Of all the common health problems, perhaps none are as familiar as the cold. Inflammation of the upper airways is viral in origin, but as there are many types of rhinoviruses, it is common that each time a new one causes infection. There is no vaccine against the cold, and treatment boils down to dealing with symptoms - such as a runny nose and cough, muscle aches, head and throat, and malaise - that are not caused by viruses but by the body's reaction to the invasion.
Category In details
In addition to water, carbon, nitrogen and oxygen, phosphorus is also important to living things. This element is, for example, part of the hereditary material and energy molecules of ATP. In some respects, the phosphorus cycle is simpler than the carbon and nitrogen cycles, as there are not many gaseous phosphorus compounds and therefore no passage through the atmosphere.
About 260 million years ago, every region where today is the semiarid was seabed, but the Caatinga biome is very recent. Just ten thousand years ago it was a huge rainforest, like the Amazon. To get to know this Brazilian semiarid biome, just visit the Serra da Capivara Archaeological Site, in the south of Piauí.
Flooding is not always that disaster you may have seen on TV: flooded cities, island people and animals, people who lose their homes with everything inside. Floods are natural phenomena that happen in all rivers. During the rainy season - which usually occurs during the summer in southern Brazil and during the winter in the northern region - rivers flood and flood the surrounding lands, called natural flood areas.
The light that bathes the earth is a component of the broad spectrum of electromagnetic radiation from the sun, which propagates like waves. How these waves propagate depends on energy: the more energy a wave has, the shorter it will be. Within the broad spectrum of electromagnetic radiation, only a small part is visible to our eyes - radiation whose wavelengths range from 380 to 760 nanometers.
Photosynthesis occurs in two major stages, which involve various chemical reactions: the first is the light phase (also called photochemistry) and the second is the dark phase (also known as the chemical phase). Generally speaking, the main events of photosynthesis are the absorption of light energy by chlorophyll; the reduction of an electron acceptor called NADP, which becomes NADPH 2; ATP formation and glucose synthesis The dark phase of photosynthesis need not occur in the dark.
See in more detail the photochemical phase. It is also called the "clear phase" of photosynthesis, as its occurrence is entirely dependent on light. As this is a stage that counts on the participation of chlorophyll molecules, it happens inside the tilacoids, in whose inner faces of their membranes the molecules of this photosynthesizing pigment are "anchored".
Lactobacilli (bacteria present in milk) perform lactic fermentation, where the end product is lactic acid. For this, they use as their starting point lactose, the sugar that is unfolded, by enzymatic action that occurs outside the bacterial cells, in glucose and galactose. Monosaccharides then enter cells where fermentation occurs.
Photosynthesis is the main autotrophic process and is performed by chlorophyllate beings, represented by plants, some protists, photosynthetic bacteria and cyanobacteria. In photosynthesis performed by photosynthesizers, except bacteria, carbon dioxide (CO 2) and water (H 2 0) are used for carbohydrate synthesis, usually glucose.
As we have seen, glycolysis consists in the transformation of one glucose molecule over several steps into two pyruvic acid molecules. In this process four hydrogens are released, which combine two by two, with molecules of a cell substance capable of receiving them: NAD (nicotinamide adenine dinucleotide).
Cloning is a common mechanism of reproduction of plant species or bacteria. A clone can be defined as a population of molecules, cells, or organisms that originated from a single cell and are identical to the original cell. In humans, natural clones are identical twins that originate from the division of a fertilized egg.
Pinocytosis In this case, the vesicles are small and the cell eats soluble molecules that would otherwise have difficulty penetrating the membrane. The pinocytic mechanism involves energy expenditure and is very selective for certain substances such as salts, amino acids and certain proteins, all of them water soluble.
Reticulum Types The eukaryotic cell cytoplasm contains numerous pockets and tubes whose walls have an organization similar to that of the plasma membrane. These membrane structures form a complex network of interconnected channels known as the endoplasmic reticulum. Two types of reticulum can be distinguished: rough (or granular) and smooth (or agranular).
Golgi's complex denomination or apparatus is named after the Italian cytologist Camilo Golgi, who in 1898 discovered this cytoplasmic structure. By ascertaining that certain regions with cellular cytoplasm were stained with silver osmium salts, Golgi imagined that there must be some kind of structure, later confirmed by electron microscopy.
The pockets originated by the fusion of lysosomes with phagosomes or pinosomes are called digestive vacuoles; Inside, the substances originally present in phagosomes or pinosomes are digested by lysosomal enzymes. As intracellular digestion occurs, the particles captured by the cells are broken down into small molecules that cross the membrane of the digestive vacuole into the cytosol.
When hyaloplasma is said to be a viscous fluid, one gets the impression that the animal cell has a soft consistency and is deforming at all times. It's not like this. A true "skeleton" made up of various types of protein fibers crosses the cell in various directions, giving it consistency and firmness.
Every day your cells produce proteins that contain amino acids in a certain sequence. Imagine, for example, that one day an epidermis cell in your skin produces a different protein. Suppose also that this protein is an enzyme that acts in a chemical reaction that leads to the production of a yellow pigment instead of the pigment normally found in the skin, melanin.
Plant cells have a thick, relatively rigid outer envelope: the cellulosic wall, also called the cellulosic skeletal membrane; Primary and Secondary Cellulosic Walls Young plant cells have a thin and flexible cellulosic wall called the primary wall. The primary wall is elastic to allow cell growth.
The library (from the Greek karyon, nucleus and theke, casing, box) is a envelope formed by two lipoprotein membranes whose molecular organization is similar to other cell membranes. Between these two membranes there is a narrow space called the perinuclear cavity. The outer face of the library, in some parts, communicates with the endoplasmic reticulum and often has ribosomes attached to its surface.
Gametogenesis is the process by which gametes are produced in organisms endowed with sexual reproduction. In animals, gametogenesis occurs in the gonads, organs that also produce sex hormones, which determine the characteristics that differentiate males from females. The fundamental event of gametogenesis is meiosis, which halves the amount of cell chromosomes, resulting in haploid cells.