For a long time, in the past, the human species could get food only by hunting, fishing and harvesting grains, fruits and roots. But about ten thousand years ago, our species also began to plant vegetables and raise the animals that serve as their food. It was the starting point for the development of agriculture.
The Greenhouse Effect is Earth's way of keeping its temperature constant. The atmosphere is highly transparent to sunlight, but about 35% of the radiation we receive will be reflected back into space, with the remaining 65% trapped on Earth. This is mainly due to the effect on the infrared rays of gases such as carbon dioxide, methane, nitrogen oxides and ozone present in the atmosphere (totaling less than 1% of this), which will retain this radiation on earth, allowing us to watch their calorific effect.
Water has two cycles: Short or small cycle It is the one that occurs by the slow evaporation of water from the seas, rivers, lakes and lakes, forming clouds. These condense, returning to the surface in the form of rain or snow. Long cycle It is the one in which water passes through the body of living beings before returning to the environment.
Set of all living beings that interact in a certain region and may be called biocenosis, community or biota. As we have seen, according to the way food is obtained, the community of an ecosystem is generally made up of three types of beings: Producers: the chemosynthesizing (bacteria) and photosynthesizing (bacteria, algae, and vegetable) beings.
The activity of an ecosystem can be assessed by gross primary productivity (PPB), which is the total organic matter produced in grams over a period of time in a certain environmental area: PPB = mass of organic matter produced / time / area Discounting this Total amount of organic matter consumed by the community during this period, in respiration (R), we have the net primary productivity (PPL), which can be represented by the equation: PPL = PPB - RA The productivity of an ecosystem depends on several factors, among which the most important are light, water, carbon dioxide and nutrient availability.
By burning fossil fuels to power plants, factories and vehicles, sulfur is released into the air. This sulfur rises into the atmosphere in the form of gas called “sulfur dioxide”, a major air pollutant. When sulfur dioxide joins with atmospheric moisture, it forms sulfuric acid, one of the main components of acid rain.
Evolutionary Origin of Chloroplasts Chloroplasts are believed to have originated from photosynthetic prokaryotic organisms (blue algae), which settled in primitive endosymbiosis aerobic eukaryotic cells. This symbiosis, about 1.2 billion years ago, would have given rise to red algae, then brown and green algae, and higher vegetables.
At first glance, photosynthesis has little or no association with electronics, yet there is potentially a strong connection between these two fields of knowledge. Today, we seek to develop information transmission technologies that are as fast and compact as possible, reaching the molecular dimension (nanotechnology).
Each time the glucose molecule disassembles, energy is not simply released into the medium. Energy is transferred to other molecules (called ATP - Adenosine Triphosphate), which will serve as temporary energy reservoirs, which can release energy pills wherever they are.
The great news of Dolly was precisely the discovery that a differentiated mammalian somatic cell, such as the skin cell, the heart cell, etc. it could be reprogrammed to the early stage and again totipotent (that is, to be able to give rise to any cell type again). This was achieved by transferring the nucleus from a somatic cell of the sheep mammary gland that originated Dolly to an anucleated egg (egg without nucleus).
As we saw in the previous item, DNA fragments formed with the action of restriction enzymes have different sizes. The most widely used technique for separating DNA fragments is electrophoresis through agarose gels. Agarose is a polysaccharide (such as agar and pectin) that dissolves in boiling water and then gels when it cools down like gelatin.
This section is dedicated to science education (elementary school content). Click on the name of the desired subject to view its content. Universe Emergence of the Universe Stars Constellations Galaxy Solar System Planets Satellites Comets Asteroids Meteors The Moon Eclipses Air Carbonic Gas Nitrogen Noble Gases Water Steam Atmospheric Pressure Weather Forecast Air Masses Temperature and Humidity Meteorological Stations Air Pollution O Greenhouse Effect Thermal Inversion Water Physical States of Matter Physical State Changes Water Properties The Water Cycle The Water Quality Water Pollution Sources Treatment Stations Transmitted Diseases Water, Mosquito and Diseases The Planet Inside and Out Plate Tectonics Earthquakes Volcanoes Rocks, Minerals and Soil Magmatic or Igneous Rocks Sedimentary Rocks Metamorphic Rocks The Soil Cycle Soil Formation Soil Types Farming Agriculture Sustainable Agriculture Pollution Destination Soil Erosion Recycling Importance and Benefits Recycling Symbology recycling Paper recycling Glass recycling Metal recycling Plastic recycling Recycling batteries and batteries Recycling debris Tire recycling Non-recyclable materials Cooking oil recycling Ecology What does ecology study?
A first attempt was made to cure Severe Immunodeficiency Syndrome in newborns, a disease caused by the absence of the enzyme adenosine deaminase, which causes failures in the immune response, leading to death. The gene coding for this enzyme has been successfully cloned and injected into leukocytes taken from affected children.
With the fragmentation of DNA molecules using restriction enzymes and their recognition by gel electrophoresis, the next step is to multiply (clone) the obtained fragment and subject them to recombinant DNA technology. The technique of DNA strand multiplication is called PCR (polymerase chain reaction).
Plant cell vacuoles are interpreted with expanded regions of the endoplasmic reticulum. In young plant cells some of these regions are observed, forming small vacuoles isolated from each other. But as the cell reaches adulthood, these small vacuoles fuse into a single large central branch with branches reminiscent of their reticular origin.
The Cell Border In today's world, it is common to think of a country as a portion of land spatially bounded by the presence of a border. Let's think about the case of Brazil. We are surrounded by sea in half of our territory, and in the other half, we have a land border with nine other countries in South America.
They are mobile structures, found externally in cells of various living beings. Eyelashes are short and may be related to locomotion and the removal of impurities. In cells lining the human trachea, for example, the ciliary beats push impurities from the inspired air, work facilitated by mixing with mucus that, produced by the trachea cells, lubricates and protects the trachea.
It always occurs in favor of the gradient, in order to equalize the concentrations on both sides of the membrane. It does not involve energy expenditure. Water moves freely through the membrane, always from the lowest solute to the highest concentration. The pressure with which water is forced to cross the membrane is known as osmotic pressure.
Plastos Classification and Structure Plastos are cytoplasmic organs found in plant and algal cells. Its shape and size vary by body type. In some algae, each cell has one or a few plastos of large size and characteristic shapes. Already in other algae and plants in general, plastos are smaller and are present in large numbers per cell.
The genetic message contained in DNA is formed by a four letter alphabet that corresponds to the four nucleotides: A, T, C and G. With these four letters it is necessary to form "words" that have the meaning of "amino acids". Each protein corresponds to a "phrase" formed by the "words", which are the amino acids.
Prophase II - each of the two daughter cells has only one batch of duplicate chromosomes. In this phase the centrioles duplicate again and the cells in which the library was formed, it begins to disintegrate. Metaphase II - As in mitosis, the chromosomes attach by the centromere to the spindle fibers, which depart from both poles.