The outermost part of prokaryotic cells is their cell wall, and in this case the capsule or glycocalyx. Thanks to it we can distinguish two large groups of bacteria: Gram+ and Gram-. Next we find the cell membrane, which except in the case of archaebacteria, is like that of eukaryotic cells, a bilayer (double layer) of lipids with proteins, but more fluid and permeable for not having cholesterol.
Telomerase is an important enzyme responsible for maintaining telomere length . Telomeres are the structures formed by DNA, together with proteins, at the ends of chromosomes . Chromosomes are, strictly speaking, linear DNA sequences, accompanied by proteins that contribute to their folding.
In order to understand the importance of Okazaki fragments, some fundamental knowledge of DNA replication is needed. When a cell receives internal or external signals that it has to multiply, one of the first things it has to do is copy its genetic material, this phenomenon is known as the process of DNA replication.
Water is the most abundant substance in living things. Although this statement should be qualified: a seed can only have 20% water and the tissue called "dentin" present in our teeth has only 10% water. At the opposite extreme, in algae it can represent 95% of its weight, the same as in the human brain.
Coral reefs are one of the most diverse ecosystems on the planet. What are the biological interactions that structure this diverse ecosystem? What is a coral? Corals are members of the phylum Cnidaria, a diverse group that includes jellyfish and sea anemones.
The quaggas or quaggas were a subspecies of the common zebra that we find today in Africa. This species was extinct due to hunting by humans , which used its meat and skin, although it was also exterminated so that it would not compete with domestic ruminants that wanted to enter the territories previously occupied by this variety.
Blood is a fluid-like tissue that circulates throughout the body of vertebrates . It is a conjunctive or connective tissue, since all the types of cells that make up the blood have their origin in the embryonic mesenchyme . In addition, the function of all connective tissues is to unite the body, giving it support and integrating the other tissues.
The World He alth Organization (WHO) is the body in charge of establishing, managing and coordinate standards and guidelines for he alth, prevention, intervention and promotion in he alth issues worldwide . The WHO emerged as a specialized agency, following the concern of the United Nations Organization (UN).
Living matter is extremely complex. So much so that the biologist has the need to organize such diversity, in order to rationally be able to study it. If we consider a living being, an animal for example, there are many ways to approach its study.
Polysaccharides are formed by the union of hundreds of monosaccharides, linked by “O-glycosidic” bonds. There are some formed by pentose units, called pentosans , but those with biological importance are the polymers of hexose units, also called hexosans, and most especially the polysaccharides formed from glucose.
In most plants the stems are aerial, but in some cases they develop above or below the surface of the soil. Although the latter have the appearance of roots, their structure is that of a stem. Some biennial or perennial species defend themselves from the cold season by forming underground stems that store reserve substances, which serve, the following year, for the formation of aerial shoots.
The heart is the organ responsible for propelling blood or hemolymph through the circulatory system that extends throughout the body of animals . The organ is constituted in vertebrates by 3 types of tissues: the heart tissue responsible for muscle contraction is made up of cardiac muscle cells (cardiomyocytes), a special type of muscle cell, of which you can read more in his article here (coming soon).
White blood cells or leukocytes are a set of cell types whose joint function is to defend the body against the intrusion of foreign bodies, whether these organisms or toxins. White blood cells travel in the blood and are able to cross the wall of blood vessels to enter the different tissues in response to signs of invasion.
By the name of chameleons all the species belonging to the Family Chamaeleonidae are known. Description : Chameleons are small reptiles quadrupeds. Like snakes, chameleons shed their skin twice a year. Most species have a size between 15 and 20 cm.
Five Base Perspectives: A contractual perspective Contractarianism holds that morality has arisen from humans making agreements or contracts with each other. Since animals cannot make contracts, they are essentially a resource for human use.
What should we try to protect? Expanding human demands on land, sea, and freshwater, coupled with the impacts of climate change, have made conservation and management of wilderness and wildlife a top priority. But there are many different reasons to think that such conservation is important, and these reasons can shape conservation policies in different ways, and can create ethical dilemmas and disagreements.
Cell death or apoptosis is one of the processes that must be more regulated in the body of multicellular beings. If this were not so, the signals caused by the cell to die could damage and eventually mark the surrounding cells for death. We have already discussed apoptosis in the animal model in its own article here.
Telomeres are repetitive DNA regions composed of the conserved sequence of TTAGGG and associated proteins located at the chromosome ends. DNA and proteins form a loop structure and serve to protect the ends of chromosomes from end-to-end fusion, recombination, and degradation.
As evo-devo studies explain, evolutionary diversification is also due to, for example, genetics (epi), correlation, phenotypic integration, self-organization, and physics. Restrictions. Vervoort (2014) proposed a developmental theory that compares plant to animal development, especially with regard to the independent origin of multicellularity.
Several types of homology (“uniformity”) exist in metazoan animals, as well as in vascular plants. When comparing iterated parts (eg, limbs, leaves) in organisms with modular construction (metameric), we often speak of "serial homology.
