manipulating genomes

What are VNTRs in the context of genetic fingerprinting?

Variable Number Tandem Repeats are non-coding, repetitive DNA segments that vary in sequence and length between individuals.

What is the primary purpose of genetic fingerprinting?

To identify unique DNA patterns in individuals for profiling.

List the five main steps in creating a genetic fingerprint.

1. DNA extraction and PCR amplification, 2. DNA digestion with restriction enzymes, 3. Gel electrophoresis, 4. Hybridisation with fluorescent probes, 5. Development of DNA band patterns.

What are three key uses of genetic fingerprinting?

Establishing paternity, identifying suspects from crime scenes, and identifying genetic disorder risks.

What are the limitations of genetic fingerprinting?

Environmental contamination, similarity between close genetic relatives, and the need for corroborating evidence in court.

What is the function of a thermocycler in PCR?

It precisely heats and cools the PCR mixture to facilitate the different stages of DNA replication.

Why must DNA polymerase used in PCR be heat-stable (e.g., Taq polymerase)?

To avoid denaturation during the high-temperature stages of the PCR process.

What are the three stages of a PCR cycle and their approximate temperatures?

1. Separation (95°C), 2. Addition of primers (55°C), 3. DNA synthesis (72°C).

What are the advantages of PCR?

Rapid speed, high precision, ability to work with tiny DNA samples, and no requirement for living cells.

What is the purpose of the buffer solution in gel electrophoresis?

To maintain a constant, suitable pH during the separation process.

In gel electrophoresis, why do DNA fragments move toward the positive electrode?

Because DNA molecules are negatively charged.

How does gel electrophoresis separate DNA fragments by size?

The gel matrix slows down larger fragments more than smaller ones, causing them to travel at different speeds.

What is the purpose of adding loading dye to DNA samples before gel electrophoresis?

To make the samples visible while loading them into the wells.

What is the purpose of 'terminator bases' in Sanger sequencing?

They stop DNA synthesis at specific points, resulting in fragments of all possible lengths tagged with fluorescent colors.

How is the DNA sequence determined in modern Sanger sequencing?

A laser detects the fluorescent colors on the terminator bases of separated fragments, and a computer reconstructs the original sequence.

What is 'massive parallel sequencing' in Next Generation Sequencing?

A high-throughput method that allows for the simultaneous sequencing of millions of DNA fragments.

Define bioinformatics.

The development of tools and models to collect, store, and analyze biological data, such as DNA sequences.

What is the role of computational biology?

It uses bioinformatics tools to model complex biological systems and processes.

How is pathogen genome sequencing used in public health?

It monitors disease outbreaks, detects antibiotic resistance, and identifies potential drug targets.

What is DNA barcoding?

A technique that compares DNA from unknown organisms to reference databases to identify species and reveal evolutionary relationships.

Why are proteins treated with a chemical agent before gel electrophoresis?

To ensure all proteins have the same charge, allowing them to be separated based on size.

What is the role of primers in PCR?

They are short sequences of nucleotides that attach to the start and end of the target DNA fragment to initiate copying.

What is the primary difference between Sanger sequencing and Next Generation Sequencing?

Next Generation Sequencing is automated, high-throughput, and allows for massive parallel sequencing, significantly increasing speed and reducing costs compared to traditional Sanger methods.

Why can the number of unique proteins produced by an organism exceed the number of its genes?

Processes such as alternative mRNA splicing and post-translational modification allow a single gene to code for multiple proteins.

What is the primary goal of synthetic biology?

To design and build new biological systems or re-engineer existing ones, such as synthesizing functional genes or creating artificial genomes.

What is the definition of genetic engineering?

The manipulation of an organism's DNA, typically involving the extraction of a gene from one organism and inserting it into another.

What is a transgenic organism?

An organism that has been genetically engineered to include a gene from a different species.

What role do restriction enzymes play in recombinant DNA technology?

They are used to isolate the desired gene fragment from an organism and to cut open the vector DNA.

What are the two common types of vectors used in genetic engineering?

Plasmids (small, circular DNA molecules in bacteria) and bacteriophages (viruses that infect bacteria).

What is the function of DNA ligase in the formation of recombinant DNA?

It joins the sugar-phosphate backbone of the vector DNA and the inserted gene fragment, a process known as ligation.

How does the Bt gene in genetically modified soybeans benefit agriculture?

It produces a protein toxic to specific insect pests while remaining harmless to humans and other organisms, reducing the need for traditional pesticides.

What is a potential environmental disadvantage of herbicide-resistant GM plants?

They may cross-breed with wild plants, potentially creating herbicide-resistant weeds.

What is 'pharming' in the context of biotechnology?

The production of pharmaceuticals by inserting human genes into animals so that therapeutic proteins can be extracted from their milk or blood.

How can genetically altered pathogens be used in medicine?

By disabling disease-causing genes, researchers can turn pathogens into tools, such as engineered poliovirus that targets and kills cancer cells.

What is a major ethical concern regarding the patenting of GMOs?

It creates legal and financial barriers for smallholder farmers in developing countries who cannot afford patented seeds.

What is the primary purpose of gene therapy?

To treat or prevent genetic disorders by replacing faulty genes with healthy, functional versions.

How is a faulty recessive allele typically treated in gene therapy?

By adding a working dominant allele to the target cells.

How is a mutant dominant allele typically addressed in gene therapy?

By silencing the gene through the insertion of a piece of DNA using a vector.

What is the difference between somatic and germline gene therapy regarding inheritance?

Somatic modifications are not inherited by offspring, whereas germline modifications can be passed down to future generations.

Which cells are the primary targets for somatic gene therapy?

Somatic cells, specifically those most affected by the disorder, such as lung cells in cystic fibrosis.

What are the target cells for germline gene therapy?

Germ cells (egg and sperm) or embryos.

What is a significant ethical concern specifically associated with germline gene therapy?

It raises concerns about violating the rights of the unborn child and the potential for non-therapeutic enhancements.

What are two major challenges in the technical execution of gene therapy?

Successfully delivering healthy alleles into the cell nucleus and maintaining the long-term expression of those alleles.

What is one advantage of germline gene therapy for carrier parents?

It allows parents to ensure their children do not inherit a specific genetic disorder.

What is a disadvantage of using bacteriophages as vectors?

The process relies on the virus infecting the host bacterium to inject the recombinant DNA.

Why does the use of GM crops sometimes lead to reduced genetic diversity?

It encourages the practice of monocultures, making the crop population more vulnerable to environmental changes.