They are all made of eukaryotic cells and have a nuclei
<span>Bacteria are tiny. A typical bacterial cell is just a few micrometres across (a few thousandths of a millimetre). The structure of a bacterial cell is different to an animal or plant cell. For example, they do not have a nucleus but they may have a flagellum. This is a tail-like part of the cell that can spin, moving the cell along.A unicellular organism is a living thing that is just one cell. There are different types of unicellular organism, including:
bacteria
protozoa
unicellular fungi
You might be tempted to think that these organisms are very simple, but in fact they can be very complex. They have adaptations that make them very well suited for life in their environment.Protozoa are unicellular organisms that live in water or in damp places. The amoeba is an example of one. Although it is just one cell, it has adaptations that let it behave a bit like an animal:
it produces pseudopodia (false feet) that let it move about
its pseudopodia can surround food and take it inside the cell
contractile vacuoles appear inside the cell, then merge with the surface to remove waste
You may be familiar with fungi from seeing mushrooms and toadstools. Yeast are unicellular fungi. They are used by brewers and wine-makers because they convert sugar into alcohol, and by bakers because they can produce carbon dioxide to make bread to rise.
Yeast have a cell wall, like plant cells, but no chloroplasts. This means they have to absorb sugars for their nutrition, rather than being able to make their own food by photosynthesis
Yeast can reproduce by producing a bud. The bud grows until it is large enough to split from the parent cell as a new yeast cell.</span>
This is the process of photosynthesis and photosynthesis occurs in the chloroplast, ¿?
DDT stands for dichloro-diphenyl-trichloroethane. The first kind of synthetic/artificial insecticides came into use in the 1940s. The earlier usage of DDT include: a) Killing of malarial vectors, b) Combatting Typhus and other insect borne human diseases, c) As a pest control in crops d) as a pest control in garden, live stock production and even at homes.
The negative impact of DDT could be felt for the first time when the pests that were earlier killed by use of DDT have now become pesticides resistant. In the 1950s in USA, the regulatory measures were adopted to reduce the usage of DDTs as its effects as a pesticides were no more long significant and also it was creating detrimental physical and psychological impacts on the human and environment.
It was in 1972 that the U.S. Environmental Protection Agency cancelled the order for banning the usage of DDT based on the adverse impact it produced on the environment, human and other life forms. Since then continuous studies are being conducted to analyse the impact of DDTs. In some later years it was established that DDT is the cause of producing tumors in liver.
Some of the common negative impacts produced by DDT as per the U.S. Department of Agriculture :
a) The non destructive nature – DDT can not be destroyed and thus it remains persistent in the atmosphere
b) It attacks the tissues of living organisms especially the animals and humans ( fatty tissue)
c) It can penetrate the atmosphere to deeper extent.
Now as per the current stuation, The use of DDT is controlled and other alternatives of pest control organisms is being deduced. As per the treaty of Stockholm Convention on POPs (Persistent organic pollutants) , usage of DDT for malarial control is justified but it puts a restrictive use of DDT as pesticides in other areas.
A silent mutation. This is when the new codon will work just as well as the old one without changing the amino acid shape.
