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Introduction to Biological Science:

          Biology is considered one of the natural sciences, which deals with the study of living organisms. The term biology is derived from the Greek word (bios, life + logos, study).

          Biology has been divided into two main branches, botany which deals with the study of plant and plant life, and the word is derived from the Greek word (botanikos means the herbs). The second, a branch that deals with the knowledge of animal life called zoology, which is derived from the Greek word (zoon, animal + logos, study).

          Zoology and Botany have a large number of specialized branches and no one can know the entire field of biology precisely. They again divided into major fields, that include:

1-    Anatomy: The study of the structure of living organisms.

2-    Cytology: The science which deals with the study of structure, function, growth and reproduction of cell components.

3-    Ecology: The study of the interrelationship between living organism and its environment.

4-    Embryology: The study of development of the organism from the zygote or fertilized egg.

5-    Entomology: The science which deals with the study of insects.

6-    Genetics: The science is concerned with biological inheritance.

7-    Histology: The study of the structure and arrangement of the tissues of organisms.

8-    Microbiology: The science which deals with the study of a microscopic organisms, a bacterium, virus or protozoan.

9-    Molecular biology: This science which attempts to interpret biological events in terms of molecules in the cell.

10-                      Parasitology: The study of Parasites.

11-                      Physiology: This science which studies the life processes and function in cells, organs, and whole organism.

12-                      Taxonomy: A study aimed at producing hierarchical system of the classification of organisms, or the naming of organisms.

13-                      Virology: The science which deals with the study of virus, and it is specialized part of clinical microbiology.

Manifestation of life:

          Although both living and nonliving things are subjected to the common physical and chemical laws, there are several biological manifestation which clearly distinguish. Them and are considered the most important biological activities which characterize the living things, and they include:

1-    Feeding (Nutrition): The assimilation of materials for use in metabolism, producing of energy and synthesis of molecules and structures for growth development and reproduction.

2-    Respiration: The release of energy by oxidation of food molecules to perform many functions (e.g. metabolism, movement).

3-    Excretion: Elimination of metabolic by products and other substance present in excess of requirements.

4-    Movement (Locomotion): Either movement of the whole organism or part of it.

5-    Sensitivity: Ability to respond to changes in the environment.

6-    Growth: The increase in size (development) leading to full mature individual.

7-    Reproduction: The production of new offspring.

Lecture  2

The composition of living matter

Introduction:

          All plants and animals, including the smallest bacteria, are widely diverse organisms that differ functionally and morphologically but have a very similar chemical composition. All cells contain water, minerals, carbohydrates, lipids, proteins, and nucleic acids. All biological phenomena are ultimately based on biochemical processes. Therefore, it is important to understand the nature of the biochemical reactions that occur in the cell. Such important processes as photosynthesis, nitrogen fixation, cellular energy transformations, and the genetic control of cell structure and function can best be explained at the molecular level.

          Matter and energy are the components of our universe. Matter is anything that occupies space and has mass. It can assume the form of a solid (ice), a liquid (water, gas (water vapor), or plasma. Whatever from it assumes, it will always occupy space and have mass. Energy is defined as the property of matter that enables it to do work. The forms of energy are potential, kinetic, electrical, magnetic, chemical and radiand. Chemical energy of food enables the bodies of organisms to perform work. Biological systems most often use stored chemical bond energy in order to grow, reproduce, and move.