Genetics Timeline: Key Discoveries and Techniques

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Questions and Answers

What is the primary role of the vector in a gene cloning experiment?

It is a type of living organism used as a host.

It transports the gene into a host cell. (correct)

It amplifies the gene without cellular involvement.

It assists in the process of thermal cycling.

Which step in gene cloning ensures that multiple copies of the recombinant DNA are produced?

Initial mixing of reagents in PCR.

Identification of the cloned gene.

Division of the host cell. (correct)

Insertion of DNA fragment into the vector.

How does PCR differ from gene cloning?

PCR creates colonies of identical cells.

PCR requires pre-programmed temperature cycles. (correct)

PCR is performed in multiple test tubes.

PCR involves manipulation of living cells.

What happens to the recombinant DNA during the growth of the host cell?

It replicates along with the vector. Signup and view all the answers

What is created after a large number of cell divisions in a gene cloning procedure?

A colony of identical host cells. Signup and view all the answers

What major breakthrough occurred between 1952 and 1966 in the field of genetics?

Discovery of the double helix structure of DNA Signup and view all the answers

What was the primary limitation faced by molecular biologists in the late 1960s?

Insufficient experimental techniques for detailed gene study Signup and view all the answers

Which technology developed between 1971 and 1973 sparked a new age of genetics?

Recombinant DNA technology Signup and view all the answers

What was a significant application of the techniques developed during the gene cloning revolution?

Producing proteins and compounds for medical and industrial use Signup and view all the answers

What was Kary Mullis credited with inventing in 1985?

Polymerase chain reaction (PCR) Signup and view all the answers

What key feature distinguishes the polymerase chain reaction (PCR) from gene cloning?

PCR enables the amplification of DNA sequences Signup and view all the answers

What culminated in the turn of the century related to genetic research?

The completion of various genome sequencing projects Signup and view all the answers

What consequence did the gene cloning revolution have on our understanding of diseases?

It helped to understand how gene activity aberrations contribute to diseases like cancer. Signup and view all the answers

What is a primary function of plasmids in bacteria?

To carry genes responsible for useful characteristics Signup and view all the answers

Why are antibiotic resistance genes considered useful in laboratory settings?

They act as selectable markers for plasmids Signup and view all the answers

What characteristic do plasmids often possess to multiply within bacterial cells?

An origin of replication Signup and view all the answers

Which type of plasmid is specifically mentioned as carrying antibiotic resistance genes?

RP4 Signup and view all the answers

What happens to E. coli cells that do not contain specific plasmids like RP4 in a culture with antibiotics?

They cannot survive and grow Signup and view all the answers

In genetic engineering, what is a common application of plasmids?

To clone genes for research purposes Signup and view all the answers

Which of the following statements is accurate regarding plasmids?

They can provide multiple antibiotic resistances Signup and view all the answers

What is the significance of the term 'selectable marker' in relation to plasmids?

It signifies the presence of a gene useful for identification Signup and view all the answers

What happens immediately after the λ phage particle attaches to an E.coli cell?

The λ phage injects its DNA into the E.coli cell. Signup and view all the answers

What is the role of the cohesive ends (cos sites) during λ phage infection?

They enable the circularization of the linear DNA molecule. Signup and view all the answers

During the lysogenic infection cycle, what occurs after the λ DNA integrates into the host chromosome?

The host cell undergoes division. Signup and view all the answers

What triggers the induction of the λ DNA during the lysogenic cycle?

The excision of λ DNA from the host chromosome. Signup and view all the answers

What is the first step in the process after the λ DNA excises from the host chromosome?

The production of new phage particles. Signup and view all the answers

What is meant by ‘sticky ends’ in the context of λ phage DNA?

They are segments that promote the circularization of DNA. Signup and view all the answers

What characteristic of λ DNA allows it to integrate into the bacterial genome?

The circularization of the λ DNA. Signup and view all the answers

Which of the following statements correctly describes the lytic cycle following the induction of λ DNA?

The E.coli cell lyses to release new phage particles. Signup and view all the answers

What essential element does M9 medium primarily provide for bacterial growth?

Nitrogen Signup and view all the answers

What is a key characteristic of Luria-Bertani (LB) medium?

