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Recombinant DNA (GATE - BT)

Description: GATE NET SLET
Number of Questions: 15
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Tags: GATE NET SLET Recombinant DNA Technology
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Which of the following is a pair of homologous recombination methods?

  1. DNA shuffling and Genome shuffling

  2. Exon shuffling and ITCHY

  3. DNA shuffling and Exon shuffling

  4. Genome shuffling and Exon shuffling

  5. Genome shuffling and ITCHY


Correct Option: A
Explanation:

This option is correct because DNA shuffling and Genome shuffling are homologous recombination methods.

In reciprocal recombination,

  1. recombination occurs between two genes with high sequence identity

  2. recombination occurs between two DNA sequences with little or no sequence identity

  3. a symmetrical exchange of genetic material occurs between two DNA strands

  4. specialized nucleotide sequences exhibiting some degree of target site specificity are moved between non-homologous sites within a genome

  5. offspring are produced with combinations of traits that differ from those found in either parent


Correct Option: D
Explanation:

In site-specific recombination, specialized nucleotide sequences exhibiting some degree of target site specificity are moved between non-homologous sites within a genome.

All of the following are examples of non-homologous recombination methods, except

  1. DHR

  2. SHIPREC

  3. SISDC

  4. YLBS

  5. RACHITT


Correct Option: E
Explanation:

Random chimeragenesis on transient templates (RACHITT) is an example of homologous recombination method to perform molecular mutagenesis at a high recombination rate.

Which of the following statements are false?

  1. Transposition occurs by non-replicative mechanism only.
  2. Homologous recombination between multiple copies of a transposon causes rearrangement of host DNA.
  3. Homologous recombination between the repeats of transposons may lead to precise or imprecise excision.
  4. Imprecise excision describes the removal of a transposon plus one of the duplicated target sequences from the chromosome.
  1. 1 and 2

  2. 1 and 3

  3. 1 and 4

  4. 2 and 3

  5. 3 and 4


Correct Option: C
Explanation:

Correct answer. Transposition occurs by both replicative and non-replicative mechanisms. All transposons use a common mechanism in which staggered nicks are made in target DNA, the transposon is joined to the protruding ends, and the gaps are filled. The order of events and exact nature of the connections between transposon and target DNA determine whether transposition is replicative or nonreplicative. Precise excision describes the removal of a transposon plus one of the duplicated target sequences from the chromosome. Imprecise excision occurs when the transposon removes itself from the original insertion site, but leaves behind some of its sequence.

Which of the following types of random mutations involve substitution of a purine nucleotide by a pyrimidine?

  1. Transitions

  2. Transversions

  3. Deletions

  4. Insertions

  5. Inversions


Correct Option: B
Explanation:

Transversions involve substitution of a purine nucleotide by a pyrimidine, or vice-versa.

Which of the following blotting methods is used to check the presence of protein post translational modification?

  1. Southwestern blot

  2. Southern blot

  3. Western blot

  4. Eastern blot

  5. Northern blot


Correct Option: D
Explanation:

Eastern blotting is a technique to detect protein post translational modification and is an extension of the biochemical technique of western blotting.

Assertion (A): Transposition starts by forming a strand transfer complex in which the transposon is connected to the target site through one strand at each end. Reason (R): Replicative transposition proceeds through a cointegrate.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answer as follows:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. (1)

  2. (2)

  3. (3)

  4. (4)

  5. (5)


Correct Option: B
Explanation:

Correct answer. Transposition starts by forming a strand transfer complex in which the transposon is connected to the target site through one strand at each end. Replicative transposition proceeds through a cointegrate. Replication of a strand transfer complex generates a cointegrate, which is a fusion of the donor and target replicons. The cointegrate has two copies of the transposon, which lie between the original replicons. Recombination between the transposon copies regenerates the original replicons, but the recipient has gained a copy of the transposon.

