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the S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA. in this way, the genetic material of a cell is doubled before it enters mitosis or meiosis, allowing there to be enough DNA to be split into daughter cells.
in S phase, the cell synthesizes a complete copy of the DNA in its nucleus. it also duplicates a microtubule-organizing structure called the centrosome. the centrosomes help separate DNA during M phase.
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B)heterotrophs
-autorophs
Encyclopedic entry. An autotroph is an organism that can produce its own food using light, water, carbon dioxide, or other chemicals.
-heterotrophs
An organism that cannot manufacture its own food and instead obtains its food and energy by taking in organic substances, usually plant or animal matter. All animals, protozoans, fungi, and most bacteria are heterotrophs. Compare autotroph.
-producers
In ecology, we define producers as organisms that are able to make their own food through photosynthesis or chemosynthesis. ... An organism that cannot make its own food cannot be a producer in ecology by definition.
During the krebs cycle NADH (Nicotinamide adenine dinucleotide) and FADH (<span>Flavin adenine dinucleotide) are made and used in the electron transport chan. Hope this helps!</span>
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.
The Cỉculatory system is an organ system that permits blood to everywhere in the body and transport nutrients, oxygen, carbon dioxide, ...to help fighting diseases ,.... The main parts of the Circulatory system are heart , lungs , veins , vessels, arteries,...