It is a complex or undefined medium. Signup and view all the answers

Which component of M9 medium is primarily responsible for supplying carbon and energy?

Glucose Signup and view all the answers

What additional factors are generally required for M9 medium to support bacterial growth?

Trace elements and vitamins Signup and view all the answers

What is the role of tryptone in Luria-Bertani (LB) medium?

To supply amino acids and small peptides Signup and view all the answers

What content in yeast extract contributes to the nitrogen requirements in LB medium?

Undetermined mixtures Signup and view all the answers

Which of the following is NOT a component of M9 medium?

Tryptone Signup and view all the answers

What type of substances must be added to M9 medium to make it suitable for different bacterial species?

Trace elements and vitamins Signup and view all the answers

What type of DNA is primarily used as the source of material for cloning genes?

Total cell DNA Signup and view all the answers

Why are viruses considered useful as cloning vectors for higher organisms?

They can replicate within non-bacterial cells. Signup and view all the answers

Which of the following viruses is commonly used in gene therapy applications?

Adenovirus Signup and view all the answers

In the preparation of plasmid DNA, what is the key procedural difference compared to total cell DNA preparation?

The plasmid DNA must be separated from chromosomal DNA. Signup and view all the answers

What type of organism's DNA includes genomic DNA and additional DNA molecules like plasmids?

Bacteria Signup and view all the answers

Which of the following is NOT typically a characteristic of phage DNA used as a cloning vector?

It is usually larger than plasmid DNA. Signup and view all the answers

What is one common application of baculoviruses in biotechnology?

Producing pharmaceuticals in insect cells Signup and view all the answers

What role do plasmids play in the context of total cell DNA during DNA preparation?

They are extrachromosomal DNA that can be included. Signup and view all the answers

Study Notes

1952-1966: Initial Genetic Discoveries

DNA structure elucidated
Genetic code cracked
Transcription and translation processes described

Post-1966: A Period of Lull

Experimental techniques of the late 1960s were not sophisticated enough for detailed gene study
Frustration among molecular biologists

1971-1973: Revolution in Genetic Research

Recombinant DNA technology (genetic engineering) emerged
Enabled previously impossible experiments
Led to gene cloning, DNA sequencing, and understanding gene regulation

Advancements in Genetics & Biotechnology

Rapid DNA sequencing allowed gene structure determination
Massive genome sequencing projects, including the Human Genome Project (completed 2000)
Understanding of gene aberrations in diseases like cancer
Sparked modern biotechnology for protein and compound production in medicine and industry

Polymerase Chain Reaction (PCR)

Invented by Kary Mullis in 1985
Simple technique complementing gene cloning
Significantly easier alternative for DNA manipulation

Gene Cloning Process

DNA fragment insertion into a vector (circular DNA molecule)
Vector transports DNA into host cell (often a bacterium)
Vector replication produces numerous copies of the gene
Host cell division copies recombinant DNA
Colony (clone) of identical host cells is created
- Each cell has copies of the recombinant DNA molecule
- Cloned gene

PCR Process

In-tube process using DNA, reagents and a thermal cycler
Incubation at programmed temperatures

Plasmids

Independent genetic elements in bacterial cells
Often carry genes for useful characteristics (e.g., antibiotic resistance)
Antibiotic resistance used as a selectable marker in lab experiments
Contain DNA sequences that allow replication within cell

Viruses as Cloning Vectors

Used as cloning vectors for higher organisms
Plasmids are uncommon in organisms other than bacteria and yeast
Eukaryotic viruses (adenoviruses, baculoviruses, caulimoviruses, geminiviruses)

DNA Purification

Genetic engineers need different types of DNA (total cell DNA, plasmid DNA, phage DNA)
Total cell DNA used as a source of genes for cloning
- Bacteria, plants, animal cells
Plasmid DNA isolation differs from total cell DNA purification
Phage DNA is needed if using phage vectors

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Description

Explore the significant milestones in genetics from 1952 to the present. This quiz covers initial discoveries, breakthroughs in genetic engineering, and advancements like PCR and genome sequencing. Test your knowledge of how these developments have influenced biotech and medicine.