Genetic Integration and Replication Quiz

Questions and Answers

What role does the origin of replication play in the multiplication of DNA?

It catalyzes DNA cleavage.

It initiates replication of DNA. (correct)

It prevents DNA degradation.

It links DNA pieces together.

What is necessary for an alien piece of DNA to multiply within a host organism?

It must become part of a chromosome. (correct)

It must be in a linear structure.

It must be detached from the host DNA.

It must be integrated into a plasmid.

Which enzyme is crucial for linking a piece of DNA with plasmid DNA?

DNA ligase (correct)

Restriction enzyme

DNA polymerase

RNA polymerase

Who were the scientists that accomplished the first construction of an artificial recombinant DNA molecule?

Stanley Cohen and Herbert Boyer Signup and view all the answers

What was the first recombinant DNA constructed by linking a gene encoding?

Antibiotic resistance Signup and view all the answers

What is the function of restriction enzymes in genetic engineering?

To cut DNA at specific locations Signup and view all the answers

What type of DNA is referred to as plasmid DNA?

Circular, extra-chromosomal DNA Signup and view all the answers

What organism was mentioned as a host for the replication of the first recombinant DNA?

Escherichia coli Signup and view all the answers

What is the first step in genetically modifying an organism?

Identification of DNA with desirable genes Signup and view all the answers

What is the role of restriction endonucleases in recombinant DNA technology?

To cut DNA at specific sequences Signup and view all the answers

How are restriction enzymes named?

From the organisms they are isolated from Signup and view all the answers

Which of the following best describes endonucleases?

They can cut DNA at specific internal locations. Signup and view all the answers

What distinguishes EcoRI from other restriction enzymes?

It recognizes a specific sequence of six base pairs. Signup and view all the answers

Which type of enzyme removes nucleotides from the ends of the DNA?

Exonucleases Signup and view all the answers

How many restriction enzymes are known to date?

More than 900 Signup and view all the answers

Which of the following is NOT a step involved in genetically modifying an organism?

Development of the desired phenotype in the host Signup and view all the answers

What is the purpose of elution in agarose gel electrophoresis?

To purify DNA fragments from the gel Signup and view all the answers

What is one of the key features required for successful cloning in a vector?

Origin of replication Signup and view all the answers

Why are plasmids and bacteriophages suitable for cloning?

They replicate independently of chromosomal DNA Signup and view all the answers

How do cloning vectors aid in identifying transformants?

They include a selectable marker Signup and view all the answers

Which feature of a cloning vector is responsible for controlling the copy number of linked DNA?

Origin of replication Signup and view all the answers

What property distinguishes bacteriophages from plasmids in terms of genome replication?

Bacteriophages can have very high copy numbers Signup and view all the answers

What is the primary function of a selectable marker in a cloning vector?

To provide antibiotic resistance Signup and view all the answers

What type of DNA can be linked to plasmids and bacteriophages for replication?

Any foreign DNA segment Signup and view all the answers

What role does the antibiotic resistance gene play in selecting transformants?

It helps identify those that have incorporated foreign DNA. Signup and view all the answers

Why is the selection of recombinants through insertional inactivation considered cumbersome?

It requires the use of multiple antibiotics. Signup and view all the answers

What occurs when a recombinant DNA is inserted within the β-galactosidase coding sequence?

The gene for β-galactosidase becomes inactive. Signup and view all the answers

What indicates the presence of a chromogenic substrate in bacterial colonies?

Colonies that produce a blue color. Signup and view all the answers

Which organism is known for delivering T-DNA to transform plant cells?

Agrobacterium tumefaciens Signup and view all the answers

What is a consequence of poorly understanding gene delivery systems in pathogens?

Inefficient gene transfer in plants. Signup and view all the answers

How are genes delivered to eukaryotic cells based on the understanding of pathogens?

By exploiting natural vectors. Signup and view all the answers

What kind of genes are retroviruses known to transform in animals?

