Composition and Powers of the Public Accounts Committee

The Public Accounts Committee (PAC) comprises 22 members: 15 from Lok Sabha and 7 from Rajya Sabha. Its primary power is to audit government expenditure and ensure financial accountability. Recent examples include scrutinizing the COVID-19 relief funds and evaluating PM CARES Fund expenditures for transparency.

Understanding ‘Panchsheel’

Panchsheel refers to the Five Principles of Peaceful Coexistence, established in 1954 between India and China. These principles include mutual respect for sovereignty, non-aggression, non-interference, equality, and peaceful coexistence. Recent applications include efforts to resolve conflicts in South Asia and promote regional cooperation through forums like SAARC.

Most of the Bacterial Cell Walls Are Made Up of Which Substance?

Introduction

The cell wall is a critical component of bacterial cells, providing structural support, protection, and shape. The composition of bacterial cell walls varies between different types of bacteria, influencing their classification and response to various treatments. Understanding the primary substance in bacterial cell walls is essential for comprehending bacterial physiology and developing targeted antibiotics.

Primary Substance in Bacterial Cell Walls

1. Peptidoglycan

• Description: Most bacterial cell walls are primarily composed of peptidoglycan (also known as murein). Peptidoglycan is a complex polymer made up of glycan chains cross-linked by short peptide chains. It provides rigidity and strength to the bacterial cell wall, helping it maintain its shape and resist osmotic pressure.
• Structure: Peptidoglycan consists of alternating units of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), which are cross-linked by peptide bridges. This mesh-like structure is crucial for the mechanical stability of bacterial cells.

Recent Examples

a. Gram-Positive Bacteria

• Example: Staphylococcus aureus
  • Description: Staphylococcus aureus, a common Gram-positive bacterium, has a thick peptidoglycan layer in its cell wall. This thick layer retains the crystal violet stain used in Gram staining, which classifies it as Gram-positive.
  • Recent Relevance: Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), is a significant cause of hospital-acquired infections. The thick peptidoglycan layer contributes to its resistance to certain antibiotics and affects treatment strategies.

b. Gram-Negative Bacteria

• Example: Escherichia coli (E. coli)
  • Description: Escherichia coli, a Gram-negative bacterium, has a thinner peptidoglycan layer compared to Gram-positive bacteria. In addition to the peptidoglycan layer, it has an outer membrane containing lipopolysaccharides (LPS), which contributes to its structural integrity and contributes to its endotoxin properties.
  • Recent Relevance: E. coli is a major cause of urinary tract infections and foodborne illnesses. The presence of peptidoglycan, though thinner, is still crucial for its survival and interaction with antibiotics.

Significance in Medical and Biotechnological Fields

1. Antibiotic Target

• Penicillin and Related Antibiotics: Peptidoglycan is the target of several antibiotics, including penicillin, which inhibits the synthesis of peptidoglycan by blocking the enzyme responsible for cross-linking the glycan chains. This action is effective against many Gram-positive bacteria and some Gram-negative bacteria.
• Recent Developments: The rise of antibiotic-resistant strains, such as MRSA, highlights the ongoing need for new antibiotics and alternative therapies targeting peptidoglycan synthesis or bypassing traditional mechanisms of resistance.

2. Vaccine Development

• Vaccine Targets: Components of peptidoglycan can be used in vaccine development to stimulate an immune response. For example, vaccines against some bacterial pathogens use polysaccharide components from the peptidoglycan layer to induce immunity.
• Recent Advancements: Advances in vaccine technology, including conjugate vaccines that combine polysaccharide components with proteins to enhance immunogenicity, reflect the importance of peptidoglycan in vaccine design.

Conclusion

Most bacterial cell walls are primarily made up of peptidoglycan, a vital substance that provides structural support and rigidity. The composition of peptidoglycan varies between Gram-positive and Gram-negative bacteria, influencing their characteristics and susceptibility to antibiotics. Recent examples, such as Staphylococcus aureus and Escherichia coli, illustrate the significance of peptidoglycan in bacterial physiology and its implications for medical treatments and vaccine development. Understanding the role of peptidoglycan continues to be essential for addressing bacterial infections and developing effective therapeutic strategies.

अधिकांश जीवाणु कोशिका भित्तियाँ किस पदार्थ की होती हैं?

