This set of Genetic Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Drosophila”.
1. Transgenic Drosophila can be created by microinjection of DNA into the embryos. These embryos are at which stage of development?
a) One-cell stage
b) Pre-blastoderm stage
Explanation: Transgenic Drosophila can be created by microinjection of DNA into the embryos. The embryo should be at pre-blastodermal stage. Other developmental stages such as blastoderm and morula follow the pre-blastodermal stage.
2. Syncytium is a layer of ______ that have not been separated into individual cells.
d) nuclei and cytoplasm
Explanation: Syncytium is a layer of nuclei which is not divided into separate individual cells. This is found at pre-blastodermal stage of development.
3. In Drosophila, only nuclei cells give rise to germline cells.
Explanation: In Drosophila, only nuclei cells give rise to germline cells. These germline cells are located at one end of the embryo and acquire DNA stably.
4. ______ integration systems are used for the transfer of DNA in Drosophila and it is composed of ______
a) Artificial, P elements
b) Artificial, S elements
c) Natural, P elements
d) Natural, S elements
Explanation: In Drosophila, the natural integration systems are used for the transfer of DNA and it is composed of transposable elements. These transposable elements are known as P elements.
5. Only the _____ part of Drosophila is transgenic and the rest is not. This is known as ______
a) germline cell, mosaic
b) nurse cells, mosaic
c) germline cells, hybrid
d) nurse cells, hybrid
Explanation: Only the germline cells portion (but not necessarily all germline cells) is modified and the rest is non-transgenic. This is collectively known as mosaic.
6. rosy gene is used as a selectable marker for transformation in Drosophila, it produces an enzyme required for the synthesis of ____________
a) wing pigment
b) eye pigment
c) both eye and wing pigment
d) thorax pigment
Explanation: Rosy gene is used as a selectable marker for transformation in Drosophila, it produces enzyme xanthine dehydrogenase and it is required for pigments of the eye.
7. Wild type flies have crimson red eyes whereas rosy mutant have brick-red eyes.
Explanation: Wild type genes have brick-red eyes whereas rosy mutant have crimson red eyes. Thus, rosy genes can be used as selectable marker.
8. Wild-type Drosophila flies are _____ to ethanol supplied in food.
c) resistant at low concentration and non-resistant at higher concentration
d) resistant at higher concentrations and non-resistant at lower concentration
Explanation: The wild type flies are resistant to ethanol supplied in the food. This property can be exploited as a selectable marker and which is in the form of alcohol dehydrogenase gene.
9. Cis-acting sites should be present in the vector for ________
b) selecting recombinants by acting as a marker
d) providing high copy number
Explanation: Apart from selectable markers, cis acting sites should also be present. These are required for transposition.
10. The host should ____ P elements, these elements lead to _______
a) not have, instability
b) have, stability
c) not have, increase the time taken for integration
d) have, reduces the time taken for integration
Explanation: The host should not have P elements, these elements lead to instability. It is so because they are responsible for transposition.
11. Where do P elements integrate into the genome?
a) At specifically defined sites
c) Only at the ends of the genome
d) Integration depends on reaction conditions
Explanation: P elements integrate into the genome randomly. This makes it non-feasible to be used directly for gene disruption.
12. Transient gene silencing can be carried out by microinjecting ______
a) single stranded RNA
b) double stranded DNA
c) double stranded RNA
d) either double stranded DNA or RNA
Explanation: Transient gene silencing is carried out by microinjecting double stranded RNA. Long term gene silencing can be carried out by synthesizing an inverted copy of the target gene.
Sanfoundry Global Education & Learning Series – Genetic Engineering.
To practice all areas of Genetic Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.