The "scissors" of the molecular biology are: DNA Restriction enzymes.
A restriction enzyme is a protein capable of cleaving a DNA fragment at a characteristic nucleotide sequence called a restriction site. Each restriction enzyme thus recognizes a specific site. Several hundred restriction enzymes are currently known.
Naturally present in a large number of species of bacteria, these enzymes have become important tools in genetic engineering.
The "glue" of the molecular biology are: DNA ligase
In molecular biology, DNA ligases are ligase-class enzymes that catalyze the formation of a phosphodiester bond between two segments of DNA. DNA ligases are involved in several essential cellular processes of DNA metabolism: in DNA replication, suture of Okazaki fragments, and in DNA repair and homologous recombination.
The use of these tools in molecular biology: Cloning
Molecular cloning is one of the bases of genetic engineering. It consists of inserting a DNA fragment (called insert) in an appropriate vector such as a plasmid for example. The new plasmid thus created will then be introduced into a host cell, generally the Escherichia coli bacterium. This will then be selected and multiplied to obtain a large amount of the plasmid of interest. Cloning a gene involves inserting it into a plasmid. A clone will be the bacterial transformant that contains this particular plasmid. In this case we speak of clone because all the individuals of the bacterial colony are genetically identical. Molecular cloning is thus different from reproductive cloning (creating an individual genetically identical to another but of a different age) or therapeutic cloning (making tissues from stem cells to perform transplants compatible with the recipient).
Molecular cloning requires restriction enzymes capable of cleaving the DNA, and DNA ligase capable of re-gluing the DNA fragments. Ligase was isolated for the first time from T4 bacteriophage. This enzyme is involved in the repair and replication of DNA. It can bind DNA fragments with compatible sticky ends. At higher concentration, this enzyme is also able to bind two ends of DNA as shown here. T4 DNA ligase works using ATP and Mg ++. It has an activity optimum of 16 ° C, but remains active at room temperature.
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B. An egg cell and a sperm cell unite.
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it regulates blood volume and blood pressure.
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the point of science is to disprove hypothesis so having a hypothesis that doesn't allow that to happen is not good science
2. they don't fit in our mouths so are a trait from when we had larger jaws
3. bones of your lower jaw, middle ear and voice box (they aren't actually gills fyi, they just look like them)
4. likely yes as their bones were hollow but likely only able to fly short distances, the thought was that they couldn't do their size and weight but with hollow bones they were able to like a quail would
5. no because they could be sister taxa, you would have a hard time proving exactly that this new fossil is the common ancestor that birds came from to replace the old hypothesis (guess) of which one did.
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