Cell as a fundamental unit of life:
The building wall is made up of numerous bricks. In the similar manner, a bee hive is composed of numerous hexagonal units. Some of the organisms are represented by a single cell. Therefore, they show a simple organization. The basic functional unit of an organism is called, a cell. Structure of a cell represent the arrangement of parts or organells in a cell.
Function is the activity of each part or organell in a cell. Cells are the basic building blocks of an organism. You learnt that atoms are the basic building blocks of matter in chapter three. Likewise, human body is made up of animal cell and plant is made up of plant cell.
Some simple organisms, are made up of only one cell. They are called unicellular organisms, which can be seen with the help of a microscope. There are many single – celled microscopic organisms.
Have a look at the image. Chlamydomonas and an Amoeba, a single cell organisms which carryout entire functions. The body of all organisms are made up of tiny building blocks called, cells. Bacteria are also one celled unicellular organisms.
The cells are organized into tissues, organs and organ systems in a multicellular organism. Macroscopic organisms are visible and consists of many cells. The body of macroscopic organisms involves various functions. You can see cells of onion and human through a microscope. Onion and man are examples for multicellular organism.
Cell to organism
Many cells function together to form tissues, different tissues combined together to form an organ and different organs to form an organ system, which leads to form an organism.
Many types of organ systems function together in a body, e.g. respiratory system, digestive system, excretory system circulatory system etc.
Many organs together form an organ system, which is concerned with a specific function. For example, Respiratory system, which has organs like nostrils, nasal chamber, wind pipe and lungs that helps in the process of respiration. In a plant, the root system consists of primary root, secondary root and tertiary root, which does the function of conduction of water, mineral and also fixation.
A collection of different tissues worked together to perform a specific function or functions is called an organ. Human body has different organs like stomach, eye, heart, lungs etc., are made up of different type of tissues. Plant have organs such as leaves, stems, and roots.
Tissue is a group of cells, organized for a specific function. Tissues have following features like same shaped cells or different shaped cells to perform a common function. Human and other animals are made up of nervous, epithelial, connective and muscle tissues. Plants have transport, protective and ground tissues.
The cell is a basic structural and functional unit of life. Cell is the building unit of living organisms. You can see in a hand, how many types of cells are there to work together to perform its functions. So, cell is known as the basic unit of life.
Find out major organs that are part of the circulatory system of a human body and listout their functions
Heart - It pumps out blood.
Auricles - Upper chambers of the heart
Ventricles - Lower chambers of the heart
Arteries - They carry oxygenated blood to different parts of the body.
Veins - They carry oxygen-poor blood back from the body to the heart
Capillaries - They bring nutrients and oxygen to the tissues and remove waste products from the tissues.
Lungs - The alveoli in lungs purify the blood by supplying oxygen and removing CO2 from blood.