LE 7 -2024 Flashcards
- ECOR1 is a:
A. DNA ligase enzyme
B. A vector used for insulin synthesis
C. Restriction endonuclease
D. A plasmid used as a vector
C. Restriction endonuclease
- Construction of a recombinant DNA involves:
A. Cleaving DNA with restriction endonuclease and joining with ligase
B. Cleaving DNA with ligase and joining with endonuclease
C. Cleaving and joining DNA with restriction endonuclease
D. Cleaving DNA with restriction endonuclease and joining with polymerase
A. Cleaving DNA with restriction endonuclease
and joining with ligase
- “Thermal Cycler” is used in the reaction:
A. Enzyme linked immuno sorbant assay
B. Polymerase chain reaction
C. Ligation reaction
D. Immobilization reaction
B. Polymerase chain reaction
- The restriction Endonucleases are called so because they:
A. Have a very restrictive or site specific endonuclease activity
B. Cut DNA at a few restricted sites
C. Restrict the entry of foreign DNA into the cell by cleaving the DNA due to their endonuclease activity
D. Their distribution is restricted to only some bacterial cells
A. Have a very restrictive or site specific endonuclease activity
- A segment of DNA that reads from the same forward and backward is called:
A. Palindromic DNA
B. Plasmid DNA
C. Complementary DNA
D. Copy DNA
A. Palindromic DNA
- A part of nucleic acid used to find a gene by hybridization is called:
A. Vector
B. Clone
C. Probe
D. Cybrid
C. Probe
- cDNA, a term used in recombinant DNA technology means:
A. Competitive DNA
B. Complex DNA
C. Chemical DNA
D. Complementary DNA
D. Complementary DNA
- During the recent tsunami disaster a child was separated from its parents in Sri Lanka. Later with the help of technique the child was made to reunite with its true parents. The technique is:
A. DNA finger printing
B. Tissue culture
C. Gene therapy
D. Hybridoma technology
A. DNA finger printing
- Electrophoresis, a technique used in DNA fingerprinting helps to separate:
A. DNA segments
B. Tissues
C. Cells from DNA
D. RNA from DNA
A. DNA segments
- RFLP is:
A. Repeated fragment length polymorphism
B. Renewed fragment length polymorphism
C. Required fragment length polymorphism
D. Restriction fragment length polymorphism
D. Restriction fragment length polymorphism
An example for autonomously replicating a mini chromosome is:
A. virus
B. Phage
C. Plasmid
D. Lichen
C. Plasmid
In restriction endonuclease EcoR1, “E” stands for:
A. Extraction
B. Endonuclease
C. The first letter of the genus in which it is present
D. Endangered
C. The first letter of the genus in which it is present
Which one of the following statement are attributes of plasmids, EXCEPT:
A. They are circular DNA molecule
B. They have antibiotic resistant genes
C. They have the ability of autonomous replication
D. They have DNA that is as long as chromosomal DNA
D. They have DNA that is as long as chromosomal DNA
- Which of the following statement about a vector is correct:
A. All vectors are plasmids only
B. Plasmids, phages can be used as vectors
C. Fungi can also be used as vectors
D. Cyanobacteria can also be used as vectors
B. Plasmids, phages can be used as vectors
An ideal plasmid to be used for recombinant DNA technology must have:
A. Minimum amount of DNA
B. Relaxed replication control
C. One recognition site for one restriction endonuclease
D. All of these
D. All of these
- Prior to the production of recombinant insulin, insulin obtained from cows and pigs were given to patients. Some of the problems faced by this treatment was:
A. The insulin was not active
B. In some humans it induced antibody production
C. It reduces the weight of patients
D. Loss of memory power
A. The insulin was not active
- The first human protein produced through recombinant DNA technology is:
A. Insulin
B. Erythropoietin
C. Interferon
D. Somatostatin
A. Insulin
- A plasmid consisting of its own DNA with a foreign DNA inserted into it is called:
A. Recombinant DNA
B. Junk DNA
C. Non-coding DNA
D. None of the above
A. Recombinant DNA
- A recombinant DNA molecule is produced by joining together:
A. One mRNA with a DNA segment
B. One mRNA with a tRNA segment
C. Two mRNA molecules
D. Two DNA segments
D. Two DNA segments
- A gene produced for recombinant DNA technology contains a gene from one organism joined to the regulatory sequence of another gene. Such a gene is called:
A. Oncogene
B. Junk gene
C. Chimeric gene
D. None of the above
C. Chimeric gene
A group of genetically similar organisms obtained by a sexual reproduction is called:
A. Clone
B. Population
C. Assembly
D. None
A. Clone
- To be useful in the preparation of recombinant DNA, a plasmid must have:
A. No origin of replication
B. An origin of replication
C. The ability to alternate between the linear and circular forms
D. Restriction endonuclease activity
B. An origin of replication
- Restriction endonucleases have the ability of cutting:
A. DNA at random site
B. DNA at specific sites
C. DNA and RNA at random sites
D. BothAandB
B. DNA at specific sites
Endonucleases, a group of enzymes cleave DNA:
A. Externally
B. Internally
C. Both Aand B
D. Neither A nor B
B. Internally
The extra chromosomal, self-replicating, double stranded, closed, circular DNA molecules are called:
A. Plasmids
B. Phages
C. Viruses
D. Chloroplasts
A. Plasmids
Which of the following best describes semiconservative replication?
