Types of Antibiotics:

1. Penicillin G:
Penicillin G is a narrow spectrum antibiotic that is effective against Gram-positive bacteria such as Streptococcus and Staphylococcus species. It works by inhibiting the formation of bacterial cell walls, leading to bacterial cell death. Penicillin G is commonly used to treat infections caused by these specific types of bacteria.

2. Ampicillin:
Ampicillin is a broad spectrum antibiotic that is effective against a wide range of bacteria, both Gram-positive and Gram-negative. It is a derivative of Penicillin G and has an extended spectrum of activity. Ampicillin is commonly used to treat various types of infections, including urinary tract infections, respiratory infections, and gastrointestinal infections.

3. Amoxicillin:
Amoxicillin is also a broad spectrum antibiotic that is similar to Ampicillin but has improved oral bioavailability. It is effective against a wide range of bacteria and is commonly used to treat various infections such as ear infections, bronchitis, and sinus infections. Amoxicillin is one of the most commonly prescribed antibiotics in clinical practice.

4. Chloramphenicol:
Chloramphenicol is a broad spectrum antibiotic that is effective against a wide range of bacteria, both Gram-positive and Gram-negative. It works by inhibiting bacterial protein synthesis. Chloramphenicol is used to treat a variety of infections, including respiratory tract infections, meningitis, and typhoid fever.

Conclusion:
Among the antibiotics listed, Penicillin G is the narrow spectrum antibiotic, as it is effective against a specific group of bacteria (Gram-positive) compared to the others, which have a broader spectrum of activity. It is important to use the appropriate antibiotic based on the type of infection and the bacteria causing it to ensure effective treatment and prevent the development of antibiotic resistance.