Categoría: Biology

Metabolic reactions need activation energy to either build or break down molecules. Cells also use special proteins that aid metabolic reactions. These proteins, called enzymes, work by speeding up a chemical reaction. This chemical activity increases the reaction rate, or rate at which a reaction occurs, measured in terms of reactant used or product formed […]

In the summer of 2001, a forest fire that had been started by a lightning strike raged through Kootenay National Park in British Columbia. Park officials allowed the fire to progress because the area was scheduled for a prescribed burn. Fires are a natural part of forest ecology and are important in forest regeneration. For […]

Large molecules can be broken down to release energy. Alternatively, they can be formed to build cellular structures or store information. In biological systems there are four major types of chemical reactions involved in breaking apart andbuilding molecules: acid-base or neutralization reactions, which transfer hydrogen ions between molecules, redox, or oxidation-reduction reactions, which transfer electrons […]

Large molecules can be broken down to releaseenergy. Alternatively, they can be formed to buildcellular structures or store information. Inbiological systems there are four major types ofchemical reactions involved in breaking apart andbuilding molecules:acid-base or neutralization reactions, whichtransfer hydrogen ions between molecules,redox, or oxidation-reduction reactions, whichtransfer electrons between molecules,hydrolysis reactions, in which molecules reactwith H2O […]

The atoms of four elements make up roughly 99 percent of the mass of most cells: hydrogen, nitrogen, carbon, and oxygen. With only a few exceptions, molecules that contain carbon atoms are called organic compounds. There are millions of different organic compounds. Nearly all organic compounds contain hydrogen as well as carbon, and most of […]

Living things are unique among all forms of matter.Unlike non-living things, all living things — from single-celled organisms such as the Euglena in Figure 1.1 to multicelled organisms such as whales and redwood trees — interact with and manipulate matter and energy. For example, all cells take in essential substances such as oxygen, water, and […]

IntroductionThe movement of materials within the body tissues or between tissues in multicellular organisms like high plants and animals occurs in transport systems. In unicellular or low plants and animals, such movement is by the transport mechanisms of molecules within a transport medium by diffusion, osmosis, active transport and mass flow, among others.In multicellular animals, […]

ANIMAL NUTRITION Nutrition in animals is heterotrophic. This means that animals feed on other living things. Animals can be classified according to their nutrition function: herbivores (plant eaters), carnivores (eat other animals), omnivores (eat animals and plants) and saprophytic (feed on decaying organic matter). In order to perform the vital function of nutrition, animals have different systems: digestive, respiratory, circulatory and excretory. Digestive system The digestive […]

Like all living things, plants can perform the three vital functions of nutrition, interaction and reproduction. PLANT NUTRITION Plants use autotrophic nutrition. In order to carry out this process, they start by taking in inorganic matter through their roots and leaves: Water and the mineral salts form the raw sap which travels to the leaves through the vessels […]

In order to live, organisms use the function of nutrition to obtain the matter and energy they need. They interact with their environment thanks to the function of interaction, and they continue to have descendants due to the function of reproduction. NUTRITION The purpose of nutrition is to renew and help preserve the organism’s structure as well as obtaining energy to […]