This set of Marine Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Transgenic Technology in Marine Organisms”.
1. Morpholinos attack by ________________
a) inhibiting transcription
b) inhibiting translation
c) inhibiting replication
d) altering pH
View Answer
Explanation: Morpholino phosphorodiamidate oligonucleotides (MOs) are group of chemically modified oligonucleotides. These exhibit a strong stability, less toxicity to live cells and inhibit gene expression through translation only.
2. Loss-of-function transgenes interfere with the expression of host genes.
a) True
b) False
View Answer
Explanation: The loss-of-function transgenes are constructed in such a way that they interfere with the expression of various host genes at the transcriptional or translational level. This leads to an altered or lost function of the gene.
3. Catalytic RNAs – ribozymes can _________________ gene expression.
a) knock-out
b) elevate
c) not affect
d) knock-down
View Answer
Explanation: Catalytic RNAs can cleave specific target messenger RNAs and reduce the level of gene expression, hence knock down specific genes. The transgene prototype consists of Pol II responsive promoter, designed ribozyme and poly(A) tail.
4. RNA-induced silencing complex is activated by __________________
a) ribozyme
b) ribosome
c) lysosome
d) siRNA
View Answer
Explanation: Small interfering RNA (siRNA) containing transgene constructs have sequences homologous to host endogenous mRNA that has to be silenced. Small interfering RNAs lead to activation of the RISC complex that recognizes and degrades the respective messenger RNAs.
5. Zinc finger nucleases (ZFN) are used for ________________ in zebrafish.
a) gene knock-down
b) gene-knock in
c) gene modification
d) gene editing
View Answer
Explanation: Zinc finger nuclease (ZFN) is a prototype of transgenes used in biomedical research. It leads to inactivation of a gene thereby editing the genomes of various fish species such as zebrafish and yellow catfish.
6. Fok1 is a _______________
a) restriction endonuclease
b) restriction exonuclease
c) reporter gene
d) enhancer element
View Answer
Explanation: Fok1 is a zinc finger nuclease (restriction endonuclease) whose cleavage domain is linked to messenger RNAs that encode for zinc finger proteins in a loss-of-function transgene construct. ZFN mRNA helps in genome editing without using embryonic stem cells.
7. The source of TALE in TALENs is ________________
a) Xanthomonas
b) Pseudomonas
c) Penaeus monodon
d) Macrobrachium rosenbergii
View Answer
Explanation: DNA-binding motif of transcription activator like effector (TALE) protein from the bacterium Xanthomonas is assembled with Fok1 nuclease. Xanthomonas causes various diseases in plants.
8. TALEN is a type of loss-of-function transgene.
a) True
b) False
View Answer
Explanation: Zinc finger nucleases (ZFN) are used to edit the genomes of various fish omitting the use of embryonic stem cells. To counter the limitations associated with the use of ZFN, TALENs have been developed.
9. For gene transfer studies in fish, which parameter should not be considered?
a) Life cycle length
b) Background data availability
c) Culture conditions
d) Absence of body patterns
View Answer
Explanation: Depending upon the intent of study various parameters are considered for gene transfer studies in fish. The vital parameters include life cycle length, year-round availability of sperms and eggs, background information on physiology and genetics, culture conditions, and size of adult at maturity.
10. Which is not a feature of Japanese medaka and zebrafish?
a) Seasonal breeding
b) 1 – 1.5 mm eggs
c) 3 months to mature
d) Thin, semi-transparent chorions on eggs
View Answer
Explanation: Japanese medaka (Oryzias latipes) and zebrafish (Danio rerio) are used as model organisms in biomedical research because of their attributes. The fish are easy to maintain in the laboratory for 2-3 years and do not show seasonal breeding.
11. Why is tilapia a better and preferred model for endocrinology and biochemical studies, compared to zebrafish and medaka?
a) Bigger size
b) Greater background knowledge
c) Transparency in embryological stage
d) Male to female ratio
View Answer
Explanation: The tilapia is a better model for endocrinological and biochemical studies as compared to medaka and zebrafish because of the former’s bigger size. A bigger size makes the ample collection of blood and tissue easier.
12. Which is not a large body size model fish species for transgenic studies?
a) Common carp
b) Salmon
c) Tilapia
d) Rainbow trout
View Answer
Explanation: Tilapia is a medium-sized fish model used in biomedical research for transgenic studies. Rainbow trout, common carp, salmon, channel catfish are large-sized fish models used in transgenic studies.
13. Which is the most preferred method for introducing transgene into fish models?
a) Calcium phosphate precipitation
b) Direct microinjection
c) Lipofection
d) Particle gun
View Answer
Explanation: Electroporation and direct microinjection are the most widely used techniques of introducing foreign DNA into fish model. In recent years pantropic retroviral vectors have also been a method of choice.
14. During gene transfer, eggs are microinjected ______________
a) after 2-3 days
b) after cryopreservation
c) within first few hours
d) after maturation
View Answer
Explanation: In gene transfer using direct microinjection the eggs are microinjected within the first few hours after fertilization. The injection apparatus consists of dissecting stereomicroscope and two micromanipulators.
15. If medaka eggs are maintained at 4°C immediately after fertilization, __________________
a) micropyle remains for few hours
b) micropyle remains visible forever
c) chorion is degenerated
d) chorion is stiffened
View Answer
Explanation: If japanese ricefish – medaka eggs are maintained at 4°C immediately after fertilization the micopyle remains visible for at least 2 hours. The linearized DNA solution (without plasmid DNA) can be injected.
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.
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