemical reactions
• It involves the transfer of electrons (redox reactions) between reactants
• Oxidation occurs at the anode (electron loss) and reduction occurs at the cathode (electron gain)
• The driving force of these reactions is the electrical potential difference or voltage between the electrodes

Electrochemical Cells

• Electrochemical cells consist of two half-cells connected by a conducting material
• A half-cell contains an electrode immersed in an electrolyte solution
• The half-cell with the oxidation reaction is the anode, and the one with the reduction reaction is the cathode
• Electrons flow from the anode to the cathode through an external circuit, generating an electric current

Types of Electrochemical Cells

1. Galvanic (voltaic) cells:
   • Spontaneous redox reactions
   • Produce electrical energy
   • Anode is negatively charged and cathode is positively charged

2. Electrolytic cells:
   • Non-spontaneous redox reactions
   • Require an external power source (battery) to drive the reaction
   • Anode is positively charged and cathode is negatively charged

3. Concentration cells:
   • Involve the same species in different concentrations as the redox couple
   • Difference in concentration drives the reaction

Standard Reduction Potentials

• The tendency of a substance to gain or lose electrons during a reduction-oxidation (redox) reaction is represented by its standard reduction potential (E°)
• Standard reduction potentials are measured with respect to the standard hydrogen electrode (SHE)
• More positive E° value indicates a stronger tendency to gain electrons (better oxidizing agent), while more negative E° value indicates a stronger tendency to lose electrons

Nernst Equation

• The Nernst equation relates the cell potential (Ecell) to the concentrations of reactants and products

• Nernst equation for a galvanic cell: Ecell = E°cell - (0.0592 V/n) log(Q)

  where E°cell is the standard cell potential, n is the number of electrons transferred in the balanced redox reaction, Q is the reaction quotient (concentrations of species involved)

• The Nernst equation helps determine the cell potential under non-standard conditions

Industrial Applications of Electrochemistry

• Electroplating for coating objects with a layer of metal
• Electrorefining for purifying metals
• Production of chemicals like chlorine and sodium hydroxide using electrolytic cells
• Batteries and fuel cells for portable power supply
• Corrosion prevention through cathodic protection