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1. The genetic material of a prokaryote is present in the ______________
a) Nucleus
b) Cytoplasm
c) Nucleoid
d) Plasmid
Answer: c
Explanation: Bacteria does not contain a true nucleus. Nucleoid is a poorly demarcated region of the cell that contains the bacterial genetic material or bacterial DNA.
2. Which of the following is not true for both prokaryotic and eukaryotic cells?
a) Same composition of plasma membrane
b) Both contain shared metabolic pathways
c) Genetic information encoded in DNA with similar genetic code
d) Both contain Golgi apparatus for protein trafficking
Answer: d
Explanation: Prokaryotic cells do not have organelles such as Golgi Apparatus. However, the composition of plasma membrane is the same. The metabolic pathways such as TCA cycle and glycolysis take place in both. Both contain DNA as the genetic material.
3. Which of the following is present in both prokaryotic and eukaryotic cells?
a) Proteasomes
b) Plasmids
c) Lysosomes
d) Peroxisomes
Answer: a
Explanation: Proteasomes and protein digesting structures present in both archaebacteria and eukaryotes. Proteasomes degrade unnecessary and damaged proteins by proteolysis. Plasmids are double stranded circular DNA found in prokaryotes whereas lysosomes and peroxisomes are only found in eukaryotes.
4. Which of the following polysaccharide is not present in the eukaryotic plant cell wall?
a) Cellulose
b) Chitin
c) Hemicellulose
d) Pectin
Answer: b
Explanation: Chitin is a polysaccharide that is present mainly in exoskeletons of Arthropods and are not a component of plant cell wall. Plant cell wall is majorly composed of cellulose, hemicelluloses and pectin.
5. Pseudopeptidoglycan is a found in the cell wall of _______________
a) Fungi
b) Archaea
c) Bacteria
d) Protozoa
Answer: b
Explanation: Pseudopeptidoglycan is a cell wall component of some Archaea. It differs from bacterial peptidoglycan in chemical composition but has similar physical structure and function as that of bacterial peptidoglycan.
6. Biofilms are ________________
a) Thin polymeric films made of biopolymer
b) Strings of protein filaments
c) Complex, multispecies communities
d) A metabolic product for prokaryotic organisms
Answer: c
Explanation: Prokaryotes such as bacteria were initially thought to be solitary creatures, but they are capable of living as complex communities called as biofilms. A biofilm is defined as a group of microorganisms in which cells stick or adhere to a living or non-living surface. These adherent cells become embedded within a slimy extracellular matrix composed of extracellular polymeric substances (EPS).
7. Escherichia coli commonly inhabit the _______________ place.
a) Human endodermal layer
b) Human digestive tract
c) Human bronchioles
d) Human skin surface
Answer: b
Explanation: Escherichia coli or E.coli is a Gram negative, facultatively anaerobic, rod-shaped bacteria. It mainly inhabits the human digestive tract and is commonly found in the lower intestinal regions of warm-blooded animals such as humans.
8. How many basal body rings do Gram positive bacteria have in the flagella?
a) 2
b) 3
c) 4
d) 1
Answer: a
Explanation: Gram positive bacteria have 2 basal rings in the flagella, one in the peptidoglycan layer and one in the plasma membrane. Gram negative bacteria have 4 basal rings in their flagella. The L ring is located in the plane in the outer membrane, P ring in the plane of peptidoglycan around flagellar rod, MS ring that is located within and above cytoplasmic membrane and C ring extends into the cytoplasm.
9. The rotary engine made of protein at the base of the flagella is driven by ______________
a) Vanderwaal’s foce
b) Proton- motive force
c) Electron passage
d) Exchange of sodium and potassium ions
Answer: b
Explanation: Proton motive force is the flow of protons or hydrogen ions across the bacterial cell membrane due to a concentration gradient set up by cell’s metabolism. This force drives the motor engine at the base of the flagella and helps in flagellar movement.
10. Escherichia coli and Vibrio cholerae are ________________
a) lophotrichous; monotrichous
b) amphitrichous; lophotrichous
c) peritrichous; monotrichous
d) peritrichous; amphitrichous
Answer: c
Explanation: 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.
11. Nitrogen fixation can be done by ______________
a) All prokaryotes
b) Certain cyanobacteria
c) Certain archaebacteria
d) None of the mentioned
Answer: b
Explanation: 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.
12. F-plasmid contains ______________
a) Only OriV
b) Only OriT
c) Both OriV and OriT
d) None of the mentioned
Answer: c
Explanation: 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’.
13. Which is the main building block of cilia?
a) Tubulin
b) Nexin
c) Dyenin
d) Actin
Answer: a
Explanation: 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.
14. 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 Flagella; Sweeping slow movement of cilia
Answer: c
Explanation: 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).
15. 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
Explanation: 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.
16. Exotoxins are produced by _______________
a) All prokaryotes
b) Gram positive bacteria
c) Gram negative bacteria
d) Archaea
Answer: b
Explanation: Exotoxins are produced by Gram positive bacteria. Endotoxins are produced by Gram negative bacteria.
17. 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
Explanation: 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.
18. Which of the following are a Gram negative bacteria?
a) Neisseria gonorrheae
b) Mycoplasma pneumonia
c) Cornybacterium diptheriae
d) Streptococcus pyogenes
Answer: a
Explanation: Neisseria gonorrheae is an example of Gram negative bacteria. However, Mycoplasma pneumonia, Cornybacterium diptheriae, Streptococcus pyogene are some examples of Gram positive bacteria.
