Genetic Engineering Multiple Choice Questions on “Organelle Transformation”.
1. Mitochondrial genome encodes tRNAs ___________ and polypeptides involved in _______
a) mRNAs, oxidative phosphorylation
b) rRNAs, oxidative phosphorylation
c) rRNAs, reductive phosphorylation
d) mRNAs, reductive phosphorylation
Answer: b
Explanation: Mitochondrial genome encodes tRNAs, rRNAs and polypeptides which are required for oxidative phosphorylation. tRNAs and rRNAs are also encoded by chloroplast genome.
2. Atrazine is a herbicide and it acts on _________
a) reaction centre in photosystemI
b) reaction centre in photosytemII
c) reaction centre in both the photosystems
d) neither of the photosystems
Answer: b
Explanation: Atrazine is a herbicide and it acts on a reaction centre present in photosystem II. This herbicide is a product of chloroplast psbA gene.
3. Allotopic gene expression is the case when the presence of a normal gene in an organelle is not a problem in expression.
a) True
b) False
Answer: a
Explanation: At times, the presence of a normal gene in the organelle doesn’t create a problem and thus inserting modified organelle genes into the nucleus may be expressed well. Such an expression is called a allotropic gene expression.
4. atpB encodes _______ subunit of ATP synthase, an enzyme used for generation of ______
a) beta, ADP
b) alpha, ATP
c) beta, ATP
d) alpha, ADP
Answer: c
Explanation: atpB encodes a beta subunit of ATP synthase, it is a multisubunit complex used for generation ATP and it is done in the presence of light reaction.
5. Bacterial aadA gene is responsible for conferring resistance to _________
a) spectinomycin
b) streptomycin
c) ampicillin
d) spectomycin and streptomycin
Answer: d
Explanation: Bacterial aadA gene is responsible for conferring resistance to both streptomycin and spectomycin. It is used a selectable marker for chloroplast transformation.
6. How many types of the chloroplast are there in Chlamydomonas?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: Chlamydomonas is having only one type of chloroplast and this property makes it easier to use it for transformation.
7. For transformation of the chloroplast of higher plants, a vector is used which ______ in the chloroplast.
a) doesn’t replicates
b) replicates
c) may or may not replicate
d) replicates under certain specified conditions
Answer: a
Explanation: For transformation of the chloroplast of higher plants, a vector is used which doesn’t replicates in the chloroplast. There is a selectable marker which is present and the gene of interest is flanked by chloroplast DNA.
8. Chloroplast can be transferred through pollen in all crops.
a) True
b) False
Answer: b
Explanation: Cholorplast can’t be transferred through pollen for all the crops. Thus incorporation of transgenes in chloroplast may offer more biological containment then that incorporation into nucleus may offer.
9. Mutant strains of Saccharomyces cervevisiae in which endogenous DNA are deleted are called as _________
a) rho0
b) synthetic rho
c) rho+
d) rho-
Answer: a
Explanation: Mutant strains of Saccharomyces cervevisiae in which endogenous DNA are deleted are called as rho0. Synthetic rho- strains are produced when DNA is introduced into mitochondria and concatamers are produced.
10. COX3 gene is a selectable marker. Choose the correct statement with respect to it.
a) It confers the ability to grow by anaerobic respiration
b) It confers the ability to grow by aerobic respiration
c) It confers the ability to grow in absence of uracil
d) It confers the ability to grow in lithium acetate medium
Answer: b
Explanation: COX3 gene is used as a selectable marker. It confers the ability to grow by aerobic respiration in the mutant cells for mitochondrial COX3 gene.
11. The ARG8m gene which produces an enzyme for arginine biosynthesis is located in _______ and is of ______ origin.
a) mitochondrial, nuclear
b) nuclear, mitochondrial
c) nuclear, nuclear
d) mitochondrial, mitochondrial
Answer: a
Explanation: The ARG8m gene which produces an enzyme for arginine biosynthesis is located in the mitochondria but is of nuclear origin. It is designed for expression in the mitochondrion and will confer the ability to grow in the absence of arginine.
12. Barstar is _________
a) RNAse
b) RNAse inhibitor
c) DNAse
d) DNAse inhibitor
Answer: b
Explanation: Barstar is RNAse inhibitor. And Barsar is RNAse and inhibitor is used as a selectable marker. Barsar is used for degrading the mitochondrial RNA. Barstar added helps in suppressing the function of Barsar and thus restoration of mitochondrial function takes place.
13. Caenorhabditis elegans is a model organism of great importance in biological systems. It is a/an _________
a) algae
b) parasite
c) fungi
d) nematode
Answer: d
Explanation: Caenorhabditis elegans is a model organism of great importance in biological systems and it is a nematode. The genetic manipulation of the organism is quite complex.
14. DNA can be injected into Caenorhabditis elegans by biolistic transformation. The injected DNA forms arrays of extrochromosomal copies which are stable in nature.
a) True
b) False
Answer: b
Explanation: DNA can be injected into Caenorhabditis elegans by biolistic transformation. The injected DNA forms extrachromosomal copies but these are not stable in nature. This can be avoided by the incorporation of poison sequences.