Life Sciences Questions and Answers – Classification System

This set of Life Sciences Questions and Answers for Aptitude test focuses on “Classification System”.

1. What is the basic taxonomic unit?
a) RNA
b) Phylogenetic tree
c) Species
d) Cell
View Answer

Answer: c
Explanation: Species are the basic taxonomic unit; it is assigned to a genus. In eukaryotes, the species are the group of similar organisms which reproduce. Bacterial species identified as a group of organisms having similar phenotypic properties.

2. What is numerical taxonomy?
a) Determine phenetic relationships among organisms
b) Determine phylogenetic relationships
c) Determine numbers of phylogenetic tree
d) Determine evolutionary tree on the number of genus
View Answer

Answer: a
Explanation: Numerical taxonomy was given by Sokal and Sneath. It determines the relationships among organisms on the basis of their phenetic system. It is summarized with a tree diagram called dendrogram.

3. Which of the following is not used to determine DNA relatedness in the phylogenetic system?
a) Thermal stability of related DNA
b) Genome size
c) GC content
d) Amino acid sequences
View Answer

Answer: d
Explanation: DNA relatedness can be determined by following five factors: GC content, genome size, the thermal stability of related DNA sequences, DNA relatedness when the condition is optimal for DNA reassociation, and DNA relatedness when the condition is superoptimal for DNA reassociation.

4. The collective study of genotypic, chemotaxonomic, and phenotypic method is________
a) Polyphasic approach
b) Numerical taxonomy
c) Bacterial taxonomy
d) Phylogenetic approach
View Answer

Answer: a
Explanation: Polyphasic approach is a grouping of organisms on the basis of the physiological, morphological, and biochemical feature. It is a most popular approach currently for classifying bacteria.

5. What is the causative agent of Q-fever?
a) R. typhi
b) Coxiella burnetii
c) Plasmodium
d) Mycobacterium
View Answer

Answer: b
Explanation: Coxiella brunetii is gram-negative, non-motile, and obligate intracellular parasites which belong to the class of rickettsias. These organisms grow and reproduce within a host cell.
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6. Name the bacteria which are responsible for the odor of moist soil.
a) Mycoplasma
b) Borelia burgdorferi
c) Streptomyces
d) Cyanobacteria
View Answer

Answer: c
Explanation: Streptomyces belongs to the class of actinomycetes, which are strict aerobes, non-pathogenic and bear the nonmotile conidia. Streptomyces produces a volatile substance i.e. geosmin which gives an odor of moist soil.

7. Name the causative agent of syphilis.
a) Mycobacteria
b) Streptococcus
c) Pseudomonas
d) Treponema palladium
View Answer

Answer: d
Explanation: Treponema palladium is an example of the spirochete, which causes syphilis. Spirochetes are gram-negative, helical shape, and chemoheterotrophic bacteria which exhibit creeping or crawling movements.

8. Mark the INCORRECT statement about cyanobacteria.
a) Gram-negative bacteria
b) Photolithoautotrophic organism
c) They do not have a fully functional citric acid cycle
d) Reproduce only by binary fission
View Answer

Answer: d
Explanation: Cyanobacteria are gram-negative, oxygenic photosynthetic organisms. It can reproduce by binary fission as well as budding and multiple fission.

9. Is archebacteria a type of bacteria?
a) True
b) False
View Answer

Answer: b
Explanation: Archaebacteria placed in a different class as that of bacteria. They do not classify as bacteria due to their differences. It is usually present in the extreme aquatic and terrestrial habitat.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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