Cell Biology Interview Questions and Answerson “Two Fundamentally Different Classes of Cells – 2”.
1. Escherichia coli and Vibrio cholerae are ________________
A. lophotrichous; monotrichous
B. amphitrichous; lophotrichous
C. peritrichous; monotrichous
D. peritrichous; amphitrichous
Answer: C
Clarification: Monotrichous bacteria have single flagellum (eg. Vibrio cholerae). Lophotrichous bacteria have multiple flagella in same spot which helps in unidirectional movement. Peritrichous bacteria (eg. E.coli) has flagella projecting in all directions. Amphitrichous bacteria have single flagellum on opposite ends.
2. Nitrogen fixation can be done by ______________
A. All prokaryotes
B. Certain cyanobacteria
C. Certain archaebacteria
D. None of the mentioned
Answer: B
Clarification: Certain cyanobacteria have the unique property to fix nitrogen i.e., conversion of nitrogen gas into reduced ammonia. Certain cyanobacteria remain in a symbiotic relationship in the roots of legume plants such as peas and help in nitrogen fixation. Eg. Rhizobium, Azotobacter, etc.
3. F-plasmid contains ______________
A. Only OriV
B. Only OriT
C. Both OriV and OriT
D. None of the mentioned
Answer: C
Clarification: The F-plasmid is an episome formed during bacterial conjugation. It contains its own origin of replication called as ‘OriV’ and Origin of transfer called as ‘OriT’.
4. Which is the main building block of cilia?
A. Tubulin
B. Nexin
C. Dyenin
D. Actin
Answer: A
Clarification: Tubulin proteins are the main building blocks of cilia in prokaryotic organisms. Dyenin forms bridges between neighbouring microtubule doublets in structure of cilia. Nexin is present between microtubule doublets and prevent them to slide over one another.
5. Which of the following is not a difference between cilia and flagella?
A. Cilia is short hairlike; flagella is long thread-like
B. Nexin present in cilia; Nexin absent in flagella
C. Axoneme present in cilia; Axoneme absent in flagella
D. Rapid rotational motion of cilia; Undulating, sinusoidal slow movement of flagella
Answer: C
Clarification: Inside both cilia and flagella, is a microtubule-based cytoskeleton called axoneme. Axoneme is the central strand of either a cilium or flagellum which is composed of an array of microtubules. Microtubules are arranged in nine pairs around two central microtubule (9+2 combination).
6. Which of the following is absent in Gram- negative bacteria and present in Gram- positive bacteria?
A. Teichoic acids
B. Periplasmic space
C. Outer membrane
D. Lipopolysaccharide
Answer: A
Clarification: Teichoic acids are present in Gram positive and absent in Gram negative bacteria and they stain purple by Gram stain. Periplasmic space and outer membrane are present in Gram negative while they are absent in Gram positive bacteria. Lipolysaccharide content is high in Gram negative and almost none in Gram positive.
7. Exotoxins are produced by _______________
A. All prokaryotes
B. Gram positive bacteria
C. Gram negative bacteria
D. Archaea
Answer: B
Clarification: Exotoxins are produced by Gram positive bacteria. Endotoxins are produced by Gram negative bacteria.
8. Which of the following statements is false?
A. Gram negative bacteria is less resistant to physical disruption than Gram positive.
B. Gram positive bacteria is inhibited by basic dyes
C. Gram negative bacteria cell wall is thin and single layered.
D. Gram negative bacteria is more resistant to antibiotics than Gram positive.
Answer: C
Clarification: The cell wall of Gram negative bacteria is thick and two layered. However, the cell wall of Gram positive bacteria is thick and single layered.
9. Which of the following are a Gram negative bacteria?
A. Neisseria gonorrheae
B. Mycoplasma pneumonia
C. Cornybacterium diptheriae
D. Streptococcus pyogenes
Answer: A
Clarification: Neisseria gonorrheae is an example of Gram negative bacteria. However, Mycoplasma pneumonia, Cornybacterium diptheriae, Streptococcus pyogene are some examples of Gram positive bacteria.
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