Biology PDF

BIOLOGY Bio mean life and Logy mean study The study of living organisms is called Biology LIFE Life is form from various chemical combination like carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. These form the nucleic acids, proteins, carbohydrates, and lipids that are the...

BIOLOGY Bio mean life and Logy mean study The study of living organisms is called Biology LIFE Life is form from various chemical combination like carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. These form the nucleic acids, proteins, carbohydrates, and lipids that are the fundamental components of living matter. Characteristics of life include: 1. Living organisms are responsiveness to the environment (nerve impulses).  All living things detect changes in their environment and respond to them. A response can take many forms, from the movement of a unicellular organism in response to external chemicals (called chemotaxis), to complex reactions involving all the senses of a multicellular organism. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (called phototropism).  2. They grow and change their body size and shape (cell division).. The have the ability to reproduce and increase their population (reproduction).  All living things are capable of reproduction. Reproduction is the process by which living things give rise to offspring. Reproduction may be as simple as a single cell dividing into two cells.  4. They are performing the function of metabolism and respiration (metabolisms).  All living things can use energy. Their cells have the "machinery" of metabolism, which is the building up and breaking down of chemical compounds. Living things can transform energy by converting chemicals and energy into cellular components. This form of metabolism is called anabolism. They can also break down, or decompose, organic matter, which is called catabolism  They have ability to maintain homeostasis (excretion and Absorption). All living things are able to maintain a more-or-less constant internal environment. They keep things relatively stable on the inside regardless of the conditions around them. The condition in which a system is maintained in a more-or-less steady state is called homeostasis. Human beings, for example, maintain stable internal body temperature.  Living things have multiple levels of organization. Their molecules are organized into one or more cells. A cell is the basic unit of the structure and function of living things. Cells are the building blocks of living organisms. They are made from cells.- A unicellular organism is an organism that consists of a single cell. This means all life processes such as reproduction, feeding, digestion and excretion occur in one cell. Amoebas, bacteria and plankton are just some types of unicellular organisms.  The body of a multicellular organism such as a tree or a cat shows organization at several levels tissues, organs, and organ systems. Similar cells are grouped into tissues, groups of tissues make up organs and organs with a similar function are grouped into an organ system. There traits pass to offspring