Title: What does the term "sticky ends" refer to in gene splicing?
Post by: marylove on Mar 13, 2012
2) Why is it essential that the same restriction enzyme be used to cleave (cut) the DNA of both organisms used to creat a transgenic organism?
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: duddy on Mar 13, 2012
When you splice a gene into a preexisting DNA molecule, the itself has two ends. These two ends must are stripped away its complementary strand. So, when you go to splice a gene with a DNA molecule, those stripped ends (which we called sticky ends) must complement the DNA into where it's being spliced into.
For example, say your gene was this:
AAATATATGACGAGCGA
ATATACTGCTCGCTGCG
For AAA and GCG are the sticky ends that will need to attach to a DNA molecule that has complementary nucleotides.
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: ilovebio. on Mar 13, 2012
2. Restriction Enzymes make precise cuts within the DNA that creates complimentary 'sticky ends.' If another RE is used the transgenic DNA will not be able to be 'pasted' into the DNA strand because it will contain a different arrangement of 'sticky ends.'
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: testbank2012 on Mar 13, 2012
Most restriction enzymes cut the DNA double-strand so that one of the two strands will be longer at that end than at the other. Since there will be unpaired bases on that longer end that are looking for nucleotides to comlete the base pairs, those unpaired bases are called 'sticky ends'. Look up a diagram on restriction enzymes in your book and I think you'll get it.
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: biokid2011 on Mar 13, 2012
Of course there is no glue in DNA.
When you splice a piece of DNA with a restriction enzyme, and want to insert the new gene, the "glue" that holds the two pieces together are the complementary bases, or sticky ends.
2. If you are refering to genetic engineering where a gene from humans eg producing insulin is inserted in a bacterial plasmid...
The same restriction enzyme is used to cut the DNA between particular base sequences. This creates 'sticky ends' so that the cut human enzyme will match the cut ends of the bacterial plasmid so the gene can be inserted. The human gene is then bound in place in the plasmid by a ligase enzyme. the plasmid is now replaced in the bacterial cell.
When the bacterium is allowed to grow in a nutrient medium it will reproduce the human gene along with its own during DNA replication. This means that when the bacterium carries out protein synthesis it will make human insulin along with its own proteins. The insulin can now be purified and given to diabetic patients.
Sorry if this is too long winded, hope it helps!
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: bubbagump344 on Mar 13, 2012
|
Restriction enzymes are short nucleotide sequences isolated from bacteria cells that protect them from virus. When a viral DNA enters the bacterial cell, the restriction enzyme is able to recognize a specific sequence (restriction site) on the DNA molecule, which is usually 4-8 nucleotides long. The restriction enzyme will cut the viral DNA at these sites and hence restrict the growth of the virus. Several hundreds of these enzymes have been isolated from various organisms and most are available commercially. These enzymes are used to cut a segment of gene from a human DNA molecule. Restriction enzymes can either produce sticky ends or blunt ends. Sticky ends are produced by cutting the DNA in a staggered manner within the recognition site producing single-stranded DNA ends. These ends have identical nucleotide sequence and are sticky because they can hydrogen-bond to complementary tails of other DNA fragments cut by the same restriction enzyme.
Sticky ends will tend to recombine to form a single strand of DNA. |
LigasesWhen two sticky ends meet, hydrogen bonds will form between the complementary bases at the sticky ends, but the covalent bonds that hold the sugar-phosphate backbone together have not. These breaks have to be sealed to produce a stable molecule. Ligases are enzymes that catalyse the formation of phosphodiester linkages between adjacent nucleotides. This process is known as Ligation. |
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: trinibaby652 on Mar 13, 2012
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: caitlin1292 on Mar 13, 2012
When restriction enzymes cut DNA (most) leave what are called sticky ends. This is when there is an offset between the position where each strand is cut.
eg:
ATCGGCTA -> ATCGG...............CTA
TAGCCGAT -> TA...............GCCGAT
The same restriction enzyme must be used to ensure that the 'sticky ends' match between the two sets of DNA (from each organism).
I dont know how well I have explained it - just tell me if you need a better explanation.
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: neveronlypeace on Mar 13, 2012
Title: What does the term "sticky ends" refer to in gene splicing?
Post by: George on Mar 13, 2012
so that the strands can be complimentary to each other and they kind bind to create recombiant DNA, using another restriction enzyme cuts the DNA strands at different points and so they would not be able to bind.