Manipulating Genomes Flashcards
1
Q
What is Genetic engineering ?
A
- Genetic engineering is the manipulation of the DNA sequences of an organism
- Example - take the insulin gene and place it inside the genome of the ecoli , meaning the bacteria can produce insulin.
2
Q
Why is this useful?
A
- As you can make lots of copies of bacteria , its inexpensive and less time consuming
3
Q
What name is given to this area of biology and what is it ?
A
- Synthetic biology- involves transfer of fragments of DNA from one organism/Species
- The resulting genetically engineered organism will then contain recombinant DNA and will be genetically modified.
4
Q
How can human DNA work inside a bacteria ?
A
- As the genetic code - Universal, meaning that almost every organism uses the same 4 bases - A,T,C,G and the same codons for the same amino acids in living things (meaning that genetic information is transferable between species)
- Mechanisms of transcription and translation are also universal means that DNA can be translated within cells of the genetically modified organisms.
5
Q
What are the principles of genetic engineering ?
A
- Scientists can artificially change an organism’s DNA by combining lengths of nucleotides from different sources
6
Q
What is recombinant DNA ?
A
- The altered DNA
7
Q
What is a transgenic organism ?
A
- If an organism contains nucleotide sequences from a different species
8
Q
What is genetically modified organism ?
A
- Any organisms that has introduced genetic material (GMO)
9
Q
What are the uses of genetic engineering ?
A
- Genetic modification of crops to increase crop yield through resistance to drought,disease,pesticides and herbicides or to provide increased nutritional value.
- Genetic modification of livestock t give disease and pet resistance and increased productivity
-Genetic modification of bacteria to produce medicines,e.g insulin - Additionally bacterial can be modified to decompose toxic pollutants or carry out large scale chemical production.
10
Q
What are the steps for genetic engineering?
A
- Isolate and obtain the desired gene
- A copy of the gene is put into a vector (Plasmid or bacteriophage)
- The vector carries the gene into a recipient cell
- The recipient cell is selected for
- The recipient expresses the new gene
11
Q
What is the first method for genetic engineering and how does it happen ?
A
- Obtaining the desired gene
- A DNA probe can be used to locate a gene within the genome
- The gene can be cut out using a restriction endonuclease
-This leaves sticky ends which make it easier to insert the gene into the DNA of another organism - Amplify DNA
12
Q
What is a DNA probe ?
A
- Can be used to locate a gene within the genome
- It is short, single stranded
- A piece of DNA complementary to the gene
- It has a tag - flurosence or radioactivity
13
Q
Explain a restriction endonuclease
A
- They are palindromic sequences within DNA that cuts the sequence
- The active site of an enzyme is complementary to its recognition site
14
Q
Explain obtaining the desired gene (method 2 )
A
- Induce (Switch on gene ) expression of the desired gene
- Extract mRNA
- Use reverse transcriptase to form single stranded cDNA
- Amplify cDNA
- Cut the ends of cDNA with a restriction endonuclease
15
Q
Explain placing the gene into a vector
A
- The isolated gene is now inserted into a vector
- The most common vectors are bacterial plasmids
- This is now described as recombinant DNA
16
Q
What happens after you place the vector, how can this be a problem ?
A
- Both the desired gene and vector are cut with same restriction endonuclease
- They now have complimentary sticky ends
- The plasmids and genes are incubated with DNA ligase
- DNA ligase catalyses the formation of the phosphodiester bond between the complimentary sticky ends.
- The plasmids can reseal
17
Q
What are the types of vectors?
A
- Plasmids - transfer DNA into bacteria or yeast
- Viruses - transfer DNA into human cells or bacteria
- Liposomes- fuse with cell membranes transfer DNA into cells
-Agrobacterium - is a bacteria often used to transfer DNA to cells
18
Q
How do you transfer vector ?
A
- The vectors are now transferred into a host cell- this process is called transformation
- DNA is shared through plasmids
19
Q
What is electroporation?
A
- An electrical current is applied to the bacterium causing the membrane to become porous to allow the plasmids to pass through.
- Used to get DNA fragments into eukaryotic cells - have to make sure not to harm cell.
20
Q
How do you select transformed host cells?
A
- The marker genes
