This set of Marine Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Isolation of Marine Natural Products – Set 2”.
1. Discodermin-A is a bioactive ________________ of marine origin.
a) nucleic acid
b) organic acid
c) quinone
d) peptide
View Answer
Explanation: Discodermin-A is the first bioactive peptide to be isolated from the marine sponge Discoderma kiiensis. Isolation of peptides from marine origin has shown rapid progress due to development of reverse-phase HPLC.
2. Edman degradation can not be used to analyze the sequences of unusual peptides such as those of marine origin.
a) True
b) False
View Answer
Explanation: Edman degradation is a method used to sequence the amino acids present in a peptide. However this method cannot be used for sequencing the unusual peptides such as those belonging to the marine origin because the latter have blocked N-terminus.
3. Which nucleoside has been isolated from the marine sponge Cryptotethia crypta?
a) Spongocytosine
b) Spongothymidine
c) Spongomycin
d) Spongoguanine
View Answer
Explanation: Three unusual nucleosides, spongothymidine, spongouridine and spongosine have been isolated from the marine sponge Cryptotethia crypta by soxhlet extraction with acetone.
4. An octapeptide of glutamic acid has been isolated from which of the following?
a) Blue algae
b) Green algae
c) Red algae
d) Brown algae
View Answer
Explanation: Haas and Hill isolated an octapeptide of glutamic acid from the brown algae Pelvetina canaliculata. After the isolation of this bioactive compound, many peptides have been isolated from marine algae.
5. The peptides isolated from marine sponges are usually ____________________
a) cyclic
b) linear
c) toxic
d) acidic
View Answer
Explanation: The peptides isolated from the marine sponges are usually cyclic and lipophilic. Linear or more polar peptides might have been missed because of using a specific bioassay that interferes with the activity of isolated compound.
6. Which bioactive compound from marine organisms are purine derivatives?
a) Alkaloids
b) Phycocyanins
c) Cytokinin
d) Toxins
View Answer
Explanation: Cytokinins isolated from marine organisms are purine derivatives. Cytokinins play a major role in cell division and differentiation in plants. Ion-exchange chromatography followed by preparative TLC on silica is used in the isolation process.
7. After preparative TLC, how can silica gel be viewed?
a) Gram staining
b) Fluorescent labeling
c) Desalting
d) Iodinine vapor
View Answer
Explanation: After preparative TLC (Thin Layer Chromatography) the gel can be viewed either using UV light or I2 vapor. This procedure is used usually at the purification step of the isolation process.
8. Marine pyridoacridine alkaloids exhibit anti-HIV activity.
a) True
b) False
View Answer
Explanation: Several types of alkaloids are isolated from marine organisms; of significance amongst them are the pyridoacridine alkaloids because of their significant biological activities such as anti-HIV, Ca2+ releasing activity etc.
9. Iminoquinone system present in the alkaloids can be reduced by ________________
a) sodium borohydride
b) sodium chloride
c) magnesium chloride
d) copper sulfate
View Answer
Explanation: Iminoquinone system present in the alkaloids can be reduced by sodium borohydride. The alkaloids exhibit facile redox reactions due to variability in their oxidation states.
10. The ascidian Eusistoma olivaceum is a rich source of ______________ alkaloids.
a) tryptophan derived
b) ethylated
c) iodized
d) carboxylated
View Answer
Explanation: The ascidian Eusistoma olivaceum is a rich source of tryptophan-derived alkaloids. Various alkaloids named eudistomins have been isolated from this source and they exhibit antiviral activity.
11. The majority of marine toxins are produced by ________________________
a) microalgae
b) benthos
c) nektons
d) baleen whale
View Answer
Explanation: The majority of marine toxins are produced by microalgae, especially dinoflagellates. There are two types of algae prevalent in marine environments, microalgae and macroalgae (seaweeds).
12. Which type of chromatography was used in the isolation of first saxitoxin?
a) Thin-layer chromatography
b) Alumina chromatography
c) Paper chromatography
d) Ion-exchange chromatography
View Answer
Explanation: Saxitoxin is known to cause paralytic shellfish poisoning (PSP) and it was first isolated from the Alaskan butter clam using Amberlite IRC 50 and alumina chromatography. Alumina chromatography is used for the isolation of acid pigments and strong acids.
13. Which of the following was isolated from Gymnodinium breve?
a) Domoic acid
b) Saxitoxin
c) Brevetoxin
d) Ciguatoxin
View Answer
Explanation: Brevetoxin has been isolated from the dinoflagellate Gymnodinium breve by culturing the latter in artificial seawater medium and then acidifying the medium to pH 5.5 and extracting with diethyl ether.
Sanfoundry Global Education & Learning Series – Marine Biotechnology.
To practice all areas of Marine Biotechnology, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
