Genetic Engineering Flashcards
What are the three basic steps in genetic engineering?
- Finding the DNA segment with the desired gene.
- Isolating the DNA segment from the genome.
- Using a vector to place desired gene in new organism.
What must you start with to find the DNA segment ?
A protein or mRNA
If starting with protein, what then happens to this protein?
Synthetic mRNA is made based on amino acid sequence of protein.
What does the radioactively labeled mRNA do?
Radioactively labeled mRNA anneals to heated [ssDNA] It will stick to the piece of DNA with the desired gene
If starting with mRNA, how is the mRNA accessed?
A cell that is active in protein synthesis makes lots of mRNA, so scientists isolate its mRNA from the cytoplasm and label it radioactively.
Which version of finding the DNA segment introduces less error?
Starting with mRNA.
Why does starting with mRNA introduce less error?
Because there are multiple codons for different amino acids, so making mRNA based on amino acids won’t be as accurate.
What is used to randomly cut up the DNA in step 2?
Restriction enzymes
Explain step 2. (isolating the DNA)
Isolating the DNA.
- restriction enzymes randomly cut up DNA.
- Pieces are separated through gel electrophoresis.
- labelled mRNA is used to locate large pieces of DNA in target gene.
- These pieces of DNA are cut out of the gel.
What are the steps to solving location of gene problem?
- Write segment numbers of DNA on gel grid based on relative lengths.
- Based on step 1, write segment letters on digested DNA grid corresponding to protein synthesis data.
- Identify the segment of DNA that produces a normal protein. This segment contains the gene.
- Any segment that produces a smaller, not useful protein is missing the stop codon at the end of the gene.
- Any segment that produces no protein until a promoter is added has the start codon, but is missing the promoter (found just upstream from the gene)
Explain step 3 (using a vector)
Genetically engineered Plasmids with cutting places and known antibiotic R genes are placed into the chromosomes of bacteria. The target gene is then placed into the plasmid. If the bacteria integrates it, bacteria will resist the antibiotic, indicating that the target gene is there.
Other than bacteria, what are these plasmids used for?
to infect plants and integrate the target gene into the plant.
How is a virus used as a vector?
It must be a DNA virus that undergoes a lysogenic cycle. First, it is modified to remove all the harmful genes. Then the virus injects its genetic material (containing the target gene) into an animal cell.
What is a useful application of using viruses as vectors?
For children born with a defect in their immune system. Their cells are removed from their bone marrow and transformed with the target gene injected using viruses.