Tumor suppressor genes into cancerous genes. Signup and view all the answers

What is the primary function of restriction endonucleases in DNA manipulation?

They inspect and cut DNA at specific recognition sequences. Signup and view all the answers

What characterizes a palindromic sequence in DNA?

It reads the same on both strands in both directions. Signup and view all the answers

What is the outcome of cutting DNA at palindromic sites using restriction endonucleases?

It leaves sticky ends that can form hydrogen bonds. Signup and view all the answers

What role do sticky ends play in DNA recombination?

They allow for the formation of hydrogen bonds with complementary DNA pieces. Signup and view all the answers

How do restriction endonucleases contribute to genetic engineering?

They allow for the joining of DNA from different sources. Signup and view all the answers

Which statement about the cutting mechanism of restriction endonucleases is true?

They cut both strands of the DNA sugar-phosphate backbone at different locations. Signup and view all the answers

What is the role of DNA ligase in the process involving restriction endonucleases?

It joins DNA fragments together after they have been cut. Signup and view all the answers

What is the result of using the same restriction enzyme on different DNA sources?

The resultant fragments will have compatible sticky ends. Signup and view all the answers

Study Notes

Integration and Replication of Alien DNA

Alien DNA can become part of the host genome, allowing it to replicate and be inherited.
Requires integration into a chromosome, particularly at the origin of replication for multiplication.
The process of cloning generates multiple identical copies of a template DNA.

Construction of Recombinant DNA

First recombinant DNA constructed in 1972 by Stanley Cohen and Herbert Boyer.
Involved linking an antibiotic resistance gene from a plasmid of Salmonella typhimurium to a plasmid vector.
Discovery of restriction enzymes enabled precise cutting of DNA at specific sequences.

Role of Vectors

Plasmids serve as vectors to transfer DNA into host organisms, akin to how mosquitoes transfer malaria.
DNA ligase is vital to join cut DNA molecules, resulting in recombinant DNA.
When introduced into Escherichia coli, recombinant DNA can replicate using host DNA polymerase.

Steps in Genetic Modification

Identification of DNA with desirable genes.
Introduction of the identified DNA into the host organism.
Maintenance and inheritance of introduced DNA in the host and its progeny.

Tools of Recombinant DNA Technology

Restriction Enzymes

Isolated in 1963; they cut DNA at specific recognition sequences.
Hind II was the first characterized endonuclease, recognizing and cutting a six base pair sequence.
Over 900 restriction enzymes known, each recognizing different nucleotide sequences.

Types of Nucleases

Nucleases are categorized as exonucleases (cutting at DNA ends) and endonucleases (cutting within DNA).

Cloning Vectors

Plasmids and bacteriophages replicate independently within bacteria.
High copy numbers of genomes enable efficient multiplication of linked alien DNA.
Cloning vectors must have essential features: origin of replication and selectable markers.

Essential Features of Vectors

Origin of replication (ori): Initiates replication and controls copy number.
Selectable marker: Identifies and eliminates non-transformants, aiding in the identification of successful recombinants.

Insertional Inactivation

A method to distinguish recombinant bacteria; insertion of foreign DNA inactivates genes such as β-galactosidase.
Non-recombinant colonies produce color (blue) while recombinant colonies do not (white) when a chromogenic substrate is present.

Gene Delivery in Plants and Animals

Pathogens like Agrobacterium tumefaciens deliver T-DNA to transform plant cells.
Retroviruses can convert normal cells into cancerous cells, suggesting mechanisms for gene delivery.

Recognition Sequences and Sticky Ends

Restriction endonucleases recognize palindromic sequences in DNA.
Palindromic sequences read the same forward and backward on complementary strands.
Sticky ends created by restriction enzyme cuts facilitate the joining of DNA fragments via DNA ligase.

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Description

Test your knowledge on the processes of genetic integration, replication, and recombinant DNA technology. This quiz covers the basics of DNA replication, the historical development of recombinant DNA, and the role of DNA ligase. Dive into the fascinating world of genetics and see how well you understand these key concepts.