Module 6 Flashcards
What is the purpose of Polymerase Chain Reaction (PCR)?
To amplify fragments of DNA, creating enough material for accurate analysis.
What components are required in the PCR mixture?
DNA sample, free DNA nucleotides, primers, and DNA polymerase.
Why is DNA polymerase used in PCR extracted from thermophilic bacteria?
Because it can withstand the high temperatures used during PCR.
What are the three stages of PCR?
Separation of DNA strands (95°C), Annealing of primers (60°C), DNA synthesis (72°C).
What happens during the separation stage of PCR?
DNA strands are separated by breaking hydrogen bonds at 95°C.
How is gel electrophoresis used to separate DNA fragments?
DNA fragments are separated by length as they move through an agarose gel towards a positive electrode.
Why is DNA negatively charged?
Due to its phosphate backbone.
What is the role of a fluorescent tag in gel electrophoresis?
It binds to DNA and fluoresces under UV light, making the DNA visible.
What are restriction enzymes and what is their function?
Enzymes that cut DNA at specific recognition sequences.
What are the two types of DNA ends produced by restriction enzymes?
Blunt ends and sticky ends.
What is DNA profiling used for?
To compare DNA samples for crime investigations, paternity testing, or determining evolutionary relationships.
Describe the process of DNA profiling.
Amplify DNA using PCR. Separate fragments using gel electrophoresis. Compare banding patterns under UV light.
How is recombinant DNA created in genetic engineering?
By cutting DNA and plasmids with the same restriction enzymes and joining them with DNA ligase.
What is electroporation in genetic engineering?
Using an electric field to make bacterial membranes more permeable to recombinant plasmids.
How are genetically modified plants created?
By infecting plant cells with GM bacteria, integrating the desired gene into the plant genome.
How are genetically modified animals used to produce drugs?
By inserting drug-producing genes into fertilized eggs, which are then implanted into animals.
What are the two types of gene therapy?
Germ line therapy and somatic therapy.
Why is germ line therapy controversial?
Because the changes are heritable, affecting future generations without their consent.
What is the chain-termination method used for?
DNA sequencing by determining the order of bases in a DNA strand.
How are fluorescently-labelled nucleotides used in the chain-termination method?
They stop DNA synthesis when incorporated, allowing identification of terminal bases.
What is synthetic biology?
Designing and building artificial DNA sequences to create proteins, such as the antimalarial drug artemisinin.
How does genome sequencing work for long DNA strands?
The DNA is fragmented, sequenced in pieces, and reassembled using overlapping sequences.
Name one application of comparing DNA sequences in epidemiology.
Identifying genes associated with diseases, like APOE4 in Alzheimer’s.
What is a potential ecological risk of using GMOs in agriculture?
Cross-pollination leading to herbicide-resistant ‘superweeds.’
How can GMOs reduce allergic reactions in medicine?
By using human proteins like insulin instead of animal-derived versions.
What is the process of genetic engineering?
1)The insulin gene is removed from human DNA using restriction enzymes.
2)A plasmid is also cut with restriction enzymes.
3)DNA ligase joins the complementary sticky ends to form the recombinant DNA.
4)The recombinant plasmid is mixed with bacteria and placed in a machine called an electroporator – this creates an electric field to make the bacterial membrane more permeable.
5)The transgenic bacteria are grown in large fermenters to produce large amounts of insulin, which can then be extracted.
Why are brain cells and muscle cells different despite having the same set of genes?
They produce different proteins because different genes are activated or deactivated in each cell, leading to changes in structure and function.
What determines which proteins are made in a cell?
The activation of certain genes, which are transcribed into mRNA and then translated into proteins. These proteins alter the cell’s structure and function.
How do stem cells differentiate into specialized cells, like red blood cells?
Specific genes are activated to produce proteins (e.g., hemoglobin) while other unrelated genes are inactivated, causing the cell to specialize.
How do activators and repressors affect gene transcription?
Activators bind to the promoter region and help RNA polymerase bind, while repressors bind to the operator region and block RNA polymerase.
What are transcription factors (TFs)?
Proteins that regulate gene activation or deactivation. Activators turn genes on, and repressors turn genes off.
What is an operon in prokaryotes?
A section of DNA that controls a cluster of genes through a single promoter and includes structural genes, control elements (promoter and operator regions), and regulatory genes.
What is the role of the lac operon in E. coli?
It controls the production of enzymes needed to digest lactose. When lactose is present, the lac repressor is inactivated, allowing the transcription of genes to digest lactose.
How does the lac repressor function in the lac operon?
When lactose is absent, the lac repressor binds to the operator region, blocking RNA polymerase and preventing gene transcription. When lactose is present, it inactivates the repressor, allowing gene transcription
What is splicing in gene expression?
Splicing is the process of removing non-coding regions (introns) from mRNA before translation, which only occurs in eukaryotic cells.
What is cyclic AMP (cAMP) and its role in post-translational control?
cAMP is a molecule that activates proteins, such as protein kinase A (PKA), by changing their 3D structure to make them active.
What are Hox genes and their role in body development?
Hox genes control the body plan by regulating the formation of body structures. They activate or deactivate other genes to determine the location and type of body parts.
How do apoptosis and mitosis contribute to body plan development?
Mitosis generates the necessary cells for body parts, while apoptosis shapes those parts by removing unnecessary cells (e.g., forming fingers and toes).
What is apoptosis?
Apoptosis is controlled cell death where enzymes break down the cell’s components, and the cell fragments are removed by macrophages.
What triggers apoptosis?
Apoptosis can be triggered by internal stimuli (e.g., DNA damage) or external stimuli (e.g., pathogenic infection).
What are the types of mutations?
Substitution, insertion, deletion, and inversion, which can lead to changes in the amino acid sequence and protein function.
What is a frameshift mutation?
A mutation caused by an insertion or deletion of bases, altering the codon sequence and changing the amino acid sequence of the protein
What can cause a neutral mutation?
If a mutation changes a base but results in the same amino acid being coded for or if the mutation doesn’t affect the protein’s function (e.g., amino acids far from the active site).
What is an example of a beneficial mutation?
Antibiotic resistance in bacteria, where a mutation allows the bacteria to survive exposure to antibiotics.
What is an example of a harmful mutation?
Mutations that cause diseases such as cystic fibrosis or cancer, as they result in proteins with altered structures that do not function correctly
