Unit 8 Questions Flashcards
Why is it easier to determine the genome of a simple organism rather than a eukaryote?
Simple organisms have just one circular piece of DNA that is not associated with Histones. It also does not contain any non-coding sections of DNA.
What is an application of determining the proteome of simpler organisms?
Allows identification of proteins acting as antigens on the surface of pathogens. These can be used to produce effective vaccines against the disease.
What’s an example of a bacteria who’s proteome has been determined for vaccinology?
Plasmodium falciparum which causes malaria.
Why can recombinant DNA technology occur?
The genetic code is universal, as well as transcription and translation mechanisms. So the transferred DNA can be translated within cells of the recipient organisms.
What are the 3 methods of producing DNA fragments?
- conversion of mRNA to complementary DNA (cDNA), using reverse transcriptase
- using restriction enzymes to cut a fragment containing the desired gene from DNA
- creating the gene in a ‘gene machine’
Advantages of gene machine
- Any nucleotide sequence can be produced
- In a short time
- Very accurate
- Artificial genes are free of introns (so can be translated)
During in vivo gene cloning, why might not all bacterial cells possess the DNA fragments with the desired gene for the desired protein?
- only a few bacterial cells take up the plasmids when mixed together
- some plasmids close up before incorporating the DNA fragment
- sometimes the DNA fragment ends joins together to form its own plasmid
DNA technology could allow micro organisms to be used to control pollution. Give an example of this.
Breaking up and digesting oil slicks or harmful gases released from factories.
What is a potential disadvantage of micro organisms being used to control pollution ?
Could affect delicate ecosystems by changing the amount of one population at a trophic level, which may affect populations at others.
What’s a disadvantage of genetically modified bacteria having an antibiotic resistance gene marker?
This could spread antibiotic resistance to more harmful bacteria
What’s an example of a genetically modified crop which has been modified to help prevent diseases?
Golden rice, with a gene for vitamin A production, which helps people with vitamin A deficiencies.
What’s a disadvantage of golden rice?
May disadvantage local rice farmers.
Could affect evolution of rice, then we’d be tampering with nature.
Could have unimaginable ecological consequences we could not fore see.
What do primers do?
Attach to the end of a DNA strand that is to be copied and provide the starting sequences for DNA polymerase to begin DNA cloning.
DNA polymerase can only attach nucleotides to the end of an existing chain.
They also prevent two separate strands from rejoining.
How is cDNA made using reverse transcriptase?
The mRNA of the desired protein acts a template to which cDNA can be formed using reverse transcriptase. The cDNA is isolated by hydrolysis of mRNA.
cDNA gains its other strand by DNA polymerase
How are restriction endonucleases used to cut DNA into fragments?
Restriction endonuclease is extracted from bacteria and is specific to a particular recognition sequences which is where it cuts DNA.
