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.
<span>B. Marsupials. </span>Amniotic eggs is a unique kind of egg because they possess a semipermeable shell to protect the egg but it also allows gas exchange. Inside an amniotic egg contains the amnion, chorion and allantois. Animals that lay amniotic eggs are called amniotes, which include reptiles, birds, dinosaurs, monotremes (platypus).
Answer:
The phylogenetic graph uses several types of variables to be formed, while other models use only one type of variable.
Explanation:
To create a phylogenetic chart, matrices with data on the studied species are used. These data are composed of morphological, chemical and / or genetic information that allow a detailed investigation about the ancestry of each species, in addition to allowing the correct grouping based on this ancestry and evolution.
A phylogenetic graph is different from other molecular models due to the number of data considered by it, since other models, such as the molecular clock, for example, only consider genetic based information.
Explanation:
What are the different pools and fluxes of carbon? Why are they important? This page provides a compilation of information and relevant links to help answer some of these questions.
The Carbon Cycle: What is the Carbon Cycle? What is the fast and slow cycle and how are they influenced?
Carbon Measurement Approaches and Accounting Frameworks: Approaches and methods for carbon stock and flow estimations, measurements, and accounting
The North American Carbon Cycle: The latest (2018) assessment and budget
Webinar Series Videos: 'The State of the Carbon Cycle: From Science to Solutions'
The Global Carbon Budget : The Global Carbon Budget as calculated by a global group of scientists
Frequently asked questions and their answers: Answers to commonly asked questions such as the following are listed here: Can you quantify the sources and sinks of the global carbon cycle? How much carbon is stored in the different ecosystems? In terms of mass, how much carbon does 1 part per million by volume of atmospheric CO2 represent? What percentage of the CO2 in the atmosphere has been produced by human beings through the burning of fossil fuels?
Answer: D. Sedimentary
Explanation:
Sedimentary rocks are formed overtime are different particles of sand, shells, pebbles and other fragments of materials form layers and harden into rock.
