Using gene sequencing Flashcards
What is a genome
The total of all the genetic material in an organism
Where is the DNA in prokaryotes
In the cytoplasm
What are exons
The coding region
what are introns
The large non-coding regions of DNA that are removed before the messenger RNA is translated
What do we analyse in gene sequencing
Individual strands of DNA or individual gene, giving us a pattern of bases that codes for a particular protein in cells
What do we analyse in DNA profiling
The pattern in the non-coding areas of DNA and use them to identify individuals
What doe it mean when DNA is amplified
It is replicated repeatedly using a polymerase chain reaction to produce a much bugger sample
How did a scientist solve the problem of needed 90-95 degrees to amplify DNA
He used an enzyme from a bacterium that lives in hot springs to develop a technique for replicating artificially in a laboratory
How does PCR work
1) DNA sample that’s amplified is mixed with the enzyme Taq, DNA polymerase, primers and a good supply of 4 nucleotide bases,suitable buffer reaction and placed in a PCR machine
2) Heated to 90-95 degrees which causes DNA strand to separate as hydrogen bonds between them break
3) The mixture is cooled to 50-55 degrees so primers bind to single DNA strand
4) Finally, the mixture is heated to 72 degrees (optimum temp for Taq to build complementary strands of DNA)
What are the basic principles seen in all DNA sequencing
1) DNA strands chopped into smaller pieces
2) Double strands are separated into single strands
3) PCR is involved in replicating DNA fragments to produce large quantities of material for analysis
4) Labeled terminator bases are added to the single strands of DNA
5) The colored tags enable the sequence of bases to be read very rapidly by an automated system
What is a terminator base
A modified version of one of the four nucleotides bases; adenine (A), thymine(T), cytosine(c) and guanine(G)
What happens when a terminator DNA is incorporated into the DNA molecule
The chain is halted as no more bases can be added
What can DNA sequencing be used for
To determine the protein produced from any particular gene
How do we recognise the start and stop codon
By looking at the genetic code
What does DNA sequence make possible for us to see
To identify a faulty gene, see which bases have changed and understood how the changes in the DNA affect the Proteins produce
What are many diseases a result of
The inheritance of a number of alleles or gene variants that increase the risk of an individual developing a specific disease such as diabetes, obesity, or coronary heart disease
What has DNA sequence told us about heart disease
That certain genetic combinations greatly increased the risk of heart disease
What happens to the bases that cause heart attacks
What does this do to the heart
Around 25 bases are deleted from the gene, which causes major changes in the MYPBC3 protein
Damages heart muscles and make individuals 7 times more likely to suffer serious heart disease than someone without the mutation
How many genes does the human genome have
between 20000 and 25000 genes
How much DNA do introns make up
Over 90%
What can introns code for
what does it do
Some of them can code for small interfering RNA (siRNA)
Works with mRNA to stop some proteins from forming
What are there within the introns
There are short-sequences of DNA that are repeated may time to from micro-satellites and mini-satellites
How cany baes would be repeated in:
Micro-satellites
Mini-satellites
2-6 bases repeated between 5 and 100 are times
10-100 base sequence will be repeated 50 to several hundred times
What is the restriction endonucleases
The stand from a sample are cut into fragments using special enzymes known as restriction endonucleases