A. The replication of DNA takes place at a defined period in the cell cycle
B. A DNA molecule consists of one parental strand and one new strand
C. The number of DNA molecules is doubled with every other replication
D. The replication of DNA never takes place with 100% accuracy
B. A DNA molecule consists of one parental strand and one new strand
- The final product of DNA replication is:
A. mRNA, tRNA, and rRNA molecules
B. A wide variety of proteins
C. One DNA molecule
D. 2 DNA molecules, each of which contains one new & one old DNA strand
D. 2 DNA molecules, each of which contains one new & one old DNA strand
- Meselson and Stahl separated DNA from different generations using:
A. Density gradient centrifugation
B. Gel electrophoresis
C. An electron microscope
D. Differential radioisotope labelling
A. Density gradient centrifugation
- Which of the following cause the unwinding of the DNA double helix?
A. DNA polymerase
B. DNA helicase
C. RNA primer
D. Primosome
B. DNA helicase
- A replication fork is:
A. Only seen in bacterial cells
B. A Y-shaped structure where both DNA strands are replicated simultaneously
C. A site where one DNA strand serves as a template, but the other strand is not replicated
D. Is created by the action of the enzyme RNA polymerase
B. A Y-shaped structure where both DNA strands are replicated simultaneously
- In replication, once the DNA strands have been separated, reformation of the double helix is prevented by:
A. DNA helicase enzyme
B. Single-stranded binding proteins
C. DNA polymerases
D. ATP
B. Single-stranded binding proteins
Enzymes called ____________ form breaks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.
A. Topoisomerases
B. DNA polymerases
C. RNA polymerases
D. DNA ligases
A. Topoisomerases
- Which of the following adds new nucleotides to a growing DNA chain?
A. DNA polymerase
B. DNA helicase
C. Primase
D. RNA polymerase
A. DNA polymerase
- The reason why DNA synthesis only proceed in the 5 ́ to 3 ́ direction:
A. DNA polymerases can only add nucleotides to the 3 ́ end of a polynucleotide strand
B. The 3 ́ end of the polynucleotide molecule is more electronegative than the 5 ́ end
C. That is the direction in which the two strands of DNA unzip
D. That is the only direction that the polymerase can be oriented
A. DNA polymerases can only add nucleotides to the 3 ́ end of a polynucleotide strand
- The 5 ́ end of each Okazaki fragment begins with:
A. The same RNA primer that began synthesis on the leading strand
B. A DNA primer binding to the template DNA
C. DNA polymerase binding to the template DNA
D. A separate RNA primer
D. A separate RNA primer
- Primase is the enzyme responsible for:
A. Introducing nicks into the DNA double strand in order to prevent the formation of knots
B. Hydrolyzing ATP to facilitate DNA unwinding
C. Making short strands of RNA at the site of replication initiation
D. Forming a replication fork in the DNA double helix
C. Making short strands of RNA at the site of replication initiation
Okazaki fragments are joined together by:
A. RNA polymerase
B. DNA ligase
C. DNA polymerase
D. RNA ligase
B. DNA ligase
- How is the chromosome of a bacterial cell replicated?
A. Linear DNA molecule is replicated from multiple
origins of replication bidirectionally
B. Linear DNA molecule is replicated from one origin of replication bidirectionally
C. Circular DNA molecule is replicated from one origin of replication bidirectionally
D. Circular DNA molecule is replicated from one origin of replication unidirectionally
C. Circular DNA molecule is replicated from one origin of replication bidirectionally
- The manner by which eukaryotic cells replicate their chromosomes:
A. The linear DNA, from multiple origins of replication bidirectionally
B. The linear DNA, from one origin of replication bidirectionally
C. The circular DNA from multiple origins of replication bidirectionally
D. The circular DNA from one origin of replication bidirectionally
A. The linear DNA, from multiple origins of replication bidirectionally
- The correct designation for the DNA strand labelled “A” is:
A. Leading strand template
B. Okazaki fragment
C. Lagging strand template
D. RNA primer
A. Leading strand template
- The segment labelled “F” is:
A. Lagging strand
B. Lagging strand template
C. Okazaki fragment
D. RNA primer
C. Okazaki fragment
The segment labelled “B” is:
A. Leading strand
B. Lagging strand
C. Lagging strand template
D. Okazaki fragment
A. Leading strand
- The segment labelled “E” is:
A. RNA primer
B. Okazaki fragment
C. Leading strand template
D. Lagging strand template
A. RNA primer
- The segment labelled “D” is:
A. Replication fork
B. Okazaki fragment
C. Leading strand template
D. Lagging strand template
A. Replication fork