Most living organisms spend the most formative part of their lives, embryonic development, exposed to the vagaries of the environment. Despite the environmental buffer provided by parental resources, protective membranes, and favorable microhabitats, an embryo has no choice but to develop in the microhabitat in which it settles, facing often unpredictable or fluctuating environmental conditions.
Chromatin compaction is a critical means of regulating gene transcription by rendering genes inaccessible to transcription factors and RNA polymerases. Modes of chromatin compaction include histone methylation. The combinatorial results of these and other histone modifications can promote regional chromatin compaction that is easily reversed, while DNA methylation leads to stable long-term repression.
The Earth is a dynamic planet, undergoing constant changes driven by internal forces such as internal and external magma currents such as the sun. The sun's rays provide light and heat to Earth, and the regions that receive the most exposure heat up the most.
A region's climate is the biggest determinant of the life found there, making it a key focus in ecology. Variations in climate include daily and seasonal cycles. Climate variation also includes changes over several years, or even decades. Longer-term climate change occurs as a result of changes in the intensity and distribution of solar radiation reaching the Earth's surface.
Proximity to large bodies of water influences climate on a regional scale. Coastal areas experience less seasonal variation in their climates than continental interiors. Winters are milder, summers are cooler, and the temperature change between daytime high and nighttime low is much less extreme.
Gas exchange between plant shoots and the atmosphere plays a key role in plant function and performance through uptake of carbon dioxide (CO2) to supply photosynthetic carbon fixation and diffusion of water vapor by transpiration. This latter process, transpiration, is driven by evaporative demand, that is, the dramatic drop in vapor pressure between plant tissues and the atmosphere.
Cytokinins Kinetin is known to prevent senescence by stopping the degradation of proteins, and chlorophyll and also acts as a senescence retardant in fruits, particularly in the peel. Infiltration of kinetin into fresh banana slices improves ethylene production and respiration, but other ripening changes in banana fruit slices are delayed, particularly skin fading.
Phytohormones play an important role in the ripening of fruits. A complete understanding of hormonal control of ripening is lacking due to insufficient data on endogenous phytohormone levels and the effect of different hormonal ratios. There are several pieces of evidence indicating a primary role for ethylene in inducing fruit ripening.
Defined as the degradation of grasslands in arid and semi-arid regions as a result of various factors, including climate change and human activity. Desertification has caused significant environmental and socioeconomic problems in many arid and semi-arid areas of the world.
The characterization of a few tomato mutants unable to produce climacteric ethylene and to ripen their fruit, even after treatment with exogenous ethylene, has shown that other factors also play an important role in controlling fruit ripening.
Investigations into the genetic and phenotypic differentiation of plant lineages along environmental gradients are crucial to understanding the evolutionary responses of plants to current and future climatic variations. As plants cannot simultaneously optimize competing ecophysiological functions, an important question is how plant adaptation occurs under the influence of important trade-offs between traits.
The physical attributes of the pigments involved in obtaining light were important factors that contributed to the evolutionary selection of the chemicals used for photosynthesis. However, why higher plants use the specific complement of chlorophylls and carotenoids is a matter of speculation.
The remarkable diversity of flowers has a profound impact on humanity. The diversity of flowers inspires masterpieces of art and literature, fuels roadside beautification schemes, provides amateur gardeners with moments of great joy and pride, and nurtures the industries of bulb growers, seed companies, and horticultural supply houses.
Intensification of food production is often accompanied by increased nutrient inputs, heavy pesticide applications, frequent tillage and irrigation management. Negative environmental implications of these practices include eutrophication, increased salinization, soil erosion, and loss of biodiversity.
Soil data of adequate quality and quantity to make inferences are extremely important for sustainable land management. There is increasing pressure on agricultural land, coupled with increasing demands for food production due to global population growth.
Electricity demand is increasing worldwide and the trend is expected to continue in the coming years. About 70% of India's electricity is generated by coal-fired power plants, which produce approximately 65 million tonnes of fly ash (FA) a year as a by-product.
Currently there is particular interest in the relationship between biodiversity, simply defined as the number of species present in the system, and their function in the soil. This is part of a more general concern to conserve biodiversity and its role in maintaining a functional biosphere.
Human activity has greatly accelerated the rate at which species have disappeared from Earth, and the current rate of species loss is likely to increase by an order of magnitude over the next century. While the loss of plant species directly alters the remaining community by reducing its diversity, there is considerable debate about whether reductions in plant diversity will affect how terrestrial ecosystems function.
Rural communities living in the Monte region have undergone extreme changes in social and ecological settings. Most of them are agro-pastoral societies living in precarious conditions and whose land shows notable signs of degradation. Wild plants represent an important part of its dietary components;
The growing interest in nutraceuticals and functional foods has generated more research into new foods that are beneficial to he alth. For this reason, studies on fruits, herbs and seeds characterized by their antioxidant, free radical scavenging and anti-aging activities acquire crucial importance, since these properties are strongly linked to the prevention and treatment of chronic diseases such as cardiovascular diseases and heart disease.