Terminology refers to the set of words and phrases used in a particular field, subject or domain. It is crucial in ensuring clarity and accuracy of communication within a specific context. The practice of terminology involves identifying, defining, and standardizing terms used in a specific field o...
LIFE PROCESSES
LIFE PROCESS
The maintenance of living organisms must go on even at the conditions, when they are not
physically active. Even when we sit idle and during sleeping, this maintenance job through
cells functioning has to go on. The life process includes the activities performed by the
different organs to maintain the body.
Some of the life processes in the living beings are described below:
Nutrition
The process of obtaining energy through consumption of food is called as nutrition.
Respiration
The process of acquiring oxygen through breathing and make it available to cells for
the process of breaking down of organic substances into simpler compounds is called as
respiration.
Transportation
Transportation is the process by which the food and oxygen is carried from one organ
to other organs in the body.
Excretion
It is the process by which the metabolic waste by-products are removed from the
different organs and released out from the body.
INTEXT QUESTIONS PAGE NO. 95
Question 1: Why is diffusion insufficient to meet the oxygen requirements of multi-
cellular organisms like humans?
Answer : Multicellular organisms such as humans possess complex body designs. They have
specialised cells and tissues for performing various necessary functions of the body such as
intake of food and oxygen. Unlike unicellular organisms, multicellular cells are not in direct
contact with the outside environment. Therefore, diffusion cannot meet their oxygen
requirements.
Question 2: What criteria do we use to decide whether something is alive?
Answer : Any visible movement such as walking, breathing, or growing is generally used to
decide whether something is alive or not. However, a living organism can also have
movements, which are not visible to the naked eye. Therefore, the presence of life processes is
a fundamental criterion that can be used to decide whether something is alive or not.
Question 3: What are outside raw materials used for by an organism?
Answer : An organism uses outside raw materials mostly in the form of food and oxygen. The
raw materials required by an organism can be quite varied depending on the complexity of the
organism and its environment.
Question 4: What processes would you consider essential for maintaining life?
Answer : Life processes such as nutrition, respiration, transportation, excretion, etc. are
essential for maintaining life.
,NUTRITION
The process by which an organism takes food and utilizes it is called nutrition.
NEED OF NUTRITION
Organisms need energy to perform various activities. The energy is supplied by the nutrients.
Organisms need various raw materials for growth and repair. These raw materials are provided
by nutrients.
NUTRIENTS
Materials which provide nutrition to organisms are called nutrients. Carbohydrates, proteins
and fats are the main nutrients and are called macronutrients. Minerals and vitamins are
required in small amounts and hence are called micronutrients.
TYPES OF NUTRITION:
Autotrophic Nutrition: The mode of nutrition in which an organism prepares its own
food is called autotrophic nutrition. Green plants and blue-green algae follow the
autotrophic mode of nutrition.
Heterotrophic Nutrition: The mode of nutrition in which an organism takes food from
another organism is called heterotrophic nutrition. Organisms; other than green plants
and blue-green algae follow heterotrophic mode of nutrition.
AUTOTROPHIC NUTRITION
Autotrophic organisms are able to produce organic matter from simple inorganic materials.
They consequently create their own food—but require a source of energy to do this.
Photoautotrophs harvest energy from light to produce organic matter.
Chemoautotrophs use energy from inorganic reactions in the environment to drive the
creation of organic matter.
, HETEROTROPHIC NUTRITION
Heterotrophic nutritrion is typical of animals. These organisms eat organic matter in other
organisms—either alive (as hunters) or dead (as scavengers).
Saprotrophic organisms are the decay organisms. They digest dead materials using enzymes
that they secrete externally. Fungi and many bacteria are saprotrophes.
Parasites (biotrophs) feed on living organisms without killing them.
Heterotrophic nutrition can be further divided into two types, viz. saprophytic nutrition and
holozoic nutrition.
o Saprophytic Nutrition: In saprophytic nutrition; the organism secretes the digestive
juices on the food. The food is digested while it is still to be ingested. The digested
food is then ingested by the organism. All the decomposers follow saprophytic
nutrition. Some insects; like houseflies; also follow this mode of nutrition.
o Holozoic Nutrition: In holozoic nutrition; the digestion happens inside the body of
the organism, i.e. after the food is ingested. Most of the animals follow this mode of
nutrition.
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