k-tree
E-learning book

Basic concepts of biology

An organism is a hierarchy of complex systems. By organizing simple systems in the body, new, previously inaccessible, opportunities appear. With each new level, unpredictable opportunities appear.

Organism

All actions performed by a living organism are necessary for its existence. The functions of the body are connected with each other and together form a living system. All phenomena are explained by the structure and form of life of the cell, therefore the basic unit a living organism has been selected cell. The properties of the cell are regulated by parts, responsible for the development and work of living beings, including nucleic acid, amino acids, enzymes, hormones and membrane components are macromolecules that are not represented in inanimate nature.

Some creatures consist of one type of cell, for example, bacteria and are called unicellular organisms. Others consist of many different cells, in such organisms all processes depend on from the successful coordination of its constituent cells. Such organisms are called multicellular.

Metabolism

Any substance entering the body goes through a series of chemical reactions, during which decomposition or creation of more complex compounds occurs. All living beings need in nutrients and energy to maintain a high level of organization, grow and multiply. Nutrients enter the body from the air, water, earth or from other living organisms, then they are transformed into molecules necessary for the body. This kind of transformation is called metabolism.

In inanimate organisms, energy and matter can also be exchanged, unlike the latter, in living beings, all processes are synchronized and follow genetically embedded information

Metabolic processes occur throughout the life of the body, if the process has stopped, then the body is considered dead.

Anabolism

Anabolism is a set of all reactions in the process of which simpler substances are synthesized more complex. In anabolic reactions, bonds are created between molecules, thus accumulating energy in substances, borrowing it from the environment.

Catabolism

Catabolism includes reactions of decomposition of complex substances into simple ones, for which it is necessary breaking the bonds of molecules, which generates the release of energy.

Example of metabolism

In the process of photosynthesis, sugar molecules are formed (in the presence of sunlight and chlorophyll):
6CO2 + 6H2O → C6H12O6 + 6 O2
During respiration, glucose breaks down into carbon dioxide and water, releasing energy:
C6H12O6 + 6 O2→ 6 CO2 + 6H2O + energy

The life of the organism

Homeostasis

Living beings are characterized by the presence of control, regulation and feedback mechanisms, which maintain the body in a constant state, such mechanisms are absent in inanimate nature. A living organism maintains its internal state even when the parameters of the external environment change, they react by returning to a stable state. Support for such a condition is called homeostasis.

Homeostasis of a living organism is the ability to keep the state of the internal environment constant. Examples homeostasis: regulating body temperature, maintaining blood pressure, maintaining the water level in the body.

Height

In general, living organisms tend to grow and develop. In these processes, there is an increase in the masses, so qualitative and visible changes. Since inanimate objects also have the property of growing, for example, stalagmites or diamonds, then biologists have introduced such a concept: growth of the organism denotes an increase in living matter in the body, which implies an increase in the number of cells or their size.

Sensors

The life of an organism implies a constant exchange of information with both the external and internal environment. Each cell has its own set of sensors, some perceive light (located in the retina of the eye), others react to temperature or pressure, smell perception is a chemical reaction, and so on.

Reproduction

Living organisms create offspring - new living organisms with the same characteristics, preserving genetic information. Reproduction can be bisexual and asexual. In asexual reproduction, only one parent is involved, which is divided into two or more a descendant. Special gamete cells participate in bisexual reproduction. Female Gamete it is called an egg and the male is called a sperm. When they connect, they turn into a zygote cell, from which a new organism is formed.

The structure of the organism

An organism is a system of organs functioning synchronously. The organ system is a group bodies that implement a single function. An organ is a collection of tissues that performs a specific function. A tissue is a collection of cells. A cell is a basic structural unit lives. The cell consists of organelles. An organelle is a complex, highly organized structure molecules. Molecules consist of atoms, atoms of subatomic particles, the latter of quarks.

Download article in PDF format.

Do you find this article curious? /

Seen: 23 765


Read the following
Biological systematics