🦠🦠 BACTERIA (ADRE)

BACTERIA (ADRE)

BACTERIA

Bacteria are **single-celled microorganisms** that belong to the domain of prokaryotes, which means they have cells that lack a true nucleus and other organelles. They are incredibly diverse, existing in a variety of shapes and sizes, and can be found in virtually every environment on Earth, from soil to water to the human body.

Here are some key characteristics of bacteria:

-Cell Structure: Bacteria have a simple cell structure without a nucleus or other membrane-bound organelles. Their genetic material is contained in a single, circular DNA strand located in a region called the nucleoid¹.

- Cell Wall: Most bacteria have a strong cell wall made of peptidoglycan, which provides shape and protection.Certain bacteria possess an extra coating on their exterior known as a capsule.

Shapes: The three main shapes of bacteria are cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

- Reproduction: Bacteria typically reproduce asexually through binary fission, where one cell divides into two identical daughter cells¹.

- Metabolism: They exhibit a wide range of metabolic types, adapting to different environments by altering their method of energy acquisition².

- **Beneficial and Harmful**: While some bacteria are pathogenic and can cause diseases, many are beneficial and play crucial roles in processes like fermentation, decomposition, and nitrogen fixation².

Bacteria were among the first life forms to appear on Earth and are essential to many of Earth's ecosystems, as well as human health and industry.-------------------- --

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Here are 10 multiple-choice questions (MCQs) on bacteria:

1. 1. **Which of the following describes a bacteria's shape NOT?**

   A) Cocci

   B) Bacilli

   C) Spirilla

   D) Cuboidal

   *Answer: D) Cuboidal*

2. **Bacteria that can live without oxygen are called:**

   A) Aerobic

   B) Anaerobic

   C) Facultative anaerobes

   D) Microaerophiles

   *Answer: B) Anaerobic*

3. **The rigid structure outside the plasma membrane of bacteria is known as the

   A) Cell wall

   B) Capsule

   C) Endospore

   D) Plasmid

   *Answer: A) Cell wall*

4. **Which process allows bacteria to exchange genetic material?

   A) Binary fission

   B) Conjugation

   C) Transduction

   D) Transformation

   *Answer: B) Conjugation*

5. **Bacteria that derive energy from inorganic compounds are called-

   A) Heterotrophs

   B) Autotrophs

   C) Chemotrophs

   D) Phototrophs

   *Answer: C) Chemotrophs*

6. **What is the function of pili in bacteria?

   A) Movement

   B) Reproduction

   C) Attachment to surfaces

   D) Protein synthesis

   *Answer: C) Attachment to surfaces*

7. **Which of the following is NOT a product of bacterial fermentation?

   A) Alcohol

   B) Lactic acid

   C) Oxygen

   D) Vinegar

   *Answer: C) Oxygen*

.8. **Bacteria that can cause diseases are referred to as-

   A) Pathogens

   B) Commensals

   C) Symbionts

   D) Saprophytes

   *Answer: A) Pathogens

9. **The DNA of bacteria is found in the--

   A) Nucleus

   B) Nucleoid

   C) Mitochondria

   D) Ribosomes

   *Answer: B) Nucleoid*

10. **Which of the following bacteria is beneficial to humans?

    A) Escherichia coli in the intestine

    B) Mycobacterium tuberculosis

    C) Vibrio cholerae

    D) Clostridium botulinum

    Answer: A) Escherichia coli in the intestine