Retroviruses are used for inserting a normal gene into the genome to replace an abnormal disease-causing gene in gene therapy of

  1. ADA deficiency
  2. Alpha-1-antitrypsin deficiency
  3. Cystic fibrosis
  4. Haemophilia b
  5. Rheumatoid arthritis
  1. 1 and 2

  2. 1, 4 and 5

  3. 2, 3 and 4

  4. 3 and 4

  5. 3, 4 and 5


Correct Option: B
Explanation:

Correct answer. First viruses to be used as vectors in gene therapy experiments were retroviruses. Retroviruses are used for inserting a normal gene into the genome to replace an abnormal disease-causing gene in gene therapy of ADA deficiency, haemophilia b, rheumatoid arthritis etc.

Which of the following are examples of random mutagenesis strategies?

P. DOGS Q. StEP R. SeSAM S. Error-prone PCR

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S


Correct Option: E
Explanation:

This option is correct because SeSaM and Error prone PCR are examples of random mutagenesis strategies. Sequence saturation mutagenesis (SeSaM) is a conceptually novel and practically simple method that truly randomizes a target sequence at every single nucleotide position and Error prone PCR is a method by which random mutants may be inserted into any piece of DNA.

Immunoblot is another name of

  1. northern blot

  2. southern blot

  3. western blot

  4. eastern blot

  5. northwestern blot


Correct Option: C
Explanation:

The western blot (also known as immunoblot) is used to detect specific proteins in a given sample of tissue homogenate or extract. The method was invented and named by W. Neal Burnette.

Which of the following is a method of gene delivery using nanomaterials?

  1. Electroporation

  2. Impalefection

  3. Microinjection

  4. Biolistics

  5. Liposome mediated transfer


Correct Option: E
Explanation:

Liposomes are able to interact with the negatively charged cell membrane more readily than uncharged liposomes, with the fusion between cationic liposome and the cell surface resulting in the delivery of the DNA directly across the plasma membrane.

Which of the following methods is/are named after its/their inventor(s)?

  1. Southern blot
  2. Northern blot
  3. Western blot
  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3


Correct Option: A
Explanation:

This option is correct because Southern blot is a method used to check for the presence of a DNA sequence in a DNA sample. The method is named after its inventor, the British biologist Edwin Southern.

Match column – I (blotting technique) with column – II (used in detection of) and select the correct option.

 
Column – I Column – II
p. Southern blot i. Proteins
q. Northern blot ii. DNA
r. Western blot iii. RNA
  1. p - i, q - ii, r - iii

  2. p - i, q - iii, r - ii

  3. p - ii, q - i, r - iii

  4. p - ii, q - iii, r - i

  5. p - iii, q - ii, r - i


Correct Option: D
Explanation:

Correct answer. Southern blot is a method used to check for the presence of a DNA sequence in a DNA sample. The northern blot technique is used to study gene expression by detection of RNA (or isolated mRNA) in a sample. The western blot (or immunoblot) is used to detect specific proteins in a given sample of tissue homogenate or extract.  

Match column – I (Disease) with column – II (Target tissues for gene therapy) and select the correct option.

 
Column – I Column – II
A. Haemophilia b 1. Synovial membrane
B. Cystic fibrosis 2. Respiratory epithelium
C. Rheumatoid arthritis 3. Skin fibroblasts
  1. A - 1, B - 2, C - 3

  2. A - 2, B - 1, C - 3

  3. A - 3, B - 2, C - 1

  4. A - 2, B - 3, C - 1

  5. A - 3, B - 1, C - 2


Correct Option: C
Explanation:

Correct answer. Respiratory epithelial cells are target tissues for gene therapy for the treatment of respiratory insufficiency in cystic fibrosis. Skin fibroblasts are target tissues for gene therapy for the treatment of haemophilia b. Synovial membrane (the soft tissue found between the articular capsule and the joint cavity of synovial joints) are target tissues for gene therapy for the treatment of rheumatoid arthritis.  

Assertion: Gene recombination refers to the exchange of blocks of genetic material among two or more DNA strands. Reason: In site-specific recombination, specialized nucleotide sequences exhibiting some degree of target site specificity are moved between homologous sites within a genome.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answer as follows:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. (1)

  2. (2)

  3. (3)

  4. (4)

  5. (5)


Correct Option: C
Explanation:

Correct answer. Gene recombination refers to the exchange of blocks of genetic material among two or more DNA strands. In site-specific recombination, specialized nucleotide sequences exhibiting some degree of target site specificity are moved between nonhomologous sites within a genome.

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