Define Life processes in Biology

Updated on Jan. 8, 2021 03:24 PM IST by Lakshmi Arya

Life processes:-

The basic functions performed by living organisms to maintain their life on this earth are called life processes.
They are nutrition, respiration, transportation, circulation and excretion etc.


There are large number of chemical reactions that take place inside a living body. As a result, a variety of waste products are constantly being generated. The living body needs to remove these wastes. Excretion is the removal of metabolic waste products from the body.

Excretion in Unicellular and Multicellular Organisms:-

Unicellular Organisms:- Remove wastes by diffusion from the body surface into the surrounding water.

Multicellular Organisms:- Remove wastes from body by specialised organs.

Excretion in Human Beings:The main function of human Excretory system is to remove the nitrogenous waste such as urea or uric acid from the body. It includes a pair of Kidneys, a pair of Ureters, a Urinary Bladder and a Urethra. The purpose of making urine is to filter  out waste products (urea or uric acid) from the blood. These wastes are removed from the blood by Kidneys and are passed down to the Urinary bladder by a pair of Ureters. Then through Urethra urine is thrown out of the body.

Nephron, the filtration unit of Kidney:

  1. It is the structural and functional unit of Kidney.
  2. Blood at high pressure travel into these tubules by blood capillaries called Glomerulus, which are surrounded by a cup shaped capsule called Bowman’s capsule.

Formation of Urine:- Urine is formed in the body by following process.

  1. Ultrafiltration occurs in the glomerulus under high pressure forcing substances dissolved in the blood into the Bowman’s capsule.
  2. Then blood passes through the tubular region where glucose, amino acids, salts and water are Selectively absorbed.
  3. As the urine passes through the tubule some of the ions like K+(Potassium ion) and NH4+(Ammonium ion) from blood are secreted into the urine.
  4. The collecting duct then collects the urine. Water is reabsorbed. 
  5. The urine now contains Urea and uric acid and also the pigment giving yellow colour to the urine

Removal of urine: The urine formed in the kidney enters the ureter, from ureter it is stored in the bladder until the pressure of the expanded bladder leads to the urge to pass it out through urethra .

Total Views: 1118

Related FAQs

Q. What are metabolic processes ? Give one example.

Ans: Chemical reactions occurring inside the cell are known as metabolic processes. In these chemical reactions either some substances are formed, like synthesis of protein (Anabolic process) or a substanc... read more

Q. Do plants breathe at night ?

Ans: During night, the process of respiration also take place in plants.plants give out carbon dioxide and take in Oxygen through the stomata. The process of photosynthesis does not take place at night. As... read more

Q. what are the three characteristics of respiratory surface ?

Ans: 1. Respiratory surface must be relatively large. 2. It's wall must be thin and moist. 3. It must come in contact with either air or water.... read more

Q. Name the respiratory organ of the plant.

Ans: All parts of the plant respire but the main respiratory organ of the plant is leaf.Leaf contains small pores called stomata through which gases like oxygen and carbon dioxide enters the plant.... read more

Q. How do unicellular organisms perform excretion?

Ans: Unicellular organisms are made up of single cell like Amoeba. so, all functions in unicellular organisms are performed by single cell . This, unicellular organisms remove waste by diffusion from the ... read more

Q. How are the excretion in multicellular organisms different from unicellular organisms?

Ans: Excretion is the process of removal of waste product from the blood. In multicellular organisms, excretion occurs by specialised organs called kidney but in unicellular organism excretion occurs by ... read more

Q. The process of ultrafiltration is essential in urine formation, where does this step occur in nephron?

Ans: Glomerular filtration is also called ultrafiltration. This is the first step in urine formation. in this process, the metabolic wastes are separated from the blood and urine is formed. The p... read more

Q. What is the functional unit of kidney?

Ans: Nephron is called the functional and filtration unit of kidney. It is composed of a renal Capsule (Bowman's capsule) and a renal rubble. The renal capsule consists of a tuft of capillaries calle... read more

Q. Why does a piece of bread start tasting sweeter after chewing for some time ?

Ans: A piece of bread is generally composed of starch molecules. The enzyme secreted in our mouth for digesting starch start breaking down carbohydrates present in starch converting into sugar. So, it tast... read more

Q. Which is the largest gland in human digestive system ? what is its function ?

Ans: Liver is the largest gland in human digestive system. Liver secretes bile, a digestive enzyme which is stored in gallbladder. Bile helps in breakdown of fats in the small intestine during digestion.... read more

Q. Give reasons for the following: (a) Arteries are thick walled. (b) Blood goes only once through the heart in fishes. (c) Plants have low energy needs.

Ans: (a) Arteries are thick walled because these vessels carry blood from the heart to all the parts of the body and blood emerges from the heart under high pressure. (b) A fish has a two chambered hear... read more

Q. Describe in brief the role of lungs in the exchange of gases.

Ans: Role of lungs:-- When we breathe in air, the diaphragm contracts which results in the increase of chest cavity. Due to this expansion of chest cavity, the air pressure in the lungs decreases. Thus, a... read more

Q. How are oxygen and CO2 transported in human beings? How are lungs designed to maximise the area for exchange of gases?

Ans: Exchange of gases in tissues occurs through diffusion. Oxygen is carried as oxyhaemoglobin from lungs to tissues. It dissociates and carbon dioxide diffuses out into blood from tissues. It is transpor... read more

Q. Explain the importance of the following: (a) salivary amylase (b) villi (c) pepsin

Ans: (a) Salivary amylase:- It’s an enzyme present in the saliva, secreted by salivary glands. It digests starch into maltose there by starting the digestion of carbohydrate in the buccal cavity. ... read more

Q. Which is the universal source of energy in all cells?

Ans: Universal source of energy in all cells are :- ATP,  Adenosine Tri Phosphate.... read more

Q. If no apparent work is being done by an organism, why does it takes food?

Ans: Organism takes food to carry out the following activity :-  Growth, Reproduction and for repair of worn out tissues.... read more