Problem 3 - Biology the Easy Way (E-Z Biology)

Question

An example of a disease caused by a bacillus is (a) meningitis (c) syphilis (b) yaws (d) tetanus

Step-by-Step Solution

Answer

Tetanus is caused by a bacillus.

Step 1: Understand the Question

The question asks you to identify which of the listed diseases is caused by a bacillus, which is a rod-shaped bacterium.

Step 2: Analyze Each Option

- **Meningitis**: Can be caused by various pathogens including bacteria like Neisseria meningitidis (not a bacillus) and Haemophilus influenzae (a bacillus). - **Syphilis**: Caused by *Treponema pallidum*, a spirochete bacterium, not a bacillus. - **Yaws**: Caused by *Treponema pallidum pertenue*, also a spirochete bacterium, not a bacillus. - **Tetanus**: Caused by *Clostridium tetani*, a gram-positive rod-shaped bacterium, which is a bacillus.

Step 3: Identify the Correct Option

Based on the analysis, "d) tetanus" is caused by a bacillus, specifically *Clostridium tetani*, known for its rod-shaped form.

Step 4: Finalize the Answer

Review the analysis to confirm that "d) tetanus" is the correct choice, as it is the disease caused by a bacillus.

Key Concepts

Disease Causation

Bacteria are microscopic organisms that play various roles in our world, including being crucial agents of disease. Disease causation by bacteria occurs when these organisms invade the body, multiply, and disrupt normal body functions. This can lead to a range of diseases affecting different parts of the body. For example, tetanus is caused by the bacterium *Clostridium tetani*. This bacterium produces a toxin that attacks the nervous system:

• Entry: The bacteria usually enter through cuts or wounds.
• Effects: The toxin blocks nerve signals, which can cause muscle stiffness and spasms.
• Prevention: Vaccination is an effective preventive measure.

Recognizing the causative agent behind a disease is a key to developing effective treatments and preventive measures. This is why understanding which bacteria cause which diseases is incredibly important.

Bacteria Classification

Classifying bacteria involves grouping them based on various characteristics such as shape, gram-stain reaction, and metabolic properties. One major category is based on shape, where bacteria can be classified as:

• Cocci: Spherical-shaped
• Bacilli: Rod-shaped
• Spirilla: Spiral-shaped

This classification helps in identifying and studying bacteria more effectively. For instance, *Clostridium tetani*, which causes tetanus, belongs to the bacilli category due to its rod-like shape. Additionally, bacteria can be classified based on their cell wall structure using Gram staining:

• Gram-positive: Retain the purple dye
• Gram-negative: Do not retain the dye

Such classifications are essential for determining the appropriate antibiotic treatment to target and eliminate harmful bacteria.

Bacillus

Bacillus refers to bacteria that exhibit a rod-like shape. It's a general term; however, it also refers to a specific genus of bacteria. The genus Bacillus includes many species that are widely found in soil, some of which are pathogenic to humans and animals. An example of a disease-causing bacillus is *Bacillus anthracis*, the bacterium responsible for anthrax. However, when talking about the rod shape rather than the genus, various important pathogenic bacilli include:

• *Clostridium tetani*: Causes tetanus, known for producing a potent toxin that affects the nervous system.
• *Haemophilus influenzae*: Can cause infections such as meningitis.
• *Escherichia coli*: Sometimes causes food poisoning and urinary tract infections.

Understanding the characteristics and impacts of different bacilli is crucial in microbiology and medical fields for developing treatments and preventive strategies.