Biology: Restriction Enzymes and Nucleases

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Questions and Answers

What is the primary goal of maintaining a sterile ambience in chemical engineering processes?

To preserve genetic information

To enable the growth of only the desired microbe or eukaryotic cell (correct)

To prevent contamination of microorganisms

To manufacture biotechnological products like antibiotics and vaccines

What is the major advantage of sexual reproduction over asexual reproduction?

It leads to inclusion and multiplication of undesirable genes

It preserves genetic information

It allows for variations and unique combinations of genetic setup (correct)

It is a faster process

What is the limitation of traditional hybridisation procedures?

They preserve genetic information

They lead to inclusion and multiplication of undesirable genes (correct)

They introduce only desirable genes

They are used in genetic engineering

What is the purpose of genetic engineering techniques?

To isolate and introduce only one or a set of desirable genes Signup and view all the answers

What happens to a piece of DNA transferred into an alien organism?

It gets integrated into the genome of the recipient and multiplies Signup and view all the answers

What is responsible for initiating replication in a chromosome?

The origin of replication Signup and view all the answers

What is the significance of gene cloning in genetic engineering?

It allows for the isolation and introduction of desirable genes Signup and view all the answers

What is the ultimate goal of genetic engineering?

To introduce desirable genes into an organism Signup and view all the answers

What is the purpose of having a single recognition site for restriction enzymes in a cloning vector?

To simplify the gene cloning process Signup and view all the answers

Which antibiotic resistance gene is commonly used as a selectable marker in E. coli?

All of the above Signup and view all the answers

What is the consequence of inserting foreign DNA at the BamH I site of the tetracycline resistance gene in the vector pBR322?

The recombinant plasmids will lose tetracycline resistance Signup and view all the answers

What is the function of the 'ori' region in the pBR322 vector?

It is involved in the replication of the plasmid Signup and view all the answers

Why are normal E. coli cells not resistant to antibiotics?

They do not carry resistance genes Signup and view all the answers

What is the purpose of plating transformants on ampicillin-containing medium?

To select against non-recombinant plasmids Signup and view all the answers

What is the name of the restriction enzyme site where foreign DNA is commonly ligated in the vector pBR322?

BamH I Signup and view all the answers

What is the advantage of using a cloning vector with antibiotic resistance genes?

It allows for the selection of recombinant plasmids Signup and view all the answers

What does the letter 'R' in EcoRI represent?

Name of the strain of bacteria Signup and view all the answers

What is the function of exonucleases?

They remove nucleotides from the ends of the DNA Signup and view all the answers

What is the characteristic of a palindrome in DNA?

It is a sequence of base pairs that reads same on the two strands Signup and view all the answers

What is the purpose of restriction endonuclease in DNA?

To make cuts at specific positions within the DNA Signup and view all the answers

What is the general name of the class of enzymes that restriction endonuclease belongs to?

Nucleases Signup and view all the answers

What is the recognition sequence of a restriction endonuclease?

A specific palindromic nucleotide sequence Signup and view all the answers

What is the direction of reading in a palindrome in DNA?

5' to 3' direction Signup and view all the answers

What is the role of restriction endonuclease in forming recombinant DNA?

It makes cuts at specific positions within the DNA Signup and view all the answers

What happens to the antibiotic resistance gene when alien DNA is inserted?

It gets inactivated Signup and view all the answers

What is the purpose of using two antibiotics in the selection process?

To differentiate between recombinants and non-recombinants Signup and view all the answers

What is the result of insertional inactivation of β-galactosidase?

No production of colour Signup and view all the answers

What is the purpose of using a chromogenic substrate?

To differentiate between recombinants and non-recombinants Signup and view all the answers

What type of colonies are produced when the plasmid has an insert?

Colourless colonies Signup and view all the answers

What is the result of inserting a recombinant DNA within the coding sequence of β-galactosidase?

Inactivation of β-galactosidase Signup and view all the answers

What is the advantage of using alternative selectable markers?

It is simpler and more efficient Signup and view all the answers

What happens when a plasmid does not have an insert?

It produces blue colour Signup and view all the answers

What is necessary to increase the efficiency of DNA entering a bacterium?

A specific concentration of a divalent cation Signup and view all the answers

What is the purpose of heat shock in introducing recombinant DNA into bacteria?

To allow the bacteria to take up the recombinant DNA Signup and view all the answers

What method is used to introduce recombinant DNA into plant cells?

Biolistics or gene gun Signup and view all the answers

What is the first step in recombinant DNA technology?

Isolation of DNA Signup and view all the answers

What is the purpose of ligation in recombinant DNA technology?

To join the DNA fragment into a vector Signup and view all the answers

What is the genetic material of all organisms?

Deoxyribonucleic acid or DNA Signup and view all the answers

Why is it necessary to have DNA in pure form, free from other macro-molecules?

To cut the DNA with restriction enzymes Signup and view all the answers

What is the final step in recombinant DNA technology?

Extraction of the desired product Signup and view all the answers

Study Notes

Restriction Enzymes

EcoRI is a restriction enzyme with 'R' derived from the name of the strain of bacteria it was isolated from
Restriction enzymes are a type of nucleases that make cuts at specific positions within the DNA
Endonucleases, like restriction enzymes, cut DNA at specific positions, whereas exonucleases remove nucleotides from the ends of the DNA

Palindromic Sequences

Palindromes are groups of letters that form the same words when read both forward and backward
In DNA, palindromic sequences are sequences of base pairs that read the same on the two strands when orientation of reading is kept the same

Genetic Engineering

Genetic engineering involves creation of recombinant DNA, use of gene cloning, and gene transfer
This technique allows for the isolation and introduction of only one or a set of desirable genes without introducing undesirable genes into the target organism
Traditional hybridization procedures in plant and animal breeding often lead to inclusion and multiplication of undesirable genes along with the desired genes

Gene Cloning

Cloning sites in vectors need to have very few, preferably single, recognition sites for commonly used restriction enzymes
Presence of more than one recognition site within the vector will generate several fragments, which will complicate the gene cloning process

Selectable Markers

Genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline, or kanamycin are considered useful selectable markers for E. coli
Normal E. coli cells do not carry resistance against any of these antibiotics
Alternative selectable markers have been developed which differentiate recombinants from non-recombinants on the basis of their ability to produce color in the presence of a chromogenic substrate

Recombinant DNA Technology

Recombinant DNA technology involves several steps in a specific sequence such as isolation of DNA, fragmentation of DNA by restriction endonucleases, isolation of a desired DNA fragment, ligation of the DNA fragment into a vector, transferring the recombinant DNA into the host, culturing the host cells in a medium at large scale, and extraction of the desired product

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Description

This quiz is about restriction enzymes, specifically EcoRI, and their relationship to nucleases. It covers the origin of the name 'R' in EcoRI and the classification of these enzymes.