जीवाणु कोशिका भित्तियाँ मुख्य रूप से पेप्टिडोग्लाइкан (या म्यूरिन) से बनी होती हैं।

पेप्टिडोग्लाइкан एक संरचनात्मक पोलिसैकेराइड है जिसमें निम्नलिखित तत्व शामिल हैं:

• ग्लाइकोपेप्टाइड चेन: ये लंबे पॉलीसैकेराइड अनुक्रम होते हैं जो जीवाणु कोशिका भित्तियों की संरचना प्रदान करते हैं। इनमें N-acetylglucosamine (NAG) और N-acetylmuramic acid (NAM) जैसे शर्करा युक्त यौगिक होते हैं।
• पेप्टाइड क्रॉस-लिंक्स: ये पेप्टाइड बंधनों के रूप में होते हैं जो ग्लाइकोपेप्टाइड चेन को आपस में जोड़ते हैं, जिससे एक मजबूत और कठोर संरचना बनती है।

महत्वपूर्ण बिंदु:

• ग्राम-पॉज़िटिव बैक्टीरिया: इनकी कोशिका भित्तियों में पेप्टिडोग्लाइкан की परत बहुत मोटी होती है, जो कोशिका को एक कठोरता और संरचनात्मक समर्थन प्रदान करती है।
• ग्राम-निगेटिव बैक्टीरिया: इनकी कोशिका भित्तियों में पेप्टिडोग्लाइкан की परत अपेक्षाकृत पतली होती है, और इसके बाहर एक बाहरी झिल्ली होती है जिसमें लिपोपॉलिसैकेराइड्स (LPS) होते हैं।

निष्कर्ष:

जीवाणु कोशिका भित्तियाँ मुख्यतः पेप्टिडोग्लाइкан से बनी होती हैं, जो उनकी संरचना और स्थिरता के लिए जिम्मेदार है।

Examples of Chemical Change

Chemical changes involve the transformation of substances into new substances with different chemical properties. These changes are often accompanied by observable indicators such as color change, temperature change, gas production, or the formation of a precipitate. Here are several examples of chemical changes, including recent instances:

1. Combustion of Fossil Fuels

Example: Forest Fires in Canada (2023)

• Description: Combustion of fossil fuels and biomass, such as wood, results in chemical changes where hydrocarbons react with oxygen to produce carbon dioxide, water, and energy. The recent forest fires in Canada during the summer of 2023 are a vivid example. These fires led to the combustion of vast amounts of wood, altering the chemical composition of the material and contributing to significant atmospheric pollution.
• Significance: This process releases greenhouse gases and other pollutants, which impact air quality and contribute to climate change.

2. Rusting of Iron

Example: Rusting of Steel Infrastructure

• Description: Rusting is an oxidation-reduction reaction where iron reacts with oxygen and moisture to form iron oxide (rust). An example is the rusting of steel bridges or outdoor structures over time due to exposure to rain and air.
• Significance: The rusting process deteriorates the material, leading to structural weaknesses and increased maintenance costs.

3. Photosynthesis

Example: Agricultural Crops

• Description: Photosynthesis is a fundamental chemical process where plants convert carbon dioxide and water into glucose and oxygen using sunlight. Recent advances in agriculture, such as the development of genetically modified crops, have enhanced photosynthetic efficiency to improve crop yields.
• Significance: This chemical change is crucial for plant growth and sustains the oxygen levels in the atmosphere.

4. Neutralization Reactions

Example: Acid-Base Reactions in Water Treatment

• Description: Neutralization is a chemical reaction between an acid and a base to form water and a salt. An example is the treatment of acidic industrial wastewater with a base like sodium hydroxide to neutralize the acidity.
• Significance: This process is essential for treating wastewater and reducing environmental pollution.

5. Formation of Carbon Dioxide in Fermentation

Example: Alcohol Production

• Description: Fermentation is a chemical change where yeast converts sugars into ethanol and carbon dioxide. Recent advancements in biofuel production have utilized fermentation to produce ethanol from various feedstocks.
• Significance: This process is significant for producing alcoholic beverages and biofuels, contributing to energy resources and the beverage industry.

6. Decomposition of Hydrogen Peroxide

Example: Use of Hydrogen Peroxide in Wound Cleaning

• Description: Hydrogen peroxide decomposes into water and oxygen gas in the presence of catalysts like manganese dioxide. This reaction is used in medical settings to clean wounds.
• Significance: The decomposition of hydrogen peroxide helps in disinfecting wounds by releasing oxygen that aids in removing debris and bacteria.

7. Chemical Reaction in Battery Operation

Example: Rechargeable Batteries

• Description: Rechargeable batteries operate through chemical reactions where reactants in the battery undergo oxidation and reduction reactions. For instance, lithium-ion batteries used in electronic devices involve chemical changes during charging and discharging cycles.
• Significance: These reactions are fundamental to the functionality of modern electronic devices and renewable energy storage solutions.

8. Baking Bread

Example: Bread Making Process

• Description: Baking bread involves a chemical change where yeast ferments sugars in the dough to produce carbon dioxide and ethanol. The carbon dioxide causes the dough to rise, while heat further transforms the dough into bread.
• Significance: This chemical change is essential in baking, affecting the texture and flavor of the bread.

Conclusion

Chemical changes are pervasive in everyday life and industrial processes, impacting everything from environmental conditions to food production and technology. Recent examples such as forest fires, advancements in agriculture, and innovations in battery technology illustrate the importance and scope of chemical transformations in modern society. Understanding these changes helps in harnessing their benefits and mitigating potential risks.