Genome projects and gene technology Flashcards
What does it mean to ‘sequence a genome’? (1)
To know the exact sequence of bases that make up the entire DNA of an organism
What is the proteome? (1)
Full range of proteins produced by cells
Applications of determining the proteome (1)
Allows identification of potential antigens for use in vaccine production
Why can the genome not be easily translated into the proteome in more complex organisms? (2)
Due to non-coding DNA and regulatory DNA
What is meant recombinant DNA technology? (1)
Transfer of DNA fragments from one organism to another
What does the term universal mean? (1)
The same triplet codes for the same amino acid
What does degenerate mean? (1)
More than one triplet codes for the same amino acid
What does non-overlapping mean? (1)
Each base is part of only one triplet
(a base from one triplet cannot be used in an adjacent triplet)
Why is recombinant DNA technology possible? (3)
Because the genetic code is:
degenerate
universal
non-overlapping
What are the 5 steps in recombinant DNA technology? (5)
Isolation of genes
Insertion
Transformation
Identification
Growth/cloning
How can reverse transcriptase (RT) be used to produce fragments of DNA? (4)
mRNA mixed with free DNA nucleotides and RT
Free DNA nucleotides bind to single stranded mRNA template via complementary base pairing
RT joins DNA nucleotides together to form a single stranded cDNA molecule
DNA polymerase required to make cDNA double stranded
What are the advantages of using reverse transcriptase to produce fragments of DNA? (2)
mRNA is much easier to obtain
Using mRNA isolated from cytoplasm means introns have been removed, whereas genes have introns
How can restriction endonuclease (RE) be used to produce fragments of DNA? (3)
RE hydrolyse DNA at specific recognition (base) sequences
DNA sample is incubated with the specific restriction endonuclease which hydrolyse the DNA into fragments wherever the recognition sequence appears
If the target gene has recognition sequences before and after the target gene, the fragments will contain the desired gene
Why do different restriction endonucleases hydrolyse DNA at different specific recognition sequences? (1)
Because the shape of the sequence is complementary to the enzyme active site
Recognition sequences are sometimes what? (1)
Palindromic
What does palindromic mean? (1)
The base pair read is the same in opposite direction
What happens if the recognition sequence for the selected restriction endonuclease occurs within the DNA fragment you want to isolate ? (1)
This will cut the gene and it will not code for a functional protein
When can a promoter region be added? (1)
Once a DNA fragment is isolated
What does adding a promoter region, once a DNA fragment is isolated, do? (2)
Allows transcription factor to bind
Allows the gene to be expressed once inserted into the bacterial plasmid
What does a terminator region do? (1)
Stop transcription of gene of interest
How can the gene machine be used to produce fragments of DNA? (4)
Desired nucleotide sequence fed into a computer
Synthesis of oligonucleotides
Assembly of gene - oligonucleotides are overlapped then joined together and made double stranded using polymerase chain reaction (PCR)
Gene is inserted into the bacterial plasmid
Advantages of producing DNA fragments via the gene machine (2)
Artificial genes are easily transcribed and translated by prokaryotes
As they have no introns in their DNA