Questions on Bacteria – Structure, Nutrition, Habitat, Reproduction
Multiple-Choice Questions: Bacteria – Structure, Nutrition, Habitat, Reproduction
Structure
1. Which of the following structures is common to all bacteria?
A) Nucleus
B) Mitochondria
C) Peptidoglycan cell wall
D) Chloroplast
E) Cilia
2. The capsule surrounding some bacteria helps in:
A) Protein synthesis
B) DNA replication
C) Protection against phagocytosis
D) Active transport
E) Cell division
3. What is the function of flagella in bacteria?
A) Genetic transfer
B) Photosynthesis
C) Movement
D) Nutrient absorption
E) Structural support
4. The plasmid in bacterial cells is:
A) A ribosomal subunit
B) A metabolic enzyme
C) A small, circular DNA molecule
D) A type of protein
E) Part of the cell membrane
5. Ribosomes in bacterial cells are responsible for:
A) DNA storage
B) Energy production
C) Protein synthesis
D) Lipid breakdown
E) Cell wall construction
Nutrition
6. Bacteria that obtain energy from inorganic compounds are called:
A) Heterotrophs
B) Phototrophs
C) Chemolithotrophs
D) Parasites
E) Saprophytes
7. Bacteria that feed on dead organic matter are known as:
A) Autotrophs
B) Pathogens
C) Symbionts
D) Saprotrophs
E) Chemotrophs
8. Bacteria that carry out photosynthesis but do not produce oxygen are:
A) Cyanobacteria
B) Green sulfur bacteria
C) E. coli
D) Streptococcus
E) Spirochetes
9. Obligate anaerobes are bacteria that:
A) Require oxygen to survive
B) Cannot survive in the presence of oxygen
C) Use oxygen but prefer fermentation
D) Switch between oxygen and no oxygen
E) Perform photosynthesis only at night
10. Facultative anaerobes are bacteria that:
A) Die in oxygen
B) Use only fermentation
C) Can grow with or without oxygen
D) Need intense sunlight
E) Live only in saltwater
Habitat
11. Bacteria are found in which of the following environments?
A) Deep-sea vents
B) Human intestines
C) Arctic ice
D) Soil and air
E) All of the above
12. Thermophilic bacteria thrive in:
A) Cold environments
B) Dry desert soil
C) High-salt lakes
D) Acidic environments
E) High-temperature environments
13. Bacteria that live in symbiosis with other organisms often:
A) Compete with their host
B) Kill the host slowly
C) Benefit both themselves and the host
D) Cause mutations
E) Require oxygen
14. Halophiles are bacteria that live in:
A) High-pressure environments
B) Highly acidic areas
C) Saline conditions
D) Freshwater lakes
E) Within fungi
15. Bacteria found in roots of legumes that fix nitrogen are called:
A) Cyanobacteria
B) Clostridium
C) Rhizobium
D) Salmonella
E) Escherichia
Reproduction
16. The most common form of bacterial reproduction is:
A) Meiosis
B) Mitosis
C) Budding
D) Binary fission
E) Sporulation
17. During binary fission, the result is:
A) Four daughter cells
B) Genetically different cells
C) Two genetically identical cells
D) One large and one small cell
E) No cell division
18. Bacteria can exchange genetic material through:
A) Photosynthesis
B) Respiration
C) Conjugation
D) Fermentation
E) Endocytosis
19. Endospores in bacteria are used to:
A) Reproduce faster
B) Resist harsh environments
C) Produce energy
D) Move
E) Infect host cells
20. Which process does not contribute to genetic variation in bacteria?
A) Conjugation
B) Transformation
C) Transduction
D) Binary fission
E) Mutation
Answer Key with Explanations
1. C – Most bacteria have a cell wall made of peptidoglycan; they lack organelles like nuclei.
2. C – Capsules protect bacteria from immune system attacks like phagocytosis.
3. C – Flagella allow motility, helping bacteria swim toward nutrients or away from harm.
4. C – Plasmids are small DNA circles carrying genes, often for antibiotic resistance.
5. C – Ribosomes translate mRNA into proteins in all cells, including bacteria.
6. C – Chemolithotrophs derive energy from inorganic substances (e.g., sulfur, ammonia).
7. D – Saprotrophs (or decomposers) feed on decaying organic material.
8. B – Green sulfur bacteria perform photosynthesis but do not release oxygen.
9. B – Obligate anaerobes are harmed or killed by oxygen.
10. C – Facultative anaerobes can use oxygen but also survive without it.
11. E – Bacteria are incredibly diverse and can inhabit virtually any environment.
12. E – Thermophilic means heat-loving; they thrive in hot springs, geysers, etc.
13. C – Symbiotic bacteria benefit from and support their host (e.g., gut bacteria).
14. C – Halophiles are salt-loving and live in places like the Dead Sea.
15. C – Rhizobium forms nodules in legumes and fixes atmospheric nitrogen.
16. D – Binary fission is asexual, fast, and produces two identical cells.
17. C – Binary fission creates clones—two genetically identical daughter cells.
18. C – Conjugation involves transfer of plasmids between bacterial cells.
19. B – Endospores are dormant structures allowing survival in extreme conditions.
20. D – Binary fission is a form of cloning and does not create variation on its own.
Dive into the groundbreaking science of neurotransmitters—your brain’s invisible architects—in Chemical Harmony: How Neurotransmitters Shape Our Lives (2025). This meticulously researched book reveals how serotonin, dopamine, GABA, and other brain chemicals silently orchestrate every aspect of your existence, from decision-making and relationships to mental health and emotional resilience.Click here to buy
👉 +3000 Biology Questions with Answers Key.
Share Online!
